How to differentiate between Disc and Drum Master Cylinders?
 

I'm going to be going down to south jersey to pick up a GSL rear end for my car, and he has various master cylinders lying around, but dosent know which is from an -SE, which is GSL and which is drum rear.

so i'm getting the read and the d-shaft, and i'll need the master cylinder, but it's up to me to figure out which one i need for my application, or do i just need the proportioning valve... i dunno, help me out. Thanks.
-Kurt

Look at what you have under the hood right now if you have a drum rear....that's what you don't want. Rear calipers have more fluid volume than drum slave cylinders, so the master reservoirs should reflect that...:cool:

go to my site under the suspension swap in the how to section I beleive i have pics of both.

SevenSportcc

anyone else? i was not able to discern from the pictures.

They acctually appear the same. And the wheel cylinder in the drum brakes acctually require more fluid to operate than the calipers. That is why it is so imperitive that you swap in the master cylinder for the rear discs. If you dont's swap the M.C. you WILL have rear brake bias and that sucks, belive me I know!!!!

And to be on the safe side just buy a new master cylinder, they are very cheap as compaired to a citation for "failure to control to avoid an accident" and the possible civil repercussions ;)

Ryan

damnit, someone is telling me that there is a visible difference.

can anyone give me a decisive answer, one that will help?

*begs*

would i be able to put fluid into them and press the pushrod and have them squirt fluid out into 2 cups, and determine by the amount of fluid in each cup afterwards?

No visible difference, I did the swap parts look the same

Hit up the Auto-Zone website or something and see if the part numbers are the same.

I use www.carparts.com and www.auto-zone.com as reference and for average pricing a lot of the time.

EDIT: Yes they're different... Although at $41 with a $20 core, you cant go wrong wiht a new one.

the master cylanders are the same, the difference is the porportioning valve located next to the master cy. ..

so all i need is the prop valve? i can use my current master?

There are differences in both the prop valve and the master cylinder (check the parts list for GS and GSL cars and you will see 2 part numbers). You definately need the proportioning valve. I have been driving mine with the rear disk proportioning valve and the original drum master cylinder. Seems to be working fine. However, I am told that there is some type of check mechnaism in the drum master cylinder that is not in the disk master cylinder. I will take a look tonight (I have both) and see if I can tell any difference.

Yeah thats what I thought, even tho I have the same thing my drum brake car had on, and thats with the discs, I had no problems leaving the the drum one on :D

Dude... just get a new one. I just got one from autozone for 50 bux and it comes with a lifetime warranty. Can't beat that. Where as if you goto a junk yard you are going to get one that may or may not work to begin with or you are going to get one that's going to die in 6 months. Why spend the hour or so in labor only to do it again in 6 months.. Just get a new one and you'll never have to worry about it again.

yes, i'll get a new master, but i still need the correct prop valve, because i'm sure the $40 autozone master dosent come with one, and if it does, than thats a perfect deal.