2001 Chevrolet Tahoe • 270,000 miles

Good evening,
My grandma was driving the tahoe yesterday when she called to say that the brake pedal was about an inch from the floor suddenly.
She was able to make it to the house.
I replaced the master cylinder, bench bled before installing.

Installed the cylinder, and now there are NO brakes at all.
Tried bleeding the system at the wheels.
Plenty of fluid at each wheel, but still no brakes and pedal all the way on the floor.

Is it possible the cylinder is defective, or possibly the booster failed?

I would appreciate any info, tips or suggestions.

August 9, 2012.

I'll bet the fluid level is going down in the new master cylinder. Look for an external leak, especially inside the rear wheels and front flex hoses. It's not likely the new master cylinder would develop exactly the same problem.

Aug 9, 2012.
Hi cardiodoc

I failed to say that when the pedal went low, but still had brakes even though just barely we switched the M/C, then had no brakes even after bleeding, but the fluid is still at the top of the resevoir, and doesn't seem to be dropping.
That's why I thought maybe the M/C or booster.

I will check the wheel cylinders and calipers however, even though I saw no sign of leaks anywhere

I appreciate the speedy reply and assistance,


Check the flex hoses too while a helper is pressing the pedal. If the outer cords are torn the hose will balloon up in one spot. You have to look pretty close to see that because it won't be much of a change. Usually the outer layer of rubber will be split in the area too.

Aug 10, 2012.

Thanks again for your help.
I finally did find that leak.
A very small pin hole in one of the steel lines heading to
the rear brakes.
The truck is at the brake shop now having all new lines installed.
Looking deeper, all of the steel was in bad shape, ad the bleeders were rusted in the calipers.

Thanks again,

Dandy. Happy to hear you found the problem.

Aug 12, 2012.