Need brake adjustment help

[poppop]

I need to know how to do the major brake adjustment on my M54 dump. I have a paper copy of TM 9-2320-260-34 and it refers me to TM 9-2320-260-20. I do not have that one, but I found it on site but it will not down-load to my computer. Can someone give me a quick run-thru. I have adjusted brakes on large trucks before. I have looked at these and am not quite sure what I see. Looks like two large bolts at the bottom of the brake assemlly. Are these cam bolts and does each one adjust one shoe???? If so then tighten until drag is felt and back off a little, or tighten until wheel won't move and then back off until slight drag is felt???

 

[doghead]

Lloyd, did you try to right click on the TM and save it to your computer. Then open it on your own computer. This usually works faster than opening it by just clicking on it on the SS site.

 

[poppop]

Thanks doghead, I will give that a try, but they usually open without doing that.

 

[Scrounger]

There are a couple of ways to adjust the brakes on this 5 ton. First off the each shoe is adjusted separately by turning the bottom mounting bolt.
Always check the level of the brake fluid in the master cylinder just to make sure it is full.
I always spray some penetrating oil on the lock nuts that hold the adjusting studs in place then check the brake fluid.
The quick down and dirty way to adjust the brakes is to raise the wheel that is to be adjusted off the ground, loosen the two locknuts and use a crescent wrench to rotate the adjustment stud of each shoe till it prevents the wheel from turning. Then back off till it doesn’t drag on the drum. Then retighten the locknut. Repeat for the remaining wheels.
Now the book method is to remove the wheels so the access cover on the drum is available, remove cover. Loosen the locknut and rotate the adjustment stud as above and adjust the brakes so the clearance is .010” at 10 o’clock and 2” o’clock, .020” at 8 o’clock and 4 o’clock. The last way allows one to check the linings for wear.

 

[poppop]

Thanks Scrounger, thats just what I needed.

 

[poppop]

Worked on the brakes today. All the adjusters are frozen solid. Tried heat on a couple, just heating the outside and not the bolt itself. No luck yet . Will it be detrimental to heat the bolt itself??? Another problem seems to be that the master cylinder piston is no returning to the home position. I think I rebuilt it when I got the truck. Thought the push rod might need adjusting but when I lenghtened it the pedal now bottoms out about two inches from the floor. I know the shoes help push the piston back with fluid pressure but I think the spring should pust the cup back. Tried bleeding the system, but since the piston will not return to home, no recharge of fluid. My next move is remove the master and check it out. Any thoughts from anyone out there????

 

[Scrounger]

"All the adjusters are frozen solid."
Are you referring to the locknuts or the adjusting studs? If it is the locknut I find that they usually require some find of penetrating oil to loosen them. And I cheat; I use a six point impact socket with a ½’ air gun. If it is the stud, I’ve never had them freeze up. After removal of the locknut more lube and a long wrench should free them up.
As far as the master cylinder that my require removal from the truck to make sure there isn’t something hanging up somewhere.

 

[poppop]

All the nuts came off with no problem. I can't get a wench into the space very well to get a good bite on the flats on the studs. I took a half inch wrench and bent it to fit and with a pipe on the wrench spread the jaws of the wrench. I built a wrench out of heavy flat stock with a large nut welded on for a wrench to fit. It just ate into the soft steel and rounded out the hole. I then put two nuts on each stud and locked theme together but they will not hold enough to turn the adjuster. If we remove the wheels and drum is there a head on the inside for a wrench??? The master cylinder is in the vise as we speak. I came home to read the book about it. There is a quarter inch hole in the bottom for fluid to inter the chamber. About one inch forward of that is a smaller hole that does not go all the way through, is it supposed to???

 

[poppop]

Tonights installment. I honed the master cylinder because it was a little corroaded. Reinstalled the cup and the aluminim piston and cup and it still hung up and would not return to home. I used some sandpaper to hone down the aluminium piston for a better fit. Reinstalled it and with liberal amounts of brake fluid for lube finally got it working fairly smoothly. Reinstalled master on truck and it will not pump. Tried for two hours to bleed system and cannot get it to pump much at all. I know with a power bleeder I can force fluid thru and bleed, but I don't have one. Anyone got any suggestions????

 

[poppop]

BRAKES FIXED. After much thought last night I decided the small hole in the master cylinder needed to go all the way through. Removed Master and drilled hole, reinstalled and brakes work great. I think this is why the air-pac was removed when I got the truck. The master cylinder looked new. I think it was installed and the brakes still would not work so they pulled the air-pac, then decided to send the truck to DRMO.

 

[poppop]

OK, just in case someone is following this I have learned more today. I saved a couple of sad dueces from the torch this week, but thats another story. They have been sitting a long time, at least 15 years, and I pulled both master cylinders today. Apparently that one hole is not supposed to be drilled all the way thru. It is almost with just a pin hole into the bore. I think this is supposed to limit the backflow of fluid when you releace the brake pedal. But by being so small it can stop up very easily. If it is stopped up the main cylinder will not charge with fluid. I have now driven the dump truck and the brakes work fantastic. I see no problem with inlargeing that hole. With the larger hole it took no time to pump up the brakes and with no further bleeding I have a full petal and can lock the wheels with one push on the petal.

 

[redass73]

glad you got them fixed..

 

[bchauvette]

could point to thebrake adjustment TM for aM944a1 with page number?(sameas a M923a1but extra long chassis thanks in advance
Butch.

 

[simp5782]

could point to thebrake adjustment TM for aM944a1 with page number?(sameas a M923a1but extra long chassis thanks in advance
Butch.

They are auto adjusting unless they are the wedges are froze up. You can pop the lil access cover on the backing plate and move them by hand but they should auto adjust. You may need to cage the spring can. Pull it off. Then remove the tube to the wheel. Then pull out the spring and wedge. Clean and lube it up good. You also need to make sure that the air brake on that wheel is working properly.

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