Pnuematic Parking Brake

This topic contains 5 replies and was last updated by ben 11 years 1 month ago
March 31st, 2010 12:54pm
Hello to everyone out there. My name is Matt and I am from Detroit. I'm working on a crazy bus here and looking for some help. I have a 1990 Marco Polo Coach on an Oshkosh chassis. This thing has an air operated parking brake with a "Rotor" mounted on the tail shaft of the trans. Basically something happened to freeze the caliper and my pads are destroyed. Caliper seems to operate fine now, but I have to replace my pads. I have been on the phone, internet, and everywhere else I can think of looking for a set of pads with no luck at all. I used a picture of the pads as my "Avatar" to register on the forum. Anyone out there ever seen anything like these before?
April 1st, 2010 6:57am
Do you want to know where to find new pads? Or why the the pads were destroyed. If your air compressor is failing to keep up with the demand for air, sometimes the parking spring brake will activate as a safety precaution, usually when pressure drops below 80 PSI on a bus and sixty psi for on highway tractors. I would start by doing a basic air system check. The driver indicator light could be faulty as well. Fire up the bus and wait for pressure to build then press the brakes several times until pressure drops below 80 and see if the warning indicator comes on. Secondly if the driver was braking excessively especially in steep gradients the compressor can't keep up with the demand and overusing the service brakes can damage the chemical composition of braking material and change the properties (aka "going plastic")you should talk to the driver and ask what kind of conditions the were driving under. I would also check the ABS for faulty modulator. and slack adjusters if applicable. These areas are the most common failures for excessive wear. How long has it been since the brakes were last serviced? How many drivers are there. I hope this information points you in the right direction. As far as parts,for replacement I would check RV dealerships in other provinces and or U.S. like country coach in Junction City, Oregon Good luck and keep us posted on your results. Remember, " Don't work hard , Work smart." Good luck.
April 1st, 2010 8:39am
In my part of the world, vehicles over 10 years old are also still allowed on roads.. finding OEM parts is really difficult.. on problem like that I will consult machineshops, they are connected too with brake rebonders and used parts traders.. my pennyworth idea.. goodluck.
April 1st, 2010 10:45am
Yeah that reminds me of when I needed brake shoes for an old Massey Ferguson tractor. Find a local friction surface shop and have the shoes relined with new friction material. Most towns "especially motor city" have shops that specialize in friction material. I have one here in Eugene, Oregon. That would be cost effective and smart. You'll be happy knowing that you have the exact part. It's OEM at a reduced cost. A machine shop can point you in the right direction, but I think you would be able to find a local "friction surfaces" by Google. A perfect example of "don't work hard , Work Smart. Let us now how it goes. I took the liberty of finding a shop in Detroit Michigan.Here is the link and phone# (586) 775-3000 I bet they can tell you what kind of failure may have caused them to go plastic. Now go forth and conquer. VINI,VIDI,VICCHI That's Latin for "I came, I saw, And I conquered." Julius Ceaser
April 1st, 2010 11:42am
We used to get our Oshkosh brake components from The Bus Center here in Alberta. Their number is 780-962-4645/ 1-800-661-5646. Website is

Ask for AJ in parts. Might be worth a call.
April 13th, 2010 1:25pm
Found Em'!!! What a pain in a$$ this turned out to be. I swear, I spoke with everyone I could that was involved in making this vehicle and no one could help identify these things. Could have had them "Relined", but one metal backing was bent so it would have had to been machined and the lining bonded on and this is on a vehicle that is rented out, so liability was a problem. Anyway, found the mfg. (only about 12-15 hours searching online). Hayes Performance Brakes. Mostly make brakes for bicycles, but do have a few on highway applications they have made over the years. Felt like gold miner in 1800's.

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