Hard brake pedal solution, finally!!
Pro
Joined: Oct 2004
Posts: 628
Likes: 6
Great thread; very very interesting. When I bought my '92 in 2004 the brakes were excellent (and I think huge brembo's on the front make a difference). HOWEVER - in the last year or so the brakes have been just OK - probably about as good as my wifes minivan, and I have a very hard brake pedal. I have also noticed that the 4mph ABS self-test which used to be quite noisy is very quiet now.
Theory - sticky valves in the ABS?
Anyway, as soon as I get a chance I will be excercising the ABS and will report back here.
Also - I wonder if anyone has a software solution via Datamaster (or similar) that might mimic the ASR/ABS "diagnostic and exercise tests" and therefore avoid the need to exercise the ABS in real-world situations?
Theory - sticky valves in the ABS?
Anyway, as soon as I get a chance I will be excercising the ABS and will report back here.
Also - I wonder if anyone has a software solution via Datamaster (or similar) that might mimic the ASR/ABS "diagnostic and exercise tests" and therefore avoid the need to exercise the ABS in real-world situations?
Drifting
Joined: Feb 2003
Posts: 1,614
Likes: 163
From: Davis CA
I noted something yesterday that I thought might go with this thread. While sitting in a traffic jam with my foot lightly on the brake, I turned the HVAC system off and my foot went toward the floor a noticeable amount. I suppose that the vacuum required for the system reduced the amount available for the power assist. I think that my brakes are OK but I can see that competing vacuum needs or losses could make a considerable difference and might not be easily detected. My MVAC system works very well by the way.
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Hmmm tis is more than interesting as always thought brakes just fine but got in a situation that required lots of brake yesterday and locked fronts with no feed back from abs. me thinks reseting abs might be worth a try and brakes not nearly as good as first thought. There are so many things I have found on this car that were 'rigged' from a/c to interior trim to radio I wonder if abs has been played with seems like at every turn I get deeper into this thing I get more disappointed in PO BS...
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
So how did you make sure each wheel went through ABS? Trial and error? I will be sure to give this a shot. When the ABS activated did the dash light go on? (I do not recall if I have been able to activate my abs recently since this a summer driver up on stands for some repair) Do you have the j55 or standard brakes?
We have the same year so I am hoping this will help.
We have the same year so I am hoping this will help.
Sorry, been away..
Yes, it was trial and error -- thankfully some of my back roads pool water in spots I knew about -- so just a bit of steering and timing -- although did I actually test each wheel -- not sure, but think so..
Don't remember if dash light went on, but don't think so.
BTW, our 94 has standard brakes (not the upgraded j55's), all OEM replaced new (rotors through rebuild calipers and many flushes/bleeds) in 2003 by me -- with only about 5-6k on them so far).
So, hopefully, when yours comes off the jack-stands, and you can find some water or dirt, you can do the 'test' and see if it fixes yours too.
Racer
Joined: Mar 2007
Posts: 419
Likes: 1
From: La Grange IL
brakes continue to improve
After allt he work done on brakes and after proper bedding, I have taken the car out and have done some simulated panic stops and activated the ABS many times to check. The brakes started out good and have improved both in feel and stopping power. I am not sure of the reason; better bedding of pad, system is self bleeding a little (especially in the ABS).
Note: I did this all on safe roads with no traffic, and being the goofy person I am, had the instructions off of the HAWK pads box with Bedding instructions, in case I got spotted and pulled over with these stops.
What a difference knowing I now can stop the car as needed. A major frustration and possible sale deal breaker has been eleimniated.
Just my 2 cents,
Note: I did this all on safe roads with no traffic, and being the goofy person I am, had the instructions off of the HAWK pads box with Bedding instructions, in case I got spotted and pulled over with these stops.
What a difference knowing I now can stop the car as needed. A major frustration and possible sale deal breaker has been eleimniated.
Just my 2 cents,
Heel & Toe
Joined: Oct 2006
Posts: 22
Likes: 0
From: Belleair Bluffs, FL
I am happy to report that this solution has worked for me! My brakes have been getting progressively worse since I bought the car a couple years ago and reached a point where I could not engage ABS even in the rain and the car was scary to drive on the street no matter how much flushing/bleeding of the system I did. I finally decided to give this solution a shot and talked to my local Chevrolet service department. I explained the situation and set up an appointment, I went into it thinking I was just throwing $100 away. I told the service manager I wanted to be present to make sure I could hear the ABS pump being cycled and he agreed to have the tech bring the tech 2 out to the car. He went through every diagnostic check in the tech 2 and definitely gave the ABS pump a workout. It didn't instantly cure things, but afterward I was at least able to engage the ABS on damp pavement, so I proceeded to repeatedly engage ABS over and over and eventually got the car to the point where I could easily engage ABS on dry pavement and the brakes actually work pretty darn well now. Its still not the hardest pedal ever, but the brakes/ABS are now fully functional! Anyone having these issues I can definitely recommend giving this procedure a shot.
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Safety Car
Joined: Jul 2004
Posts: 3,845
Likes: 30
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Great thread; very very interesting. When I bought my '92 in 2004 the brakes were excellent (and I think huge brembo's on the front make a difference). HOWEVER - in the last year or so the brakes have been just OK - probably about as good as my wifes minivan, and I have a very hard brake pedal. I have also noticed that the 4mph ABS self-test which used to be quite noisy is very quiet now.
