itr_hybrid

Hi all,
I recently reassembled the brake system after an extensive suspension overhaul. Calipers, abs sensors, etc. were all removed during the overhaul. One of the fluid on the top of the ABS pump was also disconnected.

System was pressure bled (Motive pressure bleeder).

Now I have a new fun problem. When I come to a stop, the ABS system engages at ~ 1mph. The pedal pulses, you can hear the buzzing behind the dash, and the brakes momentatrily release and then regrab. A slight clunk is heard during the release and regrab.

Does not matter how gently yu brake, it does it consistently.

The ABS light does not come on (except when you start the car, of course). The pedal is nice and firm and the car brakes very well at all other times. Pads are Porterfield R4s. Brake lines are stainless, and the fluid is Valvoline synthetic (for what it is worth).

All bushings, ball joints, etc.are in good shape. This is a new problem that emerged since the car was reassembled.

At this point, I suspect the following things -in this order. I would love any input from folks - particularly if they have experienced this problem before.

My guesses:
1) Damaged wheel sensor
2) Wheel sensor gap off
3) Air in the lines
4) Long shot...bad ground

Any and all input appreciated.

- Phillip

poss

iTrader: (5)

It ONLY happens when you are going slow?

Ok , after re-reading it, I think I understand better. The first place I'd check is the sensors. Check the resistance and make sure they are all in the right spot, clean and also check the rings to make sure they are in decent shape.

OneBadFox

yea check for damaged or dirty ABS reluctor rings. I have seen this problem on a few cars, its amazing how very little damage to the reluctor ring can cause the abs to engage early.

mad_7tist

rust and junk has a nasty habit of building up there on the sensors and the ring. check the air gap on the sensors also. if the abs module does not see a steady on off pulse from the sensors it assumes the wheel is locked up and it wil isolate, dump and repressurize that wheel. you could disconnect one of the sensors so the abs is disabled and see if the prob persists also

itr_hybrid

Hi folks,
Y'all nailed it on the head. Right front sensor's mounting tab had bent so that it was allowing 3/16" of a gap between the sensor and the abs ring. Removing the sensor & straightening the tab so the gap was correct fixed the problem. Thanks to everyone for the timely responses!

- Phillip