Hi,

I'm having some problems with my passenger side caliper piston cocking under heavy braking. It's had a clean & rebuild with new seals - which was when the problem started (maybe) - when it was rebuilt, the piston slid in easily by hand - so I don't think I put it in crooked. I also put on new pads and discs at the same time and these look ok.

Pulled the caliper apart after an inspection showed an imbalance between L&R under heavy braking, and you can see some wear on the caliper bore where the piston has cocked.
Any ideas what might have caused this? The shims are in pretty rough condition - could a small amount of unevenness in these cause the piston to ****?

Car is a JDM CL7 Euro-R - but brakes are identical to a TSX....

Col.

 

Is there any other sign of scoring on the piston walls? I'd recommend probably replacing it. I know that's probably not what you want to hear, but I'm guessing it will probably continue to re-occur if there is no obvious other reasons for it to happen especially you cleaned it all up before rebuild.

 

The piston walls actually look great to the naked eye... pistons are cheap enough that I'll probably replace it regardless - but I'd like to find the source of the problem first, otherwise I'll just munt another piston.

 

Picture here:
http://nzhondas.com/tech-help/147841...imbalance.html

 

Judging from the picture, you might as well just get a new caliper. Seems like with all the trouble you've been going through rebuilding the caliper you probably could've saved some time just replacing it.

 

The cost of a new OEM calliper shipped to New Zealand is best described as "sphincter-tightening" - to the point that it's either rebuild - or buy a Wilwood kit

 

Ahh I see. Well, good luck with the rebuild then. I'm pretty sure that caliper is shot though. On a side note: not sure how true this is but I heared wilwoods were just oe spec calipers with a fancy name and a high price???

 

Possibly - but the piston shouldn't contact the caliper during normal operation at all, so a little bore wear shouldn't affect the piston direction any measurable amount. 99% of the fluid force is directed to the bottom of the piston.

Only if you ignore the fact that they're made from a completely different material, have 4x as many pistons and are much higher quality
Wilwood make a lot of different calipers - for the price of a single new OE caliper, I could proabably get most of a pair of 4 pot Dynapros - unfortunately I'd also need new pads and have to bin my exceptionally good, near new Hawk HP+s - so lots of cash either way.
Will try running without the shims for a day - maybe it will help, if I can bear the noise.