vagluv

Couldn't find a DIY, but I found the kits on pelican http://www.pelicanparts.com/catalog/..._pg1.htm#item0

There you go!

I've had that done on other cars, so that may end up being the fix. Doesn't cost too much either, so it doesn't hurt much to try it. When you had that issue, did you feel vibration in your pedal too??

Masher

Yes. Pedal vibrated a lot as did the steering wheel. All OK now though.

R6XTERRA

what was the end result?

Masher

Me? Brake judder manifested through vibration in the pedals and through the steering wheel was cured by skimming the discs (on the car).

HalV

^^^^This...I thought I had warped rotors but it turned out to be pad deposits. I used the Hawk Blues to clean them and all was good.

vagluv

Might be more effective/easier to just have them turned (skimmed)??

KaiB

Nope.

FAR easier to slip in some Blues and drive around the block.

TrackDays247.com

Think of what has changed since the last time it did NOT do that - you may be surprised what you can come up with in these cases...

vagluv

tfitch03 was kind enough to give me a hand working on this yesterday. got the rotors off, but could not find anyone to skim them due to them being crossdrilled. Did get to see them on a lathe, and one of them is definitely not straight. I'm reading that this is more likely pad deposits than warping. Seems to me like I would be able to see pad deposits on the rotor, but I guess the blues are worth a try.

Kai, do you still have the ones you mentioned? Would you be willing to send them down to texas for a short while? I've got a road trip weekend coming up in less than 2 weeks and need to get this sorted out.

J richard

If you have a warped rotor (aka: "not straight") replace both, bed the pads per mfgr and youre done...

vagluv

From the rotor manufacturer:

The term "warped brake disc" has been in common use in motor racing for decades. When a driver reports a vibration under hard braking, inexperienced crews, after checking for (and not finding) cracks often attribute the vibration to "warped discs". They then measure the disc thickness in various places, find significant variation and the diagnosis is cast in stone.When disc brakes for high performance cars arrived on the scene we began to hear of "warped brake discs" on road going cars, with the same analyses and diagnoses. Typically, the discs are resurfaced to cure the problem and, equally typically, after a relatively short time the roughness or vibration comes back. Brake roughness has caused a significant number of cars to be bought back by their manufacturers under the "lemon laws". This has been going on for decades now - and, like most things that we have cast in stone, the diagnoses are wrong.With one qualifier, presuming that the hub and wheel flange are flat and in good condition and that the wheel bolts or hat mounting hardware is in good condition, installed correctly and tightened uniformly and in the correct order to the recommended torque specification, in more than 40 years of professional racing, including the Shelby/Ford GT 40s – one of the most intense brake development program in history - I have never seen a warped brake disc. I have seen lots of cracked discs, discs that had turned into shallow cones at operating temperature because they were mounted rigidly to their attachment bells or top hats, a few where the friction surface had collapsed in the area between straight radial interior vanes, and an untold number of discs with pad material unevenly deposited on the friction surfaces - sometimes visible and more often not. In fact every case of "warped brake disc" that I have investigated, whether on a racing car or a street car, has turned out to be friction pad material transferred unevenly to the surface of the disc, aka pad compound build-up. This uneven deposition results in thickness variation (TV) or run-out due to hot spotting that occurred at elevated temperatures.

So I would like to give the blues a shot before replacing my 5K or so mile rotors.

Goughary

I've been dealing with similar pad imprint probs for ages. I went to replace my pads this last time on my own, rather than having my shop do it. Found that the shop never told me about my spring plate issue, likely because the kid at the shop doing the easy jobs, has no clue about the nuances of simple things.

My caliper spring plates are not allowing the pads to move freely, so what's been happening is that my pads have been dragging hard on the rotors even when I'm not on the brakes- just hard enough to get the rotors and pads real hot. As soon as you are this hot, stop at a stoplight, and bam, pad imprint. Rebedding always helped, but then it would come back. So long story short, if you hold your brakes down while stopped, when the rotors are red hot, you will likely get a pad imprint, and therefore will begin to get a shudder that most will call "a warped rotor"- when it's not...

vagluv

Very interesting. Would the spring plate be the part I had to fit the pad back into to get pistons to compress after pushing the pedal while the caliper was off? Those did seem pretty tight...

Goughary

No not those - the spring plates, if you are looking at the Pistons, are the steel plates the metal sides of the pads ride on. They keep the pads essentially from damaging the calipers over time. They screw in with a couple small button head bolts that are apparently a real pita to remove. Apparently when the calipers heat up and things expand, you get crud building up behind them and over time they squeeze down on the pads, so the pads don't move back and forth easily in the calipers...this seems to be what is happening with mine, now to the point that my pads on one side of each front caliper just don't move at all, so once I've been hard on the brakes, one pad retracts when I'm off the brakes and the other stays, heating up the rotor. So not only do I wear pads unevenly and have worse braking, but I get pad imprints and I think this is also why my abs is screwy...cuz the abs doesn't have the force of pressing hard on the pedal...so when the abs triggers, I have really bad brakes...like 20% of the front bias I should have...

Granted, I'm guessing about the abs, but it makes sense.

So I'm at a crossroads for the moment. I want the car on the road now, but need to either buy a set of functioning calipers and sell mine, or take mine out and rebuild them, but the horror stories about removing those bolts is unnerving...Porsche only sells the bolts with the spring plates, and the cheepest option, for those following, is sunset at 38 dollars each and there are two per caliper. Mostly everywhere else is 72 dollars each. But really I only need the bolts, which are stainless and should be easy enough to find at McMaster Carr if I can find the size prior to taking the calipers off. But knowing my luck, I'll start and screw them up and destroy the calipers and have to buy a new/used set anyway...lol

Long reply. Sorry...hope some of that is helpful...

J richard

Here's the deal, if you took the rotors off and spun them on a lathe and they had excessive runout (as suggested by your comment about not being "straight") then they have to be replaced. If it is warped there is no option no matter the miles.

Pad deposits are not measurable and the rotor will still spin true.

I have had cross drilled rotors ground, the holes just need to be champhered with a grinder, you might try another shop.