Is there a way to reduce brake effort on a c-4?
04-09-2014, 11:40 AM
#21
Pro
Booster
I have read many pages of well written information regarding excessive brake pedal effort caused by failed components, over-hard pads, etc in C-4's, but I don't believe that my C-4's have a mechanical problem. They simply seem to require more effort to make them stop than I would prefer.
Why don't I think I have a problem? I purchased a '94 convertible with 26K miles in May, 2012 and a '91 coupe with 48K miles in December 2012. Both require what I consider to be too much effort when braking, but the effort required is pretty much equal car to car. The required effort has not increased since Day One with either car, so the equal and unchanging required effort leads me to believe that this is just the nature of the beast.
Assuming no actual problem, my question is: Is anyone aware of a "stronger" booster totally compatible with the C-4 that would lessen the required braking effort?
Thank you in advance!
Why don't I think I have a problem? I purchased a '94 convertible with 26K miles in May, 2012 and a '91 coupe with 48K miles in December 2012. Both require what I consider to be too much effort when braking, but the effort required is pretty much equal car to car. The required effort has not increased since Day One with either car, so the equal and unchanging required effort leads me to believe that this is just the nature of the beast.
Assuming no actual problem, my question is: Is anyone aware of a "stronger" booster totally compatible with the C-4 that would lessen the required braking effort?
Thank you in advance!
04-11-2014, 01:42 AM
#22
Instructor
Member Since: Apr 2013
Location: NW Arkansas - usually winter in FL
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There are dual diaphragm boosters out there but have no idea if they applicable to our platform or not but being a Corvette, someone has probably tried it. Perhaps they will chime in and tell us how it worked – or didn't work.
Been a while since I looked but Jegs and Summit used to carry them.
Been a while since I looked but Jegs and Summit used to carry them.
07-25-2014, 12:19 PM
#24
Safety Car
My old 95 had a very hard pedal action and you had to push very very hard to engage ABS. I bought a replacement booster from Rockauto and it was no different.
*I drove my friend's 96 LT4 car and it felt fine.
*my 91 ZR-1 has the dual diaphragm metal can booster and it feels fine.
I still haven't ever really heard of any good conclusion why some C4's have weak boosters even when they don't seem to be leaking. Because of this I will not buy a C4 sight unseen. Perhaps there is an aftermarket dual diaphragm unit out there that will fit.
*I drove my friend's 96 LT4 car and it felt fine.
*my 91 ZR-1 has the dual diaphragm metal can booster and it feels fine.
I still haven't ever really heard of any good conclusion why some C4's have weak boosters even when they don't seem to be leaking. Because of this I will not buy a C4 sight unseen. Perhaps there is an aftermarket dual diaphragm unit out there that will fit.
07-25-2014, 12:23 PM
#25
Safety Car
thinking about it, perhaps the friction of the ceramic wagner pads I was running on the 95 were at fault.
but a general comment, the C4's- even the better ones I have driven, do not quite have the braking power and response like the newer vettes. guess it depends what you are comparing it to.
but a general comment, the C4's- even the better ones I have driven, do not quite have the braking power and response like the newer vettes. guess it depends what you are comparing it to.
07-25-2014, 12:42 PM
#26
Team Owner
Pro Mechanic
07-25-2014, 02:03 PM
#27
Melting Slicks
Pads are everything on brakes. Don't skimp on pads, ever.
That being said, my C4's brakes even after I did a mastercylinder swap, fluid flushes, pads, new calipers and hoses (and the booster is good) it never felt nearly as good as the brakes on the Gen 4 F Body.
Technology's come a long long way. Compared to a car of it's era the C4 has fantastic brakes. But Modern they aren't, and it becomes evident if you do alot of mountain driving like I do. The earlier design brakes (pre 88), are even worse. THOSE I'd call a deathtrap.
C5 brakes, or any of the myriad of aftermarket kits bring them up to par.
