Warning on C4 Calipers

[jannes_z-28]

I did some work on my car and it involved removing the front calipers. I couldn't believe what I saw. They were bent! Apparently they are to weak for highpressure systems like my HydraBoost combined with a S-10 M/C.

I haven't noticed any problems with the brakes, up until now they have worked. I have to admit that they have got a fair share of abuse.

Look at the picture to see tha angle they now have. I didn't see any cracks or so. They would have held up a while longer.

I will now change to C5 Calipers which are much stronger.

https://static1.pt-content.com/images/pt/2009/05/bent_c4_caliper-1.jpg


Jan

[Yelcamino]

There's an eye opener! I have a few friends running a hydro with those same calipers. I'm going to forward them your picture and hopefully they'll check their calipers.

[Randy67]

I heard of people with Mustangs and the Cobra calipers doing the same thing. Something to watch out for with rebuilt calipers.
Sounds like a perfect excuse to call Stoptech or similar manf for some killer calipers. It's only money.

[Rick Dorion]

Wow - I ran C4 with hydroboost for years with no issues.

[Mike Holleman]

There's an eye opener! I have a few friends running a hydro with those same calipers. I'm going to forward them your picture and hopefully they'll check their calipers.
I'm guessing I'm one of those friends. I will put the Tempest on the lift today and check.
Later
Mike

[CarlC]

Wow - I ran C4 with hydroboost for years with no issues.

Wow is right. I'm still running C4/hydroboost.

Thanks for the heads-up Jan. I'll need to do a little investigating.

[Mike Holleman]

I'm guessing I'm one of those friends. I will put the Tempest on the lift today and check.
Later
Mike

I checked the C4/ hydroboosted brakes on my 64 Tempest and all was well. They have approx. 17,000 miles on them with some hard driving, but mostly cruise miles. Hopefully, your's was a isolated case. I do appreciate the heads up Jan.
Mike Holleman

[DAK]

There's an eye opener!

I wrench on cars so when comes to bleeding brakes I'm amazed how much alum and case iron calipers flex. One thing that sticks in my mind is a common late model car with alum calipers that look like they're going to snap in half. :eek:

[Apogee]

Jan, I mentioned this on lat-g, but if you're running the 15/16" stepped bore S10 master cylinder, then you're capable of generating ~40% more pressure with the same pedal input then with a 1-1/8" bore. That could be a significant part of the problem. For those who are running C4 calipers, the 1996 Grand Sport calipers are pressure-cast versus the earlier ones which are gravity-cast, so they're the better choice if/when you go to replace calipers. It probably wouldn't have made a difference in this instance, but it should increase caliper life where the pressures are more in line with the design specifications for the caliper itself.

Tobin
KORE3

[jannes_z-28]

I have been in contact with Paul at HydraTech who gave me the HydraBoost unit. I won it at the Protouring.com SEMA-dinner in 2006.

The S-10 M/C is probably a major part of the problem but I have heard about similar problems with C4 calipers with the stock setup of M/C and Booster. In fact one of the rear calipers I got first (LT1 reworked) was slightly bent.

The Camaro Cup racing circuit here in Scandinavia have banned the C4 calipers due to the tendency to bend.

Anyway I have ordered C5 front calipers and will also get a Corvette C3 M/C with 1-1/8" bore.

Jan