ABS was non-functional when I bought the car years ago, which was fine for me, since I don't drive the car in the winter. But now that I had to replace a rear brake caliper(it's a disc\disc brake system), I can't seem to bleed the new caliper without, according the the service manual I have, "re-homing" the solenoids with a diagnostic unit I don't have. And maybe also repair the ABS system, the manual seems a little vague about that. So I've just removed the EBCM; I want to put just a simple proportioning and distribution valve in its place, using as much of the original brake lines as I can.

Summit points me to a fixed proportioning block,SUM-760185, that is says will fit a 1995 Firebird. But is lists the threads as: Inlet sizes are 1/2 in.-20 and 7/16 in.-24, Outlet sizes to front are 3/8 in.-24 and rear outlet is 9/16 in.-18. The threads on the OE brake lines(and master cylinder) appear to be 1.0mm and 1.50mm by measurement with my metric thread file. Are metric proportioning\distribution valves available, or do people use conversion connectors to connect to the original lines? I looked at Wilwood's site, but didn't see anything metric there, either. I did find a 3/8-24 to M10-1.0 adapter at a local auto store. I imagine there must be a 9/16-18 \ 1/2-20 \ 7/16-24 to metric adapters out there somewhere.

Or I could go with an adjustable proportioning valve for the back brakes, and a line splitter for the front brake lines. But I didn't find metric thread versions of those, either.

 

Do you have the official factory service manual? I thought there was a back-up procedure without the Tech tool to home the motors. I’ll check my copy of the 95 manual. If you don’t have the factory manual I can provide a link to a free download.

Shoebox has tables of the (non-TCS) metric brake line connection threads:

http://shbox.com/1/brake_pipes_frt.jpg
http://shbox.com/1/brake_pipes_rr.jpg

An editorial thought…. the benefits of an effective ABS system are not limited to winter driving. It increases braking AND STEERING performance on wet pavement, dry pavement, gravel. I’ve had a personal experience on a 35 MPH dry surface of avoiding T-boning a vehicle which suddenly pulled out in front of me from a side (STOP) street, and then stopped in the middle of my lane, instead of continuing across the intersection into the opposite side of the cross street. ABS brakes alone would not have stopped my car in time, but the fact the front wheels did not lock up allowed me to steer right, missing the side of his vehicle, as I turned into the side street.

 

Yes, I have the official GM service manual. There's something about not being able to rehome the solenoids if the car has traction control. My car has a traction control button in the console, but not a 4th brake line from the EBCM. I think that means it has just a throttle relaxer, but I'm not sure.

I agree the primary benefit of ABS is to allow the operator to maintain steering control. Not sure about a shorter braking distance - ABS seems to me to usually lengthen braking distance. In any event I'm used to driving old cars without ABS - I have 2 1970s Camaros I also drive in the warm months. I've been driving them since they were new. To fix the ABS on the Formula would require a new left rear axle(holes were ground in the exciter ring to allow replacement of rusted wheel studs), probably replace all the wheel speed sensors, and maybe replace the brake line solenoids and controller. The car has 180,000 miles on it, and the original owner drove it through 10 Michigan winters. Fixing the ABS is just not worth the time and money. If it was a 25,000 or 50,000 mile car, and I thought someone might drive it after I was done with it, I would have a different attitude. But I think it will go to a junkyard when I'm through with it.

Thanks for the shbox.com links, that answers my questions about the brake line threads. I think I just need to find the adapters to connect to the short pieces of brake line I need to bend to connect everything up.

 

You indicated you removed the “EBCM”. That's ABS only. If your car has traction control, it uses an “EBTCM”. Does the vehicle have the big black servo mechanism sitting over the driver side valve cover? ….. reluctor rings and sensors on the rear axles, rather than a single sensor on top of the differential housing?

https://www.ebay.com/itm/365157084714

 

Look at the brake line diagrams in the service manual. Both ABS (page 5-10) and ABS+TCS (page 5-15) have the same three pipe connections on the side of the motor pack. The single rear brake line in ABS+TCS (101) wraps around the front of the motor pack to a brake pressure modulator on an extension below the main motor pack. That is where the rear brake line splits to provide individual hydraulic lines to the rear brakes. That section of the factory manual is also where you would have found the thread info that Shoebox copied.

