I have difficulties with the parking brake on my 1990 C4. It does not hold on hills although I have changed the caliphers and tried to adjust with the small allen screws.
I would like to change to the old system until 1987 which has parking shoes like all the older Corvettes C2 and C3.
Has anybody tried to do so? And which parts are different between up to 1987 and 1988 afterwards?
Any help would be welcome!
Thank you

 

Replace the cables as they sound stretched out.

 

Where do you find this? I have a 89 and wondered about this as it don't hold quite good enough for me.

 

Check out the front cable hasn't collapsed internally

 

The cables seem to be ok as the wheels are fully locked when I apply the parking brake on the lift. But when I go to a steep hill apply the parking barke it starts rolling backwards as soon as I lift the foot. I wonder if there could be a hydraulic problem in the calipher? But the rear brakes show very good values on the rolling brake tester.

 

My 1990 had been sitting outside for 17 years when I got it. The parking brake lever had had the Cable ripped out of the assembly. I re placed the assembly and ripped it out again. So, I went through the Calipers and replaced the Seals and loosened everything up. I replaced all 3 Cables and yet another Parking Brake assembly. Now my PB works and holds as well as any Corvette. I live in Seattle where we have hills. The General didn't sell a car that didn't have a working PB. I don't see any advantage in going to the Drum PB design, even if the General did go back to that for the newer Vettes as well.

 

Local inspections required a deepdive into the parking brake a couple of years ago.. it's really sensitive to the cables, discs and wear in the caliper mechanism. It's fully mechanical and basically 'locks' the pads in place (which is why you really have to press on the brake pedal!). Back then some/most aftermarket cables were just slightly too long - I replaced the driver's side twice and had to fiddle with the cable routing to get it to work.

In the caliper, the center axle presses the inner pad, handbrake+cable pushes on the black pin at the bottom, pivoting the grey lock piece, locking the axle (and therefore the pads) in place. Wear can be seen in the picture on the axle, also the locking piece hole was visibly worn. I managed to get everything to work by cleaning and 'unpolishing' all surfaces and replacing all cables. I had a chance to compare the functionality to an original car with an excellent handbrake - it was much better than mine with new aftermarket parts and never had had problems passing inspections. Mine holds the car and passes inspections but at a local hill the car doesn't 'feel' safe.

Of course the brake pads have effect and worn or turned rotors require setting the base distance with the allen screw. Local Vette mechanic routinely changes the discs for any parking brake failures - he "hasn't had much luck with the adjustment".

 

Thanks for your reply and the picture. Up to now I installed new brale pads, a selfmade balance to the cables as there were differencies between left and right but I did only partly dismantle the calipher and tried to improve the pressure with longer allan screws - with no success. Based on your experience i will give another trial and will totally redo the calipher. If this will not work, I will go to old Corvette parking brake system which is not perfect but works at least. Thanks again!!

 

You will have more issues changing to the earlier e-brake system than you bargain for! For starters, the early rear spindle/knuckle will change the offset of your wheels, so you will need spacers for your current rims to fit correctly. Then you will need source '86 or '87 only parts for the ABS sensor provision (not sure if wiring/sensors are the same), you'd need knuckles, calipers, e-brake assemblies, e-brake cables, camber rod mounting changed on the later C4s...definitely on the differential side...which may have changed it on the knuckle side...so you would likely need the early camber rod differential mounts (which are NOT preferable, rear stabbing), later C4s rear shocks mount differently on the body side...so the length may not be right for the early knuckle mounting location....These are just a few issues that come to mind right off the bat!!! I would check RockAuto for e-brake cables and equalizer/connectors....I haven't checked for the later C4s, but I ordered all 3 (front, lh rear, rh rear) for my '84, just to have spares in the future...all 3, AC Delco, around $60 total!!!! Since your talking about replacing everything in the rear to aquire the early setup, why not just get the correct parts new and save yourself from the other issues that you will need to address!? On a side note, how does your brake pedal feel? When you apply full pressure, does it stay rock solid, or does it drift to the floor? I'm not familiar with the later e-brake system, sounds like you apply the brakes....this squeezes the pads tight, you set the e-brake, which pins the pads in that position and then caliper piston pressure doesn't matter anymore....but if the M/C is bypassing/bleeding off on the rear circuit when the pedal is depressed, is it possible there isn't enough initial pressure on the rear pads to begin with right when you are pulling the e-brake lever!? Sorry, just thinking out loud....At any rate, my vote would be to address your current setup, rather than the can of worms that retrofitting the early setup would entail, obviously it can be done, but it's not as simple as just changing the knuckles! Good luck👍

 

I thank you very much for this indepth comment. It seems that there are too many parts different between the earlier and later C4's. So I have no alternative than to try again with the caliphers until I get a success.