MC8 w/ stock alternator
Coming home from nice bus trip and my "not charging" tell-tale comes on. Thank goodness I am nearly home and make it on in w/o instance.There was no load on the system when it quit charging.
Upon checking the situation this afternoon, I discover that the field wire coming from the rear of the alternator has a dead short.
I can unplug this wire about 6" from the back of the alternator and the wiring is not grounded from that point forward (into the bus).
From looking at the book, it would seem that either the field in the alternator has somehow become grounded or the "zener" diode is shot. What's that?
Thanks to the cool new transmission cooler that I've just installed (it works great) there is even less room to work in that compartment.
Given that I will have to remove the trans cooler and air cleaner, has anyone removed the alternator on MCI thru the side door?
Is there a possibility that I can repair the alternator w/o taking it out?
At this moment, I can't bear the thought of having to silde the cradle out to change the alternator.
Im gonna change the warning lights to one that has $ symbol and another that has a "skinned knuckle" bulb.........
Other than this mishap, the bus ran great for 800 miles with new turbo 8V71 and having the Jake was a joy.
Any ideas on the alternator? TIA
Simplest explanation
Zener diode basically allows electricity to flow in one direction (until breakdown voltage) thus it is used to take
the alternating current and make it a DC current and control the voltage.
Rebuilding on the motor: IF you can get to the back end of it easily then probably but resetting the brushes when you put it together will be a real pain. Basically if you can get to it to rebuild then with a little more contortions you be able to disconnect it. Check above, beside, below for room to remove. Since you have your batteries back there I would remove them and I am not to sure how much room you have with the AC condensor back there also. The controlling electronics (where the diode is) are usually a replace not a rebuild. You can pull them out easily and replace.
Hope this helps
Skip
I removed the alternator and it appears that the field winding is shorted out. The part 7B-3-154 isnt available from MCI. Anyone have a good one is a spare alternator that they would part with?
TIA, Chuck
Chuck, I would suggest you try and find a motor repair/rewind shop. They can tell you if the windings are bad and rewind if necessary.
Richard
Chuck. If you have removed AC/ heat blowers, a new 150 amp truck alternator is less than $200.
Hello Chuck.
Yo0ur loc0al charter company will have a regular so0urce for0 alternator parts or0 re-builds.
They will have what MCI has sto0pped sto0cking.
Keyboard tro0uble at my end...
happy coa0ching!
buswarrrior
Hi Chuck, may I ask what the alternator weighs?
Did you pull it through the side door? The air cleaner is easy to remove...the trans oil cooler is a problem. Are you using a standard MCI trans oil cooler?
What about the floor hatch? Looks like the alternator would pull up through the floor hatch?
Thanks, JR
Monster weighs ~85 lbs.
Up through floor not good, can't fit enough arm through to get suficient grip and leverage.
Using a ramp of 2 x lumber pieces in the side door to slide into place seems to be popular, and my preferred method.
In and out twice now, not really wanting any further first hand experience.....!
happy coaching !
buswarrior
Chuck,
You might want to check Nimco in Newark NJ for a used unit. Shipping may out weigh the savings however. (Bad Pun) I have dealt with them with sucess.
Good Luck & I feel for you as I aged getting my alt in and out.....
Gary