Help! Brake fade at higher speeds and down steep hills

[aja37]

Afew years ago I replace the entire brake system and everything worked great, but the last couple of years I've notice that at normal speed braking is fine but if I need to brake coming down a hill, or on highways were I need to brake quick, my peddle goes down to the floor and scares the HELL out of me.:ugh ad Any thought would be appreciated.

 

[Vettehead Mikey]

First thing to do is bleed the system to get any air out.

 

[bill81vette]

stay off the hills....

 

[JohnZ]

my peddle goes down to the floor and scares the HELL out of me.:ugh ad

If you don't have any fluid leaks and a full system bleed doesn't change anything, you need a new master cylinder; with no air or leaks in the system, the only cause for the pedal going to the floor is fluid bypassing the piston seals in the master cylinder.

 

[Gohot]

If you don't have any fluid leaks and a full system bleed doesn't change anything, you need a new master cylinder; with no air or leaks in the system, the only cause for the pedal going to the floor is fluid bypassing the piston seals in the master cylinder.

Mine is similar, not so much on downhills but in flat driving. I had my
Motorhead Daughter help me bleed the brakes, and fount the fronts to have air. I bled until I was several pump and bled past the air sputter so as to be sure it was only fluid. I initally had the petal go to the floor previously and in some cases I had to accompany braking with the emergency brake and downshift into low/1 . After bleeding all four sides in the proper order of length ie RR, LR, RF, LF , I still could only get about half pedal. But It's able to stop without the aforementioned emergency brake and downshift. Mine is an 82 C3. I feel at this time that it might be time for a master cylinder replacement along with brake hoses, and a complete re-bleed. Then hopefully I will have a nice feeling pedal and be able to lock up the brakes if needed or wanted to.

My guess is downhills exert a bit more inertia and weight to try slowing by virtue of the downhill. whereas on flat, the brakes would have less momentum to overcome.

 

[Hib Halverson]

If you don't have any fluid leaks and a full system bleed doesn't change anything, you need a new master cylinder; with no air or leaks in the system, the only cause for the pedal going to the floor is fluid bypassing the piston seals in the master cylinder.

As usual, "JohnZ" is spot on.

Also, you don't have a problem with "brake fade". In fact, it's unlikely you can exert enough pressure on the brakes, because of either leaks or a bad master cylinder, that you could even get the them hot enough for the pads to fade.

As "JohnZ" suggests, you need to inspect the brake system looking for leaks, expanded brake hoses, balooned or leaking brake pipes or leaking calipers. If you find none of that, suspect a bad master cylnder with an internal leak.

If you find a bad master, you can still buy brake master cylinder overhaul kits from Zip Products and others but, I would not do the master myself unless you can properly hone the bore. If you can do that, I'd buy a reman cylinder from Zip Products.

Good luck.

 

[Gohot]

Here's an often overlooked item for those of us without a manual and only typical disc brake knowledge. It's easy with out a manual to miss this important point on the rears.

Mind you were starting with a completely serviceable system ie. new hoses, good lines and good master and calipers, a non-leaking system.

http://www.google.com/url?sa=t&rct=...5IG3Dw&usg=AFQjCNHdZ2oZxu4tTWCavX4p8kUM8tcIuQ