Weird Brake Problem
Thread Starter
Racer
Joined: Mar 2004
Posts: 305
Likes: 0
From: Houston Texas
Weird Brake Problem
This is a very unusual problem, but it has me stomped.
I have a 1985 Coupe.
It seems that my brake master cylinder was going out. The brake pedal would travel to the floor, with no braking power at all.
I tried bleeding the brake system, no pedal difference.
I even had my wife push down on the brake pedal, while I watched the fluid in the master cylinder. The fluid never moved.
My brake discs are in good shape.
A few days earlier, I did back the car several feet with the parking brake on. (Don't know if this makes a difference.)
I let the car set for a week. I replaced the fuel sending unit and fuel pump. When I finished, I started the car. I pushed on the brake pedal, (force of habit). The brake pedal is now hard, instead of going to the floor. I NOW have brakes.
Is my master cylinder on its way out?
I am afraid to drive it now, because until I know why the brakes acted the way they did, I can't be sure that they won't go out again.
This is my 1st vette. Is there something about vettes that would make this situation make sense???
I have a 1985 Coupe.
It seems that my brake master cylinder was going out. The brake pedal would travel to the floor, with no braking power at all.
I tried bleeding the brake system, no pedal difference.
I even had my wife push down on the brake pedal, while I watched the fluid in the master cylinder. The fluid never moved.
My brake discs are in good shape.
A few days earlier, I did back the car several feet with the parking brake on. (Don't know if this makes a difference.)
I let the car set for a week. I replaced the fuel sending unit and fuel pump. When I finished, I started the car. I pushed on the brake pedal, (force of habit). The brake pedal is now hard, instead of going to the floor. I NOW have brakes.
Is my master cylinder on its way out?
I am afraid to drive it now, because until I know why the brakes acted the way they did, I can't be sure that they won't go out again.
This is my 1st vette. Is there something about vettes that would make this situation make sense???
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Replace your master cylinder ASAP. It'll work some times, and sometimes it won't.
Which means...
sometimes you'll come to a stop, and sometimes you'll plow into the back of a garbage truck at 30 mph.
The inner surfaces of the cylinder corrode, and under certain pressures and at certain pedal travel, the fluid will slip past the piston oring.
When this happened to me, I ordered a new one from Ecklers ($120) and had it overnighted. That's the only time I've ever ordered overnight shipping in my life... the vette is my daily driver.
ALSO, buy a metric set of flare nut wrenches.
Which means...
sometimes you'll come to a stop, and sometimes you'll plow into the back of a garbage truck at 30 mph.
The inner surfaces of the cylinder corrode, and under certain pressures and at certain pedal travel, the fluid will slip past the piston oring.
When this happened to me, I ordered a new one from Ecklers ($120) and had it overnighted. That's the only time I've ever ordered overnight shipping in my life... the vette is my daily driver.
ALSO, buy a metric set of flare nut wrenches.
Burning Brakes
Joined: Jul 2004
Posts: 956
Likes: 0
From: Mesquite Nevada
Could be your master cylinder or one of your calipars. A few years back I had a very similar problem, turned out to be a calipar. To eliminate them as a possibility, inspect them for leaks. Also look at your tires to see if you streaks on the inside sidewalls (starting from the wheel out). If you don't find a leaky calipar, then most likely it's your master cylinder.
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by CentralCoaster
Replace your master cylinder ASAP. It'll work some times, and sometimes it won't.
Which means...
sometimes you'll come to a stop, and sometimes you'll plow into the back of a garbage truck at 30 mph.
The inner surfaces of the cylinder corrode, and under certain pressures and at certain pedal travel, the fluid will slip past the piston oring.
When this happened to me, I ordered a new one from Ecklers ($120) and had it overnighted. That's the only time I've ever ordered overnight shipping in my life... the vette is my daily driver.
ALSO, buy a metric set of flare nut wrenches.
Which means...
sometimes you'll come to a stop, and sometimes you'll plow into the back of a garbage truck at 30 mph.
The inner surfaces of the cylinder corrode, and under certain pressures and at certain pedal travel, the fluid will slip past the piston oring.
When this happened to me, I ordered a new one from Ecklers ($120) and had it overnighted. That's the only time I've ever ordered overnight shipping in my life... the vette is my daily driver.
ALSO, buy a metric set of flare nut wrenches.
Although anything is possible with hydraulics, 99% probability that's what you need. And buy new, not rebuilt or you'll most likely be changing it again soon.
Racer
Joined: Aug 2004
Posts: 379
Likes: 170
From: Buffalo Grove IL
I'll 2nd CentralCoaster's post, I used to have a '79 Trans Am (403, 7.7 compression ratio, 185HP 
) that had identical symptoms to what you describe, problem was exactly what CentralCoaster said was happening. Solved with a new master cylinder.
Ben
) that had identical symptoms to what you describe, problem was exactly what CentralCoaster said was happening. Solved with a new master cylinder.Ben
