new pads/rotors, now car pulls left under braking Options

[mightyohm]

1972 car with S (aluminum) front calipers on 911T struts.

Installed new pads and rotors on the front to solve a steering vibration under hard braking (warped rotors). Had to remove the calipers to do this since the hard lines don't just unclip from the struts on this car.

Now when I stomp on the brakes, the car pulls left, enough that I need to correct for it or I make an unintended lane change. Most obvious on the highway, not really noticable on the city streets, except that the front left wheel locks first if I panic stop.

Bled brakes, no improvement. Also tried trading brake pads between the front calipers in case I somehow glazed or improperly broke in one side - no effect.

Other work done at the same time - pulled the top of the struts out from under the wheel well to tighten the big nut that holds the shock insert on. One was loose. Drove car after I did that and didn't notice any change in handling or brake performance.

Could I have damaged the brake lines somehow when I tightened the nuts on the shock inserts? Or is it more likely that one caliper is acting up for some reason? Maybe pushing the pistons back into the caliper has caused one to get stuck??

Going to try replacing the brake lines tomorrow, if that doesn't fix it I'm not sure what to try next short of tearing open the calipers. (IMG:style_emoticons/default/sad.gif)

[Eric_Shea]

Orange would be Koni
Green Bilstein
Black Late Model Boge (for SC's)

Those are the only struts that S-Calipers fit on. All T struts were 3" spacing.

Onward... check for any dissimilar metal fusion issues. Look for white corrosion around the outer edge of the dust seals. Factory pistons were nickel plated to avoid this. Not sure how SS holds up comparitively. If it hasn't been driven regularly that might be it. I doubt it though... seems like 5 years with a regularly driven car would be fine.

Another thing to look at is the pad cavity on these. Many times you'll need to file the edge of the pads as paint build up can make them fit very tight in the pad cavity causing them to stick. You probably would have noticed this when swapping your pads though.

When rebuilding the calipers do you recall using the knockback mechanisms in the new pistons? Aftermarket pistons can be tricky with the c-clips if you re-use them. The c-clips will distort (collapse) and although they may seem fine when you reinstall them, they could very well have come loose and you now have the knockback mechanism flopping around in the back of one of the pistons causing the issue. (this would be my bet... sticky or malfunctioning knockback mechanism)

You can elect to remove them altogether or keep them in. If that's the problem, make sure you stretch the c-clips if you decide to re-use them. You can get new clips as well. I noticed this with Harvey Weidman's calipers we just finished. There was a big difference with new c-clips in all pistons.

You'll probably need a new rebuild kit as those dustcovers are almost impossible to remove without damaging them.

Hope that helps.