I've seen this come up again and again. Mine had new front Nissan discx about 15k ago. Lately there's been a judder when check braking from high speed. Brake hard and it used to steady up. Then I did the tension rod bushes which were leaking. The judder definitely changed but it was still there at high speed. Eventually it got worse.

Checked my discs again and found inner side on O/S had a rusty band on it. Figured bad pad contact - near worn out any way. So got new pads and a seal kit for calipers. Someone here said easy job - just pop the pistons with compressed air. I found on both calipers the 2 pistons on one side of each caliper had almost seized hence reason car still pulled up straight. But even my toy tyre inflators 100psi would not shift the stuck pistons - well one came out like a shell from a gun. Had to put each caliper back on the car without the discs in place and hydraulic them out one at a time for the stuck ones - fluid everywhere even broke a G clamp! The pistons were really gunged up but cleaned up well. Cylinders surface outside the seals also gunged hence the sticking. Cleaned the rust off the disc to bright metal = might still need skimming as there is pitting left but we'll see for now - feels so much much better but still to try high speed after bedding in the pads.

 

So you lads & lasses with brake judder have you considered the possibility your 8 -12 year old calipers have stuck pistons that result in one side of each disc heating much more than the other in high speed braking giving a warp factor and judder?

 

I found the dust boots pretty perished allowing moisture onto the piston hence gunge and sticking.

So if youve done the tension rods and now are thinking of new discs or vented stock size discs fistt check out your pistons for sticking. Incidentally, once cleaned up they push back into the calipers just using your fingers!

sorry its a bit of a story!

Yeah, had exactly the same problem. Think the seal kit from US cost $17 - bargin considering a local recon guy wanted £200 !