Hi all!
I hope everyone had a filling turkey day. I have no doubt we're all very thankful.
OK, so update to starting the green machine. I installed all the new cables for the 2 8D's; from the stud in the rear to the starter; and the ground.
I remembered either Clifford or Brian having the thought of unscrewing one screw off the stop cylinder and moving it just barely enough to prevent the stop lever from making contact. So, I did that, and pushed the stop toggle on the dash up enough to get the cover to close.
I turned on the battery, the master switch and hit the start button. Surprisingly, the starter did start turning. However, my son told me to kill it because there was a spark coming from the area between the power stud and neutral safety switch. On that stud, there are two large power cables coming from the battery compartment, and my new starter cable. Once I killed the battery switch, the sparks and the starter stopped.BUT...the sparks were NOT coming from the starter. The starter wasn't hot, but the cable up on the stud end was warm.
So (in addition to those of you blessing me with your help) I think one or both of the cables on the power stud with the starter cable has bare metal touching something. I'll investigate tomorrow, but wanted all possible input from you all?
And the only thing that has ever been connected to the starter (little switch terminal) is one of the two ends of the neutral safety switch. The other end goes to rear stud 12...no starter wire on the starter, but stud 12 is for both front and rear switches and those wires are on stud 12.
Anything?
On the better news side...all four new house batteries are installed and connected to the PD4500. So when I get around to the inside...I'll have heat from the roof units (the only connections I've made thus far...outlets will be next. But I'm going to get this bus started. It's become a mission for me...I know you all understand. Help?
I would be happy to look at a schematic if available. With that said I sorta hear the starter was still engaged and turning again "until" bat power was turned off, say at battery? am I picking that up correct.
I'm thinking the stud you mention is an isolator type; junction.
That the 2- 8d battery cable positive was connected, is this a typical short 4' engine start cable or the other end/part possibly long 35' cable to battery.
If all else is perfect, the starter solenoid copper plate is welding itself each time its triggered to engage and obviously not able to release. (however that happens)
I'm not sure on the connection of neutral safety wire location, and power wire, so a photo would be best.
No doubt a designed connection is sticking and or grounded and or loose. This needs wiring removed from bus and starter checked individually.
and yes just ate more cake, hate to be disrespectful and not eat : )
good day there
Floyd
Hey Floyd.
I started with the schematics, and that's when I started to go crazy. Most of the bus wiring is where it belongs. However, when they put the new engine/auto transmission in in 2001, the mechanics in Fredricksburg didn't follow the schematics.
I have wires ( neutral relay...two places, for instance) that are either not connected to the NSS as in the schematic, or are not connected to stud 26. It was empty.
I'm not 100% sure when the starter stopped, after the mini fire last week, Logan was looking at the spark (he has since told me the spark did stop before I pulled the battery switch) and his attention focused on where to aim the fire extinguisher. Tomorrow, after I remove (hopefully) this stud block and give it a good cleaning, I'll know a bit more. I have removed and replaced every wire on the starter, and the cable going to power it, along with every single wire in the rear box...and all the relays.
But it is indeed the roughly 3-4' cable junction with 3 cables attached to it. It also has 4 screws, so I'm going to try to take it off.
I was thinking the same about the contact disc, but thus far, the rubber hammer has worked...twice. I didn't let it get hot today, so hopefully...
Ok
If the neutral safety is not working as designed~
I would disconnect battery power at main switch area 1st. Then recommend following up with removing the +battery cable at starter, bat+ solenoid connection stud.
This should keep everyone safe from vehicle starting "while" a safe checking procedure on the solenoid start/signal wire is conducted and repaired.
I have found a test light vise gripped to ground and the alligator part clipped to solenoid signal post work well if I see it. So with your helper the light can be checked in short order with in and out of gear switch signal confirmations.
As you mentioned a schematic and neutral safety wires were not likely replaced in prior work, as designed and so need traced.
Pretty straight repair, but tedious finding and connecting the neutral safety switch wires for sure. (no hill for a stepper)
Have a good weekend
Floyd
You need to be sure the installer didn't use a neutral switch at the shift tower and left the one on the transmission unhooked
The only wire connected to the shifter is a wire for a light that burnt out long ago. The neutral safety switch has 2 wires. For years, it has been connected with one wire to the starter solenoid nipple (start switch wire isn't there), and the other wire to stud 12 in rear box.
