I am thinking of removing my ABS.
Can't figure out the problem and don't want to get stuck far from home.

My brakes build presure and won't release keeping the pads dragging. After a few miles they get hot and you can't drive it anymore.

After replacing the sensors in the front the light is off but only intermitently. We checked the specs a hundred times and don't want to spend a fortune at the dealer and still get stuck away from home.

We think it may be the control module or something else like a defective designed system. Never liked how it worked anyway especially when power sliding the car.

I can get a set of lines and proportioning valve from an 86 to use that was non anti lock but it is in a messy junkyard and will be a pain in the *** to remove.

I also can make my own out of stainless steel with a double flare tool and buy an aftermarket bias control.

Anyone know if there is a kit available for racing that already has an adjustable bias proportioning valve? Maybe one with a cable that you can adjust under the dash.

I heard one person used what they called an otopus distributor block with the old lines behind the driver seat. Not sure if it was a kit or homemade. I would asume it had a bias control in it.

Is the 87 bias control built into the motor valve module because it is not in the normal place below the master cylinder.

Has anyone else done this before.
Any ideas or help?

 

Worst case is to replace the ABS Computer and the ABS Modulator Valve (Pump) all together. Keep and eye on ebay. Guys sell these together for less than $100 for both. I'm getting an ABS Pump for $45 and the ABS Computer for $30 on Ebay. Just yesterday there was a almost new looking Pump and Computer for $60.00 that came off on an 88 that no one ended up bidding on.

It seem easier to do this than to try and figure that out, and at the end have no ABS.

 

Why go through all this trouble only to end up with no ABS? You can get a good ABS Control Module and ABS Modulator Valve on ebay for less than $100 if you keep an eye out for one. I'm getting a good Modulator Valve and Control Module for $70.00 shipped to my door. Vette2Vette (1-815-673-6200) will sell you both for $150 shipped to your doorstep. If you have not already done so, use the ABS schematics in the Shop manual to see if you are getting the right resistance and voltages in the right wires at the right times.

If you do not have a GM Shop Manual, here is a helpful lik to check your ABS.

http://corvettefever.com/howto/19239/

If you insist on removing the ABS than just ignore this.

 

Are you sure the booster is operating correctly? Dragging brakes are usually more indicative of a bad booster (or stuck calipers) than a defective ABS. Yes, I got the part about the intermittent "light". I just don't think that's causing the brakes to drag. The only way I see it's possible for the ABS to be dragging is either the pump is comming on and/or there is some SERIOUS corrosion inside the ABS unit.

Oh ya, '86 has ABS too. IIRC 84 & 85 don't. The proportioning valve is on the side of the master cylinder (at least it is on my '86). Vette's don't use a standard disc/drum combination valve (no need for the metering valve w/ 4 wheel disc).

 

Have you checked your brake hoses? Most (95%) times a dragging caliper is due to the brake hose going bad. They rot from the inside-out and then act just like a check valve holding pressure against the caliper. A little-known fact is the recommended replacement interval is 5 years on brakes hoses.

A very simple test: wait till the brakes are dragging, then crack the bleeder screw on the caliper - if you have pressure (fluid squirts out), chances are very good you have a bad hose. If not, then you can trace it to the caliper either hanging up (VERY rare on a Corvette), or the slides are dirty. OEM type brake hoses are available at most quality parts stores, or you can upgrade to stainless (recommended).

YMMV

 

 

First of all I checked ever sensor and signal till no tommorrow.
I have come to the conclusion the system is a joke.
If it works you think it is great until you have a problem or get in an accident because it applied the brakes when you didn't want them to apply. This about it. You have a computer doing your safety thinking for you. How can that little box be better than the human brain. It can't and never will. I personally would opt out for that option on a new car. It is just more headaches down the line. I was accualy thinking of buying a new vehicle but i can't get it without ABS. So they lost a sale. But now on to the nightmare others will surely have.

Not all 86's had anti locks brakes
It was an option.

I have one in the junk yard without ABS that i plan to replace the lines with so i don't have to use an octopus connection behind the seat. I want to remove the spagetti of lines that go for an aft in the car.

On long trips you never know when the ABS will go. Most people have the light go on and the car still drives. Mine has the valve stick closed and the pressure doesn't release to all wheels so you could'nt get home and would need a tow. Then if I fix it I will be buying computers on Ebay every year because they are 20 years old to and will break soon. I want a permanent fix not temporary. No one has figured that out. To top it off I have to go to the dealer to bleed them because you need the special computer to open the valve during bleeding.

ABS is for girls
If you want to power slide a car you can't do it. The brakes come on because it activates the g sensor and applies the brakes.
Now that the ABS is broke it slides nicely without launching you back in the other direction. That's the main reason why i want it gone. ABS is for people who don't know how to drive a high performance car. They shouldn't be selling them to these people in the first place.

