Brake Rotors - Uneven wear

[tef89]

Driving slowly I started to hear some grinding pulsing, stopped the car, started off again, after another 200 metres the sound went.

Thinking this may have been a stone in the caliper as I've had this on other cars.

No idea if it's related but I checked the rear discs brakes and noticed that one side (rear right / offside) has uneven wear on the rotors (see below for comparison of both).

In fairness I can safely say I've never looked at the rotors before so it could have been like that for a long time.

Just wondered if this is anything to worry about ? 

 

[Piston Head]

If your car is still under warranty you may get the pads and discs replaced by Ford.

Mine car was much younger than yours and the wear pattern not so obvious but Ford changed them.

[Cal844]

Get them replaced across the axle as your only braking on half the rotor. 

 

Might be worth checking the caliper and handbrake mechanism for seized parts

[isetta]

if it was mine I would not replace unless the MOT test made me. reduced shiney areas on the disc in bands like this could cause brake imbalance (the brake on one  side being more effective than the other side). this can cause the brakes to pull the car to one side which could be dangerous in emergency stop. It is difficult to test to see if you can feel it pulling due to the camber on most roads. If you could find a dead flat area (eg empty car park) you could drive fast, take hands of steering wheel and brake moderately hard and see if steering pulls one way. Imbalance on back would not be so apparent as imbalance on front.

The MOT test brake rollers gives a more accurate reading and will fail the test if % difference is over a certain amount.

[tef89]

Just had a look at the pictures from the original advert from the Ford dealer from a year ago (yes I'm that sad). 

The same uneven scoring is present so I guess it's been like that since it was built lol... 

I'll add it to my growing list of warranty issues for just before the MOT is due in October. 

 

[isetta]

it won't have been built like that, it is probably where it was left unused for a bit and the discs went rusty.  when the discs go rusty and you then start using the car again, it is a fight between the pads and the discs. can the pads rub the rust off the disc or is the rust so rough that it sands down the pad. if you have a patch where the rust is worse then it sands down a band across the pad. so in that band the pad no longer reaches the disc which means on that band on the disc more rust forms. which sands down that band across the pad even more, a sort of vicious circle. 

[Luke4efc]

Those discs are shot imo. Regardless of whether these are causing your issue they need replacing. The scoring is pretty normal, however the large areas that aren't being touched by the pad (hence the rust developing and leaving a ridge) has left you with around 50% of your original braking area. The band in the middle is not like rust that develops over a few weeks of not being driven, you'll never get that to go away without overhauling it.

Yes you can have them skimmed, but it's far easier and probably just as cheap to just buy new ones (probably only about £30 for the pair on a car like this plus pads at around £20).

 

[tef89]

Thanks for the replies guys.

I can feel the inner non-touched (rust) part is raised a few mm.

It's been through 2x services and they never raised it as an issue (and I can see it was the same a year ago when I bought it)  but I'll call in to my garage and get them to have a look.

[Ian Lanc]

Looks 'nasty' our Son's rear discs on his ST looked the very same and the calliper wasn't sliding on the bolts freely and two pistons didn't worked as they should have, infact was starting to seize up, he decided to strip down the callipers and get everything working smoothly, new discs & pads fitted, everything on the brakes are now bedded in nicely and wearing down evenly.

[TomsFocus]

Rears are rarely used under 'normal' driving conditions, it won't be causing you any issues at all but they all end up like that after a few months.  It doesn't look nice, but I agree with Isetta, it's not worth replacing them unless they're considerably imbalanced.  Rear imbalance is checked at MOT now...I note it's a 2017 so might be worth waiting for the first MOT to see if they're still working adequately or not.

[tef89]

4 hours ago, TomsFocus said:

Rears are rarely used under 'normal' driving conditions, it won't be causing you any issues at all but they all end up like that after a few months.  It doesn't look nice, but I agree with Isetta, it's not worth replacing them unless they're considerably imbalanced.  Rear imbalance is checked at MOT now...I note it's a 2017 so might be worth waiting for the first MOT to see if they're still working adequately or not.

Cheers Tom - I'll get my local trusted garage to check them but I'm leaning toward doing as you and isetta have suggested.  I'm most likely gonna sell it before the MOT in October anyway.  I've not noticed any driving issues (other than the temporary grinding noise I mentioned in the OP that may have been a stonechip).

I really appreciate everyone's input.

[Eric Bloodaxe]

Yes, as Tom says the fronts do the bulk of the work when braking due to weight transfer and the situation is worsened if not getting much use. My Mrs had to have the fronts replaced on her Ka at frequent intervals due to little use (the service lads used to say "drive it more and brake harder"!  As mine has only done 9,600 in 2 years of irregular use and lives outside, I thought I'd better check mine, but they're ok.

I believe you mentioned in another thread this was a Ford Direct car? I wondered if it had been stood a while before you bought it with the handbrake on a bit too hard, "welding" one of the pads to the disc, the pad then being damaged when it was moved, then the pad damaging the disc as Isetta suggests.

 

[tef89]

20 hours ago, Eric Bloodaxe said:

Yes, as Tom says the fronts do the bulk of the work when braking due to weight transfer and the situation is worsened if not getting much use. My Mrs had to have the fronts replaced on her Ka at frequent intervals due to little use (the service lads used to say "drive it more and brake harder"!  As mine has only done 9,600 in 2 years of irregular use and lives outside, I thought I'd better check mine, but they're ok.

I believe you mentioned in another thread this was a Ford Direct car? I wondered if it had been stood a while before you bought it with the handbrake on a bit too hard, "welding" one of the pads to the disc, the pad then being damaged when it was moved, then the pad damaging the disc as Isetta suggests.

 

Could well be Roger m8.  Mine's only done 13,500miles in 2.5 years (it had 8,000 when I bought it) so that would make sense to me.