The starter cable (new one) goes to the + on the solenoid. The ground goes from the starter motor itself to frame. There is a jumper from the other solenoid nipple to the starter ground terminal. There is a stud that faces upwards, and a stud with a solid strap connected to it. Neither of those is connected to anything else.
I cleaned up the rear box and made a new harness for the alternator, starter and all new battery cables. Now that the starter is getting the voltage required (and once I get the grime off the junction stud and transmission and look at those other cables) Can I disconnect both NSS wires and try to start it? Even if in a different gear, as long as I'm holding the brakes on? I think one of those big cables has bare copper touching the frame.
If I accidentally switched the NSS wires when I reconnected them, would that cause sparks? I am 99.9999% sure I didn't, but anything is possible. Also, every schematic has those 2 NSS wires going to the neutral relay and different studs then to ground. When I connected them as the schematic dictated...nothing. I can't see where the NSS is connected to ground?
The wire coming from the relay that is supposed to be connected to the neutral safety switch is cut off, and the top right wire from that relay WAS connected to the starter relay directly. It is supposed to go to stud 26, from there to the starter relay (71S) and from 71S to the starter solenoid. I connected that wire, but it didn't matter.
BUT...when I moved the stop cylinder on the governor, (maybe a hair) off the lever, even though the lever didn't move, the starter began trying to start.
I also wanted to tell you all how much I appreciate your help. I know in my gut this is something I can fix...but all of you know how maddening it is when ONE FREAKING wire is wrong. And the feedback you all give me makes me consider things I wouldn't have otherwise...so thanks!
And the hits just keep on...
There are three harnesses that connect to the motor compartment stud. My new starter cable, the 4/0 from the battery switch and a 1/0 that connects to the rear junction box stud.
I went out to disconnect them so I could remove and clean the motor stud. New starter cable...no problem.
the 1/0 that goes to the rear box? Oh, my god. The terminal end is GONE. All that remains is the base, and it was melted to the washer. If the 4/0 that goes to the battery switch is OK, I can replace and reroute the 1/0. Well, at least I know where the sparks came from.
If I can figure out how to post a picture from my phone, I'll show ya.
Just somemore forward checking the start solenoid wire is momentary as suppose to be.
good luck there
The starter doesn't stop when I let off the button.
I'm calling the shop and tow tomorrow.I'm not going to risk any serious damage, and I'm not strong enough to replace the starter. I know my limits, and I'm there.
If you remove the small wire on the starter solenoid( not the small ground) turn the power back on. If it still crank's the Bendix is stuck if not it's in your wiring. I had a rebuilt starter in mine the fork to the Bendix came apart. it held the solenoid from engaging the Bendix drive to the starter but I suppose it could stick the other way also.
Quote from: daddysgirl on November 27, 2016, 05:54:36 AM
The only wire connected to the shifter is a wire for a light that burnt out long ago. The neutral safety switch has 2 wires. For years, it has been connected with one wire to the starter solenoid nipple (start switch wire isn't there), and the other wire to stud 12 in rear box.
Stud 12 in the rear j-box is supposed to go to the Front/Rear switch in the rear control panel. It then goes to studs 15 and 26 respectively, and then to the starter solenoid relay.
On the automatic transmission, 15 goes through the neutral relay contact and then to the starter solenoid relay. There are some minor differences based on the bus serial number.
Seems like yours may be bypassed the rear control panel based your description, and maybe you don't have the neutral relay?
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The starter cable (new one) goes to the + on the solenoid. The ground goes from the starter motor itself to frame. There is a jumper from the other solenoid nipple to the starter ground terminal. There is a stud that faces upwards, and a stud with a solid strap connected to it. Neither of those is connected to anything else.
The cable and ground seem correct. The jumper should be an L-shaped jumper that goes from the solenoid to the stud facing up on the starter motor. This is how power gets to the motor. The commutator in the solenoid shunts power to the motor when you activate the solenoid. The solenoid also engages the starter drive into the flywheel.
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I think one of those big cables has bare copper touching the frame.
I'm pretty sure you'd know if one of those cables has bare copper touching the frame. Those cables should be direct from the batteries. The frame is grounded.
