anti-lock pulsing at END of a stop?

[stl93fzj80]

I just finished a birf rebuild... (wished i'd replaced the birfs, because still clicks!) thought i could get away w/ seals etc, and soup was pouring out of the knuckles...
Anyway, all back together and tidied up, but strangly, now the Anti-Lock brakes pulse at the end of a stop... Like I can hit them and stop w/o a problem, but the last few inches of a stop are pulsing from the anti-lock. I thought I cleaned the rotors and pads well enough, but maybe i should get back in there and blast some more brake cleaner?
Any thoughts? Did I fubar something? YES, i did take the sensors out and put them back in... so i don't think i bumped one of those.

Any thoughts would be appreciated.
Thanks,
Doug

 

[Trunk Monkey]

Search, covered recently. Likely one of your sensors has shavings on it and needs to be cleaned - very simple.

 

[stl93fzj80]

Bummer. I tried the cleaning of the sensors, but alas, it still pulses at the end of the stop. Vacation coming up (of course). Think I may live with it or pull the fuse... It is more annoying than anything. Any other thoughts out there?
Thanks,
Doug

 

[slick621]

I have the same problem and cleaning all the sensors has not improved the pulse. I'm curious about a solution as well.

 

[Gumby]

I had the same thing on my 80. I thought it was a muddy sensor. The left rear one was cracked. As the pulse slows and gets weaker, the ECM loses signal and thinks it locked up.

Check to see if they are seated all the way. Just a tiny bit too much air gap will cause what you're experiencing too. Did you do anything to the rears?

 

[fj80psi]

I would flush your brake fluid from the master to each of the calipers if the fluid is old or appears dirty. I have a machine that gets all of them at once. But the old school way works great. Just call a buddy over for some help pumping. There is a test strip that tells you the copper & water content in your fluid. Some repair shops have these. Since brake fluid retains moisture, your calipers & ABS system may just need a little love. It is also good to do this for PM. Good luck. -Andy Oh, Yeah... is your ABS light on?

 

[Little Boss]

ABS pulsing

We've had the same problem and it most recently got very bad. Origionally it was a spiratic pulse at a stop usually when going up or down a hill and turning into a parking place. Recently it was more constant when you were slowing to a stop it would pulse every time. Then last week after cleaning the metal shavings off the sensors, it started pulsing when applying the brakes going down the driveway, not just at a stop. Today NorCalSam put on a complete new ABS sensor harness. So far, so good.

Teresa

 

[stl93fzj80]

No, No ABS light, and I didn't touch the rear sensors. I thought about pulling them to clean, but thought better of it when I realized I'd have to pull the brake lines loose just to get to the sensor's retaining bolt. (didn't want to get that serious w/ the family waiting indoors for the weekend to start!)

I have not checked the brake fluid yet. I think I'll pull the ABS fuse and rethink the situation in the fall, as winter approaches. St. Louis is famous for ice storms and slick roads in the winter, so I'd like to get them functioning normally.

Someone mentioned the spacing was critical. As you know, the Birf Job is a messy one. I wonder if there is enough crud preventing it from seating all the way? In my case, I'm sure I caused something since I was messing with the front end and it started after that. Not sure why so many others have seemingly spontaneous problems. (besides shavings, which I did get cleaned off)

BTW. Mine pulls slightly to the left when it does it, so my thinking is the problem is on the Right Sensor... cleaned both, but didn't fix it.

And, with the birfs still clicking, I don't think I'll take the family up to Montazuma's peak when we go to CO this weekend... Those steep switchbacks sound like hell on old birfs... deep sigh...

 

[MARLIN375]

I had bad peddle problems after putting pads in front and back ( got air in the rear lines while drilling out the bleeders)
Do you have CDL/pin7 mod? I also thought it was my ABS acting up. Took it for a drive and hit the CDL (to deactivate ABS) and the problem persisted.

At the end of the day I had bled the brakes about 4 times RR,LR,RF,LF,RPV (boy the master resivour on these things is small)

Replaced a liter of ugly brown fliud, and my brakes feel/work awsome now, I can bring my 315s to lock-up in short order .

 

[stl93fzj80]

No mods on it, bone stock. I think I'll bleed the lines sometime. The fluid is ancient so it can't hurt. Think I'll wait because I've spent the last 5 weekends working on a vehicle in the driveway... (2 weekends were the wifes 'rover'). I need a garage. (and an unlimited supply of time on my hands)

By the way, took out the ABS fuse, and guess what? ABS light came on!