The TCS operates on three different systems to eliminate rear wheel slip during acceleration: 1) The servo pack on the valve cover uses feedback from the PCM to the EBTCM to modulate throttle position. 2) The EBTCM provides a signal to the PCM to retard ignition timing. 3) The EBTCM operates the rear brake modulator.

There's an individual on ltxtech.com (Catmaigne) that has done brake modifications for his road racing setup. He might be able to advise on the best setup for a balance adjuster, etc.. We just don't have many active members here any more, so the chance of getting help is not good. ltxtech.com is not much better with regard to member activity, but Catmaigne posts regularly, documenting his efforts to maximize the road racing performance of his95 Formula.

In all honesty, I "deleted" the ABS on my 94 Formula. At first, while building an aggressive track car, I tried to maintain the ABS, but after I swapped in a Strange Engineering12-bolt rear with their optional ABS reluctor gear and sensor for 3 channel ABS I had problems. The Strange rear used a proprietary wheel speed sensor which was compatible with the GM system, but had to be adjusted and had a short life. Eventually I just gave up. I had installed a line lock in the system previously, and that would set off the ABS INOP light sometimes while doing a burnout. With no modifications at all too the brake system (other than some Baer larger diameter rear rotors) I stuck with a non-operating ABS system, with all the components still in the car. At the end of my ownership, the car was trapping 130 MPH and the original stock front brakes, along with the slightly larger rear rotors had no trouble pulling the car down from that speed in a reasonably short distance. In general, the car was not street driven very often.

The new owner (I decided at 80 years old it might not be a good idea to play John Force any more) has put the car deeper into the mid-9's and has trap speeds approaching 140 MPH and has no problem with the brakes, even with skinnies in the front and beefy drag tires in the rear. And he has deleted the motor pack and I believe he has a proportioning valve. I'll ask him what he used.

 

Yes, my car has individual wheel speed sensors on the rear wheels. There is a black box above the driver's side valve cover(the throttle relaxer, I suppose), and the single rear brake line out of the brake controller gets split into 2 just below it,



I think I figured out the metric vs. SAE brake line thing? The brake lines themselves are the same size either way - I measured 3/16 inch and 1/4 inch - it's just the nuts that attach them that can have either metric or SAE threads. So if I bend my own lines I can get them to fit SAE or metric holes just by picking the appropriate nut? Although I see the original lines have a "bubble" end, not a double flare like my '70s cars. I don't think my flaring tool(Snap-On, from the '70s) will do the bubble flare. I'll have to dig into that.

 

When I installed a Hurst line lock 25 years ago (fuzzy memory after all those years) Steve Spohn at Spohn Performance (Spohn.net) had the adapter/conversion fittings. Not sure if he sold them back then, but he used my car for prototype installs for some of the suspension parts he designed and built. I don’t own the car any more, or I would take a photo. If you contact him, tell him “Injuneer sent me”. Been a while since I talked to him. I should let him know the suspension I built using his parts (and advice) is producing 1.2x second 60-ft times.

 

Our dirt road finally firmed up enough for me to take my Formula out with the reworked brake system. Seems to stop pretty well; the Summit proportioning valve seems to work okay. It's actually stopping better than it has in a few years.

Getting rid of the ABS solenoid assembly and traction control pump cleared up that corner of the engine compartment a bit. The throttle cable control on top of the valve cover seems to only have the pedal cable and a cruise control cable going to it, so I guess throttle is not involved with traction control. I remember when working on the first electronic throttle control(ETC) systems, they said the justification was cost - putting an electronic throttle on the engine enabled the removal of the cruise control module, the IAC valve, and a throttle relaxer for traction control. But maybe throttle relaxer was only proposed, and didn't make it into production before they went to ETC.

Do the traction control pump and ABS solenoid assembly have any value, or can I just throw them out? I can't imagine I'd ever put them back on the car again.

 

The traction control servo (Throttle Adjuster Assembly) on the valve cover modulates (relaxes) the throttle in response to the EBTCM electronic command. Confirmed on page 5E2-9 of the factory service manual.

Drive-by-wire throttle activation, integrating cruise, TCS, idle, pedal position, etc. showed up on the 1999-2002 V6 F-Body models.

What part are you calling the "traction control pump" - the TCS modulator assembly? ABS solenoid = ABS hydraulic modulator assembly? I would think they would have decent value used, in good condition. Check on eBay.