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If I accidentally switched the NSS wires when I reconnected them, would that cause sparks? I am 99.9999% sure I didn't, but anything is possible. Also, every schematic has those 2 NSS wires going to the neutral relay and different studs then to ground. When I connected them as the schematic dictated...nothing. I can't see where the NSS is connected to ground?
No sparks. The neutral safety switch is simply switching the ground for the neutral relay. If yours is going from NSS to starter solenoid, then someone may have eliminated the neutral relay.
From your description, it seems like someone has eliminated the neutral relay and changed the NSS to switch the starter hot wire to the starter solenoid hot terminal. You said the other stud on the solenoid was jumpered to the negative terminal on starter motor. That would work. It bypasses some safety circuits, but it would work.
Quote
BUT...when I moved the stop cylinder on the governor, (maybe a hair) off the lever, even though the lever didn't move, the starter began trying to start.
Impossible. The stop cylinder is a pneumatic piston. Moving the air piston cannot make an electrical connection to the starter.
What is the serial number of your bus?
Quote from: daddysgirl on November 27, 2016, 07:56:13 AM
And the hits just keep on...
There are three harnesses that connect to the motor compartment stud. My new starter cable, the 4/0 from the battery switch and a 1/0 that connects to the rear junction box stud.
I went out to disconnect them so I could remove and clean the motor stud. New starter cable...no problem.
the 1/0 that goes to the rear box? Oh, my god. The terminal end is GONE. All that remains is the base, and it was melted to the washer. If the 4/0 that goes to the battery switch is OK, I can replace and reroute the 1/0. Well, at least I know where the sparks came from.
If I can figure out how to post a picture from my phone, I'll show ya.
That's the wire that charges your battery from the alternator. Possibly you cracked or broke it when you replaced your starter cable, or you forgot to reattach it, and it grounded to the frame.
The 1/0 cable that goes from the rear stud to the rear junction box stud MELTED. The 4/0 cable from the battery still has it's end.
The starter cable is OK, and yes, it was connected.
I've got a neutral relay, but it's not (never was) connected as it should be.
From what I can tell, the mechanic who installed the new engine and automatic tranny in 2001 used the wires on the neutral safety switch as starter wires.
Stud 26 was empty, 12-15 were/are not. I connected 29S from relay position 3 to 26 per the schematic up to 71S on the starter relay, then over. Nothing happened. 29S was going from position 3 directly to the starter relay.
The fast idle side relay contacts (6,7,8) are all connected as shown on the schematic, as is the field relay.
I am aware of the stop lever cylinder. I was just repeating what I did and what happened when I did it. Better chance the electric cylinder that shuts off the air finally opened.
The serial # is 8FV2553
Model # is 7087-7527 (Customer specified)
The unit # is 30048 September 1973
BTW Craig...
When you reference the "L shaped jumper" is that a wire or a copper strap?
I only ask because the only connections that have ever been made between the motor and solenoid are:
the power line to the solenoid
Little jumper between solenoid and motor ground
motor ground to frame stud
NSS to switch nipple on solenoid
From what I can see, there is nothing on the stud facing up, unless the strap is going to the "up" stud. I can't see that in detail the way the starter is mounted. And these are the only connections that have ever been there. 16 years...same thing. The ONLY thing I did on the starter is change the cable to positive stud on the solenoid and the cable to ground on the end of the motor (After a test directed by MCI tech, I didn't remove a wire and burnt up the starter cables...see earlier post). And thanks for your help. I'm not trying to be argumentative...just typing what is actually there.
Quote from: daddysgirl on November 27, 2016, 02:27:48 PM
BTW Craig...
When you reference the "L shaped jumper" is that a wire or a copper strap?
I only ask because the only connections that have ever been made between the motor and solenoid are:
the power line to the solenoid
Little jumper between solenoid and motor ground
motor ground to frame stud
NSS to switch nipple on solenoid
From what I can see, there is nothing on the stud facing up, unless the strap is going to the "up" stud. I can't see that in detail the way the starter is mounted. And these are the only connections that have ever been there. 16 years...same thing. The ONLY thing I did on the starter is change the cable to positive stud on the solenoid and the cable to ground on the end of the motor (After a test directed by MCI tech, I didn't remove a wire and burnt up the starter cables...see earlier post). And thanks for your help. I'm not trying to be argumentative...just typing what is actually there.
