Dragging brakes on M35A2

[DirTDel]

I’ve got a couple of M35’s that I use in my water well contracting business. One has an air compressor on it. The one I’m having the brake problem with has a cable tool drill rig mounted on it.

It was surplused from my fire Dept and I bought it thru the GSA auctions about 4-5 years ago. Used it occasionally with a 1,000 gallon water tank in it. Last summer I pulled the military bed off it and mounted the drill rig. Took it out on a job 30 miles away and back again no problems.

in December, I took it out on another job and the brakes started dragging. They weren’t fully releasing after application. Brought it back to the shop yesterday. Same problem. If I stop completely, shut the engine off and apply & release the brakes multiple times, they seem to release again. But if I apply them, while slowing for a turn, they would not release unless I completely stop and apply and release them with the engine off.

im assuming it’s the master cylinder and/or air pack. Any advice?

 

[sandcobra164]

How much free play do you have in the brake pedal? With the truck running or just air pressure built up, remove the master cylinder cap and apply and release the brakes. You should be able to see fluid drop slightly when applying and rising upon releasing. What I found on a friends truck is he adjusted the free play too "tight" on the linkage to the master cylinder and it would do the same thing after a few stops. Another issue could be a broken or missing return spring on the linkage. It the master cylinder does not return to "release completely" for whatever reason, the air pack and the rest of the system will stay applied to some degree.

 

[73m819]

This could be a air pack issue,

 

[DirTDel]

I’ve has this truck 4-5 years. Never had to do any work on it. As I remember the brake pedal used to go about half way to the floor to apply the brakes. Now I have maybe an inch or two pedal travel.

 

[gringeltaube]

https://www.steelsoldiers.com/showthread.php?51530-Deuce-Brakes-Locked-Up; posts #12 and #18

 

[gimpyrobb]

SOunds like the air-pack issue I had.

 

[doghead]

Take the plug out of the back of the booster and see if there is air pressure(with your finger over it) with it running.

If there is, you need to repair your booster.

You know, the plug you lubricate it through, for maintenance.

 

[rustystud]

Take the plug out of the back of the booster and see if there is air pressure(with your finger over it) with it running.

If there is, you need to repair your booster.

You know, the plug you lubricate it through, for maintenance.

Just to clarify for you, he means the engine running with "NO" brake applied. There should be no air at this time. If there is air present then the "air control valve" is not working correctly. Could be gummed up.

 

[DirTDel]

Thanks guys. I searched but didn’t find the thread mentioned. I got the tech manuals with the truck, but don’t really help with troubleshooting.

 

[TMNT]

Mine has been sitting for more than a year now, for the same issue. I maintain my truck pretty well but I had no idea that the air pack required periodic lubrication. The good news is that I’m motivated to get out there and fix it as soon as the weather improves a bit. Thanks.


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[gimpyrobb]

Mine has been sitting for more than a year now, for the same issue. I maintain my truck pretty well but I had no idea that the air pack required periodic lubrication. The good news is that I’m motivated to get out there and fix it as soon as the weather improves a bit. Thanks.


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With this issue, lube will not help for long. Its time to rebuild/replace.

 

[rustystud]

Thanks guys. I searched but didn’t find the thread mentioned. I got the tech manuals with the truck, but don’t really help with troubleshooting.

Did you pull the plug like Doghead mentioned ? It is a square head pipe plug in the very back of the "air-pack" (booster) .


The plug is on the left side.

 

[gimpyrobb]

Thats only if its the long air pack. They arent on the short ones.

 

[Big Tom]

Just some problems I've seen , pull the rubber boot back on the master cylinder, u should see the piston all the way back against the snap ring if not your pushrod is to long or Rust on dirt is keeping it from comming back. Witch will block return hole. Also like some said take top off fluid should move down and back up the return hole could be clogged up not letting fluid back , which will keep brakes applied . If either is Wong get rebuild kit not a hard job .
Big Tom

 

[rustystud]

Thats only if its the long air pack. They arent on the short ones.

That's true. You need to pull the tube off on them.

 

[Aussie Bloke]

G'day everyone,...


And you would lube them with a small squirt of air tool oil, yes?



Aussie.

 

[gimpyrobb]

Yup

 

[rustystud]

G'day everyone,...


And you would lube them with a small squirt of air tool oil, yes?



Aussie.

The actual oil the military wants you to use costs $50.00 a gallon. It's a RAPCO brand. Cannot remember the number off the top of my head. So just use a good light weight oil like Gimpyrobb said.