Foretravel Owners' Forum

Quick question...., are there one or two or more zerks on each disc brake which should not be greased?  (except during brake service.)

Thanks

Hope this helps

I'm only aware of  2 zerks on each brake that should not be lubed with chassis grease.

So , my takeaway from that is A. You do need to lube the caliper slide rails.    And  B. There's "3" caliper G zerks to NOT grease ?

 I just greased the slack adjusters last week.  Thought the 2 caliper zerks were the ones to avoid.

I'm no expert but on 98 U270 the three zerks on the brake assembly are not lubed by me. I have my brakes inspected annually and they lube and adjust them in Nacogdoches. I do the chassis myself as I don't want my brakes lubed incorrectly by a service technician who is not familiar with the Meritor disc brakes. It is also good to get under the bus and check things over every 6,000 miles at least.

It does, thanks. 

It occurs to me that my slack adjusters and calipers were last greased about 6 years ago (!) and a trip to Nac is not in the cards, so gonna take the bull by the horns.

  I would appreciate it if those knowledgeable in Meritor air discs could watch and comment on this short Utube video by Tim, servicing his U270 brakes. He seems to have it well in hand.  https://www.youtube.com/watch?v=0mYl8d9ir0Y

I understand NLGI-2 EP grease (Mobil 1 is this spec.) is acceptable for calipers.  Is it also good for slack adjusters?  It would be my intent to purge the old grease with new.  I'll not withdraw the pins, leave this for when I can have helper springs installed.

I've been blissfully ignoring the perfectly functioning brakes thru the years and I appreciate your help and comments.  Hopefully I won't screw it up.....

2 on each caliper. 1 on slack adjuster.
I'm not sure what the fuss is about really with the brakes. It's not a big deal it's just a different grease that you use for the caliber versus the chassis. There really is no need to go anywhere and pay somebody to do it unless you I have more money than me or you just don't want to get your fingernails dirty.. where you want to make sure that somebody is doing it the right way but unfortunately that is not 100% knowable when you go into a shop, you hope they know...
The grease fills the space behind the piston.

BUT, it is critical to purge the grease or the pads will not properly retract.

Just follow the directions that are decades old and you will be fine.

Agree, NOT rocket science.

"understand NLGI-2 EP grease (Mobil 1 is this spec.) is acceptable for calipers.  Is it also good for slack adjusters?  It would be my intent to purge the old grease with new.  I'll not withdraw the pins, leave this for when I can have helper springs installed."

Chuck, It's my understanding that the NLGI-2 spec is for the chassis grease.  The correct grease for the 3 caliper zerk fittings is the Meritor clay based grease and I do believe that Mobil and other manufacturers make a suitable (approved) alternate for the clay based grease but I don't know the part numbers for those off the top of my head.

I would recommend that you check your slide pins sooner than later.  My low mileage indoor stored mostly corrosion free coach did have some heavy pitting on the pins (lower pins) and a couple were very difficult to remove.  I replaced them all and intend to pull and lubricate them annually.  It's really easy and quick to do if they're not seized.  By far, removing the wheels was the hardest part of the job.

Thanks George, I stand corrected.  The Mobiltemp alternative SCH-32 is available from Amzn, here's the affiliate link:
Amazon.com: Mobil Mobiltemp SHC 32 1 x 12.5 oz Cartridge : Industrial &... (https://www.amazon.com/Mobil-Mobiltemp-SHC-12-5-Cartridge/dp/B071KQF9L5/ref=sr_1_1_sspa?crid=V68AUP1RU190&keywords=mobiltemp+shc32&qid=1692362425&sprefix=Mobilte%2Caps%2C163&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1&smid=A3J5NRMG7P7P87)

Unfortunately it's not possible to remove wheels in my present location, a 10' wide driveway with obstructions on either side. so the slide pins will have to wait a bit.  My last question, which I have not been able to resolve, is at what point is the pawl for slack adjuster reset.  I'm guessing it's after purge, then pads against caliper, then adjusted back 3/4 of a turn.  This sound right?

