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How to Check CRT Codes to solve ABS Light & Electrical Warnings

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Bleeding the brakes:

 

After suctioning the fluid out of the master reservoir, I turned on the key and let the pump prime back up, which took about 30 seconds.  I then used Ronnie's modified trick of using a wooden stick with a flat end, in a "T" shape to put between the seat bottom and the brake pedal to keep pressure on the brake.  With the key on, it was a breeze to bleed the back brakes......no pumping of the brake pedal up/down, but just letting the pump push the new fluid to the back calipers.  Took a good amount before clear fluid started coming out, and just had to keep refilling the master reservoir numerous times to prevent any air getting into the system.

 

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Here is the front caliper:  I tried leaving the key on and hoped that the motor would push fluid out like it did on the rear brakes.  But I only got one push of fluid into the clear tube and then the flow stopped.  So, this does require a second person to be the foot-stomper on the brake pedal.  It seemed to work both ways.....with the key on and pump allowed to cycle, or with the pump off, and just using 100% foot pedal-pumps. 

 

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Went to the last one (drivers side), and even after soaking the bleeder several days with PB Blast, it did not want to come loose.  I even used a torch to heat up the caliper around it, but it still would not come loose......and it may be on the verge of stripping/busting in half.  So, looks like a new caliper will be needed on this one. 

 

But good to learn how to bleed these Teves Anti Loc Brakes, and to have fresh fluid in most of the lines/calipers.   Got to do other general repairs while the car is still up on jackstands, but will post if this solved the ABS warning light issue in the near future. 

 

 

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I thought the discussion about '91 ABS sensors was worthy of it's own thread so I move those posts here:  1991 ABS wheel sensors     It will make them easier to find in the future.

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9 hours ago, Studebaker said:

Went to the last one (drivers side), and even after soaking the bleeder several days with PB Blast, it did not want to come loose.  I even used a torch to heat up the caliper around it, but it still would not come loose......and it may be on the verge of stripping/busting in half.  So, looks like a new caliper will be needed on this one. 

If the pads are good, and the front brakes are working good, you might want to consider just bleeding that caliper with the banjo bolt that holds the brake line to the caliper. Use rags to soak up the old fluid that comes out to prevent it from getting on the pads. That would get the old fluid out of the lines but not the caliper.  Then when the pads get worn out you can replace the pads and the caliper at the same time and bleed the brakes again.

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Ronnie......Great idea, using the banjo bolt to bleed the line on that side.  But knowing that caliper bleed screw is gonna break on the next attempt, I might just order a new caliper and put it on........I would hate to forget that its on the verge of breaking, and then bust it off in the future with brake fluid flowing like Niagra Falls, and no way to stop it.  Ironically, the computer codes said it was an issue with this front brake......Im hoping it was just the grime on the wheel sensor, but who knows.....maybe there is a huge air pocket inside, or some other issue.  Heck, maybe the computer is so good that the ABS warning light was on to alert me that the brake bleeder screw was seized up and about to break off........pretty impressive computer for 1989, and it even survived Y2K.

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Got the new front left brake caliper installed, and then bled the brake lines. 

 

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I then tried to unscrew the old bleeder screw on the old caliper, and sure enough........it snapped right off.  So, Im glad I installed the new caliper and did not risk dealing with a busted bleeder screw and fluid leaking out until I could locate a new one:

 

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You will notice the new caliper hold-down arm sitting under the old caliper........Advance Auto sent a defective caliper which had the right hand bracket instead of the correct left hand bracket on it.  So I had to clean up the old bracket, clean out the caliper pin chambers, add fresh grease, and use the old ugly one....se la ve.  (There is a bump-out tab that hits the suspension and cant be used without grinding it off......so, I just went with the old).

 

Took her out for a test drive to see if the ABS warning light would go out after driving over 18mph.  At first the ABS light was off, then it came on only when I had my foot on the brake pedal, and would go out with foot off pedal.  After driving a few minutes, the ABS light came on and stayed on.  So, do I now need to try to "reset" the computer to make the light stay off?

 

The good news is that the red colored BRAKE light now stays off.

 

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1 hour ago, Studebaker said:

So, do I now need to try to "reset" the computer to make the light stay off?

No, the computer will automatically reset and the light will go out when it no longer detects a fault.  I would check ABS codes again and see what you come up with.

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Thanks for posting all the photos. You never know, they might be very helpful to someon in the future.

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Ronnie......OK, I will insert that wire and count the flashing light and see what it is telling me this time.

Yea, sometimes the pics help shed some clarity on the words.

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16 hours ago, Ronnie said:

Thanks for posting all the photos. You never know, they might be very helpful to someon in the future.

I do like quality photos, almost as good as yours😎 That is something I need to work on.

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And here is an upclose of that busted-off bleeder screw:  (more eye candy, right?)

 

So, if that bleeder screw had broken off while the caliper was on the car, what is the best idea to stop the bleeding?

Do you grab a piece of Double Bubble bubble gum, pop it in your mouth, chew away for a couple minutes, blow a few bubbles for the hell of it, and then slap that Doubble Bubble all over that busted bleeder screw?  Would this last a few days until a new caliper arrives?

