leaking master cylinder
Thread Starter
Racer
Joined: Dec 2013
Posts: 298
Likes: 16
leaking master cylinder
i bought a new reproduction dual chamber brake master cylinder for my 67 some time ago - but just getting it all together now
i am having trouble getting the pedal to be firm, and I have bled the system a dozen times
i keep finding the bottom of the master cylinder is wet with brake fluid. I thought it was coming from the rear line, and when tightening that line did not help, i bought a new line and replaced it. despite some meticulous efforts at cleaning the master, and re-checking and tightening the lines and bleeder valves, the bottom of the master is always wet with brake fluid after a few presses of the brake pedal. it takes hours for the full effect to appear, so i cant see where the leak is coming from.
the top of the master, around the lid, is dry. this fluid must be coming from one of the fittings or perhaps from a crack in the casting
has anyone else ever seen this?
once i had a similar problem with a steering control valve - it turned out the seat for one of the hoses was damaged and would not seal
i am ready to throw the whole thing in the garbage. i guess i may just buy a new master cylinder
justin
i am having trouble getting the pedal to be firm, and I have bled the system a dozen times
i keep finding the bottom of the master cylinder is wet with brake fluid. I thought it was coming from the rear line, and when tightening that line did not help, i bought a new line and replaced it. despite some meticulous efforts at cleaning the master, and re-checking and tightening the lines and bleeder valves, the bottom of the master is always wet with brake fluid after a few presses of the brake pedal. it takes hours for the full effect to appear, so i cant see where the leak is coming from.
the top of the master, around the lid, is dry. this fluid must be coming from one of the fittings or perhaps from a crack in the casting
has anyone else ever seen this?
once i had a similar problem with a steering control valve - it turned out the seat for one of the hoses was damaged and would not seal
i am ready to throw the whole thing in the garbage. i guess i may just buy a new master cylinder
justin
Melting Slicks
Joined: Apr 2015
Posts: 3,089
Likes: 1,131
From: NEW YORK
i bought a new reproduction dual chamber brake master cylinder for my 67 some time ago - but just getting it all together now
i am having trouble getting the pedal to be firm, and I have bled the system a dozen times
i keep finding the bottom of the master cylinder is wet with brake fluid. I thought it was coming from the rear line, and when tightening that line did not help, i bought a new line and replaced it. despite some meticulous efforts at cleaning the master, and re-checking and tightening the lines and bleeder valves, the bottom of the master is always wet with brake fluid after a few presses of the brake pedal. it takes hours for the full effect to appear, so i cant see where the leak is coming from.
the top of the master, around the lid, is dry. this fluid must be coming from one of the fittings or perhaps from a crack in the casting
has anyone else ever seen this?
once i had a similar problem with a steering control valve - it turned out the seat for one of the hoses was damaged and would not seal
i am ready to throw the whole thing in the garbage. i guess i may just buy a new master cylinder
justin
i am having trouble getting the pedal to be firm, and I have bled the system a dozen times
i keep finding the bottom of the master cylinder is wet with brake fluid. I thought it was coming from the rear line, and when tightening that line did not help, i bought a new line and replaced it. despite some meticulous efforts at cleaning the master, and re-checking and tightening the lines and bleeder valves, the bottom of the master is always wet with brake fluid after a few presses of the brake pedal. it takes hours for the full effect to appear, so i cant see where the leak is coming from.
the top of the master, around the lid, is dry. this fluid must be coming from one of the fittings or perhaps from a crack in the casting
has anyone else ever seen this?
once i had a similar problem with a steering control valve - it turned out the seat for one of the hoses was damaged and would not seal
i am ready to throw the whole thing in the garbage. i guess i may just buy a new master cylinder
justin
Heel & Toe
Joined: Oct 2015
Posts: 23
Likes: 4
From: Seattle Washington
Yes, I had this exact problem. After a careful look I found a void in the casting on the back of the MC which allowed fluid to leak out and make things wet but didn't affect the operation. I replaced it...
Mike
Mike
Thread Starter
Racer
Joined: Dec 2013
Posts: 298
Likes: 16
I installed a new repro master cylinder. I am still frustrated by slight leaks by both of the bleeder valves on the master itself, but hopefully if I keep tightening, eventually that will stop
I drove the car after extensive bleeding. The brakes seem to work, but the pedal travel is long. Maybe the air is all out? It feels to me like the bore in the master cylinder is too small, and it requires too much pedal travel to work. If I really stand on it, the brakes do seem to work, although it was only a neighborhood drive. I guess the next step is to see if I can lock up the brakes.
Or maybe something is still wrong? it is a manual brake setup.
I drove the car after extensive bleeding. The brakes seem to work, but the pedal travel is long. Maybe the air is all out? It feels to me like the bore in the master cylinder is too small, and it requires too much pedal travel to work. If I really stand on it, the brakes do seem to work, although it was only a neighborhood drive. I guess the next step is to see if I can lock up the brakes.
Or maybe something is still wrong? it is a manual brake setup.
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
I installed a new repro master cylinder. I am still frustrated by slight leaks by both of the bleeder valves on the master itself, but hopefully if I keep tightening, eventually that will stop
I drove the car after extensive bleeding. The brakes seem to work, but the pedal travel is long. Maybe the air is all out? It feels to me like the bore in the master cylinder is too small, and it requires too much pedal travel to work. If I really stand on it, the brakes do seem to work, although it was only a neighborhood drive. I guess the next step is to see if I can lock up the brakes.
Or maybe something is still wrong? it is a manual brake setup.
I drove the car after extensive bleeding. The brakes seem to work, but the pedal travel is long. Maybe the air is all out? It feels to me like the bore in the master cylinder is too small, and it requires too much pedal travel to work. If I really stand on it, the brakes do seem to work, although it was only a neighborhood drive. I guess the next step is to see if I can lock up the brakes.
Or maybe something is still wrong? it is a manual brake setup.
