Front Breaks will not bleed
Thread Starter
5th Gear
Joined: Nov 2015
Posts: 5
Likes: 0
Front Breaks will not bleed on 1987 Corvette
I have just replaced my master cylinder, brake hoses, pads, rotors, and calipers. Before replacing the master, everything bled fine, but the master failed while driving. Now that the master has been replaced, the front brakes won’t bleed. The back bleeds fine. I have tried two person bleeding and a power bleeder. What am I doing wrong? Is there a secret or am I missing something?
Last edited by Shawn Wright; Jun 28, 2020 at 07:04 AM. Reason: Added year
Racer
Joined: May 2020
Posts: 345
Likes: 68
From: New Jersey
If everything was working until the master failed the logical presumption would be a bad master. It could be getting bleed-by. So the FIRST thing I would do is get the reciept and return it. Don’t go tearing into proportioning valves and other components until you try the master. You state you replaced it so presumably it’s free and under warranty.
Drifting
Joined: Nov 2018
Posts: 1,794
Likes: 579
From: Mays Landing, NJ
I have just replaced my master cylinder, brake hoses, pads, rotors, and calipers. Before replacing the master, everything bled fine, but the master failed while driving. Now that the master has been replaced, the front brakes won’t bleed. The back bleeds fine. I have tried two person bleeding and a power bleeder. What am I doing wrong? Is there a secret or am I missing something?
Thread Starter
5th Gear
Joined: Nov 2015
Posts: 5
Likes: 0
If everything was working until the master failed the logical presumption would be a bad master. It could be getting bleed-by. So the FIRST thing I would do is get the reciept and return it. Don’t go tearing into proportioning valves and other components until you try the master. You state you replaced it so presumably it’s free and under warranty.
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Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
Master
Dick Guldstrand always changed reservoirs to the double type reservoir.
he built c4’s for racing.
more fluid, and if one system loses fluid, you don’t loose all fluid.
also, more fluid with bigger diameter allows fluid to dissipate some heat.
the masters are pretty much identical.
he built c4’s for racing.
more fluid, and if one system loses fluid, you don’t loose all fluid.
also, more fluid with bigger diameter allows fluid to dissipate some heat.
the masters are pretty much identical.
Le Mans Master
Joined: May 2005
Posts: 7,348
Likes: 2,272
From: Central Maryland
If you got good flow out of both ports when you bench bled the master prior to installing it, it's time to look at other things. First thing that comes to mind if you're getting very little fluid out of the bleeders at either of the front calipers, is that the piston in the master might not be moving all of the way to the rear when the pedal is released. Try loosing the master cylinder from the booster just a little bit as a test. A turn or so on the nuts should be enough. Then see what you get at the caliper bleeders.
Live well,
SJW
Live well,
SJW
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
That is helpful. I ASSUME, that you've ensured that the bleeder itself is clear of debris? Have you removed it entirely to see if it bleeds/flows freely, then?
If so, I'd focus on the hose for that corner. I'd disconnect the hose at the frame/hard line and see if you have good flow there. If yes, replace the hose.
If not, I'd leave that hose disconnected, ensure that my reservoir is FULL (and the cap is on) then aggressively pump the brake pedal a few times to try to force the contamination/restriction through and out. Then reconnect the hose to the hardline and bleed as normal.
If so, I'd focus on the hose for that corner. I'd disconnect the hose at the frame/hard line and see if you have good flow there. If yes, replace the hose.
If not, I'd leave that hose disconnected, ensure that my reservoir is FULL (and the cap is on) then aggressively pump the brake pedal a few times to try to force the contamination/restriction through and out. Then reconnect the hose to the hardline and bleed as normal.
