Only rear brakes are functioning?
Thread Starter
Instructor
Joined: Jun 2007
Posts: 216
Likes: 20
Only rear brakes are functioning?
I am having problems with my braking. The rears are stopping the vehicle and will lock up but the fronts are not functioning. There is surface rust on both front rotors so I know they are not functioning. The fluid in the master cylinder is not low. I would suspect a caliper but cannot imagine both having problems. Any ideas?
Burning Brakes
Joined: Oct 2003
Posts: 836
Likes: 26
From: Harrisburg Pa
Have someone push on the brake and hold it there lightly as you loosen the front brake line at the master cylinder. if you get a squirt of fluid then tighten it up as the master cylinder is ok. if nothing then its bad.
Then check the proportioning valve outlet to the front brakes OR to one of the front calipers and do the same test. if you dont have fluid flow at the
INLET LINE to the caliper then the proportioning valve is bad or needs reset.
Then check the proportioning valve outlet to the front brakes OR to one of the front calipers and do the same test. if you dont have fluid flow at the
INLET LINE to the caliper then the proportioning valve is bad or needs reset.
Last edited by TOM B1; Feb 16, 2017 at 10:15 PM.
Racer
Joined: Apr 2007
Posts: 357
Likes: 0
From: Porters Lake Nova Scotia
I had an issue where my rears were not working. It was very apparent when I opened the MC cover because the fluid on the rear port was rust coloured. I agree with TOM B1, crack the front line at the MC and have someone push the pedal, slowly. If nothing, then put new seals in the MC. You can also find out if its a bad caliper or a proportioning valve by trying to bleed the fronts. If the P.V is stuck little to no fluid will come out and the pedal will still feel somewhat firm when the bleeders are open.
My valve wasnt stuck, but I took it apart and cleaned it anyway. Depending on your year you have either a proportioning valve(more complex) or a distribution valve which just shuttles pressure.
Good luck!
My valve wasnt stuck, but I took it apart and cleaned it anyway. Depending on your year you have either a proportioning valve(more complex) or a distribution valve which just shuttles pressure.
Good luck!
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
If the front brake system had a leak in it sometime in the past, chances are that the shuttle valve in the distribution block did not get reset to center position.
Assuming that all of the front brake system is OK and is capable of functioning properly, get in the driver's seat and stomp down on the pedal as hard and fast as you can. That's the usual method for resetting the shuttle valve. Is your BRAKE warning light (on the dash) lit? Will it light if you engage the emergency brake? If not, the bulb is likely bad....and you would never know if the e-brake was ON or if the brake system was malfunctioning.
Assuming that all of the front brake system is OK and is capable of functioning properly, get in the driver's seat and stomp down on the pedal as hard and fast as you can. That's the usual method for resetting the shuttle valve. Is your BRAKE warning light (on the dash) lit? Will it light if you engage the emergency brake? If not, the bulb is likely bad....and you would never know if the e-brake was ON or if the brake system was malfunctioning.
