disc break air help

[Joel Ashley]

This is not something you can put any reliance on an email about.  They don't always get read and often are auto-displaced by system settings to the junk file before the recipient sees them.  I've sent emails to Ken before without response.  Same thing happens with emails to my Ford dealer service advisor.

That's usually not the case with a phone call.

Joel

[Jeremy Parrett]

Pretty sure this caliper overheating was caused by the wrong grease being used.  When the rotor was replaced with new pads and a new oil seal  we cleaned the caliper pins and reinstalled the caliper.  I suppose the old grease is still in the caliper.
  How much clay based grease do I put in one caliper to be sure I have purged the bad grease out??
  Will be at Covington Heavy Duty Parts in Pensacola Fl tomorrow morning.

[Edward Buker]

Jeremy,

I think you will use about a third of a  tube to purge the old grease out.....that is a guess. The clay based grease is a light tan color so you should see a color change or fresh grease emerge. The older grease, even if the same type will probably have darkened some.

It is important that the lube procedure be followed. It is on pages 52 and 53 (numbers on the pages) of the Meritor Brake manual that details the procedure. There is an adjustment to set the inboard pad against the rotor using the slack adjuster, a pressure relief valve is removed and you grease the caliper grease fitting, then the slack adjuster is used to move the caliper piston fully in the opposite direction to purge excess grease out of the pressure relief valve hole. Then you wipe the excess grease and put the pressure relief valve in and adjust the slack adjuster to spec. There are diagrams that point to the proper grease fitting etc.

Basically you are filling the chamber with grease and with movement of the piston travel using the slack adjuster, purging enough grease to allow for expansion, so that the piston is not forced into the rotor due to grease expansion. Whether you do it or have a shop do it, make sure they have that procedure. If you search on Meritor Brakes you should find the manual. I thing Monaco did a document with the same info. Hope this helps.

Later Ed

[Jeremy Parrett]

Ed,
  great information.  Many thanks.  I assume 1/3 rd 0f a tube will do both drive axle calipers.   Therefore 2 tubes will be enough to do all 6 calipers.
             We are heading to Covington HD Parts today and then to Quartzsite AZ.   Best wishes.  The BGB Crew !!  ( Big Green Bus) 

[Jeremy Parrett]

FYI    Meritor Clay Based Grease per tube  $14.   I bought the 4 tubes  Covington HD Truck Parts  had in stock.

[Jeremy Parrett]

Left Florida east coast Monday Jan 4th  and arrived Blythe CA today Friday Jan 8th  .  No evidence of overheated brakes.  Hopefully someone at Quartzsite will be able to check things out.

[Adam Hicklin]

To clear up my own confusion about grease.  The meritor manual calls out 2 different types of grease for the caliper: 0-616-A which I'm guessing is the standard clay-based grease, and 0-645 which is a synthetic, the best as I can figure it.  I never hear anyone talk about the 0-645.  Am I reading something wrong?

[Edward Buker]

Adam,

Not absolutely sure of this, but in the manual they say that the fittings beyond where they require the clay based grease, like the slack adjusters, can use non clay based grease given they do not have the heat issues. I have gone to a quality chassis grease for the slack adjusters for instance. If they are not calling for that synthetic grease specifically at certain fittings then I think this is the reason behind mentioning the second grease. Of course they will give you their product number given they want to sell it.

Later Ed

[Adam Hicklin]

This is from the Meritor 4M manual:
Could I be looking at the wrong thing?  Wrong manual?

[Edward Buker]

Adam,

That table indicates that they have two versions of the clay based grease, one is synthetic, and that either of those two PNs can be used in the caliper fittings. It also shows that there are more options for greasing the slack adjusters which includes a lithium based grease which is your typical high quality chassis grease. Because you are not supposed to mix clay based and lithium grease I have been using lithium based Chevron NLG2 grease on the slack adjusters and the chassis fittings but not the calipers. Over several greasing's I have purged the clay based grease out on the slack adjusters. If you get your chassis greased at a shop while on the road they are likely to always grease the slack adjusters so I have moved away from clay based grease for those fittings.

You need to be sure that whoever is greasing the chassis understands that they are not to do the caliper grease fittings with chassis grease. I would supply them a page from the brake manual that shows the caliper fittings with a big red circle on it and a note not to grease those fittings as part of the chassis lube. It may be worth getting under the coach with them and pointing them out to whoever is greasing the chassis if there is any confusion. Hope this helps.

Later Ed

[Gorde Lang]

After taking my brake problem to sacremento truck center after overhauling this very same brake problem, the new pins passing through the honed out bushings were loose.Sacramento Truck would not warranty nor rebuild old parts.After changing into the new calipers we have been trouble free from sacremento to Arizona &back to Vallejo, California. This was an additional $2400.to bcs repair bill.We did get our first & terrific trip in to quartzite Arizona, wonderful beaver owners &friends

[John Fearnow]

Gorde,
I am dealing with the same caliper issues you are and have sent you a pm asking for additional info concerning replacement parts.

Thanks
John Fearnow
2002 Patriot-Thunder

[Eric Wallace]

Ed Buker, in reply number 10 above, you say "The procedure needs to be followed given the excess grease has to be purged out." 
Where can I find the procedure for doing this work?  I believe my 2001 Monterey 33' coach has the Meritor brake system. 

[Eric Wallace]

Ooops... I just noticed there was a second page on this brake topic.  I see that certain pages of a Meritor Brake Manual are referenced, but when I do a web search many, many Meritor manuals come up.  One I randomly chose did not even have a page 52-53.  Does anyone have the link for the appropriate one for our systems?  Thanks.

[Gerald Farris]

Eric,
Your 2001 Monterey does not have the Meritor ADB brake system that is being referred to in this post. The 2001 Monterey has hydraulic brakes that use air pressure for assist in the same manner that vacuum is used for the power brake assist on your car.

Gerald