faulty abs unit repaired, now new brake issue pulsing pedal

[spottedhaggis]

I have had new front disks and brakes fitted recently, and took my abs module off and took it to a local repair firm with a good rep, bba reman, They confirmed there was a fault, which was why my dashboard abs and tcs lights were always on, and repaired it.

Got the unit back, fitted to the car and now when I brake the car at any speed, the pedal pulses, not like abs where its very fast and short, this pulses heavy in the car, and if your doing 45++mph when you brake it pulses so bad it feels like the car is falling to pieces.

After I spoke with bba, they took it back to re-test it but fund no fault.

Anyone any ideas what the cause of this could be. We reset the computer, took it for a reasonably long drive, unplugged everything, battery etc and left it for a while but nothing.

[zollaf]

so its not pulsing like the abs, so is it pulsing like a warped disc, or a disc thats otherwise got excessive runout ?

[spottedhaggis]

I guess, never experienced a warped disk before, but i have ruled out that or the pads, as both disks and pads fro the front are less than a week old (they were done at the same time the abs module was removed from the car and sent away to be repaired)

bba suggested bleeding the brakes and taking it for a good 15 mile run, but the pads and disks were changed without any disconnection of brake lines so not sure why I should need to bleed the brakes at all? the pump connections were left in tact as well, simply the module was unscrewed, removed, and fixed then screwed back into place again.

[zollaf]

do you feel it through the steering and whole car. if so, then check the run out on the discs and check the discs for flat spots. i am presuming the hubs were nice and clean when the new discs went on ?

[spottedhaggis]

at slow speeds only through the pedal itself, not thrugh steering, at higher speeds dont know, my mechanic is the one that said at 50 its scary

[kid-jensen]

Sounds like disc runout to me too....

Most likely, one of them assembled without cleaning the mating surface, and a bit of grit got in there...

[spottedhaggis]

I unplugged the abs unit and did a 100 yard drive, same judder so I am ruling out the now repaired, and tested twice abs unit, has to be related to the new disks and pads, so having read a little on disc runout, I am in agreement about the cause, certainly the symptoms are the same as described, and prior to the disks, brakes and abs removal, the car did not have this issue.

My mechanic is coming out to take of the disks and give the hubs a good clear out, seems likely to be the issue, so hope it should be resolved by Wed.

[spottedhaggis]

ok no more shuddering, was the disks, but sadly, the abs unit was sent and repaired, and now the pump is making a right noise.