Awesome, let me know how it works out. The seal on the aluminium piston is it a lip seal or just an o ring? if it is an oring I can get solvent proof viton orings from work. Pictures would be good but good instructions are good too. Perhaps I will have to get someone to find a servicable unit at a junkyard and send it to me instead of buying a new one. As soon as you have tested your rebuilt one let us know because I may have time to pull and rebuild mine.

 

They were all O rings so far as I saw, but there were a couple of things I will look into after I pull the old one.

My bet it they are all O rings!

 

Did they appear to be standard sizes or did you have to hunt around for a match.

 

I only looked at F250's with the same or greater GVRW.
Mine is a
1991 F250 @ #8600GVW
and the one I got was
1994 F250 @ #8800GVRW

I think the difference between the various units would be changed with internal spring pressure.

Less money used on fewer casting designs.

 

Any update on this rebuild. Success or failure? I just got back to replacing all my brake pads and still got soft pedal so I think a new rabs is the next thing.

 

I'm running into problems with the sealing surface for the rear hubs, Phenolic pistons that are beat to hell and need to be found and replaced

I'll probably be a week before I get her going.

 

Your best bet would be to eliminate the RABS. It's an absolutely worthless setup, especially in slippery conditions.

 

I found the drivers side caliper, rusty as all get out, that had the bleeder fitting shredded and rusted into place.
The boot groove was buggered with rust as well so I need to replace it. .
They are only $13.50 at the local wrecker so if I find of them 2 with metal pistons, and they are not too bad, I'll get them.
If not, I'll either get a JJC machining student, or a local machinist to machine a set of 4 as they are not complicated.

I also found that one rotor was not machined for clearance so the inner surface of the outer bearing was scraping it and wore a nasty grove in it, so that will have to be ground out before reassembly.

The other rotor appears to have been overtightened as the inner race they was supposed to be pressed in was spinning easily by hand, the bearing cage had fractures all around it at the rollers and looked like they were way too close to falling apart.

 

Did you have any problems with the dot 5 in old parts that had dot 3 or 4? I have been around 5 for several years but was always under the notion that if a person switched to 5 all the parts had to replaced or resealed because of contamination. The fluids are very different and ugly things happen when mixed.


I changed my 94 over to the old brake system. I did find that "86" was the only year that had a big bore master cylinder that was in the old cast iron design. I did have to drill out the cylinder to bolt up to the booster. The mismatch may have been on purpose. The reason I changed mine was that I blew a front brake and I lost all my fluid. One thing about the old set up you will only the loose the front or back not all over one line.

 

I did once on another vehicle just flush the fluid before adding the silicone fluid.
The good wheel cylinders started leaking.
And after more reading I found that DOT3, DOT4, DOT5.1, (that's DOT five point one) are all non-silicon fluids and are NOT TO BE MIXED EVER WITH SILICON DOT5!

You get something like the vinegar and oil type of salad dressing where the oil and water separate.
Also, and this is a big one, the DOT5 will foam up if the RABS cycles so it can not be used with any ABS system.

The silicone debate!

Also, there is some debate as to silicone lasting a long time or needing to be changes more often than regular fluid as silicone will not absorb the water.
The issue is that the water will settle to the bottom of the fluid and will not float to the top to be flushed out with brake bleeding like air is.
Then the water starts to create rust that will be suspended in the silicone.

I used it before and believe that if it does not suck water from the air, it will not be drawn into the system and should be fine in non-ABS systems
Some say they have used it for 15 years and they seem to think it's fine.

But the new DOT5.1 can be used and is specifically designed for ABS systems.
Good luck finding some as I could not!
I went with DOT4 as it's maximum temp is close to the DOT5 and I will just have to flush it with new every 3 to 5 years.

So, I still have 3/4 of a gallon of the DOT5 in my garage.
Next time I do the Elantra GT non-ABS brakes I'll do a total overhaul use it.

Oh,
clear fluid is ok.
Golden fluid is slightly contaminated with water so that is when it should be changed (3 to 7 years depending on relative humidity and how often you open the system).
Brown fluid is badly contaminated fluid and corrosion could be an issue with the amount of water it is holding.
Black fluid (like mine was) is total crap and there should be corrosion issues in your system!

 

The military used 5 and hotrodders I know use it because it doesn't eat paint. I guess to be honest I think juice brakes and gas engines should be outlawed but who am I.

 

Air brakes are a whole lot less messy, can leak quite a lot never running out of air and the air will not bubble up your paint after contact!

 

I know this is an old thread but I read through it fellowed it carefully and took it apart as far as I could I haven't cleaned it up yet the poster above he says remove the piston with a pair of circlet pliers but I could not get it out because it was so stuck but when you take the guts out you can push it from the inside with the 5/16 Allen key that's how I got out and my piston was red obviously as you can see not blue part of the red is missing because I had to put on the bench grinder because it was so much cruel on it you just could not get it off but it still feels very smooth to the touch and now I'm going to clean it and put it back together here is the image of what I have for the members of this forum

 

When I say bench grinder I meant the brass wire wheel brush on my bench grinder I didn't grind the piston and if there are no mistakes and no punctuation it's because I'm dictating because my hands are covered in brake fluid I hope that works for you people thank you

 

If you know where this thread is, would you please post a link?