Foretravel Owners' Forum

Please review my five minute video at

https://www.youtube.com/watch?v=0mYl8d9ir0Y

I spent months researching how to lube air disk brakes on my 1997 U270, including:

- Barry Beams Meritor video, which I painstakingly parsed
- Meritor manual
- Other YouTube videos and articles, including this forum

This video includes lubrication of the front left air disk brake:
- Automatic slack adjuster
- Caliper
- Clevis
- Slide pin and retainer

I would appreciate your advice or improvements.

My understanding is to completely back off the adjuster to purge the brakes, not just 3/4 turn. Then re adjust the brake.

Tim,

Not to hammer your video but you wanted a review. You may want to re read the 4M manual on how to adjuat the free stroke. This is in section11 of the manual IIRC. This will tell you how to adjust the free stroke with both a template ( yellow #TP-4789) or a scale. Because backing off your stroke adjustment nut about 3/4 of a turn may not be within spec.

Mike

X2 on backing the adjuster all the way back off to purge the caliper after you
Grease it. Also I find it much easier to remove the adjuster lock with 3/4 wrench rather than trying to hold it up. You may find backing off the the adjuster 1/2 turn will give you the proper adjustment.

Tim, I don't know how to do this brake service so I can't comment on the accuracy of your video.  You are not a trained brake service professional and I think you need to be pretty careful posting "how to" videos.  In order to CYA I would suggest that if you are going to post this sort of stuff you change the name to "How I Lubricated My Own Brakes" with a disclaimer that you are not a trained professional.  Too much stuff out there that is just plain wrong or misleading.  Viewers deserve to know the veracity of the information they are looking at and the source.

Smooth voice and good video & lighting. Other's comments are helpful to perfect the steps. Also, we find removing the spring center valve with a wrench rather than lifting and opening against spring for purging. Rotating the screw back and forth is important, even more than once is helpful to fully purge all the grease.  Thanks for sharing Tim...

Thanks for your advice. I believe a bushing is missing.

I have learned a few more things since the video, but have many questions:

1. Relieving caliper grease pressure
As your feedback suggested, purging grease pressure by turning the manual slack adjuster square bolt fully clockwise and then fully counterclockwise, then 3/4 clockwise, resulted in air being sucked into the caliper through the end cap seal and relief valve. This does not seem like the correct procedure and was not shown in the 1990 Meritor video. Questions:
a. Is it OK that air is sucked into the caliper?
b. Doesn't the relief valve, as it's name suggests, relieve excess caliper grease pressure?
c. Won't excess caliper grease pressure be relieved by through brake application and automatic slack adjuster operation?

2. Slide pin accessibility without taking wheels off, in front wheels
Both upper and lower slide pins are accessible and serviceable by contorting oneself behind the tires. Question:
a. Will the rear be any different?

3. Missing bushing?
The right front wheel outer caliper bushing is missing. The slide pin rattles around because there is no bushing. This begs the question:
a. Am I dreaming?
b. Is a bushing required here?
c. How could a professional mechanic miss this?

5. Knowledge is power, and safety
My last encounter with "professional" mechanics almost resulted in a FIRE in the rig. Bobs Diesel in Yuma, Arizona used a fuel filter wrench on the main diesel fuel filter, which cracked, resulting in atomized diesel fuel spewing all over my engine and toad. Although professional mechanics are good, they are not perfect and will take shortcuts when given the opportunity. By doing my own maintenance, I validate the saying "if you want it done right, do it yourself".

6. Caging rear brakes
This is the first time I have caged brakes, which releases the parking brake. I have located the chaging bolts and watched YouTube videos. Question:
a. Other than chocking the tires, anyone have advice / tips on caging brake springs?

7. Adjust stroke
Here is my procedure, with references to the 1990's Meritor video timeline:

A. Measure INITIAL FREE STROKE (gap between lining and rotor) 16:16
1a. Disengage the "pull-pawl' with screwdriver
1. Engage pad with rotor using auto-slack adjuster adjustment nut
2. Back off 3/4 turn so pad disengages with rotor
3. Measure from air chamber face to center of large clevis
4. Engage brake with screw driver and measure again
5. The difference must be within 3/4 to 1 inch

B. Measure ADJUSTED CHAMBER STROKE 19:00
1. Chock and start vehicle
2. Measure the difference between brake and no brake.
3. The difference between must be within TBD

Thanks for your advice.

