ABS does not engage on front left wheel
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Joined: Sep 2020
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Well I finally found the time to swap the ABS unit and I'm still having issues with the ABS. The behavior is a little bit different now though...
Depending on hard I get on the brake pedal the ABS will pulse but if I really slam on the brake pedal I get full lock and lots of tire smoke. Luckily I'm running on some old 7 year old tires so I don't care too much about flat spotting them. Given that the front left is no longer consistently locking up compared to the other wheels I'm guessing that the issue is related to air in the ABS unit.
Now that I think about it the ABS has never worked in this car and this car was rebuilt by the previous owner from a completely stripped frame... So it is possible that he was never able to successfully bleed air out of the ABS in the first place and by the time I had bled the system several times I had eliminated most of the air.
I was reading some older threads and Rob Rob had mentioned that it takes about 2 gallons of brake fluid to successfully bleed out all the air when replacing the ABS unit. Someone in that thread had also mentioned that if you had the OEM Honda scan tool you could manipulate the ABS unit and bleed it correctly.
I'll do some more bleeding and report back...
Depending on hard I get on the brake pedal the ABS will pulse but if I really slam on the brake pedal I get full lock and lots of tire smoke. Luckily I'm running on some old 7 year old tires so I don't care too much about flat spotting them. Given that the front left is no longer consistently locking up compared to the other wheels I'm guessing that the issue is related to air in the ABS unit.
Now that I think about it the ABS has never worked in this car and this car was rebuilt by the previous owner from a completely stripped frame... So it is possible that he was never able to successfully bleed air out of the ABS in the first place and by the time I had bled the system several times I had eliminated most of the air.
I was reading some older threads and Rob Rob had mentioned that it takes about 2 gallons of brake fluid to successfully bleed out all the air when replacing the ABS unit. Someone in that thread had also mentioned that if you had the OEM Honda scan tool you could manipulate the ABS unit and bleed it correctly.
I'll do some more bleeding and report back...
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Joined: Sep 2011
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From: Fremont, CA
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I just now read the part about bleeding ABS. I never had any issue doing that. I had to replace my module, so I did a bleed with my power bleeder, got it most of the way there. Then go out and do some hard stops engaging ABS fully, go back and bleed again, nice firm pedal. Did not take that much brake fluid to do it at all. But I doubt that is the issue here.
I am wondering though if it is not something else in the system outside of ABS. But, one would think the ABS system would read that a wheel has locked up and at least start trying to trigger.
@vtecbrown did you only have it with one wheel as he had originally and did you try swapping sensors back and forth?
I am wondering though if it is not something else in the system outside of ABS. But, one would think the ABS system would read that a wheel has locked up and at least start trying to trigger.
@vtecbrown did you only have it with one wheel as he had originally and did you try swapping sensors back and forth?
Registered User
Joined: Sep 2020
Posts: 4
Likes: 2
I just now read the part about bleeding ABS. I never had any issue doing that. I had to replace my module, so I did a bleed with my power bleeder, got it most of the way there. Then go out and do some hard stops engaging ABS fully, go back and bleed again, nice firm pedal. Did not take that much brake fluid to do it at all. But I doubt that is the issue here.
I am wondering though if it is not something else in the system outside of ABS. But, one would think the ABS system would read that a wheel has locked up and at least start trying to trigger.
@vtecbrown did you only have it with one wheel as he had originally and did you try swapping sensors back and forth?
I am wondering though if it is not something else in the system outside of ABS. But, one would think the ABS system would read that a wheel has locked up and at least start trying to trigger.
@vtecbrown did you only have it with one wheel as he had originally and did you try swapping sensors back and forth?
Yesterday I replaced both front calipers and bled the system again. On the first hard brake, ABS worked fine. After that, the problem continued and locked up 1 tire (drivers side).
The tires are old but with properly working ABS I would think it wouldn't lock up at all. I'm running out of parts to replace, lol.
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Joined: Sep 2020
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Welp, for those who need some sort of closure on this I solved it today and it was only after finding an exact same issue on the FJ Cruiser forums. Similarly, 1 tire was locking up with all mechanical parts replaced. I traced all of my brake lines to the source after thinking about it from how the unit would send power to a locked up wheel. My front brake lines were swapped coming out of the ABS unit! I can finally get this thing back on the track. Pretty exhausted after this ordeal, but beyond happy when ABS kept working flawlessly after the fix!
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