Drive Axle Drum Brake Linings

Joe Camper · December 27, 2011, 01:40:00 PM

I have to do the drive axle on our 85XL and although I have a bunch of experience doing this kind of thing this is the first time I've needed to do them on a Prevo.

This is not the same as doing a semi tractor where you release a return spring stretch the shoe over and off and swap them with rebuilt.

The shoes remain unless they are broken or damaged only the linings are removed from them and replaced. The linings are attached to the shoes with brass tapered flathead screws. I have never done a brake job that I have been the one attaching the linings to the shoes.

My concern is what the torque on the fasteners should be what is that spec??

anything else?

thanks in advance

Joe Camper · December 27, 2011, 01:44:00 PM

300 for the linings and hardware for the drive axle only, from prevo elgin.........true right up to the end LOL

luvrbus · December 27, 2011, 02:33:16 PM

Any truck parts place or friction parts house that is pretty common setup on a bus of other types or construction equipment

good luck

Joe Camper · December 27, 2011, 03:09:04 PM

How tight?? Can they be cracked if overtightened?

Boomer · December 27, 2011, 04:19:33 PM

Might save yourself a lot of grief Joe and drop them off at the brake shop. The bolts usually spin and you have to break them off. Royal PITA

TomC · December 27, 2011, 09:08:19 PM

Whether it be a 16.5 x 7 truck type drum brake, or a 15 x 10 bus type drum brake, the linings, drums are relatively cheap compared to the labor and trouble of trying to redo the brakes yourself. Just remove the complete assembly and take it to a reputable commercial brake shop and buy new-or at least have them install new linings and buy new brake drums (turning isn't allowed [at least in California]). Brakes are NOT where you want to be cheap about!! Good Luck, TomC

Joe Camper · December 28, 2011, 02:33:27 AM

I just want to know how tight should the fastners be.

Thanks in advance.

If you have never pulled the hub on a prevo you will not understand. There is absolutly no reason to pull the shoes unless you need to.

Drums are fine.

luvrbus · December 28, 2011, 03:22:18 AM

Joe, those are Rockwell shoes look in the Rockwell manual it will give you the torque for the 4 different type bolts and rivets I am 300 miles away from home but if you don't get the info needed I will be home Friday and can PM it to you btw if you have the flat shoulder brass bolts you won't brake the shoe the bolt will break first are they 1/4 inch bolts ? if so I recall 75 inch lbs for those.

How are going to match the shoes with the drum without removing the shoes the lining have to rounded to match the drum to do it right you don't bolt the lining on and call it good

good luck

TomC · December 28, 2011, 05:17:22 AM

I consider the VERY important fact of matching the linings with the drums to get maximum lining contact and braking force an extremely good reason for removing the shoes to have a brake supplier match up the linings. Many states will not allow arching brake linings (even though linings are now asbestos free) to match your brake drums-any brake drum that is used is bigger in diameter then the original. You're going through all the trouble of taking off the wheels and drums to get to the linings-why not do it right and have everything matched up professionally? Good Luck, TomC

Joe Camper · December 28, 2011, 02:34:54 PM

There are no back plates after putting it together you can see if they are close enough or not.

Drums have no ridge at all they will be very close this chassis has not been abused.

I have the brass screws and am not doing this till next Tues so PM me with the torque #s. I have been told already about destroying the brass hardware too so those numbers will be great.

Thanks

Tom "go thru all the trouble" and " have a professional do it" that's kinda funny. I appreciate your concerns thanks for the reply.

Back when you could get oversized rollers for subsequent brake jobs/pads on existing drums that were a bit out ( so you could still go down closer to the rivits and not cam over with 50% linings still left) I had sets of them and used the hell out of them too.

They have since made those oversized rollers hard to get because they were "unsafe"
I would go thru 3 sets of shoes on 1 set of drums and the third set went in with oversized rollers. Never exploded a drum on a truck and these bus drums are EASILY over twice the mass.

Just so long as the linings and drums are close they will very quickly wear to where they should be.

Tom do you know what they get for a drive axle brake drum for an XL I don't think so if you would be pricing them as relatively cheap.
I do agree with everything you mentioned I do not think these components resemble your description

Thanks again

stevet903 · December 29, 2011, 06:19:44 AM

Joe - the manual I have says 18-23 ft-lbs for W-series brakes. I sent a copy of the manual to your gmail account - Steve

TomC · December 29, 2011, 06:49:23 AM

Joe-I can only go by what we charge for standard cast iron brake drums and standard linings for trucks-that's right at $150.00 per wheel. We also service and sell Thomas buses and service all other buses. At least for a 15 x 10 drum and lining, they are about twice what the truck's are.
It sounds like you know much more then the average busnut-let us know how it comes out. Good Luck, TomC

Joe Camper · December 29, 2011, 03:51:57 PM

Thanks Tom and everyone else too.

Tom we have had this bus for 6yr in March and I bet I have had the rear up and down to spindles at one hub or another 8 or 9 times for one thing or another.

It is a great way to "break away" for a while if you get my drift.

Girls have no clue what kind of time is involved in this kind of stuff, gotta know how to use your cards to the max when you can LOL

I will chime in when I get it done. Gonna go out and get a mini torque wrench, like that idea.

We sold it and the guy is having me help him with it like I told him I would.

ArtGill · December 30, 2011, 07:20:50 PM

I just finished a six wheel brake job on my Eagle NJT Model 20. Some of the parts were 10X's the same truck part. The rear drums were $300.00 each plus $100.00 shipping. The Rockwell s cams and shafts were considerable more than the equivalent truck part. The word "Coach" does wonders for pricing.

I had bolted on linings and choose to go with bonded on linings and lost the core charge on my shoes. But I felt that the core charge was offset by the labor to change the linings.

I ended up with $2400. in parts and 1600.00 in labor. I purchased the parts myself from the truck parts store and I believe I got shop pricing, but you never know. But his included 6 wheels of brakes, two drums, s cams and bushings and seals where needed and some wheel bearing and seals. Changed rear grease, greased s cams, u joints, and front end steering. Also purchased the sockets for the axle nuts.

The parts woman that I worked with is unbelievable with her knowledge of truck parts. If anyone ever needs help, send me a PM and I'll give you the name and phone number. They are located in the New Bern area of Eastern North Carolina.

Art

belfert · December 30, 2011, 10:01:29 PM

As already mentioned, bus brake parts can be far more expensive than truck brake parts. I seem to recall that some of the drums for my bus cost $600 each plus freight shipping! They were originally ordered from MCI, but the parts from MCI didn't fit even though MCI insisted it was the right part number.