The strap has to be going to the upward pointing stud on the starter motor. If it weren't the starter motor would not turn at all. That strap is a solid metal strap, shaped kind of like an "L" with a 90° bend in it. It connects the left stud of the solenoid to the starter motor (as you look at if from the rear of the bus).
Looking at it from the rear, the solenoid is slightly offset towards the right. There are two large studs. The positive battery cable is connected to the lower one (right most), and the strap is connected to the upper one (left most) and connects the solenoid to the motor. This is what gives the motor power to turn. That motor stud comes up from the motor basically right in between the two solenoid studs. Then, the solenoid has two small terminals. The right one (lower most) is the positive, which ultimately comes from your start button. The left one is the negative for the solenoid coil. Mine has a jumper to the negative stud on the end of the starter motor. There is also a wire that goes back into the wiring harness. Not sure what that one is.
I'm beginning to believe that your starter solenoid is stuck in the on position. It's pretty easy to test that. Use an ohm meter to measure resistance from the positive battery cable terminal to the jumper terminal. If you have continuity, then the commutator is stuck in the on position, which would allow the starter to turn as soon as the batteries are turned on.
I'm still very concerned about the melted cable, though. That doesn't make sense. One cable inside a stack of three is not going to melt unless it was either cracked or loose.
As for the wiring of the neutral solenoid, there are two diagrams in the manual you need to look at. One is the standard motor control wiring and the other is the automatic transmission wiring for you model number. The transmission one shows 29S going directly to the starter solenoid relay. The master schematic shows it going to stud 26. If stud 26 is empty, then it's following the transmission wiring, which should be just fine. However, it seems your bus has the neutral switch routing the positive start signal directly to the starter solenoid, rather than the ground to the neutral relay. Either will work, as long as you understand what has been changed and don't try to change it back without fixing the entire circuit.
Quote from: daddysgirl on November 27, 2016, 02:27:48 PM
The ONLY thing I did on the starter is change the cable to positive stud on the solenoid and the cable to ground on the end of the motor (After a test directed by MCI tech, I didn't remove a wire and burnt up the starter cables...see earlier post). And thanks for your help. I'm not trying to be argumentative...just typing what is actually there.
What test are you referring to that the MCI tech had you do, and what was the wire you forgot to remove? Maybe I missed it above.
That wire, the one that has the melted terminal, was exposed last year. I covered it in 2 layers of heat shrink tube.
I'll try to get some pictures uploaded tomorrow so you can see it.
And looking at one of those pics, I can see where the L strap would go to the up terminal. It just looks really bad. The pic was taken a while ago.
The tech had me put the start wire on the + solenoid terminal. The main power cable was NOT connected.
Afterwards, I got distracted and when I connected the + cable, I didn't remove the wire. Never will be distracted again. BUT nothing other than the starter cables and my ego...was damaged.
The starter signal wire on the solenoid needs safely removed and further circuit test to clear up the incorrect wiring and there is.
The battery+ wire at starter needs removed and taped to prevent shorting and tied off securely.
This has been getting nowhere, safety matters and re wiring this by the book/schematic is the best direction.
I'm very curious of prior test mentioned, this post is separated on other post so before anymore recommendations reviews should be made.
Its best to get a proper meter and test lights and with capabilities carry out steps or test some may mention in circuits and have mentioned.
the up connector is from the starter body to the solenoid shown in this pic
Floyd
Hi Floyd.
If you'll tell me how to post a pic, I'll show you.
The problem with further testing is that the power cables coming from the battery no longer have copper ends. they melted. The starter cable is fine, but the 1/0 is gone, and the 4/0 is melted to the washer. I'm not willing to chance another fire with all of the dry air, but prior to this, I did take each wire off and test them both under no load and while Logan was pushing the start button. They were fine, as were the rear box connections.
But (and this is only what I think) when I pushed the starter button, it started spinning. When I let off the button, it didn't stop. I had to kill the battery switch. And the wire connected to the signal terminal on the starter is one of 2 neutral safety switch wires, NOT the starter wire.
Hey Craig.
Questions:
I have both sets of schematics, but there is only one with the 2 wire NSS and because my tranny was new in 2001 I can't use the unit number for that. But I do use the motor control so I can understand where the 1974 wiring is routed.
