M35 brakes, ok to great

[Stretch44875]

Was driving the M108 the other day and noticed the brakes were getting soft. Did a hard braking stop and took way too long to stop. Knew the master cylinder was not returning all the way, causing some of the issue. I had rebuilt it, but it wasn't the best to start with. The airpack also was not the best, it had pitting in the main bore when it was rebuilt.

With the higher speed of a new overdrive gear, and 20,000lbs, it was time to fix it.

First thing was to adjust the brakes. For me this has been the #1 reason for a low pedal. Brakes had already been adjusted according to the TM before, so just a quick adjustment this time. Jacked up each wheel and turned the top adjustments until the brakes dragged, then backed them off a little. Pulled the axle shafts and hubs so the tire would spin freely.

Then replaced the airpack and master cylinder. Had a brand new master, and an airpack I had rebuilt from a good core.

A good bleeding job with a pressure bleeder finished the job. I use DOT 3.

The brakes already had rebuilt wheel cylinders, good shoes, all new rubber and steel lines. Bearings and seals also had been done.

Now I have a very high pedal, with nice feel to it. Still cannot lock the brakes, I would guess due the the heavier weight. On my M35, I can lock them up, and it has the same work done to it.

I did about 4 or 5 hard stops, one with me standing as hard as I could on the brakes. Truck stopped much better, and the pedal still felt good afterwards. It will throw you against the dash.

Feel much better about driving the truck now, since I'm going to be taking it on some long trips.

Dennis

 

[hndrsonj]

Are you going to make the GA rally this year with the M108 Stretch?

 

[Recovry4x4]

The bigger question is, will you be there Jim?

 

[clinto]

First thing was to adjust the brakes. For me this has been the #1 reason for a low pedal. Brakes had already been adjusted according to the TM before, so just a quick adjustment this time. Jacked up each wheel and turned the top adjustments until the brakes dragged, then backed them off a little. Pulled the axle shafts and hubs so the tire would spin freely.

I have never gotten the brakes "right" using the TM method. Doing the .010"/.020" adjustments as prescribed has always left me with a pedal lower than what it should be. I've done it the "right" way (only adjusting the top on what they call a "minor" adjustment) and "wrong" (resetting the lower anchor pins with used shoes) and neither has been optimal.

I do it the old fashioned way now; like what you describe. Jack it up, spin the wheel, adjust to drag, slightly release. Have never had an issue (hot drum/hub, etc.).

The brakes already had rebuilt wheel cylinders, good shoes, all new rubber and steel lines. Bearings and seals also had been done.

I assume you bent your own lines? I think in a couple of threads we went around and around looking for new preformed lines.

 

[HASSON1911]

brakes locking up

so after purchasing my first deuce a 1967 and shes in great condition. except one of the duels locked up on one side. she came home with the hub smoking so i gently poured water on her to cool her off. i have the shop manuels and they dont really have trouble shooting for this. so shes just sitting patiently waiting to get back on the road. a litle help please. p.s. her name is isabell and ill post pics soon.

 

[m16ty]

so after purchasing my first deuce a 1967 and shes in great condition. except one of the duels locked up on one side. she came home with the hub smoking so i gently poured water on her to cool her off. i have the shop manuels and they dont really have trouble shooting for this. so shes just sitting patiently waiting to get back on the road. a litle help please. p.s. her name is isabell and ill post pics soon.

Sounds like you have some oil on the brake shoes. Either from a leaking wheel cylinder, a leaking wheel seal, or both. That would explain the smoke also. You would think oil on a brake shoe would just cause it to slip but it doesn't. It causes it to grab. Could also have bearing problems. Only way to know what's going on is ti tear it down and take a look.