My parking brake is not holding. Brakes seem to work fine when stopping the coach, but, when parking brake is engaged on an incline the coach rolls forward/backward.
A truck mechanic here in Tucson tells me it is because my rear brakes are worn out. Any opinions or past experience? Ideas re: cost of brake job on rear brakes?
This is on a 1993 U225.
Roger
Roger,
Have you looked at how much brake lining is left?
Not sure without seeing it that we can give you sage advice.
Your coach has wedge drum brakes-- also popular on medium duty trucks, especially in Europe. Pretty basic system.
Rears wear out first because of weight. I had mine done in Palm Springs and it wasn't expensive.
And, although the air wedge brakes DO have automatic adjusters, at that age they may not be working and may need to be serviced.
Start by verifying the amount of brake shoe left.
BTW the manual does call for cleaning and lubing the adjusters ever 100.000 miles.
Every 100,000 miles!!!
WOW, that is like every other day!! >:D
Here is a PDF for how to check and adjust your slack adjusters: https://cbsparts.ca/admin/bulletins/Meritor%20TP9173.pdf
Pierce
Slack adjusters are not your problem. If the brake doesn't hold, baby needs new shoes.
NO. We have answers above to both OP's Meritor/Rockwell air wedge drum brakes and the air disk brakes used on other coaches.
They are not the same and their "care and feeding" is different.
I had one side with no park brake along with poor drive brake. The little rachet paw thingy had backed out. Serviced the wedge as well as the dual pancakes.
Plenty of shoe left at 150K . Its really hard to get to the adjusters. I made a bent spoon with the drum removed and practiced a couple of times. Adjusted it as big as I could fit the drum on. Now they stop as well as its supposed to.
I have not personally looked at the brake linings. I meet with the mechanic tomorrow, Monday 1/16.
Servicing the Meritor wedge brake is a little bit different than "S" cam brakes.
In operation wedge brakes work more like traditional hydraulic brakes, but in place of a hydraulic cylinder you'll find a traditional air can operating a wedge applying force to the brake shoes.
Servicing these or more akin to cleaning and lubing a watch than traditional air brakes with multiple lubricants involved, all sealed away from the elements.
General service manual PDF:
http://manuals.chudov.com/Grove-Rough-Terrain-Crane/Meritor-Wedge-Brakes.pdf
FWIW, when I sent Lynn to Texas to survey and purchase our new home, I packed a 3/4" wrench in his travel bag.
After he arrived home and I slid underneath to inspect our new toy, I said something akin to "what is going on here?"
Much reading ensued.
This is an interesting topic. The only kind of air brakes I had ever worked on before this coach
was S cam brakes. On this coach is the first time that I have worked on air disk brakes which I
don't think are that common as a friend had never worked on him or his brother who had owned
a truck shop had never worked on them either.
Fire trucks are another application where you will fine air disk brakes.
But, the OP has a completely different system-- Rockwell/Meritor air drum wedge brakes. Remember, the U225 is substantially lighter than your 1999 U320.
Pierce, this is for "S" cam brakes. The wedge brake system uses a completely internal automatic adjustment.
My mechanic seems to think I have an S cam system. Is that possible? Is he blowing smoke? I really don't know. He works on a lot of big trucks; semis.
He can see what we are only supposing. If he is a good truck mechanic he will know the difference, there is no reason for him to mislead you.
My 87 had both. S on the front and wedge on the rear. Or vice versa, I forget. You will know once the wheel is pulled.
You don't have to pull the wheel to tell the difference. If the diaphragm goes directly into the backing plate wedge. If a shaft comes out s cam.
And some people make assumptions, as in, "RV Owner's are idiots."
After the arrival of our new home, I slid underneath and took a peek. When I saw the cans bolted right to the backing plate I knew I had some reading to do. (Lucy)
If your 1993 U225 has anything but wedge brakes, it will be the very first I have either seen or heard of.
I have cam fronts and wedge rear.
Again, COMPLETELY different chassis.
If he is not familiar with the wedge brakes you better look for someone who is. They might only need to be adjusted or the spring brake might be broken. You shouldn't pay for his education.
Well after talking to the mechanic again today and having him assure me that my brake system is an s cam system, I dug out my manuals. According to my manuals my brake system is a Rockwell wedge system.
