[Archived]

On that vintage coach your problem could be caused by a hydraulic lock as a result of over greasing the slack adjuster shaft. It could also be caused by a bad automatic slack adjuster. Regardless of cause the slack adjuster needs to be loosened and readjusted.

You can back off the slack adjuster by lifting the metal disc around the square adjustment bolt, turn the adjuster counter clockwise to loosen. The correct adjustment is to use the adjuster to tighten (apply) the brake, then back off about 1/3 turn.

You do need to determine why it happened, because if it is over greasing or a bad self adjuster it can happen again.

You can fix this without getting beneath the bus by turning the wheel as far as it will go to expose the slack adjuster.

[David]

Thanks Jon, that’s what I did and drove home carefully. I’m back. More as I know it… I think another caliper replacement is in my future (did the left tag a month ago)

[CHIP]

Those calipers are usually very reliable, but over greasing and a bad automatic slack adjuster will make you think the caliper is bad.

Over greasing creates a hydraulic lock that inhibits the caliper from releasing. Clean out the excess grease and that problem is solved. You can evaluate the automatic adjuster by backing it off and then applying and releasing air to the brake chamber. I do it with shop air, but you can do it with the bus air system. You can see the slack adjuster being tightened, and you just want to make sure it does not overtighten.

If the slack adjuster bolt was not tight when you loosened it, the problem is likely not that. A hydraulic lock eventually will release it self over time usually.

[Archived]

I backed off the caliper adjuster 7 clicks and limped home. Just fitted new pads ~600 miles ago. Guess that’s a redo! Will at least do pin kits unless it is determined a caliper is in my future. At least I’m not camping out in SC this morning…

[Davy]

In our down time I rebuilt all 4 calipers, on E-bay i found the basic rebuild kits for the Meritor 1560 ADB kits were around $50 bucks apiece for them and ordered the Meritor clay base grease kits had new green bellow around piston new piston return spring, seals-O rings and more. I did this because one of the guys on the Forum pulled his apart to see the wrong grease and they were a mess, Mine looked really good inside but anyways they all return really good now. I installed pads also ,and like Jon said about the grease follow the instructions on greasing and last thing back adjuster back all the way off with pop it valve out and get all the extra grease out. I had a problem in the beginning with the foot valve not realising front brakes rite away, the duck sound would take 5 or 6 seconds delay

[Archived]

A remarkable amount of problems encountered on coaches over the years are caused by lack of knowledge or understanding. This is not an indictment of owners, few of whom actually are responsible for their own maintenance, but by those provided the responsibility to take care of the maintenance.

Current threads now discuss lack of greasing on a hidden fitting, or in this case the potential over greasing has to create problems on brakes.

It is impossible to list all the “gotchas” we can encounter, and a great deal of them only required a small amount of common sense. A good example is the practice of some to pump grease into fittings until rubber dust covers expand to the point where grease is streaming from them. The end result is damaged or torn dust covers. Ditto on not catching bad hoses, or noticing air leaks so bad they can be heard.

Few of us ever intend to be mechanics, but to protect ourselves we need to monitor work done by others. Sad.

[Roscoeapproved]

Coming back from Prevost service, I started to smell brake pad. It was stop and go on the freeway, so I assumed it was just the frequent braking that was heating things up. Exited the freeway but the smell was still there so I pulled over. Left front wheel was ticking like the cooling of metal. Felt the hubcap and it was pretty hot, much hotter than the right front. Prevost was able to get a hold of their mechanic and he stopped by on his way home and confirmed the caliper was locked down, as he couldn’t adjust it off the rotor. I only had 6 miles to go. so I waited (hours) until the wheel and hub felt cool. The seal was still holding the gear oil, so I drove at about 25mph stopped midway to check the temperature, felt cool and made it home. Left front wheel was only slightly warmer than the front right. I didn’t feel any pull to the side while driving.

Question: if the caliper locked up because of over greasing, would it stay locked up, or could it have released once it had cooled down? I will check things out tomorrow and follow the very helpful information on the Rockwell video someone posted Meritor brake maintenance

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Jeff and Lindsay

91 Marathon XL

[Art]

My Foretravel is also fitted with Meritor disc brakes. In the Foretravel world, the recommendation is to NOT over grease. Use clay based grease which is a high temp grease. Do NOT use chassis grease.

Then, every slide pin on every disc brake needs a Meritor Slide Pin Spring installed. This helps push the pad away from the disc when the brakes are released.

I can not emphasize enough the value of the slide pin springs to the operation of the brakes.

Hope this helps.

[Rudy]

Here on PC, type in the search word “pawl” and you’ll find plenty of info about brake mx.

Here is how Meritor says to grease calipers:
a) remove the poppet fitting
b) pump Meritor pt# A1779W283, which is NLGI#1 grease, into the 2 grease fittings until fresh grease comes out the poppet fitting hole.
c) release the pawl on the slack adjuster and adjust or loosen it(lengthen stroke) fully which is about 4 or 5 360 turns of the adjuster. This will force excess grease out of the poppet fitting hole.
d) reinstall the poppet valve/fitting
e) re tighten(shorten stroke) of slack adjuster fully until pads are clamping the rotor, then release the pawl again and loosen/release(lengthen) stroke 1/2 to 3/4 turn.

I did mine less than a month ago.

The typical grease monkey knows nothing about the proper methods and materials to use.

[Archived]

I saw my old post when I rebuilt all my calipers, And greased them all Just like Don wrote,And as per Meritor. Now I will not grease them again, At least not for a real long time and when I do it will be just a shot.I rebuilt mine because of that post about the wrong grease, I was lucky 1st owner Either used the correct grease or did not grease at all. The guys from Meritor are really sharp and know their stuff, I have called them a few times over the years and they don’t have a problem sharing info.

[Archived]

If Luc would add his coach information to a signature line he would get reasonable answers. Depending on his model year of the chassis he could have all drum or a combination of drum and disk. But right now nobody knows.

[Bill]

Jon-

’96 xl

I have this information in my profile, but for whatever reason it does not show. Bill reached out, but the email I sent with a screenshot to the address he listed bounced back.

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2005 XL Thompson Coach

Rarely tow anything behind us.

Sold: 1993 Liberty that we loved for 12 years.

[Rudy]

Luc

Jessica or I have not received an email. We are here to help.

Jessica@PrevostCommunity.com

Bill@PrevostCommunity.com

Bill3@CarlisleEvents.com

We both receive emails at these addresses hourly.

Bill III

PS thanks for the help on this thread!

[Archived]

Hi Bill,

Ok will try sending again.

Thanks

[Archived]

Rudy-

Thanks for the good information. If I’m understanding right, the buses do not come stock with these springs; this is a modification to improve the draw back of the pads?