ASK AN EXPERT: Problem with overhauled brake calipers

In this edition of Ask An Expert, we sought to find the answer to a question a reader had submitted to us about brake calipers. 

"I have a classic 1999 Porsche 986 Boxster convertible 2.5 an original no frills no abs motor. I have overhauled the Brembo 4 pot caliper all round new seals, new Brembo fluid, new pads, cleaned and polished all the guide pins, lubricated the pedal rail but I am still having a problem with when I drive it, the brakes start to stick and a quick touch of the pedal releases them. Could this be the master cylinder seals that need replacing?”

We spoke to a mechanic from JJ Performance Engineering, and he explains some of the steps to identify the issue below.

"Assuming that the pedal returns to its normal position after you’ve applied the brakes, and if the problem wasn’t there before your work, it’s likely that the refurbing and refitting the caliper is where the problem lies.

Rather than checking each one separately, you could try and trace the fault but you’re likely to need a lift or axle stands and someone to help. With the wheels off the ground (or with just one axle at a time) start the car and apply the brakes so that they don’t bind.

Then ask someone to turn each wheel separately and see if the brake pads start to bind. If one-wheel sticks, then you know it’s probably a caliper issue. However, if all the wheels start to bind at the same time then we’d look at the brake servo."

If you have a classic question you would like answered by an expert, simply complete our Ask An Expert form and we could be answering your question next week. 

The information contained in this blog post is based on sources that we believe are reliable and should be understood as general information only. It is not intended to be taken as advice with respect to any specific or individual situation and cannot be relied upon as such.