Proportioning Valve (s)

[D-a-n-i-e-l]

Here is the deal. I am in the middle of a brake swap, using the complete ABS brake system from a 2002 camaro/firebird.

The Reatta uses a porportioning valve with its ABS system. The Camaro does its portportioning throught the ABS valve body.

Would keeping the Reatta valve cause a very spongy pedal?

[Guest Drake]

Daniel, if you're going to use one brake line to feed the rear brakes, I would leave the proportioning valve in the system. It directs equal pressure to both rear brakes. If you're adding the second brake line, the master cylinder will take care of it. Second, with all the work you've done, replace the proportioning valve with a new one. I recently replaced my brake lines & hoses. The proportioning valve was a solid piece of rust. Once I removed it, I could see debis & rust inside all three ports.( Still available through GM--part #25525844--approx: $48.00 ). Hope this helps.

[Roadster90]

I was under the impression that hte proportioning valve was the most expensive part of the system. There is a "pulling symptom" outlinned in a TSB where GM dictates replacing the proportioning valve for 1990 models and the part is big bucks...1000 - 1400.00 or something outrageous like that??????

[Guest Drake]

I was under the assumption that Daniel was talking about the Rear Proportioning valve, next to the left rear brake hose. This valve is for the rear brakes only. One brake line from the master cylinder feeding both rear brake assemblies.

Nic, you are absolutely correct about the proportioning valve assembly ( valve block assembly ). It is actually a main part of the Teves unit itself.

Hey,Daniel you out there?

[Guest steakneggs]

If you have too much proportioning, which is what you will have if you employ both valves, the rear brakes will be weaker than they should be, which might cause the fronts to lock, wreaking confusion on your transplanted ABS. But if the transplanted ABS works off of some kind of differential sensor, which it should, it might compensate for the 2 pounds of rust known as the Reatta prop valve. I would try it. You can always replace the valve with a T if something is not right.

[D-a-n-i-e-l]

Well unfortunately it was not the porportioning vavle. I am almost at a loss here. The only thing that is not new are the rear calipiers. I am not one to replace parts but it is almost my last shot.

The down side is that there is not any sign of failing in either calipier.

[Ronnie]

Daniel, It seems you may be overlooking the basics of a brake system. There are two things that normally will be the cause of a spongy pedal.

1. Air in the system. Since this is a custom installation you may have a place in a line where air is trapped like a hose or steel line that turns up for a few inches and the goes down again. Brake lines must always keep fluid flowing downwards to prevent air being trapped. You cannot go down, then up and then back down. Air will be trapped at the top. You also could have air trapped in the ABS valves that needs to be purged.

2. Something mechanically is flexing. Could be a hose swelling or a metal part that is supposed to be rigidly held in place is moving. If for some reason the caliper is not able to slide as it normally does while clamping the rotor, the piston will push back on the mounting bracket and cause it to flex.

I would put my money on air being trapped in the system some where.

[Guest Bobby Valines]

I dont know if this will help but years ago i bought a 84 camaro could not get the front brakes to work properly after changing everything except rubber lines I undid lines at callipers had someone push on brakes and seen that both the rubber lines were cloged or pinched. just a thought before you buy new callipers.

[Richard S]

Daniel, what all was involved in this changeover? Did you have to modify the brake pedal? Cut any brake lines? Can you give us a little summary. If you are dealing with a spongy pedal, seems like you are way past the midpoint of this conversion. I would assume you are getting enough push rod travel to fully actuate the Camaro system.

[Guest simplyconnected]

Chevy makes a good system that works well. Everyone has their own preference on proportioning, so I suggest you use an adjustable proprotioning valve. They aren't too expensive:

Summit Brake Proportioning Valve, Knob Adjustment, 1/8" NPT, Single Inlet/Outlet, Aluminum, Each $38.95

Here's the link: Summit - Proportioning Valves

Spongy pedal can be caused by air, 3-hoses, power booster, or silicone brake fluid, and a combination of all. Each 'zone' can be isolated by blocking off with a plug. If you cannot get all the air out, use vacuum - nothing needs to be removed, and it is absolute (just like the factory). Otherwise, regular bleeding should do it.

