Deuce brake question

Hi everyone.

VERY new here, interested in getting a duece. Right now I'm intel gathering (dreaming). I just have a simple question, in regards to the brakes, is there a safety upgrade to modernize? How does the brake system work and are they known to fail? A good friend informed me that prior to doing anything else it would be very smart to upgrade the braking system from the stock system. I've looked on the "safety" forum and didn't see anything regarding the duece' standard braking system.

Appreciate your time, I'm sure you will here from me alot more. I am in the process of selling my 52 Chevy to build funds to buy a duece.

if I'm outta line in this forum, I apologize in advance as I have never posted before.

USAF Retired, 10 years in a career field, no uniform, relaxed grooming standards. Desert Shield, Desert Storm.

I'm not sure about an upgrade. They have an air over hydraulic system. The master cylinder provides brake fluid pressure to the "hydrovac", which uses air pressure to add pressure to the brake fluid to push the wheel cylinders to apply the brake shoes. I am also new here and have not worked on a m35 for years. I would not do anything but have an extra hydrovac, wheel cylinder (or 2), master cylinder, brake fluid and someone to pump the brakes. Properly adjusted, to include the pedal free travel, this brake system is fine for what your probably going to use the truck for. my.

Thanks. I was concerned of a severe failure with a 2 1/2 ton vehicle going down the grapevine.

I'm sure you're familiar with the "truck escape ramps" on the Grapevine?

I don't know what the grapevine is, but I'm guessing it's a hill. If your not going to load it and you have commonsense, you shouldn't have trouble. I've driven loaded deuces thousands of miles in Germany, up and down hills. Most of the time the brakes will start to lock up and over heat if your going to have trouble...not just go out. Military vehicles are not like your car, you have to do your PMCS and be more aware.

Thanks. I'm sure common sense and PM is a must. I was just seeking some knowledge as.... Stupid is as stupid does.

Didn't mean to sound as though I was lecturing, just trying to pass on my experiences and answer your question. I think that if there is an upgrade for a deuce, and you thought it is important to spend that kind of dough, you would be better off buying a 900 series 5 ton that has full air brakes.

No worries, didn't even think for one second that you were lecturing. I was only concerned that I was told that the hydro brakes on a duece, if they failed you were screwed, and that the "upgrade" was a must. I was looking and didn't see anything regarding brake issues so instead of assuming, I thought I'd go here and get the poop.

The Safety issue with the brake system is that it is a single stage system, not dual. So if you have a brake leak somewhere and you loose pressure, you loose your brakes completely. In todays cars you have a dual stage system so if you have a leak in the front system and loose your brakes you still have the rears to stop you and vice versa.

There have been some guys that have added a dual circuit system where they added another master cylinder or air pack to have two separate systems. I am not familiar with these but they are posted on the site here. There is a TM that is posted under the Deuce TM's that is for a dual system.

You could always go with an A3 which I believe has the dual system but I always was more partial to the looks of the A2.

The single circuit brake system needs a systematic and routine inspection. In stock form they work pretty well. As long as you make certain that all of the lines are rust free and it has fresh hoses and wheel cylinders, the brakes will be very dependable.

X2 to what Recovry said but I will add that I read on this site that some have experienced failure of gov surplus hoses that are new. I went to a DOT certified hose place and had the originals duplicated for that reason.

Thanks.

I'm impressed with the braking capability of my Deuce...the only upgrade I would consider would be to install a dual-circuit system. I'm quite happy with the drum brake design on these trucks, I've pulled some good loads on my trailer with my Deuce pulling it, and I've had NO issues with braking whatsoever.

You could always adapt an exhaust brake to help on descents if you don't want to or can't install a dual-circuit braking system.

Trango sold me the treadle & air brake setup from a heavy truck a while ago, someday I'm going to pull those out when I have time & see what I can work up on one of my trucks...

To be clear, the deuce doesn't have "air over hydraulic" brake system. It has a "air assisted brake system". There is a big difference. In a true "air over hydraulic" system, if you loose air pressure, you loose all your brakes (M105 trailers are "air over hydraulic").

The air assist setup is really no different than most modern trucks in that aspect, it just uses air instead of vacuum or hyd from the PS pump to boost the brakes.