Single knock from front brakes on A4 TDI

**vr6280** · 29-06-2007,01:22 PM

When I brake I am getting a single knock (single from each side)

It sounds like the pads moving. I have had new pads and disks fitted. I have checked all the suspension parts and they all look fine. It doesn't knock driving over bumps in the road and only seems to do it moving forward not backwards. It does it from a very low speed or moving fast. The anti-rattle spring is fitted and the pads are genuine Audi.

Help!!!

the car is a 1998 A4 1.9 TDI SE, it has the Golf VR6 style brakes (just on other side of wheel). I think it is called Type II ??

**liamsammy** · 29-06-2007,04:56 PM

i have this problem too! i would like to know what this is as its annoying

**Dozz** · 29-06-2007,05:19 PM

hmmmm roll the car forward and apply the brakes so you here the knock now reverse the car and apply the brakes does it knock again? If so i'd say it is the pads moving in the caliper I'm not completly sure of the style of caliper on a 98 a4 but if it is the single piston/slide pin set up i'd check the pins for wear

**vr6280** · 29-06-2007,05:30 PM

No it only seems to do it forwards. I did wonder about the rubbers on the caliper that the sliders go through. the sliders pins don't appear to be worn. I did clean them and the rubbers with WD40 but with little effect.

It is a single piston slide pin caliper like you said.

**Yarrum** · 30-06-2007,10:33 PM

Are the bolts holding the caliper to the hub tight ?

**vr6280** · 01-07-2007,01:17 PM

yes, checked everything like that a few times, just ordered a new set of slides, bushes and anti rattle springs from Audi (£45)

Should get them Wednesday

**adamss24** · 01-07-2007,01:26 PM

Put some copper grease on the back off the pads also, make shure there is no dirt inside the slider bolts's boot(housing), then clean really weell the pads guides on the hub carier and smidge some grease there as well. That should cure it. Also get a G clamp and push the pistons back into the caliper all the way and remember to pump the pedal beffore setting off. Repeat on the other side ! Hope this helps. Regards, Chris.

**vr6280** · 01-07-2007,01:30 PM

The pads have glue on the back of them so they stick to the caliper so you shouldn't put grease on the pads on this model. Thats what the garage had done that I bought the car from. Thats why I had to buy the new pads.

All the rest is what I did to start with. The caliper does seem quite loose on the carrier until you put the anti rattle spring on. Thats why I ordered the new slides, they didn't look worn but sometimes its hard to tell. I wondered if the rubbers were a little soft.