I bought a slave master cylinder from napa that lasted about 3 months before it started leaking. They wont take it back without a receipt,and my original is two pitted to rebuild. So I was thinking of rebuilding the one i got from napa. I noticed that the seals are one umbrella seal and one o ring seal. But the rebuild kits are two umbrella seals like the original. Will i be able to use the rebuild kit? Im assuming that it should work because the bore should be the same.. Or would I be better to find a original cylinder and rebuild it? Dan

88 5sp gt

I dont know about this rebuild but get in contact with ulhstan he has info on the use of an MR2 piston with a duel seal on them that works much better than the fiero piston inside the master cylinder.

Slave Cylinder

or

Master Cylinder?

The MR2 Piston is used in the SLAVE cylinder, not the master.

[This message has been edited by phonedawgz (edited 03-24-2010).]

This is the master. I allready changed my slave to a isuzu slave and did the mr2 rebuild (it works great).

quote Originally posted by phonedawgz: Slave Cylinder or Master Cylinder? The MR2 Piston is used in the SLAVE cylinder, not the master.

... Lol sorry i feel like an idiot. Yes the piston is used in the slave. As for the master i have never rebuilt one.

I was just looking at my origional master cylinder piston. Yes I have the two umbrella type seals on the piston also. So why can't you use the origional piston, with the new seals, in the replacement cylinder? If there is a difference you would also have to use the origional spring.

I guess I could do that --good idea

I've put a replacement master (Umbrella - O-Ring) and a rebuild slave (Honed - MR2 kit) together and if it gives me any more problems, the master will be getting a rebuild kit with two umbrella seals so it will be as close to OE as possible. BE WARNED! Two of the aftermarket masters that I have, have no hole in the cap to allow the diaphragm to work and may cause your slave to suck air! Take a 1/16 drill bit and drill a small hole in the center of the cap like the OE Master has. This may have been why I thought my slave needed rebuilding but when I got it apart it looked amlost new inside. Still swapped in the MR2 kit though!

[This message has been edited by Freshj (edited 03-25-2010).]

I just looked at the cap it has no hole in it..I wonder if that is why its blowing past the seal?

Just switch with your OE cap. You can remove the little white plastic cover from inside the aftermarket cap and it will snap into place on the OE one. I did this because I no longer had the OE rubber seal that goes under the cap and the new masters do not come with one. It snaps in but does not seal. It only keeps the fluid from squirting out the cap.

You need something there to keep the fluid from coming out the hole in the cap. At least I did.

I also have a 4speed/isuzu slave with MR2 piston on my getrag trans. 2 great mods in one! Clutch disengages at the mid point instead of the floor.

[This message has been edited by Fieroseverywhere (edited 03-25-2010).]

My replacement MC has a bayonet type cap and my origional? MC has a screw type cap.

You for sure want a diaphram type seal to keep the Brake Fluid from coming in contact with the air and absorbing the water from it.

My new aftermarket master also has the twist lock (not screw on) style cap that has a diaphragm, only needed a small hole in the top!