 

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If the screw simply broke off without moving, nothing would need be done. It wouldn't remain closed and not leak. Bleeding at the hose connection would take care of the bulk of the necessary fluid flow although messy, as originally suggested.

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3 hours ago, Studebaker said:

And here is an upclose of that busted-off bleeder screw:  (more eye candy, right?)

 

So, if that bleeder screw had broken off while the caliper was on the car, what is the best idea to stop the bleeding?

Do you grab a piece of Double Bubble bubble gum, pop it in your mouth, chew away for a couple minutes, blow a few bubbles for the hell of it, and then slap that Doubble Bubble all over that busted bleeder screw?  Would this last a few days until a new caliper arrives?

 

The gum would work if it could withstand over 2000 PSI of pressure.  🙂 I believe the bleeder it has the full pressure of the brake system on it when you  open it. It might be possible to remove the broken bleeder with an Easy-Out after soaking it with penetrating oil for a couple of days but calipers are so cheap it wouldn't be worth your time.

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2 Seater.......I guess you are right, that no fluid would come out if the bleeder snapped off without it turning any.......so, there would be no leak to worry about.  No need for the Double Bubble repair job.  Bleeding at the hose connection is an option......but you should have seen the BLACK fluid/grime that came out of that old caliper, which would have remained. 

 

Ronnie.....With 2000 psi, that would be one HUGE Bubble....probably big enough to drive on it a few miles.  I agree.....at $30 for a caliper, not worth the time to repair it.  I was just wondering the best course of action if a bleeder did snap off in the future......I was thinking the fluid would be leaking. 

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Now that it has been brought up, I wonder what the actual pressure is at the caliper? Boost pressure could be as high as 2650# but I would guess it may be modulated downwards to the wheel? I have no way to confirm one way or the other.  Nominal pressure in most articles I see is 800-1500psi

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18 minutes ago, 2seater said:

Nominal pressure in most articles I see is 800-1500psi

That is what I found to. Most say about 1200 PSI. You could probably apply 800-1200 without power boost if you stood really hard on the brake pedal. I think the pressure depends on the size of the piston in the master cylinder.

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Interesting question by 2seater.....what is the pressure at the caliper bleeder?  The wierd thing is that if the pressure was way up around 800-1200 psi, then I guess that only applies when the system is contained, or "shut".....the bleeder not open.  When I opened the bleeder and my assistant pushed down on the brakes (with the electric pump on), the fluid did not come out with any high pressure, but came out somewhat the same as bleeding an old car with normal brakes. 

 

So, someone with a fluid-dynamics degree would have a set of formulas perhaps, and show that the 1200 psi will only build up on a closed system, and as soon as the bleeder is opened, that pressure drops super fast.  Also, the assistant did not have his foot slammed down on the brake pedal BEFORE I opened the bleeder, but after I opened it.  But if he had been a "wise-guy" and wanted to play a nasty trick, then maybe the fluid would come spraying out under 1200 psi if he did have his foot slammed on the brake before I opened the bleeder.  Who wants to give that experiment a try?

 

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1 hour ago, Studebaker said:

soon as the bleeder is opened, that pressure drops super fast.  Also, the assistant did not have his foot slammed down on the brake pedal BEFORE I opened the bleeder, but after I opened it.

Brake systems are high pressure but supply a very low volume of fluid with each pump of the pedal. Under normal operation there is very little flow of fluid. That is the reason the pressure drops at the bleeder as soon as you open it.  The fluid should squirt out the hole in the bleeder but it won't spray out as you would expect with that much pressure.

 

BTW, your assistant was doing his job incorrectly.  He should pump the pedal several times and then hold the pedal down firmly until you open the bleeder...  and continue to hold the pedal on the floor until you close the bleeder. Then repeat the process until all the air is out and the fluid runs clean.

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Ronnie.....thanks for the correct bleed information......I did not know that.  I will do that next time, but I did get a pure flow of clean fluid with no air/bubbles.  We had the key on and allowed the pump to run during the bleeding.....I see some say to do it this way, and others say to leave the key off for the front brakes.  (Definitely want the key on for the rear brakes, and I found it works fantastic with that pump doing the pushing when bleeding the rear brakes).

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The incompressibility of fluid is why many pressure vessels are hydro tested. 1000psi of fluid pressure and if the enclosure ruptures, the pressure drops immediately as it leaks out. 1000psi of air pressure and it's a bomb, so if there is a significant amount of air in a brake line is can spit and sputter until gone.

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ABS Warning Light update:

 

Since the ABS Warning LIght has stayed on after the brake flush and caliper replacement, today I plugged in the jumper wire to count the flashing ABS Light for the codes.

 

This time the ABS Light would not flash at all when I inserted the jumper wire between A and H terminals (pics on earlier page of this topic).  Key was turned on, and the ABS Light was yellow before attaching the jumper wire.  Any ideas?  If the ABS is in good order, would we expect the code light not to flash?  If so, any ideas as to why it remains on?

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