[Guest steakneggs]

I also misunderstood how far you are along. The spongy pedal is probably due to a pocket of air close to the m/c that won't escape by the normal bleeding method. The easiest way to get it out is gravity bleeding a whole quart of brake fluid through the system. You can do all four wheels at the same time but the best way is a wheel at a time so that you can watch for bubbles rising in a section of clear tubing suspended from a strut. But before you do that you must bleed the m/c by loosening one line at a time (at the m/c) while someone pushes the pedal. Get tubing that fits tight on the bleeder valve so you can empty the extracted fluid into a container without making a mess. Steak

[Ronnie]

Daniel, I would like to know the outcome of your spongy brake problem. What was the problem?

[D-a-n-i-e-l]

I am not sure as of yet. I have it narrowed down to the rear portion of the system. Also it is not the calipers. I am at a loss. I may switch to the non ABS system from the Eldarodo/Riv.

[Guest steakneggs]

If you've "settled" for a non-ABS system, why don't you just connect the lines straight to the m/c? (Assuming it has a separate ABS). If you plan on scrapping the Camaro unit for another, Crazytrain2 says that his '89 Park Avenue has a Teves but some came with non-ABS and could be the direct replacement some have been looking for. Also, if you have isolated the source of spongeyness, I would try to find it. It might still be there with the new unit. Steak

[Guest crazytrain2]

Sometime over the next few days I'm replacing the Hydraulic valve assembly on my Teves Mark II system... I have similar brake sponginess issues and I'll let you know if this solves it.

I'll get the bolt pattern from my Teves system and the distance to cotter pin length (+- adjustment)for brake pedal connection to help determine if the swap out system can be used for your Reatta

[D-a-n-i-e-l]

OK I am going in a bit of a diffrent direction now, and ditching the camaro ABS. I am going to use a 91' riv abs unit. I will try to post a complete write up after it is all working.

[Guest Albert]

try pinching off the rear brake line(s) at the flex hoses and see if the pedal is a lot better, you may need a resudual valve which will keep about 2lbs of pressure in the rear lines at all times

[Guest steakneggs]

Sorry it didn't work out. 7654321 has done the '91 conversion. But he didn't use the ABS. I suggest you do the same. Steak

[D-a-n-i-e-l]

I have all the stuff to do the non ABS convertion, but the main point of my endevor is to provide a ABS replacement for those who find they no longer want the Teeves system. I was hoping to use one a bit more common than the 91' ABS system, but the communitcations proved to be more of an issue than the average back yard mechanic would be capable of dealing with.

The issue with using the camaro ABS is I can not make it open the valves to release the air for bleeding. At least that is my best gues of why it is giving me issues. I will know for sure as soon as I install the 91' set up.

[Ronnie]

Daniel, Before you give up on the Camero ABS read this page. Scroll toward the center of the page to see the procedure for bleeding the ABS.

[D-a-n-i-e-l]

I have the factory service manual and the Bosch manual for the system, and the bleeding is exactly the same. The issue I have is there is no can2 buss in the Reatta. So there is no way to comunicate with the ABS brain. This also means that the ABS light would be on due to lack of communication with the buss. If I had the tech tool I could figure out a communication set up for it, but no one in there right mind will let me play with a bundle of wires and there tech tool.

[Ronnie]

I appreciate you trying to come up with a good replacement for the Teves system. I'm sure you will find something that we all can use as a replacement if you keep trying. If I can help, let me know.

[DAVES89]

I have never claimed to be the smartest guy around, but wouldn't it make sense to just look up the parts needed for a '91 Reatta, cross reference those parts to other GM cars and get those out of a salvage yard? This way you would have a known working system.

IMHO I have watched a number of attempts to change this system because they don't like the pressure switch and accumulator. Which has a total cost aprox. $200.00 and how much time and $ is spent on these "upgrades"?

