mark b

on my C5...The car obviously stops better than the stock calipers with less effort..but I have had my fluid bled twice and still cant seem to get this loose feeling brake pedal to go away... if I push down too hard the tires screech and slide... when I gradually push down the pedal the car stops smooth but the pedal feels spungy.. and this is at high speeds on the track... Has anyone who has these calipers had this spongy pedal too? Is it because of these calipers? Im using motul brake fluid.. I was just on thunderbolt raceway and the car repeatedly stopped and performed fine...it just feels weird when the brake pedal is not giving me alot of "resistance as I push it down... Im going to get the brakes bled again to try to firm up this pedal, but the mechanic that bled them last time said that its the best they can do....Is this normal? my master cylinder is working....could it be slowly on its way out? Im concerned about this, but my braking performance has improved.. go figure..

mark b

ttt

wallyman424

I dont know anyone with those calipers (probably for a good reason :P), but I'm going to guess that the caliper piston size isnt correct for the C5 master cylinder.

You could try using the wilwood MC kit that has a bigger bore. That should firm up your pedal.

Sidney004

It is a 6 piston caliper, I believe. What are the piston diameters? You should calculate the piston area of the Force 10 and compare to stock PRB's(remember, even though the PRB is a 2 piston, because it is a sliding caliper design, the piston area is equal to 4 pistons, so multiply accordingly.)

Bill Dearborn

The Force 10 is a 3 piston design. SSBC is a company that has been providing Corvette brake solutions for 30+ years and they have a fair amount of road race experience.

I doubt the Master Cylinder is the problem. Since the Force 10 is a variation of the stock caliper and uses stock pads it could have some of the same problems the stock calipers have when used hard. What do the brake pads look like after a track session? Are they tapered? Are they tapered like this?


Bill

WHT

I have the Force 10 calipers and the pedal is firm. Each piston has it's own bleeder and most people recommend bleeding from bottom to top. BTW, my calipers came from SSBC with Hawk pads. Hope you find your problem.

SSBC developed their 3-piston design to help prevent pad taper as occurs with the stock 2-piston calipers and I haven't observed any tapering (however, you are using them harder than I have). Anyone familiar with the SSBC calipers appreciates that they are much stronger (less flex) than the stock calipers. Haven't heard of any problems with a spongy pedal with street applications. These are a few comments from a review of the brakes on a sports car (not a Corvette):

"Once properly bedded, though, the kit pays real dividends. We established a baseline for the stock system with 20 60-to-0-mph ABS-assisted stops in a row with a 2-min. break after 10 stops to measure rotor and caliper temperatures. After 10 stops, the distance jumped from 120 feet to 158 ft with smoking pads and a spongy pedal. The rotor temperature was past the Raytek pyrometer's 525°F max and the caliper showed 275°F.

The second 10 runs with the stock caliper averaged 141 ft with the rotor temp still off the scale and the caliper temperature climbing to 410°F. Pedal feel was described as 'wooden' and the fluid had been boiled, necessitating bleeding the system.

The SSBC upgrade on the other hand, averaged 128 ft over the first 10 stops (new zinc plated rotors not fully bedded) with rotor and caliper temps of 380°F and 220°F respectively with no change in pedal feel. The average stopping distance climbed slightly to 132 ft for the second set of 10 runs with the rotor temps climbing to 485°F and the caliper to 280°F and the pedal feel never changed."


For what it is worth, Corvettes equipped with these calipers have been driven by GM engineers and they were impressed with them. The calipers won the 2003 SEMA Design Award for best High Performance Product.

EDIT: Do you have the correct caliper? The C5/C6 calipers have 38mm pistons. They make larger 42mm piston calipers for truck applications.

Sidney004

I saw the website and it is a very impressive sliding pin caliper, but having (3) 38mm pistons compared to (2) 39.7mm(1 9/16) pistons in the PBR is a 37% increase in caliper area and a correspondingly large increase in master cylinder volume required during braking. Of course, I don't know the answer but I wonder if the stock master cylinder is reaching its limitation in terms of fluid volume.

96CollectorSport

You may have air in your ABS unit, unless you are bleeding using a Tech 2. Sometimes air will get trapped in the ABS and without activating the ABS while bleeding it's next to impossible to get the air out. Just a thought.

earthman01

I tried to make those calipers work for a whole season and finally went back to my OEM's. I had the same problem that you have, the pedal just never felt right. I bled the sh#t out of them, even had the ABS bled, and still they didn't feel strong enough to give me confidence. When I called SSBC about my problems they told me "of course, you have air in your system". The OEM's with Cardotecks or Hawk DTC's are much better.

mark b

So you could not get a firm pedal? Did you change the master cylinder too? Maybe my master cylinder is weak, after all the car is 9 years old....once I start driving harder the pedal firms up alittle but still feels like it travels too much...I think that its not braking and then Ill apply more pressure and the car stops too quick for the tires(they screech and slide) so I have to get used to applying the brakes softer and smoother but it feels weird when the pedal is not giving me resistance even though the car is slowing down and brakng normally... I spent 800 on these things and I want to make them work... maybe Ill replace the master cylinder

earthman01

I doubt that the master cylinder is the problem. When I finally gave up and put the OEM's back on I had a good firm pedal without any other changes. I'm going to the LGM Wilwood G-Stop package as soon as I use-up my current pads, and put my SSBC calipers on e-bay or Craig's list.

Sidney004

The master cylinder may be perfectly functional for the C5 calipers for which it was designed but may not be compatible with calipers that have almost 40% greater piston area.

rudyarias

Pad tapering can be corrected by replacing the spindles with C6 spindles. C6 front knuckle R #88965638 C6 front knuckle L #88965637. This was resolved during the C6 R&D on the NurburgRing.

As for the spongy pedal, I am fortunate to know engineers at GM's HPVO and TRW who helped me get my ABS calibrated on both my C55 Z06s to a 55/45 bias and 15% increased brake pedal pressure. I have the PBR "J56" (C6Z06) Brake Calipers which the bias/pressure calibration increased pad life by three fold compared to the stock calibration. I do not know if that calibration will be available through GM Performance as I was told since the landscape at GM has drastically changed. This is something that LT Edit or HP software cannot access to calibrate.