Theory - sticky valves in the ABS?
Anyway, as soon as I get a chance I will be excercising the ABS and will report back here.
Also - I wonder if anyone has a software solution via Datamaster (or similar) that might mimic the ASR/ABS "diagnostic and exercise tests" and therefore avoid the need to exercise the ABS in real-world situations?
Theory - sticky valves in the ABS?
Anyway, as soon as I get a chance I will be excercising the ABS and will report back here.
Also - I wonder if anyone has a software solution via Datamaster (or similar) that might mimic the ASR/ABS "diagnostic and exercise tests" and therefore avoid the need to exercise the ABS in real-world situations?
Interesting, Brembo pads are the only ones that have worked for me with excellent results.
I had tried several different pads over the years but made no progress.
When I put the J55s on things were great, until the SBS pads wore down and I could not buy another set. I put on Hawks HPS as was back to scary brakes again even with the J55. Just be accident I found a super sale on Brembo pads on Tire Rack. I was back to having good brakes again and they were so good I bought 3 more sets.
It was suggested to me that I should have tried the Hawks+ , maybe in time when I am out of pads. I am going to start to play around with the rears to see if another pad is better that what I have now.
Advanced
Joined: Jul 2010
Posts: 53
Likes: 1
From: Avon CT
Crappy Brakes
I just bought My 1990 Vette three months ago . Ever since I got it the brakes seemed spongy and I bleed them multiply times like everyone else here . I was having an issue with high idle and saw a thread on that and spongy brakes caused by a bad brake booster , So I replaced mine still no help . I was going to rebuild the back calipers as I couldn't lock up the rear wheels with the car jacked up and in gear while appling the brakes . I ended up just ruffing up the disc's as a the calipers worked fine but still that spongy brake pedal .
This morning I started to read this two years and running thread about resetting the ABS and all that trouble code stuff . I finally figured I would try the panic stop at 20 to 30 miles per hour to see if the ABS worked !!! The first few time nothing and like others have stated , but then low and behold the dam
thing started to work and the brake pedal is high and hard !!!! So like others have said and I will agree You have to go out and exersize the dam ABS to get the brakes to work correctly !!!
They feel like something that should be on a Vette not a Flint Stone car like they were before !!!
This is a very , very helpful Thread !!!!
This morning I started to read this two years and running thread about resetting the ABS and all that trouble code stuff . I finally figured I would try the panic stop at 20 to 30 miles per hour to see if the ABS worked !!! The first few time nothing and like others have stated , but then low and behold the dam
thing started to work and the brake pedal is high and hard !!!! So like others have said and I will agree You have to go out and exersize the dam ABS to get the brakes to work correctly !!!They feel like something that should be on a Vette not a Flint Stone car like they were before !!!
This is a very , very helpful Thread !!!!
But its older than 45 days
Burning Brakes
Joined: Aug 2010
Posts: 951
Likes: 3
From: Placerville CA
I guess we just need to bump the good threads every 44.5 days.
It would be nice if someone could explain what's going on.
Race Director
Joined: Jun 2004
Posts: 13,963
Likes: 709
From: WI
And we need to bump the ABS every now and then, apparently. I'm one of those who reported success with periodically exercising the ABS to get the brakes up to snuff, but I still don't understand why it works. Every time it's the same thing: the first time or two the ABS is slow to engage, but after a few hard hits it gets much more responsive and the car stops faster -- or as fast as the ABS and road conditions permit.
It would be nice if someone could explain what's going on.
It would be nice if someone could explain what's going on.
Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
And we need to bump the ABS every now and then, apparently. I'm one of those who reported success with periodically exercising the ABS to get the brakes up to snuff, but I still don't understand why it works. Every time it's the same thing: the first time or two the ABS is slow to engage, but after a few hard hits it gets much more responsive and the car stops faster -- or as fast as the ABS and road conditions permit.
It would be nice if someone could explain what's going on.
It would be nice if someone could explain what's going on.
Again.. it's just a guess.
Race Director
Joined: Jun 2004
Posts: 13,963
Likes: 709
From: WI
This is just a guess so don't quote me. Your ABS is pretty much dormant unless it goes into action. Im not sure how the ABS on the C4 is designed but ABS is pretty much hydraulics, solenoids, valves with a controller. My guess is when it sits without use it gets sticky.
Again.. it's just a guess.
Again.. it's just a guess.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
Yeah, I'd suggest everyone buy $200-$300 pads...that will cure it
how long is this thread? and you come away still saying it is all in the pad??
Just to catch the rest of you up, I posted in another thread a pair of $20 pads as an alternative to high dollar Hawk pads and J55 upgrade.......of course the topic went from which pad (the OP needed new pads) to hard brake pedal..
And as the "group think" progressed, the ABS module being the culprit was poopoo'd as an alternative to why some have really crappy brakes no matter how many parts are changed.
Fast forward to just now......and the once again the "pad" is the suggested culprit......unbelievable
Aardwolf, I have to ask you....how many have to upgrade to the J55 and buy Hawk pads.....Get no improvement.....before you might discover that a simple ABS reset may be the most economical and expedient solution??
How many are you going to send the Parts store to lay out $120 for pads before you realize that there is an alternative that many many many have had huge success with for free??