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Username Post: 1992 Caprice ABS system delete        (Topic#330575)
Forum Newbie
Posts: 37

Reg: 11-18-15
11-18-15 03:22 PM - Post#2589880    

I have a '92 Caprice that I want to completely take the ABS brake system out of. The reason is that the way they did the brake lines on these cars, routing the lines from the proportioning valve to the Bosch ABS "box" at the front of the car goes under the steering column and the A-arm and is nuts to deal with. Also, GM's brilliant use of parts lying around that were SAE and Bosch's metric parts resulted in a mismatched system that is total hell to repair.

I liked the system used on the previous 30 GM RWD cars I owned, the only brake failures I've had on GM vehicles were both on '92 ABS equipped Caprices, mainly because the brake lines were badly rusted and the repairs so awkward.

I'm thinking that if I buy the previous version master cylinder (say from an '85 or so Chevy), a basic $50 proportioning valve from Summit, all of which are SAE, I could then plumb the car in the same way GM did brakes from say from the mid-60's up until the ABS mess. I guess I could buy metric to SAE adapters and use my current master cylinder. The brake calipers on the '92 are SAE (same part as an '84) so with new brake hoses they should work.

Has anyone done this and have any pointers?

I have done all regular brake repairs and I'm familiar with bending/flaring lines.


Edited by iRt on 11-18-15 03:25 PM. Reason for edit: No reason given.


Forum Newbie
Posts: 37

Reg: 11-18-15
12-10-15 11:18 PM - Post#2594777    
    In response to iRt

Update: I ended up replacing all the lines in the ABS system. It was an epic saga of a job, mainly because of the mess GM created! Holly Schmolly! You've got 1/4" lines with a 12mm fitting on one end and an SAE fitting on the other, bubble flares on the front that split into inverted flares at the pumpkin, 3/16" lines with 10mm fittings and 3/16" lines with 12mm fittings...

But it's done and here's what I learned: I used steel line, the type that came on the car originally. Nowadays that isn't common, at least here in Hawaii. O'Reilly and Napa are both switching over to the epoxy painted lines, which although they bend easily, in my rust-prone area doesn't stand up well - I had one rust out in less than two years. I had to go to a specialty place where they made the custom bubble flare lines. It was a massive time user-upper. If I was to do it again I would have used nickel copper lines and bought a roll each of 1/4" and 3/16". It very well might be worth it to buy one of those fancy-pants $200+ flare tools.

There are 5 lines going from the combination (proportioning) valve to the ABS unit and they all go under the steering column and the A-arm and clip into plastic line separators. Easy to do when the body is off the car but I doubt many could pull it off with the body on. I opted to make 3 lines go under the A-arm and steering column and the two going from the combination valve to the ABS unit go on top of the A-arm. I didn't duplicate the 360Ëš coil shaped line shapes at the ABS unit.

Truthfully, I kind of regret not pulling the whole system out and changing it back to the pre-ABS system GM used in the past. I think it was a better system. If you don't tailgate it takes away a lot of the need for ABS brakes. It doesn't snow a whole lot at my place. The speed sensors on ABS cars take their speed reading from magnets that interact with small fins cut into the inside of the rotors and drums. Here in the Rust Center of the Universe those fins are a blob of rust within a year and the magnets are covered with a big ball of rust fragments, so I honestly don't think the ABS system even works on most older cars here.

So in the end, I'm glad it's done and it feels safe but I would have been much prouder had I yanked the whole ABS system and put it in the garbage, I think that it would be a better car, just my opinion. It would have been less work and I am really big on simplicity. Less parts = less to go wrong. To quote Leonardo da Vinci - "simplicity is the ultimate sophistication".

I think a lot of these bubble Chevy's will be sent to the crusher because nobody will want to go through what I just did. But because "in theory" ABS brakes are a "huge technological advancement" (intentional sarcasm) there will probably be little support for converting to the pre-ABS system.

Forum Newbie
Posts: 37

Reg: 11-18-15
12-11-15 11:34 AM - Post#2594854    
    In response to iRt

Another thing I learned, maybe everyone knows, that works great is using solder to measure brake lines. I took a roll of electrical solder (thicker plumbing solder would have worked better), taped it up to an old brake line with all the bends, then made a sharp bend in the solder where the old line ended. Then I straightened out the solder except for the sharp bend at the end,and there you have it - the correct length for the new line.

Also, you can use open end wrenches , like a 3/16" and a 1/4" to measure the thickness of the lines, but that only works on lines that aren't rusted to Smitherines (where exactly is that? Canada?).

This is turning into a "Lonely Guy Thread", would people get up and dance if I played "Proud Mary"?

Forum Newbie
Posts: 37

Reg: 11-18-15
12-13-15 04:05 PM - Post#2595276    
    In response to iRt

Columbo: "just one more thing"...

This repair started with my terrified wife bringing home the '92 Caprice with no brakes at all a month or so ago.

A look under the car revealed a rusted out rear brake line, one of the ones that goes from the differential to a wheel.

What bothered me from the start was - why did she completely lose all the brakes? Isn't that why they introduced dual brake master cylinders 50 years ago?

The other day I reflected back on the time 5 years ago that the same rear line rusted out on another '92 Caprice I had and at that time I also lost 100% of the brakes.

So why, in both cases, did I lose 100% of the brakes when just the rear brakes lost fluid?

My current Caprice has 105k mi, the one 5 years ago had about 95k mi at the time of the incident.

I have only lost my brakes completely those two times in 40 years and 35 or so GM RWD vehicles, and I blame the ABS system. There were never any codes sent out before the failure and the brakes always seemed correct before they failed.

I am now wondering if ABS actually stands for "all b.s." and if all these cars have a defect where the Bosch ABS system, when one master cylinder is empty causes it to act like it has only a single master cylinder.

It seems like the ABS system is a booby trap and I would highly recommend completely yanking it out of the car. Throw it in the trash where it belongs, yet another con job masquerading as an automotive improvement. That's my call. Anything to make the car cost more and what better way than something crooks can ask the ignorant "well you want your car to stop don't you?".

Convert it back to the time tested pre-ABS design, once again we were conned.

Remember back in driver ed when were taught "leave 1 car length between you and the guy in front of you for every 10mph you're going"? It seems like nowadays if you did that you'd be driving backwards and end up at home because people would be pulling in the space in front of you. In some ways it seems like ABS has enabled people to drive like idiots.


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