Front brakes imbalance, looking for advice.

Dylan Johnson · Jul 27, 2017

So my car failed an MOT today due to this;
Brakes imbalanced across an axle Offside Front (3.7.B.5B)

I just want some advice on where to start for example is there any common problems with the calipers that cause this? I'm really hoping it's not an ABS issue.
What should I take a look at first.

All help appreciated thanks.

Dikonou · Jul 28, 2017

Front Tire pressure and wear are the same?

Dylan Johnson · Jul 28, 2017

Dikonou said:
Front Tire pressure and wear are the same?

Actually yes I have a slow puncture on my near side wheel that has not been filled up with air for awhile. Could this be it even though he says the offside wheel instead of near side?

desertstorm · Jul 28, 2017

I am not sure a few PSI will make that much difference on a brake test but if the tyre was noticeably down on air and the failure of balance was marginal then it wouldn't have helped. But I wouldn't rely on that, normally they should have provided you with the brake force and percentage readings.
https://www.pistonheads.com/gassing/topic.asp?t=1236837
I believe the inbalance allowed is something like 30% which is quite a bit.
I would take the front wheels off and check the discs and pads to make sure they are all looking good. Check the sliders are working ok on the caliper and not seized. By looking at the pads you could probably work out if a piston has seized in the caliper. Pads on the inside of the disc tend to wear slightly quicker than those on the outside.

Dylan Johnson · Jul 28, 2017

desertstorm said:
I am not sure a few PSI will make that much difference on a brake test but if the tyre was noticeably down on air and the failure of balance was marginal then it wouldn't have helped. But I wouldn't rely on that, normally they should have provided you with the brake force and percentage readings.
https://www.pistonheads.com/gassing/topic.asp?t=1236837
I believe the inbalance allowed is something like 30% which is quite a bit.
I would take the front wheels off and check the discs and pads to make sure they are all looking good. Check the sliders are working ok on the caliper and not seized. By looking at the pads you could probably work out if a piston has seized in the caliper. Pads on the inside of the disc tend to wear slightly quicker than those on the outside.

Thanks for your advice I really appreciate it.

I was thinking it may be the sliders also, tomorrow I was going to tear both front brakes down and check piston movement then re grease everything and reassemble.
My only problem is how do I know if I've fixed it? The car drives and stops fine (no pulling to either side) and if I take it back for the free retest and it fails Ill have to pay for another MOT. I just hope its something obvious that's causing it so I know its fixed.
And yeah I was quite surprised when I didn't receive the % for the brake force readings, I didn't pick up the car as I was working otherwise I would've asked for it.

45bvtc · Jul 28, 2017

Do check the INSIDE faces of the brake disc also, Dylan; so often we consider the inside surfaces to be the same as the outside surfaces that we can readily see and sometimes, as on my RS3, they are not; and it was that that was giving me the 'imbalance' and minor 'vibration. Had similar on an Audi S3 (8L) some years ago where the inside surfaces just weren't working at all. Do a quick check and run your finger(s) over the inside face of the brake disc checking that it is as 'smooth' as the outside surfaces.

Dylan Johnson · Jul 28, 2017

45bvtc said:
Do check the INSIDE faces of the brake disc also, Dylan; so often we consider the inside surfaces to be the same as the outside surfaces that we can readily see and sometimes, as on my RS3, they are not; and it was that that was giving me the 'imbalance' and minor 'vibration. Had similar on an Audi S3 (8L) some years ago where the inside surfaces just weren't working at all. Do a quick check and run your finger(s) over the inside face of the brake disc checking that it is as 'smooth' as the outside surfaces.

Thanks for the advice, the front disc brakes was an advisory for TWO mot's now and they do look quite bad (pitted, scored and rusty) do you think itl be worth it just to get new discs and pads and rebuild front caliper? I done the rear discs and pads 3 weeks ago also.

desertstorm · Jul 28, 2017

I would take the opportunity to change the pads and discs then whilst you have it apart. As you say not good to fail again as you will then have to pay for a retest. So try and get it right first time.

45bvtc · Jul 29, 2017

100% agree with desertstorm; so easy to change ans sooo important when you need to stop.

I purchased a 3-year old A1 recently with full Audi warranty and yet the first thing I did was to change brake discs and pads for new OEM items; worrying about how the car came later; ALWAYS get yer brakes done first...

Search

Search

Front brakes imbalance, looking for advice.

Dylan Johnson

Test123

Dikonou

Registered User

Dylan Johnson

Test123

desertstorm

Moderator

Dylan Johnson

Test123

45bvtc

The Older I Get The Better I Was

Dylan Johnson

Test123

desertstorm

Moderator

45bvtc

The Older I Get The Better I Was

Similar threads