You mentioned the connection on the three cables being loose. I do remember it was not as difficult as it should have been to remove the nut from that bolt. All three cables were connected, but if there was a tiny bit of space between the 4/0 and the 1/0 could arc have caused them to get that hot, and leave the starter cable unscathed?
First off listen to Floyd and Craig.
Second don't have it towed! Only thing that will do is make a tow truck driver some $! the shop is only going to do what you can do yourself!
OK Now if it were me, I'd go back to square one.
First thing to do is remove ALL wires from the starter and ohm it out.
Also remove the three wires from the stud where the one melted! OHM all 3 out and see if one is supposed tobe a ground, or accidentally grounded.
Next find out where/what each of these 3 wires is. I suspect 1 is hot coming from the batteries. 1 is the hot wire going to the starter. And most likely the 3rd is coming from the main terminal on the Alt. to charge the system when running. (probably the 1/0)
Next use test light to test power on the wires going to the starter. But as Floyd (or Craig) suggested leave the signal wire unhooked while testing turning the power on.
If you can turn power on and all is well then touch the signal wire to the solenoid.
If the starter cranks w/o pushing the starter button that wire is getting power from somewhere it's not supposed to.
If it doesn't crank w/o pushing the starter button the wiring is correct.
NOW if the starter is bad YOU can change it yourself!
A 12 point socket will loosen the starter bolts, take the top one all the way out since it's the hardest to get to.
Then before taking the other two out get a floor jack and jack it up under the starter.
Once the jack is in place remove the other 2 bolts and the starter will be on the jack where you can lower it.
If you have to buy a new starter anyway might as well go a head and buy a 39MT and make it easier on yourself replacing it now and in the future!
;D BK ;D
BTW attaching pics is not hard if the are small enough.
Just click on the additional options box in the lower left corner when making a post.
;D BK ;D
(biggest issue is resizing them small enough to post!)
See if this works
OK.
The starter wire is not here...it's OK.
The wire on the right with no end is the 1/0 that goes to the rear junction box stud. The other (welded to the washer) is the 4/0 that comes from the batteries.
Quote from: daddysgirl on November 28, 2016, 06:35:05 AMOK.
The starter wire is not here...it's OK.
The wire on the right with no end is the 1/0 that goes to the rear junction box stud. The other (welded to the washer) is the 4/0 that comes from the batteries.
Are these hot wires, switched wires, or grounds? I'm confused!
Quote from: daddysgirl on November 28, 2016, 05:55:36 AM
Hey Craig.
Questions:
I have both sets of schematics, but there is only one with the 2 wire NSS and because my tranny was new in 2001 I can't use the unit number for that. But I do use the motor control so I can understand where the 1974 wiring is routed.
The switch is just a switch. It doesn't matter if the tranny is from the 70s or 2001. Use the schematic for you model number. The wiring should all be there even though it was a manual transmission originally.
The problem is that in order to fix this correctly you need to rewire the starting circuit and use the relays as they were intended. Currently you have positive going through the NSS directly to the starter, and it should have ground going through it to the relay.
I think you should probably worry about getting the starter and cables fixed first. Obviously what is there has been working for several years. Just need to figure out what got screwed up recently. Chances are good the starter is stuck or the commutator is bad.
Quote
You mentioned the connection on the three cables being loose. I do remember it was not as difficult as it should have been to remove the nut from that bolt. All three cables were connected, but if there was a tiny bit of space between the 4/0 and the 1/0 could arc have caused them to get that hot, and leave the starter cable unscathed?
Of course. Arcing inside that stack would melt things in a hurry. Think arc welder. I don't know the order you had the cables, but it's certainly possible. Corrosion on the cable ends can cause heating, also. Basically, those cables need to me clean, tight, and making maximum contact to each other, with no contact to the frame. Make sure that stud was not damaged, also. The threads have to be good to get a tight connection and the stud cannot be loose in the insulating mount. If it is bad, replace it. You saw the damage that can happen by the arcing. You're fortunate there wasn't oil in the immediate vicinity.
Quote from: Oonrahnjay on November 28, 2016, 06:41:03 AM
Are these hot wires, switched wires, or grounds? I'm confused!
These are positive cables from the batteries. The burned one is the alternator cable.