 My last question, which I have not been able to resolve, is at what point is the pawl for slack adjuster reset.  I'm guessing it's after purge, then pads against caliper, then adjusted back 3/4 of a turn.  This sound right?
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Sounds right.  At 2:44 in the video that you attached the author says that he greased with the pads against the caliper and then he backed off 3/4 turn.  I would need to watch the Meritor video again and re-read the 4M manual to be sure.  I did not grease my calipers when I serviced them because I did not have the correct grease.

Sounds right.. after final adjustment.

If you run the adjuster down until the pads touch the rotor, then back one half turn on the adjuster, your brakes will be right. The auto adjuster will take care of adjusting from there. Quick hint if you remove the adjuster pawl with a 3/4 wrench it make running the brakes in and out much easier. It will only go back pin one way.

I wonder if they could be any more non-standard, complicated. I have not found a mechanic yet that understands these brakes and how to adjust or grease them. My rears have started to hang up again. Only part of my FT that I'm disappointed in so far.

The air disk brakes are common on Fire Trucks-- check with their techs to see if they re interested in moonlighting on your Foretrael.

Just verify they ARE familiar with the Meritor air disk brakes.

That's a good suggestion, there's a firehouse right close, friendly bunch of guys.  I'll check and see if they're familiar with the system and if one of em could look over my shoulder.  Based on the amount of incomplete, and misinformation around coupled with the rarity of the gear, I want to be able to DIY, though.  Starting to look at the coach as a well equipped bugout system more so than a vacation ride so need to be able to keep her rollin, and stopping, on my own.

I GREATLY APPRECIATE everyone's help on this issue.  Thank Ya'll.

Chuck,

The first thing is the answer to your basic question is "0" as all the zerk fittings are there for a reason. The big problem is not bleeding the grease out the proper way, proper amount or proper grease.  I will even go out on a limb at the risk of getting a nasty PM or two and say you can grease those fittings when ever you like AS long as it is done properly. Now that is over kill as once in the lifetime in a set of pads is about good enough in most cases. Others may get tired of this info but if you print off a hard copy of the 4M brake book read and follow it you won't have a problem. If you were to swing by my place to do this the first thing will be reading the 4M book before even starting to do any thing. You need to look at AND READ. section 10 and 11 as it has the most info you are looking for.



Mike

Mike,

Now that's the manual I've been looking for!  Yeah, they're crystal clear on lube procedures, and a good general outline on the entire brake system.  You can bet I'll read it in its entirety and follow Meritor's recommendations.  Since they've been lubed once in 27 years I'll do the full monty.  Slide pins and helper springs will be next in line when I'm in a suitable repair area.  Printing a copy for binding as we speak.  Thanks!

As the others have said Meritor MM4 is a must read and understand before working on your brakes, your safety depends on it. Also when greasing other parts slack adjuster, u joints, steering, excess grease oozing out everywhere is just making a mess.

When I took my coach to a truck repair in Oklahoma City they had no clue. They called somebody from Kenworth that was down the road and they didn't really have a clue either. They could look up part numbers which they did and gave me a price of $8,000 to basically replace a rotor and a caliper. Then they tried to tell me that the other caliper needed to be replaced although they never gave me a quote for that. Then they told me that the parts were not available. When I said I know that the rebuild parts are available from find it parts, he told me they didn't do that they just replaced the whole systems.
Working on the brakes with John 44 at his place was a great experience although I didn't walk away unscathed. But I didn't spend $12, 000 either.
The meriter manual really does spell out everything quite well.
Yeah from what I was able to figure out only fire trucks generally have disc air brakes in the rear. I didn't feel comfortable going into a fire station and asking who the mechanic was for some reason. If I had to do it again though I wouldn't hesitate.
And there is both clay based Grease from meritor as well as the mobile one on find it parts. If I remember correctly to mobile one was quite a bit more expensive but it may have been the other way around.
Either way definitely replace the pins when you can do it as well as putting helper springs on. And at that time you may want to replace your pads and definitely check the rotor.