Sluggish Front Tire Spin

[HarryD]

Today I was getting ready for Autocross tomorrow. One of the front wheels did not spin freely.

On investigation, I found a chunk of rubber wedged between the caliper pad and the disc.



I pulled the chunk out and it still dragged. I pulled the pad and found it to be very worn so I replaced The front pads. This fixed the drag. Note the inside pad is more worn than the outside.



The other side was more evenly worn.



FWIW, I last replaced the pads 8,000 miles ago. The calipers looked ok last time. Besides normal driving for fun, I did 7 HPDE’s, 14 autocrosses, and 3 Maryhill climbs.

I noticed the rubber seals on the caliper pistons looked ragged. I am thinking it is time to rebuild or replace the front calipers. What do you recommend, rebuild them myself or just get a set of rebuilt ones?

Can I reuse the pads that will be slightly used when I do this?

Thanks for your thoughts.

[manbridge 74]

Always rebuild using best practices. The rebuilt ones are hit or miss, mostly miss.

You can use your old pads but new are cheap enough for these to start afresh.

[Locker537]

Eric and his team at PMB get my recommendation for restoring calipers.

https://www.pmbperformance.com/catalog.html

His customer service is top notch and he takes the time to help.

If the calipers aren't leaking and operating properly, you may want to replace the outer dust seal only.

[dannobee]

It's likely not the calipers sticking, but that the wheel bearings are too tight. If they're adjusted too tight, the caliper pistons won't get pushed back into their bore properly. The workshop manual outlines to verify that the washer under the "nut" is moveable with a screwdriver before installing the dust cap. In other words, tighten up the nut to seat the bearings, then back off so that the washer is loose. Then tighten the set screw.

That little bit of play in properly adjusted wheel bearings causes the brake rotor to push the caliper pistons back into their bores, reducing drag.

[Charles Freeborn]

That's pretty darned good mileage for one set of pads! I know drivers that go thorough a set in 2 HPDE days. Having been with you at one of yours, you were tooling right along so be proud and happy!
If you have room to put it up on jack stands for a few months pull all four and send to PMB. Then replace all the rubber lines, have a lookee at the MC and stop with confidence! Great driving with you this year. Look forward to more next season.

I'll say it one more time PMB... the part of a rebuild we pedestrians can't do is get the plating into the piston bores where it matters the most.

[manbridge 74]

I have seen and rebuilt many sticking calipers in the last few years. Don’t rule it out...
Wheel bearing adjust is also important as noted.

[HarryD]

Originally Posted by Charles Freeborn

That's pretty darned good mileage for one set of pads! I know drivers that go thorough a set in 2 HPDE days. Having been with you at one of yours, you were tooling right along so be proud and happy!
If you have room to put it up on jack stands for a few months pull all four and send to PMB. Then replace all the rubber lines, have a lookee at the MC and stop with confidence! Great driving with you this year. Look forward to more next season.

I'll say it one more time PMB... the part of a rebuild we pedestrians can't do is get the plating into the piston bores where it matters the most.

Hi Charles. Looking forward to fast fun next year.

All the brake hoses were recently replaced. MC seems to be non-problematic so I prefer to leave well enough alone.

I hear good things about PMB but I really do not need a concurs restoration, just working brakes. I think there are other places that can do an adequate job to win the day and be easier on my wallet. I am researching that right now.

I have checked my wheel bearings and they are adjusted properly. They are periodically checked for track days and AX a few times a year to be sure. Rarely does an adjustment need to be made.

[HarryD]

Originally Posted by Charles Freeborn

... snip ... Having been with you at one of yours, you were tooling right along so be proud and happy!

... snip ...

That's because my philosophy is that brakes just slow you down. I wanna go fast.

[Charles Freeborn]

Originally Posted by HarryD

That's because my philosophy is that brakes just slow you down. I wanna go fast.

Go get 'em tiger!

The proper restoration with plating actually is a protection of investment. The plating protects the piston bores from rust.

[fanaudical]

+1 for PMB - Had them do my calipers and they came back looking great and have had zero issues.

I did initially disassemble them thinking I would rebuild them myself; found some internal corrosion that I knew I couldn't correct. PMB took care of that without issue.