Yes, they are hot. As you can see, that one was really hot! ::)
Quote from: gumpy on November 28, 2016, 06:52:18 AM
These are positive cables from the batteries. The burned one is the alternator cable.
Yes, they are hot. As you can see, that one was really hot! ::)
Thanks. Color coded black on that model of bus?
The colors correspond to the colors of the cables in the battery compartment. The battery kill switch as a positive cable just under it that supplies power to the two cables above. One (red end) goes to the stud in the picture. The other (blue) goes to the AC junction box. The negative goes up the wall to it's transfer cable, but it has no color on it.
Ok. Thanks for confirming my thoughts Craig. Now at least I know what caused them to melt.
I can have a new 1/0 cable made, and I can re-route it. I'll need to remove the oil bath air cleaner to be able to reach the terminal stud on the rear box (that cable is connected to that stud, along with the alternator cable)
IF (BIG IF) I can get the starter off...I can take it apart and see how bad the disc is...I could even get the kit and rebuild it. I'm totally comfortable in my abilities at that point. Where I'm shaky is getting the darn thing off.
Craig:
Just so you know my procedure...
I always make sure to replace everything in the order it came off. With any wiring, I take a picture, tag every wire, and keep a master notebook where I write it down as I'm working. That stud had the large 4/0 on first, the smaller 1/0 on top of it and the starter cable on top of the 1/0. You can see the size of the washers. They are all original, or I should say were, as now 2 of 3 will be replaced.
You are (of course) correct that all of the wiring is still there. The reason I mentioned the schematic is because the only one that shows the routing of a two wire switch is the auto transmission HT740D effective with unit 30514, July 1979.
The schematic for 30048 only has a one wire switch and no connection to stud 26. The fast idle side is the same from what I remember, AND for the life of me, I have looked EVERYWHERE and I can not locate the terminal block stud (with the 8 connections). I have uncovered a few studs, but they are not labeled....OR the cradle harness plugs that show A, B, C, D...so I can follow either of the schematics. I mention this because those points usually show the ground and I'm anal about making sure all is grounded properly.
However, you make a good point that none of that matters until I get the starter and cables back working as they should.
If it was converted from a manual transmission you may not find what you are looking for I have a 8 manual it shows 3 different schematics for the 740 and the 70 Allison you are on the neutral switch and not the reverse switch,Just asking because I have saw people trying to wire the reverse switch to the neutral start before
Quote from: daddysgirl on November 28, 2016, 07:57:17 AM
I can have a new 1/0 cable made, and I can re-route it. I'll need to remove the oil bath air cleaner to be able to reach the terminal stud on the rear box (that cable is connected to that stud, along with the alternator cable)
IF (BIG IF) I can get the starter off...I can take it apart and see how bad the disc is...I could even get the kit and rebuild it. I'm totally comfortable in my abilities at that point. Where I'm shaky is getting the darn thing off.
You can probably have a new end put on that cable, as long as there is sufficient length. Be careful getting it undone at the junction box. It's easy to break that insulated stud. I think that's a pass through stud, and the outer nut corrodes and cracks the plastic mount. BTDT.
That starter is somewhere between 80 and 100 lbs, I think. Use a floor jack as mentioned above.
Oil bath air cleaner? Was this added by somebody? I believe that bus came with a paper filter cartridge.
Quote from: daddysgirl on November 28, 2016, 07:57:17 AMThe colors correspond to the colors of the cables in the battery compartment. ...
Thanks, I think I see the remnants of some color coding, now that I look for it.
Re: the starter, yeah, all you need to do is find a dependable way to support it. Somebody (Gumpy???) mentioned supporting it with a jack. On the engine I recently took out of my bus, there was no way to get a jack in there, but I was able to lift it with one hand using a motorcycle tiedown strap, looped around the starter housing and tied in place. Or maybe putting together a wood cradle or platform would work. Yeah, these things are a bear but with the right "help", it'll work OK.
Craig, it came with 1 single large oil bath air filter fwiw
Quote from: luvrbus on November 28, 2016, 02:12:19 PM
Craig, it came with 1 single large oil bath air filter fwiw
I was not aware of that. I wonder when they changed. The 78 MC8 I had was paper medium. I didn't realize MCIs had the oil bath filters. Only ever heard of them on the older GMs.
