BRAKES

[big daddy]

Man what a day!Little by little ,I rebuilt the master cylinder a while back still no brakes! Never had an airpack apart much less knowing what one is ,but armed with a blow up diagram from one off of an M809 ( was hoping it was the same) took it all apart cleaned and unstuck (technical term) it. Today weather in the 60's ,drag boys outside let them pump while I bleed the wheel cylinders. I can't believe it, now the pedal goes down about 1 1/2 in. and is rock hard! I'm just starting out working on these trucks and it seems to get easier everyday! I can't believe how well built and designed these trucks are,to be over 40 years old and everything still unbolts without breaking(no bleeders broke or stuck) Man I can't wait to get it done and legal!

 

[Recovry4x4]

[No message]

 

[poppop]

[No message]

 

[big daddy]

[No message]

 

[DaveP]

any harm in mixing silicone and plain ole brake fluid ? from the evidence under the seat of the 5 ton i think its already been done i was just wondering what i was in for down the trail. a couple of cyls show signs ,so a complete rebuild is not far off. just wanted to wait till late fall if possible as i need this truck now.

 

[red devils dude]

I dont know why but you SHOULD NEVER MIX DOT3 AND DOT5(silicone brake fluid)

 

[rmgill]

DOT 3 and 4 are Glycol based fluids, DOT 5 is silicone based. Mixing them and then agitating them makes Mayonnaise. Just as mixing and agitating water and oil does (real mayonnaise being a mix of vegetable oil and egg plus other stuff for taste).

 

[cranetruck]

When you mix them in a glass jar you can observe the layers. Still works as a hydraulic fluid.
A little DOT3 mixed with the silicone based stuff may even be a benefit if water is present. The DOT3 will mix with the water and keep it from freezing. Water and silicone based brake fluid will not mix and water will collect in pckets and freeze.
I use DOT3 in my deuce. Costs less and has worked well for me for ten years.

 

[Recovry4x4]

When switching from DOT 3 to DOT 5 the military reccomended that no sovent flushing take place, simply remove all of the DOT 3 possible than purge the rest by thorough bleeding. TB 43-0002-87 explains the procedure. I think this is avialable on Logsa. I don't see any reason you couldn't do the same thing when going from DOT 5 to DOT 3. A simple test to see what you have is to take a small amount and put in a clear container. Add water, if it mixes, it's DOT 3. Either fluid will do the job just fine in my opinion and Cranetruck proves it. I've run DOT 5 for many years and he has run DOT 3 for as long or longer. Nice thing about DOT3 is its much cheaper and much more readily available. Heck, I can get DOT 3 from the grocery store!

 

[Gatnom]

First I'd like to say hello as this is my first post. I've lurked her for some time but never got around to registering, (just never thought I had that much to add!). This is a first class site. That said, I've read this topic with interest. I've considered changing the Dot5 in my duece to Dot3, but have had to many concerns to actually try it. There does not seem to be any info out there on going this direrection, only info on going from Dot3/4 to 5. The most serious issue seems to be confusion as to what reaction the rubber components that have been exposed to 5 fluid will have when exposed to the differnt base of the Dot3. Some say they will swell or shrink, (dry out) in excess requiring replacement of all ruber parts. Still others say no serious issues at all. Below I'm going to try placing a couple links to some conversion info. An internet search can turn up quite a bit, but just not enough to convince me one way or the other. I guess I could always soak some new cyl. cups in some Dot5 for a few months, then switch them into some Dot3 to see what happens!



[color=#800080>http://www.type2.com/library/brakes/dot5.htm</FONT>[/u]

<FONT color=#800080>http://www.imperialclub.com/Repair/Brakes/brakefluid.htm[/color]</U>[/url]

 

[Recovry4x4]

Welcome aboard and amongst the posters Dave. Everybody has something of value on this site. Great to have you!

 

[cranetruck]

Dave, couldn't help but notice that your handle spells montag backwards, which is German for Monday. What else does "gatnom" mean? Just curious...

 

[Gatnom]

Bjorn: I'm Impressed! It means exactly as you surmised. It is my last spelled backwards. I use it as a handle most places only because it is unusual enough to not have been used already, plus if someone stumbles upon it on another forum it stands out as someone they recognize. I should probably be using it on the auction sites as well, might keep us from bidding prices up against ourselves!

 

[big daddy]

I couldnt believe the price of the silicone so while I had the airpack apart when it all went back together I had to bleed the brakes anyway so I bought a gallon of the regular brake fluid. I just bled them out till I could see the color change ( old fluid ? ) They work fine so far and nothing is leaking yet ! I haven't had to add anymore brake fluid either ! Besides I want something in there thats readily obtainable ( like at the grocery store ).So far they still work great I'll post any bad effects.

 

[cranetruck]

Don't think we'll have any problems with the DOT3, the trucks were designed for it to begin with.

 

[MVtrucker]

I have several vehicles, some are older civvy, and it's not unusual for them to sit for long periods before I get around to taking them out for a spin. This inevitably led to wheel cylinder problems where DOT 3 was involved, so I converted them to DOT 5 and eliminated the problem.

 

[cranetruck]

Hi Joe,
What kind of wheel cylinder problems? Please, be more specific.
Thanks,

 

[DaveP]

is there a proper sequence to bleeding the brakes on the 5 ton . or is it like any thing else just start with the longest run ?

 

[MVtrucker]

Crane,
Rust! The pistons seize. I restored my MB in 1992-93 and put DOT 5 in. The Jeep sits in an unheated shed and I never have a brake problem. It's parked alongside my 1957 Cadillac Hardtop, one of my vehicles that I never got around to putting DOT 5 in. Every spring when I get it out, I have a wheel cylinder sticking. I plan on selling the Caddy and won't bother converting it.

 

[cranetruck]

It appears that the silicone type leaves some sort of residue, preventing rust from getting hold.
I feel that if my deuce is used without long periods of inactivity, the DOT3 will be just fine.
A lot of bearing surfaces may be attacked by rust if the vehicle is just stored and not used.
One of the best preventive maintenance measures is simply to drive it.