Hello. Im baffled by my master cylinders way of performance. Heres the story. Many of you know my car has been sitting for years. No secret there. The problem im having is when bleeding the brake system, the front brakes are taking fluid from the small rear resevoir and not the front resevoir.
I took it off and cleaned the heck out of it. Came out almost new. I bench bled the master and had Zero bubbles remaining. Worked great. So i Re attached it to the car and started to bleed from the furthest point to the closest and keeping an eye on fluid levels in the master. After some time fluid was streeming from all bleeders and no air bubbles left in system. Perfect. Welll not exactly. Ive got the color of fluid to be right at all brakes but when bleeding the back brakes, it takes it from the small resevoir, great, well now when doing the front brakes, i noticed the rear small resevoir is depleating of brake fluid and not the big one in the front as it should be. So no matter what brake im bleeding, it only takes it from the rear resevoir in the master cylinder.
Whatis causing this to happen and how should I go about fixing it?
Seemed great when bench bled and getting fluids to the bleeders.
Any help or recomendations would be greatly appreciated. Thanks in advance.
Jesse

 

Hey Jesse,
My car was sitting around also 1971 since 87ish. I noticed My master cylinder reservoir were empty alittle.
I decided to buy a new AC/Delco master cylinder because it was leaking ever so slightly at the back of the master down onto the frame inside the engine compartment are you sure yours isn’t leaking?
Very strange that the front is taking from the rear.
I would just get a new master cylinder for the $50 bucks if you already did not,
because it might be shot and you don’t wanna loose brakes!

 

Hello johnny.
I just went an checked and the fluids in the master are at the exact same point they were lastweek when I filled em. Left about 1/4" ish to the top. I did notice after I applied the brake to make sure I had "A pedel" today, the main (bigger) side of the master is a little fuller then the last. Not sure if its back filling or im seeing things but all in all its mind boggling

 

First the obvious question: are you SURE the M/C is plumbed correctly?

Assuming yes, the problem is that the seals on the M/C internal piston are shot and you're getting internal leakage. Replace it.

 

Thanks Joe. All be looking into a new one to replace it. Much appreciated.