M 74 MC-8 also has paper
Rick
My 78 was a oil bath
I've seen both oil bath and paper in MC 8 & 9's my guess is they came w/oil bath and at sometime they get converted to paper for convenience!
;D BK ;D
BTW Daddy's girl I would waste time rebuilding that heavy starter when the MT-39 is so much more convenient!
Quote from: daddysgirl on November 28, 2016, 06:33:07 AM
See if this works
Once a cable end starts corroding the same amount of current now has to pass through a smaller and smaller conductor. First result is heat, then comes sparks as it corrodes away to nothing and starts arc welding your connection.
Minor update:
I spoke to Luke yesterday. He's sending me a new stud block, a new junction box stud block (just in case) and a few other odds and ends.
My new starter should be in Petersburg today, but I can't get the old one off. The top bolt should be the easiest, but the bottom is going to require going under the bus. I think I'm going to have one of my friends (Works for big equipment tow company) come over and raise the rear end for me.
Oh, BTW...I got a new 40MT. Even Luke told me that was indeed what I should have.
Air filter was a matter of original purchaser spec.
1975 MC8, one has paper, one has oil bath, within 100 serial numbers of each other.
Oil bath was a former GLC, paper was a former GCL.
GLC has stud pilot wheels, no stock air drier, GCL has hub pilot and an AD2.
happy coaching!
buswarrior
MINOR UPDATE #2:
And a question
I got the beautiful (heavy as heck) NEW starter, all the up-sized 2/0 cables, the new frame stud (thanks for the advise on that, btw...the old stud threads look terrible) and a new rear J box through stud (even though I managed to disconnect everything from it and did not break it).
I was looking at the routing and I realized something. Just south of the frame stud, on the right side, is a long tube that comes out by the starter with 3 wires that have been cut off forever. As I was looking at the routing, I realized why the NSS is being used as a starter wire. The wire that goes to the left stud on the starter relay (71S), and the small (29G) the ground for the relay...wire on the small front screw of the relay are the wires that have been cut off.
The starter has a large ground stud on the motor end, and the connector line from the solenoid. Although it's "internally grounded"...I'll reconnect it properly.
Question: Because I am replacing all of these harnesses, should I connect the system through the starter and neutral relay as shown in the schematic (my gut choice), or go back to using the NSS as the starter wire?
Thoughts? Please??
Oh, and...
The power cables connected to the rear box were completely CORRODED. Inside the old fabric conduit, the 1/0 has more green gunk than wire...and has so many broken strands I can't believe it ever started...generated...and didn't catch fire.
My thoughts are that you should get the starter installed and working with the current wiring configuration which has been working for the past 15 years. Then, at your convenience, replace and rewire according to the schematic.
While you are in there, double check the cables on the alternator. There's a big cable that goes from the alternator to the pass through stud on the rear junction box which can vibrate and break. If this should break and arc against the starter, it can actually burn a hole in the case, allowing oil to leak out and the arcing can ignite it and burn up your bus. This wire was the first on-road failure I had after buying my bus. Luckily it did not arc to the case.
Hi Craig.
I'm sorry I wasn't clear in my description. ALL of the cables and wires for the starter AND alternator are off. I've remade ALL the harnesses (except the 4/0 cable to the battery. Because it's all out, I can put it back either way. Do you think I should reconnect it as it should be...like the schematic?
And the alternator cable was totally corroded and exposed at the rear stud about 12 inches down. Patina, bare, partially broken cable.
Take a look
The first picture is the cable that goes over to the big stud. Second is where the alternator cable connected to the rear box.
Wow! Yeah, good call on replacing those.
Again, I think you should put it all back the way it was and get it working. Then focus on updating to the schematic, one piece at a time.
Primarily, the cables you have off are not related to the schematic changes. That will involve only the solenoid control wiring, so all small stuff.
OK. I agree Craig.
I have no problem getting it back the way it was...save one question.
The cable that goes from the rear frame stud to the rear junction box plug had three wires attached to it that I had to cut to get it off.
One of the wires went to the left side large stud on the starter relay. The other was the smaller starter relay ground. HOWEVER...after they left the rear box, they were not connected to anything. They ran across with the cable, then into a metal tube that ran along the frame to the area of the starter.
Should I put them back?
And thanks Craig. I really appreciate all of your help.