My coach has been at the shop for six days and has only been moved once. It was supposed to be done yesterday, then later today; now tomorrow by noon. I suspect the mechanic has not looked at the coach; maybe one of his guys has. Needless to say I'm very frustrated.
Maybe it's time to call around to other truck shops and mobile mechanics? There is some specialized knowledge necessary to changing the brake shoes and resetting the automatic adjusters, and personally, I don't want a mechanic learning on my nickel with my equipment.
I find it best to meet in person, that way I can watch their eyes for that "Deer in headlights" look as they realize that they have no idea what I'm talking about. right before they answer, "Sure, No Problem!" in a confident voice.
"Run Forrest run!" Find someone knowledgeable of these excellent but complex brakes. The consequences of improper adjustment or repair are not only dangerous but expensive as well.
Once they are properly set they should be rock solid for years.
Yup, our wedge air drum brakes were still working well and still had plenty of lining left at 170,000 miles when we sold it.
"Doing the reading," I found that there was a change made that means parts before a certain year and parts after a certain year can't be interchanged. Of course that's the brake shoe clearance adjustment, which does the same work as the cable and pawl on an automobile or light truck, but is much nicer and totally enclosed in clay based grease.
So Yes! Run! Forest Run!
Definitely take the motor home out of there and find out exactly what your brakes are. They should be wedge brakes. I suggest that you call Old Toolmaker. It sounds like he has read up on them and can talk you through this. I think that they probably only need adjusted.
Yep. I ran. Now I'm looking for someone who knows Rockwell air wedge brakes.
OK, coach is back in the shop; different shop. Mechanic (who recently purchased a Foretravel, a U280, I believe) tells me my wedge system shoes are worn out. He has had trouble locating new proper shoes for this system, but, he knows someone local that is able to fabricate new shoes/linings. The drums are not worn out and are still useable, but, do shoe some wear. The drums are worn some and show some heat cracking that he thinks is not too serious. Replacement drums are available to the tune of $2600 including shipping; and only about six pairs of these drums are in existence in the U.S.
Options:
Spend the $$$ and replace the shoes now; should be good for the rest of our years in the coach. Sell/throw away the old drums
Or
Not spend the $$$ for the drums, just replace the linings; may be good for the rest of our days. A little bit of a gamble.
Or
Buy the new drums and save them for 'that day' when they may be needed.
Thoughts/experiences?
p.s. front brakes are 'perfect'.
Your mechanic (assuming familiar with truck drum brakes) should be the one to decide on whether the drums are OK or need to be replaced. Not reasonable for us to express an "over the internet" opinion.
If replacing, do it in pairs so all brakes on an axle are the same.
There should be a dia. number on the drums. If they are under that number I wouldn't personally worry about heat checks. Relining shoes with new material is rare but if he has someone to do it go for it.
I haven't relined brake shoes in over 50 years, we used to do it all the time.
There are still a couple of old school truck parts places in Orlando Fla that still reline shoes.
Roger. I would probably opt for the ,buy the drums and sit on them until i need them or ? .... Cause of availability,and the cost will likely not go down. But that's just me... we (i) am possibly hard on brakes ,either that or I'm a slow learner. Just had our brakes worked on for third time.
Thanks. Bret.
I agree; decision has to be made here with the mechanic. Drums are still well within spec.
I think.either way would be ok.
There's also a company in Kentucky and one in New Jersey. Re-lining clutch disks and brake shoes is a common practice for parts that are no longer available.
Brake Relining and Clutch Relining Services (https://industrialbrakeclutch.com/)
Custom Fabricator & Distributor of Specialty Friction and Brake Shoe... (https://www.indbrake.com/index.html)
Kentucky Clutch | Car, Tractor & Truck Clutch Repair & Kits - If you're... (https://kyclutch.com/)
And finally, a pair of unobtainable 11" by 2 1/2" Studebaker Lark V-8 brake shoes.
I have about 150K miles on mine and the shoes are about 1/2 in thic or more. Not much taper on the shoes. My drums are heat cracked a little and belled a little also. Not a lot . just enough to require bedding the shoes and readjusting if the parts get moved around. Take pics and mark each shoes for placement back to the same place if re using.
I find it odd that you shoes are worn out.
One of my adjusters came un linked and that wheel would not stop or lock on the park brake . Only out maybe 1/8 of an inch .
My rear brakes are 15 In? maybe. Foregot the width tho. Yours may be smaller .