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Uneven brake wear

Hi all,

A few weeks ago the front brakes started rumbling under braking. I got the front offside wheel off but both pads still had 5mm left. I then took it for it's MoT and it nearly failed on worn brake pads so I bought some and fitted them when I got home. The nearside pads where only just above minimum thickness (1.6mm in the Fiesta IIRC).

Is there anything wrong or is it because I often brake hard while turning right at roundabouts? :) (I suspect not as surely the braking force applied to the pads isn't related to the load on the wheel).

Can't be a sticking calliper can it? I'd imagine that would cause different pad wear rates on the same wheel but each pad was the same thickness as it's partner.

Not much difference I know but I'd like to sort it.

Thanks,

Peter.

Reply to
Peter Spikings
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Somethings up. I'd get the lot changed and bled, and then go and ask the MOT man to give it a quick go on his rollers to check for imbalance.

Reply to
Doki

Whilst the force to the pads should be equal both sides, I would expect the pad wear to be proportionate to the rotation of the disc whilst under braking. Whilst going round corners, the inside disc will rotate less than the outside disc - thus, if over the life of the pads, the car makes significantly more turns under braking to one side than the other, this may account for the difference. However, I would expect that normally, left/right turns would probably even out over the life of the pads (although I guess roundabouts, as you suggest, make that assumption a bit less likely).

D
Reply to
David Hearn

If it were a sticking caliper then one might have thought that the brakes would be out of balance and it might have failed the MoT. Maybe when the brakes were changed last time whoever did it only did one side.

Reply to
adder1969

Most likely a sticking caliper piston. If the piston partially seizes, then both pads will bind an equal amount. However it could also be something like an internally collapsed brake hose causing the brake to bind slightly.

If it's pads stuck in the caliper, or the caliper slides sticking, then one pad will usually wear quicker.

Best option is to make sure everything is free when you replace the pads, and that the pistons on both sides require a similar amount of leverage to get them pushed in. If everything seems free enough, then just keep an eye on them for any sign of binding/overheating (rust being an orangy/red colour around the outside of the disk)

Reply to
moray

Could be a sticking piston then. I'm confident it's not binding, wheels don't heat up during normal driving and it slows down slowly while coasting without pulling to one side.

Not that then.

Pads already replaced. Dunno about leverage pushing the pistons back in as I've got a nifty retraction tool that you connect a 1/2" ratchet to (much much easier!).... no wait, got that after finding that I couldn't push the offside piston all the way back in, got it into within a few mm but not enough enough to fit the new pads. Maybe that's it, if so what do I do about it if the same thing happens again with the new pads?

Didn't notice any rust on the edge of the disk.

Thanks,

Peter.

Reply to
Peter Spikings

That'll probably be it then, I usually do mine with my hands, but I would have thought the MoT might have picked up an imbalance.

If you're happy that it's free now and you want to fit new pads then you've have to grind down the pads. Not a great idea.

Take a pad out and have someone slowly press on the brakes. The caliper and piston(s) should move easily and move back fairly easily under a contant pressure.

Reply to
adder1969

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