ABS cuts in after new shocks put in.

[mike65]

The ABS is cutting in at very low speed then "releasing" just as I come to a halt. The shocks were changed earlier today (not by me), might this be as simple as a dirty sensor caused by the taking the brakes off the hub etc prior to the dampers being fitted? The ABS light does'nt come on.

Mike.

 

[television]

The ABS is cutting in at very low speed then "releasing" just as I come to a halt. The shocks were changed earlier today (not by me), might this be as simple as a dirty sensor caused by the taking the brakes off the hub etc prior to the dampers being fitted? The ABS light does'nt come on.

Mike.

Are you sure mike that it is the ABS cutting in, and that its not some other vibration.

 

[mike65]

Nope its ABS, the pulsing sensation and a rapid tap-tap-tap from the ABS box in the engine bay.

Mike.

 

[w124nut]

If it is the ABS, you will feel it activating through the brake pedal. Was the work done by a Merc garage or independant?

 

[jibcl500]

what MB model is it, changing the shocks is a simple task on a MB that wouldn't require the brakes to be removed.

jib

 

[television]

I cannot see the connection in the ABS pump and the shocks

 

[mike65]

Sorry I drive an Audi (see sig), but I thought I'd just post to get some feedback, on the A6 you have to remove lots of stuff to install dampers.

Mike.

 

[television]

Sorry I drive an Audi (see sig), but I thought I'd just post to get some feedback, on the A6 you have to remove lots of stuff to install dampers.

Mike.

Hi Mike, the sensors on the wheels should have nothing to do with it,you probably have a separate speed sensor, but I do not know audis, so this just leaves the ABS pump, if its mounted near the top of the wing, could this have been disturbed whilst doing the shocks.

 

[mike65]

Thanks Malcolm, the speed sensor sounds like a plausible culprit.

The Haynes manual does'nt cover ABS (take it to dealer blaa blaa blaa) but the schematic wiring diagrams shows wire from speed sensor to brake fluid sensor unit.

from autospeed.com article

As you may be aware, a vehicle’s ABS monitors the rotational speed of each wheel and can identify when a wheel is locked during hard braking. When a locked wheel is identified, the ABS module releases some hydraulic pressure applied to the brake of that particular wheel. This allows the wheel to turn and, as a result, adhesion and control are regained.

The Haynes does say the sensors need to be removed when the caliper assembly is pulled clear of the action.

Mike.

 

[television]

Do Audis have any system like the BAS we have on the MBs this being the case there would be an extra sensor for this. if there are only the wheel sensors then if one was not quite pushed home, could this do it,hard to say, anyway the car was fine before the shocks went on.

I also note that its speed related and happens at low MPH, so something is reading wrong, that only leaves a sensor dirty or not quite home.

 

[mike65]

Proberly was'nt pushed fully back in. I'll drop it back for the chap to check on Friday.

Mike.

 

[television]

Proberly was'nt pushed fully back in. I'll drop it back for the chap to check on Friday.

Mike.

Just for the record it is much harder to count low speeds than high, due to gaps in the count rate. and things like noise can get in on the cables and sensors, it could be that one is not sitting square.

 

[willum]

Aaaaaaahhhhh.

I'll be very interested to see the outcome of this. Mine's ('96 E300D) doing exactly the same trick as I come to a standstill............ and the ABS light comes on if I get up to or over *)mph. Goes off again if the ignition is cycled on/off

Will

 

[mike65]

I did'nt get back the my man on Friday but will on Tuesday.

Mike.

 

[mike65]

Right got the ABS checked, the chaps at Audi or rather thier code reader says - rear speed sensor shot! The price of a new one for an A6 C4 chassis is a fupping fortune so I'll be looking for a dismantlers example.

Mike.