Total Brake Failure on my Air over Hydraulic Tacoma

[BrianScott777]

My most prized possession, my 1971 M35A2 Deuce in pristine original condition has failed me. A bit off topic, my son threw a baseball shattering the drivers side windshield. So I spent the better part of the day replacing it, along with the wiper arm and wiper blade. The truck sat idle for more than 3 weeks while I was waiting for the replacement window. So after completing the repair, I proudly started her up and began to drive toward the main gate of the compound. Can you imagine my surprise when I tried to slow down and the brake pedal went straight down to the floor. Pump, Pump, Pump, and real aww shi# moment. I mean a really check your shorts event.

My question is what would cause a perfectly maintained, air over hydraulics Tacoma system to suddenly fail without warning. Foul play? I'm in good with the wife... Hmmm. I'm looking for any advise on what I can check, the most common reasons for a total and catastrophic failure. Thank you in advance as this is my first military vehicle.

 

[Jeepsinker]

My most prized possession, my 1971 M35A2 Deuce in pristine original condition has failed me. A bit off topic, my son threw a baseball shattering the drivers side windshield. So I spent the better part of the day replacing it, along with the wiper arm and wiper blade. The truck sat idle for more than 3 weeks while I was waiting for the replacement window. So after completing the repair, I proudly started her up and began to drive toward the main gate of the compound. Can you imagine my surprise when I tried to slow down and the brake pedal went straight down to the floor. Pump, Pump, Pump, and real aww shi# moment. I mean a really check your shorts event.

My question is what would cause a perfectly maintained, air over hydraulics Tacoma system to suddenly fail without warning. Foul play? I'm in good with the wife... Hmmm. I'm looking for any advise on what I can check, the most common reasons for a total and catastrophic failure. Thank you in advance as this is my first military vehicle.

You should have started your own thread or found a similar one on this subject. But you are new so I'll let it slide this time.
The first thing you should check is the fluid level in the master cylinder. It is under a small trap door in the floor in front of your driver seat. Has a vent line running to a square plug shaped screw on cap. Unscre the line, then the cap. The line is 7/16", the cap is 3/4". Fill it with DOT5 fluid ONLY, or you may destroy what is left of the brake system. Look under your truck at the backside of every wheel if you see any wetness at any one wheel you probably have a leaking wheel cylinder. That is almost certainly your problem. You need to check/ change all six of your wheel cylinders before you put that truck back on any roadway under its own power. You can kill someone with another one of those underwear filling moments. Wheel cylinders are available at napa for around$30 each.


Edit: And wtf is a Tacoma other than a cheaply built pickup truck? We call them brakes here...

 

[m16ty]

My question is what would cause a perfectly maintained, air over hydraulics Tacoma system to suddenly fail without warning. Foul play? I'm in good with the wife... Hmmm. I'm looking for any advise on what I can check, the most common reasons for a total and catastrophic failure. Thank you in advance as this is my first military vehicle.

It could be numerous things that have nothing to do with foul play. You pretty much need to check your whole brake system, from the wheels, to the master cylinder, to the airpack. Pretty much any part in a deuce brake system is a common reason for failure. They use a single circuit system that requires a lot of maintenance and pre-trip inspection to keep it operational and safe.

My best advice is to read up in the technical manual on the brake system. For starters I'd look for signs of fluid leaks under the truck. These trucks really require a full, detailed brake system inspection before you ever drive it on the road.

PS, I moved your post to it's own thread.

 

[gimpyrobb]

I'd start by putting some brake fluid in and bleeding the system. If you get good brakes, keep an eye on your fluid level. If not, its time to start pulling the hubs and seeing whats going on in there.

When was the last time you were in the hubs and looked at the brakes?

 

[doghead]

When did you last check your brake fluid?

You do know it uses dot 5, right?

Have you ever inspected your brake wheel cylinders, and serviced your wheel bearings?

You should always check the brake pedal BEFORE moving a truck.

Was your parking brake enough to stop safely? Is it adjusted and used always?

 

[Floridianson]

Hope you find the problem. If the peddle ever goes to the floor on me around the yard I pull the engine shut down before I even try to pump the peddel again.

 

[USAFSS-ColdWarrior]

Greetings, from San Angelo, Texas.

First off....

Welcome aboard

Find a bunk, stow your gear, and prepare to get underway

Ok, now for the meat of the matter....

Your location says that you are generally somewhere in the Great State of TEXAS. What city are you in or near? There is a possibility that other SS Members are near enough to you to provide some hands-on advice or assistance.

You've already gotten some worthy replies. et us know how it's going please.

 

[clinto]

What is the Tacoma connection? I'm confused. Have you installed a take-out brake system from a Toyota on your deuce? Is your deuce named Tacoma? Are you in Tacoma, Texas?

 

[drivebymashing]

Im curious on the tacoma deal too.

 

[clinto]

I think 1958_M274 figured it out.

He means "TACOM", like "Tank-automotive and Armaments Command".

His truck probably has a sticker like this:

 

[USAFSS-ColdWarrior]

I think 1958_M274 figured it out.

He means "TACOM", like "Tank-automotive and Armaments Command".

His truck probably has a sticker like this:

View attachment 539934

Thank you for decoding that for us all.

You must have been an expert at using your PF FLYER SECRET DECODER RING, weren't you?

 

[gimpyrobb]

Nah, he drinks a gallon of Schlitz and when he slurs his speech it sounds like tacoma!

 

[Jeepsinker]

Well it looks like I came off too harsh and scared him off anyway.

 

[ranchhopper]

I don't blame him for not replying back I wouldn't either.

 

[Jeepsinker]

I didn't mean to come off that mean looking back at my post. I feel bad about that. It's just that these things can be so dangerous without tip top brakes.

 

[gimpyrobb]

Your a meanie!

 

[73m819]

I didn't mean to come off that mean looking back at my post. I feel bad about that. It's just that these things can be so dangerous without tip top brakes, ect.

This is how a lot of the old time members feel, people buying a big MV, with NO idea of the care and feeding of what they have, it seems that it is getting WORSE, it is more like "I have a bigger pu then you", and get OFFENDED if told to read the TM, what should be done to PREVENT the same thing from happening again or what could have happened because of the issue. So Jeep, you are not the first or will you be the last to tell the truth there by offending a poster, all well.

 

[steelandcanvas]

Well it looks like I came off too harsh and scared him off anyway.

I don't think he ever saw your post (#2) in the thread, looks like he was gone a minute before you wrote it. It's interesting when folks will describe a brake problem and not even hang around, or come back within a hour or two to see if anyone responded. I just hope he does some research and becomes a lot more familiar with his truck.

 

[gimpyrobb]

I don't think he ever saw your post (#2) in the thread, looks like he was gone a minute before you wrote it. It's interesting when folks will describe a brake problem and not even hang around, or come back within a hour or two to see if anyone responded. I just hope he does some research and becomes a lot more familiar with his truck.

He seems fairly new. I bet he hasn't got "the addiction" yet, he is probably just a "recreational user". I bet he is off having fun for the weekend and will check back while bored at work.

Soon enough he will have 4 trucks, 10 trailers, and 4 gensets...

 

[Clay James]

Those situations can be scary. Had it happen on my 109 and it's something that has well maintained brakes. Luckily it was parked when the peddle went to the floor and it didn't move again until i fixed it.