Hi all,
Does anyone have the Rockwell part number for the rear brakes shoes on a
GM4107?
Don and Cary
GMC4107
Neoplan AN340
Do you know the shoe size? or drum size?
Are you looking for the complete show or just the linings?
If you need linings, or shoes for that matter, I believe the PD4104, PD4106, PD4107 and PD4108 share the same shoes as the MC8 and MC9, Call Mohawk MFG and ask them.
Or download the Webb Brake catalog and look through it.. there is a wealth of information in that catalog.
Don,
I'd just pull them and either buy the brake blocks and install them myself or go to your local commercial brake provider and have them relined. They can also turn them for your drum size without major cost.
Fitting to the drum circumference is important. New blocks often don't properly fit the drum circumference. If you change the linings yourself, put the shoes into the drums and see how well they fit, if they are tight on the ends, they have to be ground to fit, (rearched) or you won't have much for brakes for some time while they seat.
Some machine shops can probably arc the shoes for you to.
Just FYI, in the heavy duty business we never arch shoes to fit drums.
Now taking your shoes to a local commercial brake reliner...that's okay. Be sure and get new springs, maybe pins/bushings, usually sold as a "brake kit"
Only the quality shops "arc grind" brake linings for you to fit the drum diameters. Most of these shops also have the equipment to turn your drums if needed as well. If you want the best and you are reusing drums it is worth the time to me.
Full service shops like Mutual Wheel Co in Illinois do these procedures for truck/bus customers everyday. (mutualwheel.com), so does my local rebuilder, but they don't have a web site.
Most of us in the bus crowd don't put enough miles on to seat a set of shoes to a drum very soon. We probably only go through a set on the bus in a lifetime, especially with a Jake or Retarder, so that's why I made that recommendation.
Why drive without maximum shoe contact if you don't have to.
Here's another question.
When we brake clear to the floor, we don't hear any air lose in the rear. If it is a partial brake application, there is a lot of air blowing. That doesn't seem right to us. We can loose about 5 lbs of air pressure in a minute or less. Air pressure lasts a lot longer with hard braking than easy braking. The blowing air is normal when letting off the brakes, but is it normal when applying the brakes partially?
We have checked the lines and chambers, and the air sound is coming from either the relay valve or the inversion valve. We have to get it up someplace where we can really get up under it to check further.
Any ideas or reassurances?
Don and Cary
GMC4107
Neoplan AN340
If you need to have your drums turned you will need to pull the hubs and take them with the drums. I had to to give the shop something to true the drums up on. On my 4104 I put new shoes and drums on the front axle and turned down the drums with new shoes on the drive. Every wheel had new springs and new rollers. Now it will stop on a dime. As all these components fit the MCI 9 I am taking them of the 04 and putting them on the 9.
The hard part on all this is getting the springs back on. The last time I used a heavy duty set of extra long nosed pliers. Does anyone know of a tool to do this?
Thanks
John
John
John,
I don't have an MCI, but usually its easier to hook the springs and then insert the rollers. May need a long screw driver for a pry bar, but you can usually put them togather by hand if the S cam is backed all the way off.
NJT,
Yes its near impossible with the rollers in, so I have always left them out and as you say with the slack adjusters backed off allowing the shoes to be as close as possible. The front and Tags are difficult but the drive axle with the one monster spring is very hard. I will make me a tool for next time.
Thanks
John
Quote from: Cary and Don on August 13, 2009, 04:50:24 PM
Here's another question.
When we brake clear to the floor, we don't hear any air lose in the rear. If it is a partial brake application, there is a lot of air blowing. That doesn't seem right to us. We can loose about 5 lbs of air pressure in a minute or less. Air pressure lasts a lot longer with hard braking than easy braking. The blowing air is normal when letting off the brakes, but is it normal when applying the brakes partially?
We have checked the lines and chambers, and the air sound is coming from either the relay valve or the inversion valve. We have to get it up someplace where we can really get up under it to check further.
Any ideas or reassurances?
Don and Cary
GMC4107
Neoplan AN340
You need to tell a little more story here. There should be zero air loss from anything (ideally) with the brakes applied. The only time there should be a release of air related to brake application is when the application is released. Then, the quick release valves let the air out quickly, and you hear a whoosh of air front and rear. Hard brake application or light brake application should be identical - zero air release from anything while the brake is applied, whoosh when it is released. The most likely candidate, or what I would check first, are the quick release valves. they have a diaphragm that seals under pressure and sends the air to the brake chambers. As soon as the air pressure is off, the diaphragm unseals to vent the air, getting the brakes to release promptly. They are what makes the whooshing sound.
Having an air-leak audible under a brake application is a DOT downcheck, so it's illegal to drive the bus if that's what's happening. You also need to pass the engine off, brake application for 1 minute, lose 3 psi or less test, but it sounds like you could maybe pass that test with a hard enough application yet fail it with a light application. Safety first!, don't fiddle the tests!
Brian
Most buses will use standard truck or bus shoe sizes. Typical truck sizes are 15x4, 15x5, 16.5x5, 16.5x6 for the front shoes, and 16.5x7, 16.5x8.65 for the rear. If you have one of these sizes, then any large truck dealer (like Freightliner, Kenworth, Peterbilt, International, Volvo, Mack, etc) will have your replacement shoes and rebuild kits (should be around $150.00 per brake including new drums).
If you have 14.5x6 front brakes and 14.5x10 rear brakes, then you have bus brakes that many truck dealers will have. I know we do since Freightliner also makes the Setra bus, and we are also a Thomas bus dealer. The easiest is to take your shoes in to be relined and then get the spring kits. Consider new drums since they are not especially expensive.
A note on brake linings. Brake linings have become very use specific since the American truck companies and consumers are being very resistant to switching to disc brakes. The lining companies make linings for transit buses (metallic or semi metallic that work well when hot), linings for regional use (hot running linings that don't wear out the brake drums like metallic linings), over the road trucks (linings that work well when both hot and cold), in dusty conditions (like for dump trucks and off road trucks), and on and on for about 15-20 different types. My suggestion is to use a lining that is a bit softer for better stopping capability and one that works well when both cold and relatively hot. I know my transit bus still has the same brakes when I bought it and they have to warm up in the morning to get to the better gripping temperature. You can't go wrong with what they call a medium gray block-the type that most OEM truck manufacturers install in new trucks from the factory. This gives 20,000lb rating on a standard 16.5x7 brake lining-more then enough for most of us. Good Luck, TomC
John,
Try hooking the shoes togather first on the ground, then put them on the brake spider and then slip in the rollers.