M135 Brake system question

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New member
Hallo all,
I heard a lot of historys about the brakes from a M135 truck.
I have one with no working brakes.
Many people tell me that its a hell to repair the brakes.
Is that correct ?All info to repair and what to do to fix the brakes is very welcome.
Thanks a lot


Well-known member
Steel Soldiers Supporter
Camp Wood/LC, TX
The GMCs are 69 years old now. You must replace or overhaul each component of the brake system. It is a lot of work, but not too challenging. The hard part is finding usable parts. Don’t use cylinders with pitting.


Easley SC
Well..... It depends on what you describe as too much work.

Each wheel has two brake cylinders.... so there is the finding and paying for double the wheel cylinders as a newer Deuce. Then there is the heavy work of pulling the old wheels and drums off. The brake shoes may be inundated in gear oil from the axle. That means finding new shoes and then resealing the axle.

Need to check the rubber brake lines for rottenness. Even it they look okay they might be mush on the inside and collapse when you use them. When that happens the pressure goes out to the wheel cylinders but can't come back so you get stuck wheel cylinders.

The Airpack if it is shot, rebuild kits for it are so old now the rubber parts may not be any good. Other airpacks used the same components so you will have to search for any kits or old rebuilt airpacks. I had to get three airpacks until I found enough parts to rebuild one.

The air system has to be up to par to boost the pressure.


Active member
Temple, NH

General comment on brake restoration on any truck. Making it run and move is fun, being able to make it stop is critical.

When I got in the MV hobby, to many moons ago, finding parts was relatively easier including brake parts, but after you have replace the same part every 5 years you start to look for better solutions. Brake cylinders are on of the parts seem to need replacing every 5 years or so. But there is a solution that lasts. If you have brake cylinders that are pitted but otherwise good have them sleeved.

My experience has been that this is a one and done solution. I have sleeved all the brake and master cylinders on all three of my MVs two of them are now 30+ years on the same cylinders, and the other is 20+ years with nothing having to be done to the cylinders. Now every 7-10 years I replace all the rubber parts, cups, boot, and lines and completely flush the system.

Only time I have seen any (two occasions) leakage was when rubber parts deteriorated, but this was small leakage, noted by fluid drop in the master cylinder not fluid running down a tire.

Hope this information helps. Good luck with your project. Always enjoyed driving M135 and M211 trucks.

Cheers Phil


Well-known member
Steel Soldiers Supporter
Edmonton, Canada
You're in Belgium and we have parts here across the pond. What do you need and how do we get them there?

When shiny parts show up it makes brake repair simple.


What truck do you have? Do you have pictures? We're trying to track what we can here ........https://www.steelsoldiers.com/threads/g749-vin-military-registration-database.134364/

The CDN trucks ....generally... ran with a bigger Wheel Cylinder and the American trucks were ....generally....1 1/4".

Check that E-brake drum for cracks first. Detonation can occur.

The air-pak loves maintenance so if the truck sat it will ...generally... be gummed up.

It's easier when the box is off but inspecting the rubber lines that run over the axle back to the air-pak is where we find damage. The rubber sits in a trough and can hold moisture.

I'm certainly not a mechanic so while learning under the watch of a mechanic, the M135 was a forgiving truck to do brake repairs on.
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