runtwrestlin

iTrader: (3)

When I replaced my 10bolt with the S60 I went ahead and swapped to rear disk brakes (looking back I wish I'd stayed with drums, or converted everything to 98 disks...). One of my problems now is the brake pads and rotors have a strange wear pattern on them, and in the 2nd pic you can clearly see where the rust spots are on the rotor, even though the pad should be contacting it there. The guide pins are fully lubricated and the caliper can easily slide back and forth on them.

In this pic you can see the difference between where the pad is contacting the rotor and where it is not... Also, the inner pad does not completely line up with the outside diameter of the rotor. There is about 1/16" of the pad that is not worn at all (it's highlighted red). Kindly ignore the lovely "made in china" air hose...
When I looked at the inner pad after I took the pics last night there was visibly more pad material on the part that was rough vs the part that was smooth. To me this indicates an uneven application of pressure, but how??




In this pic you can see where the outer pad should be contacting the rotor, but isn't. The inner side of the rotor does not have this issue, and despite there being uneven wear on the inner pad, that rotor surface is worn pretty evenly. I do not know why the rust spots look like spray cheese...I think it was the flash of my phone's camera.



Lastly, sometimes I would hear a "scrape scrape scrape" noise when turning. I looked at the mounting braket and it seemed very close to the rotor. I shaved that part of the bracket down (it does not come into contact with the pad or caliper, so I don't see how it could cause uneven wear. AND my pads were wearing strangly before I shaved it down), and the scraping noise has not come back. A .025" feeler gauge fits in with some wiggle room, so I'm guessing the clearance is aboue .030". Is this normal?




Parts replaced:
Calipers & Mounting brakets: I ordered the calipers and mounting brakets from partstrain.com. I no longer have the boxes they came in, so I do not think I can return them. I did notice that the driver's side braket they sent me said "corvette" on it. It had a different size both thread and was slightly closer to the rotor than the passenger side bracket. I reecntly aquired a stock bracket from a junkyard and mounted it on the drivers side, but it has not made a difference.
Pads--- The 1st set of pads I had were the economy ones from Advance. I replaced those and the current ones are the economy ones from NAPA (I wanted to fix the issue before spending $60+ on pads...).
Rotors--- The first set of rotors I had were also from Advance, but the driver side rotor acted/wore/looked like it was slightly warped, so they replaced those rotors with my current ones.


Lastly, the brakes will sometimes make a loud groaning noise when moving at ~5mph or an idle speed. If I apply pressure to the brakes, the sound stops.

QUESTION SUMMARY
1) Is is possible that BOTH of the calipers are not cast properly? I am currently at a loss for what I should do...
2) What are possible reasons for the calipers of boths sides to be applying uneven pressure to the pads?
3) Is .030" clearance between the mounting braket and the rotor normal?

wssix99

iTrader: (5)

http://www.cardone.com/english/club/...%2018-0005.pdf

I wonder if your mounting plate on the rear end is in the wrong place?

runtwrestlin

iTrader: (3)

Thanks for the link. So I have the issues of Tapered Wear and Step In Lining.
The calipers are new cardone calipers, so I don't see how the caliper bushings could be causing the tapered wear, and I know the pads are installed properly, so that's not what's causing the step in lining issue.

I don't see how it's possble for the mounting plate to be on the wrong side, and I sure can't find out... The bearings are pressed on the axle from Strange, and I can't remove the plate to see if it would be different on the other side. I know the mounting plate is not for a 98 b/c the holes for the caliper bracket fit my 97 mount, but won't fit a 98 (the holes are spaced differently). I also checked the reciept and it says mounting plates for 93-97 oem disk brakes. I guess I could try rotating the mounting plate to the front (like it is with the LS style brakes) and see if that makes a difference, but I don't see how would help, if it works at all. The rear end came completely assembeled from Strange, so I know I didn't mess anything up there, lol.

My current theory is that the metal where the outer pad seats against is not perfectly parallel with the piston, but I have no way to check that and I'm leary of just shaving some metal off to see what it changes...

wssix99

iTrader: (5)

Right, my guess is that the plate that the caliper mounts to was fabricated incorrectly or is bent, throwing the geometry off on how the caliper wraps around the rotor.

Do you have the same problem on both sides of the car, or is it just one side?

runtwrestlin

iTrader: (3)

I'm having the same problem on both sides of the vehicle. I think the first caliper bracket I had on the driver's side was from a corvette (since it said "corvette" on it...). I still had this issue with it though. I replaced it when I finally located a stock caliper bracket from a junkyard, and it has not made a difference. Both sides are wearing strangely, and it's only on the outer pad and rotor surface that its not making contact with. Although the inner pad does have the "step in line" problem, and is wearing uneven horizontally on both sides of the car, the rotor looks like its wearing normally.

Inner Pad: Step In Line & Uneven Wear (Horizontally)
Outer Pad: Uneven Wear (vertically) and not fully making contact on rotor surface.

runtwrestlin

iTrader: (3)

Thanks wssix99, I may have corrected the problem now. I think some moron (me) installed the pads incorrectly...
I had the top portion of the pads, the part with the metal spring tabs on it, poking through the caliper. This resulted in it pulling the pad away from the outer circumfrence of the rotor, rather than pushing it in to make it completely line up. So I know this was definitely causing my Step In Lining. I think it also changed the way that pressure was applied to the pad, because the wear pattern on my rotor is starting to look normal now.

All I can say is wow...lol

ZexGX

iTrader: (28)

DOH!

Thanks for the update!

rabbit320

iTrader: (11)

or your calipers could be bad? had same issue on mine, one of the pistons was pushing more than the other (front brakes)...

BMR Tech2

iTrader: (5)

If a pad is wearing more at the top than it is at the bottom, it usually means the caliper has expanded...extremly uncommon for a rear caliper, though.