Brake proportioning valve
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Joined: Apr 2004
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Brake proportioning valve
Recently I braked pretty hard. My brake light on the dash came on soon afterword. I thought it might be just that I bumped my parking brake lever as I have done that in the past. However, the light stayed on after I checked the PB lever. The brakes seem to work fine and I arrived to my destination. After restarting the car some time later, the brake light was off. Again I needed to brake fairly hard and the Brake light came on. From my research it seems like it likely that my brake proportioning valve has gone bad. Does this seem correct? There is no fluid loss in the master cyliner.
Additionally, if it needs to be replaced, any issues or pitfalls when replacing this part that I should be aware of?
Thanks for any advice.
Additionally, if it needs to be replaced, any issues or pitfalls when replacing this part that I should be aware of?
Thanks for any advice.
Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
Originally Posted by Baytraveler
Recently I braked pretty hard. My brake light on the dash came on soon afterword. I thought it might be just that I bumped my parking brake lever as I have done that in the past. However, the light stayed on after I checked the PB lever. The brakes seem to work fine and I arrived to my destination. After restarting the car some time later, the brake light was off. Again I needed to brake fairly hard and the Brake light came on. From my research it seems like it likely that my brake proportioning valve has gone bad. Does this seem correct? There is no fluid loss in the master cyliner.
Additionally, if it needs to be replaced, any issues or pitfalls when replacing this part that I should be aware of?
Thanks for any advice.
Additionally, if it needs to be replaced, any issues or pitfalls when replacing this part that I should be aware of?
Thanks for any advice.
In any event, if the light comes on, then there is an imbalance between the front and rear systems. This can be caused by low fluid, leaks, air in the system, etc... How old are your brake pads? When did you last bleed the system?
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Sounds like the proportioning valve did its job (if you have one) It is supposed to shift over (and turn on the light) in the event of a leak in the brake system that causes low pressure in one leg or the other. If the light went off the valve shifted back to normal, this indicates air in one leg. Bleed thuroghly on all 4 calipers and you should be good to go.
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
I don't believe we have a proportioning valve. Like other have already said either the front or the back is leaking and you have an imbalance in line pressure causing the pressure switch to short to one side turning on the warning light.
If the car stops well I would suspect the back as the problem. If the brakes feel mushy I would look at the front.
If the car stops well I would suspect the back as the problem. If the brakes feel mushy I would look at the front.
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
If the light stays on, pull the connector off the switch on the proportioning valve. If the light goes out, then either you have air in the system or the switch is bad. If it stays on, then it's the e-brake switch or a short to ground in the wiring.
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Drifting
Joined: Jan 2006
Posts: 1,944
Likes: 22
From: Yooperville MI
Originally Posted by Duke94
If the light stays on, pull the connector off the switch on the proportioning valve. If the light goes out, then either you have air in the system or the switch is bad. If it stays on, then it's the e-brake switch or a short to ground in the wiring.
with the diagnosis, but it's a distribution block and switch only.
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
Originally Posted by ahoover
with the diagnosis, but it's a distribution block and switch only.