Brakes
Thread Starter
Navigator
Joined: Jun 2002
Posts: 9
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From: Arlington TN
Brakes
I have a question about my 1987 C-4 brakes. It seems they are not gripping when I apply pressure. My husband looked at the pads last night and they are not worn down but they are very slick, as is the rotor. Has anyone else had this problem? Should I just replace the pads and see if that solves the problem? I just hate to put the money on new pads and that not be the problem. Any help would be appreciated! :blueangel:
Team Owner
Joined: Sep 2001
Posts: 62,154
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: Brakes (Pamela)
It may just be the pads, but are you having to push the pedal to the floor to get them to grip?
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: Brakes (Pamela)
You could pull the pads and take a coarse sanding block to them and a fine sanding block to the rotors. Also apply some brake lube to the caliper pins after cleaning them.
Then take it out and bed the brakes with several high speed "quick slow downs" followed by about 10min of highway driving to cool the brakes.
Of course it wouldn't hurt to install new pads and touch give the rotors that light sanding to break up any glaze. Bed them with new pads too as it will minimize the chance of the adhesive binder glazing the rotors and pads.
Then take it out and bed the brakes with several high speed "quick slow downs" followed by about 10min of highway driving to cool the brakes.
Of course it wouldn't hurt to install new pads and touch give the rotors that light sanding to break up any glaze. Bed them with new pads too as it will minimize the chance of the adhesive binder glazing the rotors and pads.
Team Owner
Joined: Apr 2000
Posts: 27,818
Likes: 8
From: CT
Brakes
It might be equipped with the wimpy JL9 calipers. My brakes on my '90 are the way you describe. I've got new rotors, pads, stainless steel lines, new master cylinder etc and they still feel kinda mushy gushy.
I WAS going to do a Z06 upgrade this winter...but other plans took over.
Good luck.
I WAS going to do a Z06 upgrade this winter...but other plans took over.
Good luck.
Thread Starter
Navigator
Joined: Jun 2002
Posts: 9
Likes: 0
From: Arlington TN
Re: Brakes (65Z01)
As a matter of fact....there is a lot of hissing, but it comes from the brake pedal. The pads should have another 1/8 of inch to go and we have checked the brake fluid in the reservoir. I read something in the manual about an in-line filter could be clogged, but I'm not sure I have an in-line filter or where to find it.
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Safety Car
Joined: Jun 2002
Posts: 3,689
Likes: 1
From: St Petersburg FL
St. Jude Donor '07,'13
Re: Brakes (vader86)
Do you know which pads you have? You need to deglaze the rotors you can turn them or use 80grit sandpaper and sand lightly in a circular motion to take the mirror finnish off the rotors. You can also sand the mirror finnish off the pads the same way. After you deglaze the pads and rotors then (re-burnish) or follow a bedding procedure to create the proper transfer film of pad material to the rotors. Then it might be a good idea to bleed the brakes very slowly due to A.B.S. which will cavitate air if pumped too fast. Also make sure the hoses aren't cracked or swollen. The hissing by the pedal usually means the booster is bad.
:flag
[Modified by VBP, 9:38 PM 9/20/2002]
:flag
[Modified by VBP, 9:38 PM 9/20/2002]
Team Owner
Joined: Sep 2001
Posts: 62,154
Likes: 1,731
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: Brakes (Pamela)
the booster is a big round black thing beside the valve covers on the firewall, and next to the Master Cylinder
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Brakes (Pamela)
If that 1/8" is total pad thickness, replace them now before you need rotors too.
The booster is the large bellows above and to the right of the battery. I've heard that when it leaks it can be heard from the driver's seat. It might be time for the Haynes on that one. Also, if the booster has failed the pedal will be harder and lower than it normally should.
The booster is the large bellows above and to the right of the battery. I've heard that when it leaks it can be heard from the driver's seat. It might be time for the Haynes on that one. Also, if the booster has failed the pedal will be harder and lower than it normally should.
Racer
Joined: Feb 2002
Posts: 362
Likes: 0
From: In
Re: Brakes (Pamela)
if you are hearing a hiss coming from the brake pedal, your brake booster is toast. not too hard to replace, but after recently replacing mine I would not buy an aftermarket one like auotzone again. It seemed cheap compared to the gm pc.
good luck
david
good luck
david
Pro
Joined: Dec 2000
Posts: 513
Likes: 30
From: Tonawanda, NY USA
Re: Brakes (hotwilzz)
I had a similar problem... The break fluid was dark like chocolate syrup. Flushed the system and it made a HUGE difference. The pedals go do so easy now. If they have not been flushed recently it may be a good idea.
Cruising
Joined: Sep 2002
Posts: 10
Likes: 0
From: Bayswater Victoria
Re: Brakes (Pamela)
Having read some of the post on this topic and as a new member myself, I thought I'd chime in with my 2 cents as I had a similar issue myself. Some other members have pointed out it may be a power booster issue, and that you can determine this if you here a hissing sound from the booster when pressure is applied to be brakes, with the motor running. While this is correct there are other symptoms of an inoperable power booster, normally they will be a very firm feeling pedal that requires a high effort to obtain any retardation and combines with poor brake performance. If you do not hear this hissing sound from the booster when holding the brakes, this does not always mean the booster is good, the PBR booster makes extensive use of plastics, these plastics while strong can crack over time in the hot engine compartment, this will lead to large vacuum leak that is not audible. As for the other casuse of poor brake performance, contaminated brake fluid generally has a very soft pedal, but does not have the very high pedal effort to push to the floor. New pads with freshly machined disks should work very well when first used without taking the ‘glaze’ off. So by the age of your car and the symptoms, I would bet on the booster being the issue.
[Modified by MartyD, 7:29 AM 9/21/2002]
[Modified by MartyD, 7:29 AM 9/21/2002]
Safety Car
Joined: Mar 2000
Posts: 3,620
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From: Hillsboro OR
Re: Brakes (Pamela)
The hissing sound under the dash is a pretty good sign that the booster is bad. Its sucking air from part where the brake pedal rod goes in. Autozone should have one for your 87 and it may still come with a lifetime warranty.
Instructor
Joined: Jan 2000
Posts: 207
Likes: 0
From: Anacortes WA
Re: Brakes (AquaMetallic94LT1)
Had the same thing on my '87 roadster. Changed out the Power Brake Booster with an aftermarket unit from AutoZone. Turned out it wasn't any good. Seems like I also had a bad Master cylinder. Got OEM parts from 18CarFan, problem solved. Wasn't too hard and I didn't break anything expensive in the process (this time!) Good luck.