Warped rotor feel after sitting for a few months

[95blklsc]

My 95 was sitting outside for the last few months until I had a chance to get to a few things. As usual when sitting outside the rotors rusted up a bit. I had just put new pads and rotors on the car all around last fall when I rebuilt the front suspension and put a new oil pan on. I started driving the car and it had the warped rotor feel when you hit the brakes, pretty bad too.

Last night I got out the porter cable DA with some 80 grit pads. I took the front rotors off and cleaned them up a bit. I could see where the pad material transferred to the rotors in the rusty areas. After a few minutes of sanding on each side of the front rotors it I put everything back together. The wobble is completely gone now, it seems like it was just a transfer of pad material. I still have a little pulsing in the pedal but that is likely from the rear rotors since I didn't touch those yet.

So before replacing rotors, if you aren't able to get them turned it might be worth a shot to hit them with some sandpaper. Just be careful to sand them as evenly as possible. It's also worth saying that these rotors were otherwise in great shape, no grooves or amount of wear, just some rust from sitting.

 

[billcu]

Yes, I'm always fighting this, as my cars sit for seasons at a time. I've bought a lot of rotors.

This year I put some old bad front rotors on the black winter Mark and put the good ones on my 97. I'll swap them back for the winter season.

Right now, I've got the problem with my CE rears. It feels weird, when braking, you feel the pulsing, but it's not in the steering wheel. I'll see if they look like they are worth sanding first.

 

[steve]

some high speed hard stops may help as well if it is not that bad

 

[95blklsc]

some high speed hard stops may help as well if it is not that bad

I would have thought this would have just taken care of it, bu it didn't. I drove it for about a week too. There really wasn't much rust, the car had only been sitting for 2 months without use (on concrete too, no wet grass and dirt).

What I think happens is the rusty area is so rough that it pulls some of the pad material off and it becomes stuck to the rotor. Anyway, the 80 grit on a DA sander did the trick. I was happy about not needing to buy new rotors since these were only 6 months old!

 

[billcu]

Yes, the light rust stuff comes off during braking, but I've noticed that the pad stains, from sitting a long time, remain.

The stains don't appear to look like rust, but there might be a difference in friction or grip there, vs the rest of the rotor?

 

[tonybrooklyn]

Great tip thanks!
I recently had a problems with a pulse after switching to Ceramic pads. Went back to semi metallic its gone. These gals of ours are fussy characters lol!