Strange brake problems - about to sell the P.O.S.
 

Need brake help – so far I have replaced the master cylinder 3 times and the combo valve once but still have the same problem. After just a few weeks the master cylinder “O”rings go bad eaten up by something.

What else could be killing my brakes.

Re: Strange brake problems - about to sell the P.O.S.
 

Replaced the master cyl 3x from different suppliers or the same supplier?
Type of fluid?

Re: Strange brake problems - about to sell the P.O.S.
 

from Kragen - the first one was new ( not remaned ) the next 2 where remaned and 2 where different the fluid was type 3 or 5 cant remember.

Re: Strange brake problems - about to sell the P.O.S.
 

I like using Raybestos or Wagner master cylinders. Is Kragens their 'name' stuff or possibly one of those?

I know some fluids require spec'd seals & such. Verify what fluid your using.

Re: Strange brake problems - about to sell the P.O.S.
 

Sounds like you're using Dot 5 fluid. That stuff is not compatible with some seals and will eat them up over time.

Just use Dot 3. It's non-synthetic and it's a lot more forgiving.

Re: Strange brake problems - about to sell the P.O.S.
 

been beat up a few times with DOT 4 or5 I use Dot 3 only. The bad experiences I have had with DOT 5 is a mushy pedal, but after getting the brakes hot the pedal comes back.

Re: Strange brake problems - about to sell the P.O.S.
 

using dot 3 - going to rebead with new master and see

Re: Strange brake problems - about to sell the P.O.S.
 

I had similar problems awhile back. the DOT 4 & 5 stuff will eat up alot of rubber seals and hoses if they are not compatible. especially in these older vehicles that still have parts that were made berfore these types of brake fluids existed.

also some of these fluids are not compatible together. If you change types of fluids without completely flushing the system, air bubbles will form and stay suspended. this causes the mushy pedal.

If you are unsure, I would flush the system completely and refill with new DOT 3. stay away from synthetic too, unless you upgrade to a system that requires it.

Re: Strange brake problems - about to sell the P.O.S.
 

ive never heard of anyone useing something other than dot3 for these brakes