Help, lost Brakes today.

[tklm539]

Hello all,

Its been a while, I have been putting my deuce to a lot of work this summer. Bomb loader has been a great addition for moving rocks and logs out of the woods. Today, about 35 miles from home, I lost all brake pressure. I was able to gear down and limp to a salvage yard nearby that had a garage. As it turns out the owner formerly had two m35 gassers from the Air Force. His first remark was that my master cylinder was dry. He loaned me a set of tools and after some messing around, the cap came off and sure enough dry as a bone.

Only DOT3 was available. I figured that it could not be too bad and I had to get the truck home. The brakes seem to work better than they have since I got the truck in the spring. Now for the question. How bad have I messed things up? Is DOT3 ok in a pinch though not spec. or have I just created a chemical nightmare in my brake lines.

Thanks in advance and have a relaxing labor day.

Tom

 

[Recovry4x4]

Decide what fluid you want to use and do a thorough (very thorough) flush with that fluid and you should be fine. Also add checking brake fluid level to your pretrip inspections.

 

[tklm539]

Thanks Kenny,

Glad to hear that I did not screw it up to bad.

Tom

 

[cranetruck]

I have used DOT 3 for ten years without a problem.
Mix them in a jar and study the effect, shouldn't be a problem, though.

 

[emmado22]

Sounds like time to a complete PMCS on the truck....

 

[jasonjc]

maybe time to rebuild the wheel cyclinders??????

 

[clinto]

Make sure to flush it good-someone was saying here the other day that when the mil did the swap from DOT3 to DOT5, they issued a bulletin or an artivle in PM mag about proper flush technique-do a search, it is pretty recent.

Find out where it's going and bleed it good-Kenny can help you with bleeding ops.

 

[tklm539]

Thanks,

No luck yet finding the article. I did find Kenny's homemade bleeder post.

Is it possible to simply open the lines at the wheels and press the fluid out with brake pressure. Obviously adding dot3 along the way to keep the mc under pressure.

Thanks

Tom

 

[DDoyle]

The military emphasized a thorough flush because any DOT 3 in the system negated the "benefit" of DOT5 (anti-moisture absorbtion). ALL the tests done by the military on silicone brake fluid indicated that there was no problem from mixing DOT3 and DOT5 other than the mixture would absorb moisture, just as DOT3 does.

I had a notable chemical lab perform a number of tests on DOT5 and DOT3 and the mix a few years ago - and they verified the goverment report - all of this info is included in an article I did on brake fluid a few years ago. However, I have talked to people who say in their experience the two products do not mix well (I don't think this was in MVs). What the cause of this is (contamination, or system specific components) I do not know.

HTH,
David Doyle

 

[nattieleather]

You need to find out why you had no brake fluid.....I think that is the bigger problem than which fluid you have. I'm thinking you might have a small leak and over time and use you've bled the system dry. Time to take a good look at your brakes and fix any problems.

Then once you've got the system fixed flush it and refill with the fluid of choice. I have seen silicone DOT 5 get jelly like when mixed with DOT 3....Might be because of the different manufactures who knows, but I've seen it.

 

[papercu]

brakes

Sounds as if it lost fluid in hurry, here is one thing to check. FYI If you use your truck regular there is no need to use the DOT 5. Wayne

 

[papercu]

brakes

The conversion manual is TB 43-0002-87. Here is a copy. Wayne

 

[Rattlehead]

While you are fixing your leak(s), be sure to check all your flexible brake lines for signs of cracking, etc. There are 4 total (2 for the front axle). They are cheap, and one of them letting go with no warning will put you in the same situation.

 

[Recovry4x4]

Excellent point Rattlehead but don't forget that 5th line running from the frame under the engine to the front axle.

 

[Rattlehead]

Oops! Its been about 4 years since I went through my brakes, should know better than to try and go off memory when I barely remember what I had for dinner yesterday!

 

[Recovry4x4]

LOL, no worries!

 

[Latrine_Commander]

You should always carry a quart of extra brake fluid for just such cases. And always carry the basics of tools in the tool bag. Such as a slotted and phillips screw driver, adjustable wrench (cresent), pliers, and a tool roll of combination wrenches. Even the harbor freight type tools are a blessing when you have nothing.

John

 

[m-35tom]

right, people who are not going to inspect, repair and have safe brakes should add a 1 gallon remote res. at least it will take longer to leak out..............

 

[jasonjc]

Here are some pic's of my wheel cylinders I just replaced. The brakes were working fine , a few were leaking a little.

 

[houdel]

Here is the brake bleed process from the TB for converting from DOT-3 to DOT-5. You are doing the just the opposite but the process is the same. Pay particular attention to the note about the sequence of bleeding - Master cylinder first (if it has a bleed screw), then air-hydraulic unit, then wheel cylinders, starting with the one FURTHEST from the master cylinder, then the next furthest etc.

It is important to bleed the wheel cylinders furthest first and closest last. This does the best job of removing air and contaminants from the brake lines and reduces the possibility of cross recontamination.