This is a question for those mechanics out there.
In reviewing progress on my ‘67 Cougar, the shop owner mentioned that he has seen a number of brake sensor failures (in my case it mounts on the Wilwood proportioning valve) where the sensor begins to leak internally.
Has anyone else experienced this issue, and if the problem reoccurred after replacing the offending unit.
What brand might be best?
Best
Ron
The sensor I think you are asking about is called the Differential Pressure Switch (DPS). In 67 through 70 Cougars it is where the two lines from the master cylinder get “distributed” to the front and rear brakes. In all drum systems it takes the place of the distribution block that was on most pre-67 cars. On disc-drum systems there is a separate Proportioning Valve that goes to the rear drum brakes. On 71-73 factory disc-drum systems, the DPS and Proportioning Valve were combined into one component commonly called a Combo Valve. The piece that I think you are referring to as a sensor is just a contact that completes a circuit to ground if the piston in the DPS is moved off center due to a pressure difference between the front and rear master cylinder outlets.
If there is fluid leakage, it is because the seals inside the DPS are leaking, not because of a problem with the contact that screws into the port on the DPS or Combo Valve. The space the contact is in is not supposed to experience any brake fluid pressure.
If your Wilwood Combo Valve is leaking, I suggest contacting Wilwood aout rebuild or replacement.
Thanks for the response. The question was about if anyone has experience with the combo valve failing and replacement of failed units.
I have not had a failure, as the final restoration steps are being completed, and the car will not see road service until late April, after several good rains to wash the roads here in Wisconsin.
Thanks
Ron
I misunderstood thinking it was a current problem.
If you have a Wilwood brake system, I would stick with the Wilwood valve should you have a problem. I don’t know if they supply an adjustable prop valve or a fixed one. As a general rule, don’t go mixing components from different systems or suppliers unless you are prepared to also be a system integrator. You would be surprised how often even the OEMs don’t seem to grasp that concept.
Being in Michigan, I totally get waiting for some good rains before the toys come out.
The question was prompted by the shop owner questioning if there was any experiences out there with Combo sensors failing.
He has seen several fail over time, and a few more than once.
Best
Ron