front brakes seized up

[benzboy]

hey. car is a 1985 Porsche 911 coupe; this week I took it out for a drive for only the second this year. car is a garage queen. And I hardly ever drive it. so, it began to pull hard to the right. and when coasting up to stop signs. it was slowing down without braking. I jacked car up. both front brakes and seized. rears spin fine, I'm assuming both calipers will need rebuilt. brake pads look brand new and rotors the same. im assuming there is anything major? i know i need to drive them. but i hardly do anymore. should there be anything i should be looking for?. i cant even compress the caliper with a c clamp.

[HarryD]

Your flexible brake lines may have swollen shut. Remove the line from the caliper and see if they move. If so, you found your problem.

Given the limited use of your car, I suspect your brake fluid has also gone bad. You will need to flush the entire system. If your calipers continue to be seized, you will need to replace or rebuild them. Also, possibly the Master Cylinder.

[917_Langheck]

It's possible that the front circuit is stuck closed, not letting the fluid pressure to bleed off. That may be a master cylinder issue.

What does the pedal feel like? Is it different from normal?

I'd first set up for a brake bleed session to see if opening the screws on the brake housings allow you to move the pucks back. See if you can cycle those a couple of times. If so, maybe do a full brake bleed the proper way starting with the furthest wheel.

2 quarts of Ate 200 should do the trick for a non track car.

As you have found, not driving the car is possibly the more damaging thing you can do to it.

Best of luck

Edit; also, what HarryD said.

[GH85Carrera]

It is punishing you for Porsche abuse and driving it enough!

And yea, it likely needs all 4 calipers rebuilt, new rubber brake lines, and total fluid flush. Possibly even a new master cylinder. Moisture in the systems causes corrosion and bad thing to happen. I replace my brake fluid every single spring and have done that for 30 years.

Once it is fixed, drive it more!

[benzboy]

update. i pulled the front calipers off. and pulled the rubber dust covers off. lots of corrision on the pistons. i guess its time for caliper rebuilds

[EC900]

For what it’s worth, I’m guilty of the same…second time out this year but only found that my brake lights don’t work! Busy with construction projects, pleasure driving became a luxury. Only went out today because Home Depot didn’t have hinges I needed. Leaving my BMW outdoors for weeks unused, rain always rusted the rotors to the calipers and dragged, but they broke free without a problem and self corrected after a few miles.

So anyway, and it’s been a ritual, that I keep a box fan going on the garage floor year around, ceiling fan at certain times too.
Spring and Fall tends to bring higher moisture up from my uninsulated garage floor as early/late Summer temps fluctuate so dramatically. There’s no Winter (salt here) and avoid rain driving if possible but atmospheric moisture and humidity is everywhere. Constant air movement circulates and helps dry things out.
Same with car washing, leaf blow everywhere and the box fan gets the leftover water to dry faster if I don’t drive it after a wash.

I agree with others, fresh brake fluid flush x two, and inspect the reservoir too for sludge… and while you’re at it change out the rubber hoses if over or close to 10 yrs old, it’s where reservoir sludge comes from. Theres a date code stamped on the hoses if you haven’t already had them replaced.

[yelcab1]

If you are doing the work yourself, how much can it be to pull the front calipers and put new seals in them, plus replacing the master cylinder as well. That job also dictates that you change your fluid. New brake lines will complete the rebuild.

[Fab64]

If you can afford it, our host sells rebuilt calipers from PMB for $355/pair. In January 2023, I had a stuck piston in one of my rear calipers. Rather than futz around trying to rebuild mine, I replaced them with rebuilt ones from PMB. They do a great job refurbishing them, and they look and perform just like brand new. Good luck!

[spoke]

Originally Posted by Fab64

If you can afford it, our host sells rebuilt calipers from PMB for $355/pair.

Yes for PMB. I just sent my 930 calipers to PMB for restoring. They look fantastic.

[emac911]

I had this same exact problem on my 88 when I got it. It had been sitting about 18 years. New rubber lines, rebuilt calipers. No change. Swapped the master cylinder and that fixed it. I looked at the old master and the equalization port was plugged up. Its a tiny port that allows the presure to bleed off when you release the pedal. In my case, the more you used the brake the tighter they got. I think I could have just cleaned it out and reused the master, as it wasnt leaking.

In reality, my problem was both flexible lines and the master from sitting too long. HTH

[emac911]

I had this same exact problem on my 88 when I got it. It had been sitting about 18 years. New rubber lines, rebuilt calipers. No change. Swapped the master cylinder and that fixed it. I looked at the old master and the equalization port was plugged up. Its a tiny port that allows the presure to bleed off when you release the pedal. In my case, the more you used the brake the tighter they got. I think I could have just cleaned it out and reused the master, as it wasnt leaking.

In reality, my problem was both flexible lines and the master from sitting too long. What was messing me up, was I could get good fluid and pedal when bleeding. Then it would get pressure after a drive. Personally, I had never had this type of problem with a master cylinder. HTH