BUS BURNINGS

[Danss]

As another bus burns do you believe there could be an inherent problem in the engine area and rear brakes in all Prevost? My rear brakes locked up on one rear wheel but was caught in time !

[Joe Camper]

It's been my experiance that the disc brakes could be a high percentage of these fires Dan. The rockwell's ( aprox pre 2000) hang when u allow the auto adjusters to let the parameters of the push rod to operate at 1 to 2 in vs 1/2 in to 1 where they will almost never hang. Then the knorr bremse ( aprox 2000yr and on) with the slide pins that very few service CORRECTLY every 5 yr. like they require.

All your beautiful buses r both very powerful and very smooth and even well seasoned drivers could be driving through dragging brakes and not know it.

I just got done yesterday putting a set of 6 caliper slide pin kits in an 02 XLII Royal in West palm.

8hrs labor is what it takes me and 450 aprox for the 6 slide pin kits from prevo every 5 yr is what it takes to keep knorr bremse happy. A small.price to pay.

The rockwell's r even less costly to keep right. All u have to do is adjust them manually every year. Pull.the ratchet bolt from the slack adjuster run it down tight and then just crack it back 1/8 of a turn and reinsert the ratchet bolt back into the slack. It will stop better and it wont hang and its a free fix, win win win.

I wonder how many other mechanics or service centers have come to this conclusion and suggest this advice. I'll bet not many.

[Joe Camper]

When these chassis r charter buses they r going through brake pads and components way quicker and dis and reassembling is happening frequently enough to eliminate the problems that materialize on a chassis that is a motorhome that is 20 yr old at 150 000 miles and the brakes have never even been touched.

The 02 Royal yesterday 150 thousand all original brakes pads and everything. Pads still had plenty of thickness. The front pads were beginning to crumble off the edges reducing the contact patch with the rotor but just barely the tag pads were like bran friggin new. All the slide pin boots were shot and the pins rusted. I'm quite sure this is the first time in 18yr the pads had even been pulled out of the calipers. That's quite remarkable to be seeing similar other chassis that r in the same condition as much as I do. I am also quite confident that many reading this may fit the description too.

I will repeat this story/ suggestion because I think it's dead on and u need to add this to your service intervals. .

Fellow pogger Loc recently bought a marathon used 12 years old came with all the service records and it was a well cared for bus stored inside. Along with the service records was the invoice for the caliper slide pins and they had been rebuilt at the 6-year point by the first owner. I crawled under the bus last summer when Loc first got it at the 12-year point and the boots are torn again.

If you guys get in the habit of doing the caliper slide pins every 5 years you'll never have to worry about anything even closely resembling a brake fire with your disc brakes. very simple doesn't cost a lot of money. U get the added benefit of getting the rims and tires off it from time to time too and if any mechanic who gets under something as big as a bus cant find a few other things going south after 5 yr while hes under there find a better wrench, there's always more. For example all the 2000 to 2010 and older too, check all your mud flaps. If not already missing the remaining will show half of them will be half cracked up next to the mounting plates and wanting to fall off.

And u Rockwell disk guys, please, adjust them as if they were manually adjusted slack adjusters anually and only back them off 1/8 turn from tight. Please.

U know PREVO tells customers DO NOT UNDER ANY CIRCUMSTANCES GREASE THE ROCKWELL CALIPERS, I've heard of them breaking off the zerts for customers who dont listen. Crazy, dont know what to say to that.

Those rockwell calipers r obsolete now so if u do not have a good core to rebuild when u have to, your mechanic will be standing there with his tool in his hand.

[Gil_J]

Joe is dead on. Don't let your K-B caliper pins go, especially if the boots are torn. The caliper repair kit is about $80 a wheel.

It amazes me that those that are telling people to zero out their new to them coaches don't include someting so critical as brake caliper pins but have you changing air bags at 10 years when they can safely go 15-20+ years.

It's your brakes...get them serviced!

[Rootdmd]

Joe, I am very happy to know you will be checking out my 14 year old coach tomorrow at the show. Sounds like you’ll find some needed maintenance issues. We should be rolling in early this afternoon.

[BGLogistics]

Being an owner of a bus with Rockwells front and tag, I am thankful Joe discovered both my tag calipers were dragging. All 4 of those hubs/rotors had obviously been replaced very recently, yet tags were dragging. Suprisingly no blueing or signs of excessive heat - how that didn't happen I'm not sure. Joe was able to free both dragging calipers using above procedure (and bleeding some grease if I remember correctly). Inital trip home with bus dragging 7K was right at 6 mpg. After calipers freed up, a much shorter trip thru hills dragging 5K was 7 mpg. Both according to DDEC. Driving feel was no different.