Quote from: daddysgirl on December 03, 2016, 07:33:47 AM
The cable that goes from the rear frame stud to the rear junction box plug had three wires attached to it that I had to cut to get it off.
One of the wires went to the left side large stud on the starter relay. The other was the smaller starter relay ground. HOWEVER...after they left the rear box, they were not connected to anything. They ran across with the cable, then into a metal tube that ran along the frame to the area of the starter.
Should I put them back?
And thanks Craig. I really appreciate all of your help.
What do you mean my "attached"? Were the wires just tie-wrapped to the cable, of were they physically connected to the cable end, like you see on a smaller vehicle battery cable?
I'm assuming the former, since attaching a positive to the ground stud on the solenoid wouldn't make sense.
These will be the wires that will conform to the schematics for your starter connections through the relays in the RJB and the transmission NSS. If they are in good condition and there's enough room to put ends on them when you get to that point, I'd say leave them. If not, pull new wires, either now, or when the time comes to update to the schematic.
They were individual wires that ran in the conduit with the cable, from just outside the junction box until the cable reached the frame stud, curbside. They then came out, and went into a tube that ended at the starter.
When I reconnect that cable, I'm going to add three 10ga wires, so as you suggested, I can wire the start circuit correctly at some point. I will dip all of the ends in several coats of liquid electrical tape until I'm ready for them.
It only took 4 days of soaking in PB Blast to remove the screws and the old frame stud. I also followed your advise again and had Luke send me a new one.
I'm going to clean up the engine area, (with steam...NOT Brakecleen) fix the holes in the fiberglass that I can reach with the engine in-frame (where all the cable hangers came loose) install the new frame lug and hook up everything except the starter. (I want to double check everything before I add my new starter to the system).
So now I have a plan...BUT...
The only issue I have at this point is that the 4/0 cable (big one from the battery) literally welded itself to the large washer. If I remove it, I don't think the copper end will be as it should, I am NOT replacing that 35' 4/0 cable, and there is no way I can cut it off and add a new end. It would be too short, and there is nothing there strong enough for me to beat a new end on. So, I'm going to try to make sure both sides of it (married to the washer) are clean and smooth...to prevent ANY chance of even the slightest arc. I don't ever want to see another arc...unless I change my name to Noah :)
If I can't get it right, I'll update again.
The new stud and washer aren't copper but it shouldn't matter. BUT, do I separate and stack the three cables with the washer, or stack them together with the washer on top?
The 4/0 cable as installed, was connector face down, washer on top of it, if it matters. I never moved it.
Well, you need to have good contact between all three cable ends. If I'm not mistaken, you now have two new cables in the stack, so those should be corrosion free. I would take a large file and clean up the battery cable end so you can get good contact with the other two. Stack them together with a dab of dielectric grease, put the washer on top and tighten nut. Use and ohm meter to ensure you have no contact with the frame.
Craig you are correct that 2 of them are new, and the 4/0 is welded to the old washer.
When it stops raining, I'm going to find a way to make it sit straight on the new stud and tighten it down so I can check it before I add my other 2 new cables to it.
It will NOT touch the frame.
How is your starter problem coming?
Well...
I have a new starter (haven't installed it yet) because I'm making ALL new harnesses, and the largest problem was the best way to fix the 4/0 from the battery.
So, I ordered a 4/0 industrial splice kit. Took a day to build the nerve to cut the old self-soldered end...but I did. Took me a while to get the cable into the joint, but that's a good thing I suppose. When I was done, I suspended the 4/0 in the air and turned on the battery. 25.2 steady volts :) I wanted to check it before I connected it to the new power stud. I just finished new 2/0 cables that run to the rear box (along with the three wires for the starter that were not being used...I labeled them and I am going to leave them coated in liquid tape until I wire the rear the way it's supposed to be) and the new cable and wires from the 50DN to the rear junction box stud and the 2-panel studs.
Funny thing...I got a VERY good deal on 75' of industrial "everything proof" conduit. Pulling the 2/0 wasn't as easy as I thought it should be. The conduit is larger than the cable...but I wrestled it in.
Spent most of a day steaming the engine bay (before the wires and yes, I made sure nothing got to the alternator) and I have a few spots to fill in before I paint what I can reach. When I get that done, and everything re-hung... the new starter should (hopefully) be in.
I'll post update when I get that beast (starter) changed out :)