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Unusual ABS Code / Cold Brakes


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1989 Buick Reatta - 42,000 miles

So the weather got a little cooler and right on cue my brakes are hard and pull to one side or the other until the car is warm.  This started happening last fall as well.  Once I got through the winter into warmer temps, no problems.  My ABS light is on and has been on for a good while.  Here are the steps I have taken:

- bled front and rear brakes using the "How To" section directions

- changed out the discs and pads.  (Probably not needed since there was only 41,000 on the originals.  Actually left the rear pads on since they showed little or no wear and just replaced the rotors.)

- pulled the ABS code from the ADL using the proscribed A / H jumper wire per 1989 specs.

 

The code I received is 9 flashes in the first set followed by 10 flashes in the second set.  Removed jumper, no further flashes.  I read an earlier post from a member who had the same set of first codes followed by more typical ABS codes.  I don't see that anyone answered his question regarding the first set.

 

I am ready to move to the conversion phase and go vacuum assisted if I can't resolve this issue.  Any thoughts or info appreciated.  Thanks!

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DAVES89

In regards to the pull to the right or left I would go with your front flexible brake hoses are bad as the problem goes away when the car warms up. Keep in mind that while you only have 41000 miles on your car rubber failure can also be a time issue [31 years].

 I also don't think you read the codes quite right. I am thinking you really got a code "27" and "28" as the light blinks twice and then a short pause and then the blinking starts again.

 That would indicate to me that you have front ABS lead issues. What I do is get my mulitimeter out and read the ABS leads using the "Ohm" setting. I reading between 800-1400 is good.

 

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Ronnie

I think you received really good advice from Dave. He knows a lot about the Reatta brakes. One thing that caught my attention is you saying, "My ABS light is on and has been on for a good while." That being the case I think it might be safe to say the ABS part of the brake system isn't causing the current problem you are having with a hard pedal and the brakes pull to one side or the other until the car is warm. The reason I say that is because if the yellow ABS light is on all the time the ABS part of the brake system is disabled all the time the light is on. Dave, please correct me if I'm wrong about that. You know more about the ABS than I do.

 

Now, assuming I'm correct about the ABS being inactive when the problem occurs, that leaves the non ABS part of the brake system to be at fault. Like Dave, I suspect a brake hose might be causing the problem but you don't say it consistently pulls to just one side.  You say it pulls to one side or the other. Usually a bad brake hose that collapses causes the car to pull just to one side when you hit the brakes. Not both.  I think a clue to what is causing the problem could be you saying you had a hard brake pedal when the problem occurs. A hard pedal is an indication of low pressure in the system. That brings two questions to mind. 1) Was the pedal hard like when all the pressure has been relieved from the system by pumping the brake pedal 25 times with the key off? 2) Did the red brake warning light flash or come on steady when the problem occurred?

 

 

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2seater

I defer to Dave's knowledge regarding the ABS system and agree if the system is deactivated when the light is on, the problem is elsewhere. When I saw the pulling comment my first thought was the front brake hoses or possibly the calipers. I have experienced more of an issue with brake dragging with either calipers or hoses bad, but it seems the other causes have been tried. An infrared temperature gun may help identify if there is a brake imbalance in progress.

 

The other issue is the temperature oddity. We have heard of a few instances of high under hood temperatures possibly causing brake boost loss, and I believe Ronnie is one. This seems like the reverse. Clearances certainly change with temperature, as well as the effectiveness of the brake pads. I know I use the GM pads on mine and they do like a little heat in them to work their best. 

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Btw - I'm not the first owner on this forum to report 9 and 10 flashes. I ran the test three times to make sure I was seeing it correctly.  It seems that 50 degrees is the magic number. This car is a daily driver and I have put 10k on it in a year. As soon as the weather cools down the problem reappears.  Last fall / winter they pulled to the right. I will run more diagnostics including ohms test and report my findings.  Thanks.

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DAVES89

Well there is no code 9 or 10. 

Edited by DAVES89
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Update - Weather in Savannah is back in the 90's so I am waiting until it cools down again before more troubleshooting.  

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Ronnie
11 minutes ago, Jay said:

Update - Weather in Savannah is back in the 90's so I am waiting until it cools down again before more troubleshooting.  

It might be a good time to get some Freeze spray for electronic parts and spray it on individual parts to see which one causes the brakes to stop working when cold. Electronic stores should have the spray. You could also use Freon if you have any on hand.

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  • 1 month later...

I decided to replace the ABS relay. The ABS light has been on since shortly after I bought the vehicle. Not sure why I had not tried that from the start.  I think I assumed it would be the wheel sensors.  That is what I get for assuming.  In any case, $15.00 and a new relay later ABS light is off and working fine.  This morning we had a low of 39 so I decided to test the car and see if my cold weather brake pull had returned.  I felt a very slight pull on the first brake but worked perfectly after the initial braking.  I will continue to monitor as the temperatures drop over the next few months. Thanks for all your thoughts and input.  Let's see what happens next!

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