I acquired my backup parts by selling used parts at Flint.

I used that money to buy a NEW accumulator from Boorata who had 2 accumulaters and 1 Reatta. Then while walking thru a u-pick yard I saw a switch with the Begium sticker on it. I got it for $5.00. These parts can be had cheap, all you have to do is keep your eyes and ears open and be patient. The most important thing to remember is that one day when you have troubles I can look in a service manual for my answers, what will you do? Ask around for help? Guess? Or if you sell the car[and one day you will], what does the new owner do with a car that is not stock, and the mechanic says "I can't help you"?

I am sorry if I offended anyone, but I just wanted to state my opinion.

[D-a-n-i-e-l]

See my worry is some one that does not know much about cars is driving there car with the teeves system and there accumulator has been out for some time. Then one day they are driving down the road and the pump, that has been woring over time for the last week over heats aned gives up. Sending the drver and any passengers into the back of the car in front of them. Once the teeves pump gives up there is not a chance of stoppong these cars in a short distance. I almost lost mine the night I bought it, for this same reason. Plus if you motor goes it will cost you $500 for a rebuilt one.

As far as the rest of the issues. A pemanate not under the hood and on the brake mastercylinder and ABS will tell any one who is going to work on the car what system it is and where to find it. Second, the 91' system should comunicate with the earlier computer set up. So all the code shoud be able to be pulled from the TCC and code readers.

I do agree a properly maintained Teeves is as good of a brake system as any other but the key is "properly". Most drivers do not maintain there vehicles the way they need to be maintained. Also I did not like the softer feel in the peadal after upgrading to the camaro front calipers. In my up grade I am keeping the Camaro mastercylinder. This should give me the braking I want and still make for a realistic swap for the 91' set up.

[DAVES89]

So not to be a wiseguy, you are going to buy all the 99-90 Reattas out there to fix them?

[Guest steakneggs]

Your efforts to replace a flawed ABS with a more conventional one is noble, but the dealings with black boxes is beyond the abilities of most potential convertees. I could be wrong, but I would guess that the loss of ABS is a small price to pay for ridding of that atrocious Teves. Steak

[jonlabree]

Read your PM's

[KDirk]

Regarding the interfacing of the electronics for the ABS, I have a thought here, and someone please correct me if I am wrong:

The ABS system isn't that tightly integrated into the vehicle electronics from what I can tell. Meaning that the BRAKE and ANTI-LOCK indicators are activated by discrete outputs from the ABS module to the IPC, not over the serial data line. Really, it's interaction with the ECM & BCM is minimal, to a point where it is almost a stand alone system.

Further, the ABS module is picking up the wheel speed sensor sensor readings directly through discrete inputs, same as the 1991 system, which does have a different harness at the module but is receiving the same signals.

From what I see looking at both a 1990 & 1991 FSM, the ABS diagnostics are not part of the standard vehicle OBD performed on the ECC (or CRT for 1988/89 cars). ABS diagnostics is accessed by grounding terminal "H" on the ALDL connector, which then "flashes out" the codes in a pulsed format using the IPC ANTI-LOCK indicator.

My point in all this is:

1. The ABS system is not so inextricably tied to the vehicle electronics that it cannot be changed to newer system, ABS controller and all. Best candidate would probably be the 1991+ Bosch system that was used on E-platform cars. This includes the pre-1995 Eldorado (still OBD 1), the 91-93 Reatta/Rivi, probably the 91-92 Toro and Trofeo among others. More sources for parts!

2. Many of the electronic components of this system are probably the same: the IPC is the same for 88 & 89, and for 90 & 91, the wheel speed sensors are almost certainly the same, the ECM is identical for 88-90, 91 is slightly revised. We all know GM likes to recycle as much of this tech as they can to reduce costs.

3. The ABS controller harness would obviously have to be changed for fitment to a newer system. If this was done right and pinned correctly using a 1991-93 E-platform Bosch system and corresponding harness, the change would probably be transparent to the rest of the on board electronics, making for the "easiest" conversion.