The brake lines may be shot and could be holding pressure
But if the valve in the module is holding the pressure to i won't know if it is the brake lines or the module. I guess i can open the line before the rubber line and then at the bleeder to see where the pressure is but the brakes free after sitting for only a few minutes. very strange problem and that is why it is not an easy fix. The master cylinder was once replaced and there could be air that worked it's way to the valves. But unless the whole system is reapaired then you just don't know. Put it this way it is not a simple fix and needs a lot of attention. So if I am going to spend all that time I want to avoid future problems.

With all the posts online with this same problem it is a major problem with a lot of owners. I feel if the car wasn't so old they would be seeing recalls and not sure why they aren't anyway since it is a safety feature that is faulting.

Thanks for that posts they have been helpful.

I plan to rebuild all the calipers and put SS lines in next.
Since I was going to apply special ceramic coating on the calipers to dissipate heat anyway.

I feel like this. The brake design worked fine for 100 years then came up with an expensive idea to make more money. My anti locks went on twice since i owned the car once when i moved the car out of the garage in the snow and the other time when one wheel was on sand in a turn and it shot me off the road like i was on ice. It must of thought i was in a panik situation. I rather do my own thinking and not have a computer do it for me.

The thing is there are no black boxs installed in the cars to see if the ABS works better or is more dangerous.
They took the word of the factories that make them.
So no one knows the real world situations.

Ask yourself this. How come they are illegal to use in almost all racing and why do race cars remove them? They may have traction control but not anti lock.

As for the bias with 4 wheel disc you still need to adjust the front to rear application pressure. I can install and manual adjustable reducer in the rear lines then tweek it to my preference if i want. Then you can run a cable under the dash to raise and lower the rear bias. That is a sweet feature in itself that ABS can't do.

In my 87 I can't find the proportioning valve on the frame rail.
It must be built into the valve module.
Going to the junkyard today to look at the 86 non ABS.

let you know how it goes.
I have a double flare tool and bender so i plan to copy the lines from the 87 and make stainless steel ones.

Then I will have a completely new non ABS system that can be fixed by a normal mechanic anywhere in the country.

There will be no need for the wizard behind a black curtain to help me.
Got to get headlight motors to since i have a winker now.
When it rains it pours

 

hmmmm, nah, no comment

 

Only kidding girls
What i should of said is ABS is for dummies.
Girl are good drivers to and better than some guys I know.

The reason ABS came along is because they said people didn't know how to pump the brakes or turn with a slide. So they invented a computer to do it for them.

Anyway I went to the boneyard to scope out the 86
I didn't see a proportioning valve on the frame rail with the non ABS car. Unfortunatly the lines were ruined and i couldn't see under the car. I may be able to use them as a template. So the octopus connector may be an option.

I have a 65 GTO I am restoring so i don't have the time to fix both. We are buying a new vehicle with a warantee soon to tow the GTO so we plan to sell the vette then. If someone wants to buy the Vette as is make me an offer.

 

I opened a caliper bleeder screw after driving it and there was still presure built up after a minute or so. It didn't squirt way out. But the car rolled a little soon as i opened it and released the presure. This shows me the brakes were still applied and something is holding presure in the lines. It could be the lines or the valve in the pump if that is posible. Not sure if the pump valve can do that or not. Anyone know? I can't find any detailed information or diagrams on this 2S system.

The master cylinder was replaced after the pedal went to the floor one day. The ABS light went on a little while after that incident. So I may have air in the lines or pump. Waht are the symptoms anyone know?

Can anyone answer these questions to?

1. Does the 87 ABS system sense pressure in the lines and can that set the light? I didn't notice any feeback wires or sensors going to the control box.

2. I plan to replace the lines with ss ones and rebuild each caliper first before i do anything. When i bleed the brakes do i need a special diagnostic tool to open the valves in the pump?

3. Can i use speed bleeders?

I would really like to keep the stock system in the car if possible to avoid all the work changing it out.

BIAS
By the way I read that the front to rear brake bias is located inside the master cylinder. There is a spring you can change if you want to add more braking to the rear.

 

I posted the headlight winker repair here:

http://www.automobiletest.com/servic...ghts/index.htm

 

Don't really know anything about the ABS system, however, I had an interesting problem on the way to Canada once after working on my unmentionable van-we had replaced the brake booster and pads and my friend adjusted the rod length -TO FAR, it was always applying the brakes to a point not noticeable-but on a stop we noticed a little smoke comming from the wheel-when I touched it it was HOT-so I pulled the wheel and guess what-the brake pads (new) were well worn-just thought I would pass this along.

 

I know this is a very old thread but hopefully some of you are still around.. I picked up an 87 to work on it's a project and the car has a very very hard pedal... the previous owner had all new brake lines installed for like $2000.. obviously the car had a brake problem.. this didnt solve it ...the pedal is still very hard as if there's a bad booster.. but there's no hissing in the booster and the vacuum is good. I noticed the fuse for the ABS was taken out of the car which makes me think somebody was trying to bypass the ABS... my question is would a bad non functioning ABS system or ABS module cause the pedal to be hard and have no pressure?
thanks in advance..

 

You may have better luck with your question by starting a new thread.