Tim,
2a. Yes with the inner duel turned like it is you will find it to be in the way. Removing wheel will be less time and effort than trying to do the work with the wheel on.  Do you prefer lying on the ground or setting on a 5 gallon bucket to do the work.

3. a.  most likely not.
b. Yes The bushing measurement specs and related info is in section 4 of the 4M brake book.
c. Could be the amount of 1560s or lack of he has ever seen or worked on.
Mike

Tim, read page 13 in the link on reply #1 getting air is not an issue with the caliper, having non compressible grease will cause the brakes to drag.

Two questions:

How do I know my brakes are ADB-1560?

Anyone have a good source for brake parts?

The sticker shown in the photo was glued onto the caliper. What do these numbers mean?

DISC W/20 & 24
96K177  A64Z1144S

These numbers yield no google results.

This is the first time the wheels need to be removed. On to chocking, jacking and spinning off the lug nuts. Fun!
 

Tim,
The diffrence in a 1540 & 1560 is the square inch of lining area.  You could have a 1540 on the front of your 270 but I doubt it. You don't have a 1760 as they won't fit in your wheels. You are going to get tired of me talking about the 4M book but it is the holy word of Meritor brakes. (or at least the last class I attended it was). IIRC in the first 4 or 5 pages of the 4M book it gives the model code info.

With your coach being a '97 you will have "Budd" wheels (stud centered wheels). You will have left handed threads on the left side (drivers side) wheel studs.

Pamela & Mike

Thanks Mike. A couple notes. Did you mean the lugs are "lefty loosey"?
I:
1. Must have ADB-1560 because of the ventilated disc. So, the bushings are on order. $20

2. Read the 4M manual. It's very good.

3. Will purge the grease better, by going fully clockwise, then fully clockwise, then 3/4 turn, then check free stroke.

4. Will get a torque multiplier to remove Budd lugs. It's my first time working with the square lugs.

5. Will get some help when removing the wheels.

How difficult are lugs to get off assuming they are not rusty?

Left side are righty loosey, right side lefty loosey. In other words left hand threads on left side right hand threads on right side. Just incase you don't know remove the 1 1/2" socket size nuts before the 13/16 square. lugs or you will have a big problem.

Tim,unless your going to get one of those crank type torque multipliers,get an actual torque wrench,I bought a Snap-on multiplier
and it would not work on the recessed rear wheels.Good deals on torque wrenches are out there,I found a 3/4 inch Proto for $165
brand new,look for a metric it's much cheaper and has an sae scale.Have used this type for years,yes they all say to have it
calibrated yearly but if you only use it on your stuff it's fine,it's not going to get uncalibrated sitting in your coach,constant use
uncalibrates it and probably less then the calculation of how much you weigh and then stand on a breaker bar and cheater pipe.

I also have a 3/4 inch Proto Torque Wrench which should be backed off to 50 foot pounds for storage and set to 375 ft lbs only when torquing lubricated nuts. This will release pressure on the spring and retain torque settings. Because my 1996 has bud wheels which means torquing both right and left hand threads, I welded wings onto the small bolts holding the face plate on. This way I can easily remove the small bolts and turn the 3/4 square drive piece around to torque left hand wheel nuts.
I also bought a trucker wheel nut tool with 1.5 inch socket on one end and the square socket on the other. I use a solid bar and pipe with this tool to break the nuts free (rather then using the Proto).

Two things:

1. My bushings are worn in many places. All four calipers should be re-worked with new bushings and pins. Maybe a project for the fall. I may seek the help of a professional mechanic to do the work. Now that I have become familiar with the large amount of time necessary to grease the caliper, slack adjuster and slide pins, I realize that I may need help removing the calipers and replacing the bushings.

2. One bushing needs to be installed and two slide pins need to be cleaned, checked and lubricated. So, three tires neeId to be removed. I just purchased a modern torque multiplier lug wrench from Walmart of all places for $50. It should fit both 1.5 inch and 13/16 inch square lug nuts.