4. Of course, there would probably be need for elimination of some of the relays used for the Teves system, but that seems a trivial part of such a conversion.

5. The mechanical/hydraulic portions of the system would be the biggest hassle in making this changeover, and Steak and others here have already tackled that.

All I'm saying is that if I had to ditch the Teves setup, I'd probably get a complete Bosch setup and put it in complete instead of fighting so many unknowns and doing so much custom work, if I really wanted to keep ABS.

Just my thoughts, YMMV.

KDirk

[Richard S]

Just a comment to follow Daniel's. I did not feel the "softer" pedal he described until after several months on the job [the change was pretty slight]. I am preliminiarily attributing that to the stock brake hoses that may be bulging or flexing. I will report back after my new stainless hoses are installed.

[D-a-n-i-e-l]

OK just a update and a bit of humility on my end. I have placed a 91 Riv ABS system in the Reatta. The ABS is wrking and the pedal feel is right. I replaced the 89' Reatta pedal with the 91' Riv pedal and powerbooster. I am using the 02' camarow master. I now know that the powerbooster I was using was the issue. I had to have the plate on the pedal extended so it would engage the brake light and cruise buttons. I will do a full write up after I figure out if the ABS light will intergrate with the 91' system.

All in all I am happy with the new brake setup.

[Guest steakneggs]

It would have been easier to ream the pushrod hole depending on how much material is there. Steak

[KDirk]

Daniel,

Any chance of a "writeup" on this conversion? I am hoping to buy a 89 in the next 18-24 months, and will probably want to de-Teves the car I end up buying, and going with the Bosch setup, as yopu have done.

It would certainly benefit anyone who has (or is planning to have) a 88-90 to get rid of that scurvy dog named Teves.

KDirk.

[D-a-n-i-e-l]

Yes I will, but I am waiting to see if I find a solution for the ABS light and communication issues.

[Guest steakneggs]

From the Anti-ABS wing: Simply remove the old unit, install the new one and drive away. If you want electronics stopping your car than it's a little more complicated. Steak

[D-a-n-i-e-l]

The ABS is working already. I just want to intergrate it with the whole system.

[KDirk]

Daniel,

Looking in further detail at the service manual, it seems the anti-lock light is activated by a direct output from the EBCM to the IPC, and not any serial data. Since the 90/91 IPC's are the same and thus utilize a common input regardless of whether the Teves (1990) or Bosch (1991) is installed on the car, then the amber anti-lock indicator should work as long as the harness at the EBCM has been pinned to reflect the different pinout between the two EBCM types.

Further, since the 88-90 use the same Teves EBCM, I would extrapolate that the 88/89 IPC expects the same signal at the Anti-Lock indicator input as would trigger the indicator on a 90 or 91. Bottom line is that this should just be a simple matter of tying the Anti-Lock indicator output at the EBCM to the corresponding input at the IPC.

Now, the brake (red) light is controlled by serial data from the EBCM by way of the BCM which then signals the IPC to activate the indicator. I would be awfully surprised if the data format differed since this seems like more re-work than GM would normally undertake. In any case, this looks like the more questionable part of the changeover.

One other thing, I note that the EBCM harness connector appears to be the same, whether Teves or Bosch. The pinouts are different, almost completely in fact. But, it is interesting to me that GM must have dictated that Bosch make the EBCM module to use the same connector type previously used on the Teves module. I certainly don't think that would have happened by coincidence, since it is a rather unusual type of connector.

Please keep us posted on this.

KDirk

[D-a-n-i-e-l]

KDirk,

You hit it on the head with that. I belive I can trick the system into turning the red light on for a low brake fluid (just as in normal braking systems).

As far as the ABS light, I thought it would be just as you said but the light is still on and I have not looked too closely as to why. I will look at the light issues this weekend. Thanks for the input, I realy do apreciate it.

Daniel