rmj951

Went to the track for a race a few weeks ago noticed Saturday morning that my brake pedal felt a little spongy. We tried to bleed the system & get through the weekend to collect points even if we weren't up to speed. We tried to rebuild the brake master cylinder Saturday night still no luck brake pedal felt the same. Durning the Sunday race into a braking zone I felt the peddle go a little further than before. I heard a clunk & felt I had a tire down. I was near pit out & rolled into grid my Mecanic brought a spare wheel but we found that the caliper had shared the tabs on the spindle. If you are tracking or racing your C5/C6 regularly be sure to keep an eye on the spindles.

stevensa

Wow, thanks for sharing!

Bowchickawowow

Whoa!

RapidC84B

Never seen that happen w/o previous crash/impact damage. FYI the latest C6 "ZR1" spindles are very very beefy in the caliper mount area and are direct replacements on all C5/C6s.

froggy47

never saw any break there period.

ZedO6

I'd be making certain the caliper adapter block is not forcing the caliper off center or twisting it under brake application. If the bolt holes are not 90 degrees and/or the mounting block surface is not square in both directions it will twist the spindle caliper mounts. I just can't believe this is a normal fatigue area. Interested to see what the high mileage T1 guys say when they check into this thread.

Glad you caught it when you did.

Olitho

I have wondered and worried about this. The reason why I worry is that I can see evidence in the pad wear that the spindles and/or caliper bracket is flexing under load on the heavy braking tracks.

I tried to buy the "new" C6/ZR1 spindles recently, but I could not verify which ones to get. How much are they?

ZedO6

I'm going to assume you mean with the fixed AP caliper you're running now, correct? I think the original C5 slide mount calipers don't put much axial load on the caliper mount.

fatbillybob

What does that look like and how is it different from say pad taper or caliper flexing as opposed to the caliper bracket or spindle?

RX-Ben

Part number is 88965637 and 88965638.
$160ish per new.

fatbillybob

Can you give us a feel for how many street miles, track miles or race miles? Any history of broken wheels or race incidents on that corner?

rmj951

Car has 40k miles all are race/track car is a body in white what has some pro race history.

Im unsure if these are the original spindles from new. There was no damage to the corner other than some curb hopping at COTA in Feb. Car has been solid under breaking since i have owned it.

I do remember that morning felling the peddle go from firm to soft. We think that was a crack in the spindle that allowed the caliper to twist giving me the soft peddle feel.

Pumba

Thanks for posting.

You may not be aware, but Corvette upgraded the front knuckles (they are not spindles) in 2009 model-year after testing on the C6 ZR1 showed deflection under heavy braking. The following picture shows a C5 and early-C6 knuckle on the left compared to a 2009+ C6 knuckle on the right:



-

Bink

Same part number as RX-BEN posted?

Pumba

Yes, RX-BEN has the correct part number.

Bink

Thank you!!!

ZedO6

And online these are about $113 a side..cheap insurance. Thanks for all the good info!

http://www.gmpartsdirect.com/results...umber=88965638

Olitho

Here is an interesting development.....

Olitho

I am kicking myself for not buying and installing the new ZR1 spindles the week before this race. I was planning to do so and then decided to do it after this latest SCCA US Majors race at BRP.

Olitho

https://www.facebook.com/photo.php?v...42287089001576