HomCom Heavy Duty Torque Multiplier Lugnut Remover Wrench - Walmart.com (https://www.walmart.com/ip/HomCom-Heavy-Duty-Torque-Multiplier-Lugnut-Remover-Wrench/167375711)

3. Can one tire be removed by one person without a dolly, or are two persons preferred?

Tim,
1. Once the tires are out of the way the parts come off in smaller pieces. No need to even try to pull the hole assembly in one piece.
2. You can either get a cheep little press or a 4# hammer to drive the old bushings out and the new ones in. You just need to have a driving tool the right size. Remember the bushings are different lengths so they have a proper place to be installed.
2.a I know some will argue that those torque multipliers aren't anything but junk. They are a lot better than an 6 or 8' cheeter to remove the lug nuts . That will work just fine on the duels just use a softener on the stop arm. When I don't have an impact gun I use one similar.
3. That depends on how much ump you have, but yes one person can handle the tire. Just lift the axle so the tire slightly off the ground and wiggle it off the studs. Once off just have a place to roll it so you can prop it up next to a wall.  A no name tire dolly and a piece of ply wood works great but not a must. 

The heaviest part of this brake work is removing the tires. You can always go get a high school football player to handle the tires for you.

Pamela & Mike

Tim I removed the front tire by myself but I only cleared the concrete about 1/2", so it was no problem to get back on.
On your torque multiplier, I would check it to see if it is giving you proper torque.  My torque multiplier looks like a  ratchet head and increases torque 4 times so I torques the nuts at 50 pounds with multiplier then checked with torque wrench and they checked out at 200 lb. but some say they will loose about 20% thats why I would test your walmart special
My final torque was 115 which should give me 460 lbs.  specs call for 450 lb.
chris

Tim,the shops that sell truck supplies have tire dollys,not too expensive.

There is a lot to learn about sevicing a critical system like your brakes.  And doing it on a specific coach means all of the time and labor saving processes and tools as well to make that job easier and more likely to get right.  Tim's "How To" video was posted before he asked for input from the Forum.  As it seems so common we are all learning a lot from the collective experience and knowledge right here on this great Forum.  Thanks!

These are the tools I found out about on the forum, except for the torque wrench which I already had.

tools to R&R wheels (http://www.foreforums.com/index.php?topic=31018.msg271508#msg271508)

Tim, thank you for publishing your video and starting this thread. This is one of the most valuable threads on this forum for me because I have studied the Meritor 4M manual but was never sure that I could lubricate the callipers properly. I have replaced pads and rotors on cars so know how disc brakes work.
I have removed tires on my coach and used a flat crow bar under the tire to lift the tire/rim and align holes with studs. I do not want to lift the tire/rim up from the ground so preplan a place to lean the tire before removal. I have done this to be sure that I am able to mount the spare tire/rim which I carry.

I plan on updating the video, based on the forum's comments so it can be of more value to planet Earth. The video is on my iPad Pro 12.9 G2 and iMovie, so it's easy do do the edits:

- Purge the grease properly: Turn the manual adjuster fully clockwise, then fully counterclockwise, then 3/4 turn, then check free stroke and adjusted chamber stroke
- How to use an Adel clamp and Vice Grips to clamp onto a slide pin to pull it out
- How to cage rear brakes
- How to replace bushings
- How to use one of these new fangled Torque Multipliers

Question: On one slide pin, there was one pit about 1/8 inch in diameter. Is this grounds for replacement? I coated the pin with WD40 dry lube containing Teflon, but I am dubious of it's claim to prevent corrosion.

Tim there is a threaded hole in the slide pin. Using a bolt and flat washer through a deep socket larger than the pin, pulls the pin out. I have a post on installing the helper springs, post below.

 Reply # 11 below.

helper springs (http://www.foreforums.com/index.php?topic=31008.msg271318#msg271318)

Tim,

Looking forward to the new revised version. With a little tweeking you will have a good video on basic brake maintance.

Mike

I will also add the following tips, with credit to craneman:
- Deep socket and screw to extract slide pin
- Helper springs