You can also if you like switch to a Hydroboost system. You want to talk about making a difference in stopping effort.... Hydroboost brake booster will definitely get the brakes working. There's kits out there for it. After driving a couple of vans that had the hydro boost option, vs a couple that didn't... it's night and day. Hydroboost is probably my next upgrade after I get a set of Baer, wilwoods, or C5 brakes for mine. Also definitely frees up the cam shaft options
since it's not vacuum operated. It's also immune to vacuum leaks causing issues, much more reliable.
http://www.powerbrakeservice.net/newc4cohypeb.html the one I'm probably going to end up with.
That being said, my C4's brakes even after I did a mastercylinder swap, fluid flushes, pads, new calipers and hoses (and the booster is good) it never felt nearly as good as the brakes on the Gen 4 F Body.
Technology's come a long long way. Compared to a car of it's era the C4 has fantastic brakes. But Modern they aren't, and it becomes evident if you do alot of mountain driving like I do. The earlier design brakes (pre 88), are even worse. THOSE I'd call a deathtrap.
C5 brakes, or any of the myriad of aftermarket kits bring them up to par.
You can also if you like switch to a Hydroboost system. You want to talk about making a difference in stopping effort.... Hydroboost brake booster will definitely get the brakes working. There's kits out there for it. After driving a couple of vans that had the hydro boost option, vs a couple that didn't... it's night and day. Hydroboost is probably my next upgrade after I get a set of Baer, wilwoods, or C5 brakes for mine. Also definitely frees up the cam shaft options
since it's not vacuum operated. It's also immune to vacuum leaks causing issues, much more reliable.http://www.powerbrakeservice.net/newc4cohypeb.html the one I'm probably going to end up with.
Last edited by MavsAK; 07-25-2014 at 02:25 PM.
07-25-2014, 03:14 PM
#28
Safety Car
I just installed new delco rotors and hawk hps pads all around. They are still bedding in but I can already notice a difference in braking power and modulation.
Sure the J55 or C5 upgrade would be better but then you're looking at big money since you'll be buying the brakes AND new wheels and tires to fit over them. If you have an early C4 that is.
Sure the J55 or C5 upgrade would be better but then you're looking at big money since you'll be buying the brakes AND new wheels and tires to fit over them. If you have an early C4 that is.
07-25-2014, 11:31 PM
#29
Race Director
My LT4 doesn't seem to have a stiff pedal but you couldn't stop very fast without sliding the front tires and going into antilock. That was about as good as saying, "We're going to let you gently crash but not let your tires get flat-spotted!" I put the heavier brake bias spring in the master cyl. to increase pressure to the rear brakes, and now it stops flat and much quicker without lockup or ABS interference.
07-26-2014, 01:04 AM
#30
Sooo...
Did Tommy replace his booster?
Did he upgrade to the C5 brakes?
Did he get better tires?
Did he install the Hawk HPS pads?
Did he look for or find any vacuum leaks?
Enquiring minds want to know...
The wife complained about her '92 having a hard brake pedal. Changed the fluid and installed Hawk HPS pads, problem solved...notice the dust flying, came into the turn a little hot...
Brakes work fine...
Al
P.S. That might be the Bandit on the left side of the pic...
Did Tommy replace his booster?
Did he upgrade to the C5 brakes?
Did he get better tires?
Did he install the Hawk HPS pads?
Did he look for or find any vacuum leaks?
Enquiring minds want to know...
The wife complained about her '92 having a hard brake pedal. Changed the fluid and installed Hawk HPS pads, problem solved...notice the dust flying, came into the turn a little hot...
Brakes work fine...
Al
P.S. That might be the Bandit on the left side of the pic...
07-26-2014, 01:34 PM
#31
Team Owner
Pro Mechanic
07-26-2014, 05:33 PM
#32
Team Owner
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My Z28 with rear drum brakes had better brakes than my 92 Vert with the 12" front rotors. The J55 didnt do a damn thing to upgrade those brakes.
