Front driver brake pad locking up

[mhunter]

Hi guys,

I just installed new bilstein front struts in my 71 porsche. It wasn't all that difficult. However, as I was installing the struts I had just enough room to pull on the brake lines to slide the struts in the front shocks. I went for a test run and as I was driving up a hill I pumped the brake pedal and it now feels a little spongy. We'll, as I was sitting at a stop sign the left brake caliper seems to be locked up. What would cause that? Did I mess something up during the installation of the struts? Has this happen to anyone? I have the car up on stands again, and thinking that I might need to change the brake lines. Any suggestions? Why would this happen now? Thanks for the feedback.

mh

[Flat6pac]

The brake hose when it is breaking down inside willl not let the fluid off the caliper and can keep the brake applied.
Bruce

[ruf-porsche]

You could also have a frozen piston(s) in the caliper.

[mhunter]

I guess that makes sense. I think I might have stretched my old hoses too much.

Mh

The brake hose when it is breaking down inside willl not let the fluid off the caliper and can keep the brake applied.

Bruce

[Flieger]

+1 on the swollen rubber brake lines.

They swell as they wear from the inside out. You can push fluid into them with your leg pressure but the caliper/piston does not have enough force to push the fluid back.

[kodioneill]

I had to replace all my brake lines they were plugged tight.

[tonythetarga]

If you changed the strut without taking the caliper off you may have kinked or damaged the hose on the inside. It appears that your braking was fine before this and something happened during the strut install. I would retract the pads and gently step on the pedal and check the caliper L/R sides for piston travel.
In any event, it may be time to put in new rubber lines or braided steel lines and/or rebuild the calipers.

[mhunter]

Thanks Tony,

I checked for kinks, I think I have to play it safe and change the brake lines. I guess I better change the MC too. About a two months ago I found a puddle of brake fluid all around the accelerator peddle. It was leaking straight through the underbelly at the access hole. It never leaked again, but I get the feeling this has to do with my brake lines swelling up. I'm going to upgrade MC to 19mm any thoughts. My brakes are stock M calipers.

mh

[tonythetarga]

I think doing the m/c as well is a good call, especially since you found some fluid on the floor. Before you put the line on the new one, you want to bleed some brake fluid through it first to purge air out of the m/c. Then connect the line and bleed the system.

[Flieger]

19mm is stock size for master cylinder bore. It is not an "upgrade" except in the sense of reliability.