88 Master Cylinder Rebuild
 

greetings,

i have an 88 vette with the orig dual reservoir master cylinder. i acquired another one and have noticed that the piston does not sit all the way back at the end "when at rest". bench checking it, it also does not build pressure or even "pass" any brake fluid at the brake line connections when the piston is pushed in as if the brake rod was actually "in action".

1.....any ideas what is wrong with this master cylinder (other then it is
broken) (grin)?
2.....do i need to do a complete rebuild on it? ( i found some rebuild kit
costs run higher then what i could get a rebuilt one for).
3.....are there individual parts that can be replaced without buying a
complete rebuild kit?

.........thanks!

If you need one bite the bullet and buy a new one. This is not a part that you want to fool with rebuilts on. Trust a master tech w/ 30+ years experience on this one......

I bought a rebuilt MC from my local AC Delco dealer and all it needed was a tedious bench bleed before it worked.

I am curious as to what is wrong with a rebuild? You have a bore (metal) and a few cups (rubber) that do the actual wearing out. Put new cups in, if the bore is cool there is nothing wrong with a rebuild.
We are talking about a rubber surface against a metal surface. What do you think wears? I'd run a rebuild ANY day of the week if the bore had no issues. ANYDAY. Oops, I have a rebuild in one of my cars. :lol:

thanks for the reply. however, i have a good one but, am "looking" to have a spare. i have rebuilt trannies all day long in my day but, never a m.c. i know it can be done and was looking for info on parts,difficulty of job. first,at this point, i am curious as to why the piston is not seating back to its at rest position (spring?). then, the no fluid or pressure, then the disassembly and so on....

thank you for the reply. multiple times i "hit that plunger" and got nothing....no fluid dribbling out the line connection holes, no pressure, no nothing. was still looking for a place and possible costs to either pick up a rebuild kit (costs?) or individual parts.

i agree with that. i also believe that if the rebuild is done correctly, i should have no problems, besides, there is a learning value to doing it yourself.

When you pull it apart you will be amazed at how much there is to a rebuild. On a scale of 1-10, 1 being easy, I would say this rebuild to be about a 2.
I too look for just the cups and checked hi and low for them. I couldn't find anything and the "rebuild kits" are priced just as high as a rebuild.
If you find the cups needed would you let me know. I would say they are worth all of $3.

I'll sell you a good one for $75.00, shipped with satisfaction guaranteed

I bought a spare on E Bay and installed the DRM Spring in it. I installed it and now have my perfectly good MC on the shelf

Yes, the MC is simply a metal cylinder (bore) with rubber pistons, but dirty brake fluid will wear out the rubber pistons and the metal bore

The rebuilder cannot add metal to the bore. So if you get a rebuilt from a bore that wa perfect, you got a great deal...but if the core the rebuilder used had lots of scratches in the bore and they had to hone it out, then you may get a rebuilt that won't last long.

I buy some stuff in my local A......A....P, not much, only stuff that comes in a nationally branded bottle and I am amazzed at the people ahead of me coming back and back to return rebuilt parts that don't work.

True they will exchange the part, but they don't pay for the time it took to remove and replace the part...sometimes several times



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buydavette@aol.com

seeya