Uneven brake wear, cause?

[Brandon302]

I swapped my pads recently for the track and noticed that my rear pads were almost down to the metal on the outside and the inside was still half worn. What might cause this? I do know that I have been running TC a lot recently with the snow and bad weather here in MD.

 

[ArizonaBOSS]

Traction control can definitely have an effect on that.

First thing I would check mechanically is that your slide pins on the rear calipers (inside the rubber boots) are properly lubed.

 

[cp85gt]

You can also flip the pads from inside to outside periodically to keep the wear even. It would also help with uneven wear from leading edge to trailing edge of the pad.

 

[Brandon302]

I will check the slide pins and also flip the pads when I rotate tires to make sure they stay even, thanks for the advice.

 

[Grant 302]

I've experienced similar wear on my last two sets, and like suggested above, I've meant to flop them to improve wear.

I suspect that it's due to the outside pad running cooler. It's better ventilated and doesn't have the same contact area without the piston. Just a guess, I haven't tried to take temps on the inside pad or rotor face.

 

[Brandon302]

I've experienced similar wear on my last two sets, and like suggested above, I've meant to flop them to improve wear.

I suspect that it's due to the outside pad running cooler. It's better ventilated and doesn't have the same contact area without the piston. Just a guess, I haven't tried to take temps on the inside pad or rotor face.

I am trying to remember but I believe my issue is the opposite of yours, so I wonder if my slide pins need to be lubed to make sure they are releasing correctly.

 

[superhero]

I will check the slide pins and also flip the pads when I rotate tires to make sure they stay even, thanks for the advice.

If you flip the pads to wear the other side. Are you not loosing alot of braking power, sense instead of 100% of the pad making contact with the rotor you will only be contacting what is left. Is that OK to do?

 

[Grant 302]

I am trying to remember but I believe my issue is the opposite of yours, so I wonder if my slide pins need to be lubed to make sure they are releasing correctly.

??? What's opposite? My outer pads were more worn than the inner ones. My understanding is that cooler pads can wear more when under 'optimal' temp range.

 

[steveespo]

Axle end play is the culprit, not much you can do with a C-Clip type retention, axles move in and out under g load and push against the pad in or out depending on the turn direction. A fresh set of C-Clips may reduce the clearance and end play somewhat, I have 2 new sets that I will install next fluid change.
Steve

 

[Brandon302]

??? What's opposite? My outer pads were more worn than the inner ones. My understanding is that cooler pads can wear more when under 'optimal' temp range.

I derp sometimes. You are correct the issue is the same, and that would make some sense.

 

[Brandon302]

Axle end play is the culprit, not much you can do with a C-Clip type retention, axles move in and out under g load and push against the pad in or out depending on the turn direction. A fresh set of C-Clips may reduce the clearance and end play somewhat, I have 2 new sets that I will install next fluid change.
Steve

That can allow for almost no pad on one end and 3/4 to half on the other? Thats some play.

 

[Grant 302]

Axle end play is the culprit, not much you can do with a C-Clip type retention, axles move in and out under g load and push against the pad in or out depending on the turn direction. A fresh set of C-Clips may reduce the clearance and end play somewhat, I have 2 new sets that I will install next fluid change.
Steve

That makes sense. So it's just a bit more wear even when not braking? Well greased sliders might help reduce the issue?

Any idea or experience if the wear bias goes away with C-clip eliminators?

 

[steveespo]

That makes sense. So it's just a bit more wear even when not braking? Well greased sliders might help reduce the issue?

Any idea or experience if the wear bias goes away with C-clip eliminators?

Yes the wear happens off the brakes under lateral load. Jack the car up and push in and pull out on the wheel. There is perceptible movement there. Imagine under 1.25 g. I have read that C clip eliminators are not recommended for road race use. A retained bearing like on a 9" rear or full floater assembly like on a Cup car will reduce the end play to the same level as the front hubs. Problem is the expense up front. You can have 9" ends welded on the 8.8 housing and then have press fit bearing axles made for about $1200, or have a custom 9" with floater stub axles and drive plates made for $5000 complete with center section gears and differential. Both options would allow fixed calipers but that would too require custom fab work. Just my $.02
Steve