Brake master cylinder

[DavidT]

Hey guys!
I have a sinking pedal all of a sudden. Coming to a stop and the brake pedal just keeps sinking. I can pump the pedal to build pressure and then come to a safe stop.
I checked it on the highway. Without pumping, the pedal will bottom out, and a partial slowing down, and then the car pulls to the left.
Anyways,
1992 sho.
I don’t see any external leaks.
The reservoir is full.
The brake fluid reservoir also has what looks like a fuel line that runs to another component almost to the front bumper.
Is this normal? (Abs system?)
Any suggestions on which replacement master cylinder to go with ?
And any how to advice?
Thanks!!

 

[luigisho]

Master cylinder, air in line, fluid leak. I would do a fluid replacement and get the abs to cycle fluid and or any air that might be trapped in there. Could be master cylinder and you will have to do the same to get air of the system with fluid replacement. Not a daily driver right?

Yes there should be boxy looking thing where the brake fluid runs that is part of the abs. Fluid lines run out of that to the wheels.

 

[DavidT]

I replaced the brake fluid a couple years ago.
I did not touch the fluid in the abs at that time.
Yes it is a daily driver.
Thanks!

 

[zoomlater]

this post might help, sperold has issues with his gen 2. I would look for a leak somewhere before assuming its the master cylinder

Master Cylinders and Boosters.

Are there differences in the years 90 to 95 for these items. Would the master cylinder and booster for a Taurus with 4 wheel disc brakes and ABS be the same as the SHO? How about automatic and standard transmission SHOs? I was sure they would all be alike for all the years until I started...

shoforum.com

 

[DavidT]

Thank you for your help.
As it stands now, anytime I press the pedal, it will keep dropping until it bottoms out. I can pump it and build pressure, but once I just step on the pedal, it bottoms out.
With that said, do you think I should still look for leaks/air in the system?

 

[luigisho]

I would make sure there are not leaks visible before I did the MC. If you have a leak that is not mc then you will still be chasing it. I am inclined to bet money on mc seals but ruling out brake line connections and pliable rubber hose leaks near the calipers is probably a good idea. All this stuff is so old

 

[zoomlater]

Thank you for your help.
As it stands now, anytime I press the pedal, it will keep dropping until it bottoms out. I can pump it and build pressure, but once I just step on the pedal, it bottoms out.
With that said, do you think I should still look for leaks/air in the system?

read through this thread, Shodded mentions the brake booster as well. checking the brake lines/calipers, etc for leaks is easier before going on to replacing the MC

Help with why I keep getting sinking pedal

Hi, So I replaced all the lines on my 90 SHO, Silvia, I know I got air in the lines and I've been trying one man bleeding with the bottle hose set up and seem to have gotten the air out, but I keep getting sinking pedal, after pumping for a while it'll get hard and stop, but then when I turn on...

shoforum.com