How to check master cylinder?
Thread Starter
Safety Car
Joined: Oct 2000
Posts: 4,286
Likes: 172
From: Lake Wylie, South Carolina
How to check master cylinder?
Well I have cleaned and disassembled the calipers, order the O-ring kit and cleaned and painted everything. Now I have switched my attention to the master cyylinder. It has been off the car in a box for about three years now and to my surprise there was no sludge in the cylinder. I cleaned the outside up and painted it cast color. It looks like new and may be since the front calipers were new. Is there anyway that I can check this off the car? I pushed the plunger in and there is a lot of force pushing through it. Any suggestions?
Pro
Joined: May 2003
Posts: 619
Likes: 0
From: winnipeg MB
Re: How to check master cylinder? (BlackRat)
Sorry i can't help you with that but i have a problem with my master cylinder. At times my brakes feel a little spongy this started late last year before i parked it for the winter, and i took the master cylinder off and the first plunger seems to be ok, orings are good. but i didnt try get the second one out. It does not leak any fluid. I can't imagine air getting in there and if it had, wouldnt it be spongy ALL the time, especially when i first start the car the brakes almost go to the floor. If I apply the brakes very slowly it also almost goes to the floor, but if i hit the brake normally as you would in traffic, it works fine. I'm baffled :confused:
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Re: How to check master cylinder? (bloodvette80)
Bloodvette.. You have the classic symptoms of a bad master cylinder. What happens is that the fluid pressure passes back into the reservoir instead of going toward the wheels. This condition will get worse. You need to rebuild it. Someday when you need your brakes... your pedal will go to the floor. Not good.
[Modified by bluevetteman, 5:25 PM 5/22/2003]
[Modified by bluevetteman, 5:25 PM 5/22/2003]
Pro
Joined: May 2003
Posts: 619
Likes: 0
From: winnipeg MB
Re: How to check master cylinder? (bluevetteman)
but i checked it and the lip seal on the piston is good and no burs on the cylinder. I agree that it's the master cylinder but how? I gotta find a problem before i can adress it. I left the brake lines intact and i removed the master from the brake booster, i then took out the C-ring and pulled out the piston. that piston is fine but i believe there is another piston beyond that. I rpedict that the problem resides there.Either way if fluid leaks passed the primary the secondary is catching it I knwo this becuase i never lose a drop of fluid and brakes go half way down but they still work as good as always. baffled :confused:
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Re: How to check master cylinder? (bloodvette80)
Yes there is another piston in the bore. You cannot look at a lip seal and tell if it is sealing every time under pressure. Just take the whole cylinder apart, Clean it with a non petrolium base cleaner like "brake Kleen", hone it and inspect very closely for even very minor pittiing. Repace the unit if there is ANY pitting. It it looks good buy a GOOD rebuild kit and rebuild it. It isn't that hard to do. I would not however BUY a rebuilt unit. New ones are not that expensive and rebuilts are pretty much junk. Don't trust them.
Instructor
Joined: May 2003
Posts: 200
Likes: 0
From: Honolulu Hawaii
Re: How to check master cylinder? (BlackRat)
i just removed and replace mine today ! i've always used rebuilt m/c on previous vehicles , one time deal , works great ! it sounds like bloodvette80 m/c has internal bleeding . needs to be r & r'd ! :thumbs:
