TXGS

Has any one had a problem with their Rotora 6 piston brake kits? I can't seem to keep the 355mm rotors from warping. When I apply the brakes the steering wheel develops a shimmy that I attribute to warped rotors. I have already had them turned once. Perhaps it is another problem???

RMMGS4

iTrader: (5)

It surprisingly can be worn bushings. A BBK kit with large rotors is just going to exaggerate the worn bushings even more.

If you have over 60k miles, and have the car lowered with sways, stiffer suspension, etc. then the bushings are taking all the punishment.

Time to get a set of Daizen Bushings.

Can't absolutely guarantee this is the problem, but if your car mods and milage are as I described, then worn bushings are part or possibly all of the problem.

TXGS

The car has 47000 miles. It is lowered with Tein CS, TRD sway bars, 18" staggered set up. I had the rotors turned once already and they removed about .1mm. Thickness before turning was 32mm. Thickness after turning is 31.9. Not much but it seemed to help. Also had an alignment very recently and I would have thought that a bushing problem would have been evident at that time.

RMMGS4

iTrader: (5)

Stock bushings even in good shape are just not a good combo with 6 piston BBKs. The Daizen bushings will be a lot firmer than the stock bushings will ever be, even new. There are definitely a lot of factors. Also when your car was lowered, did the installer loosen the A-arm bushings, let the arms compress to the new lowered position and then re-tighten? If not, then the bushings are under a constant twist, which will definitely kill their longevity.

The bushings don't need to appear all ripped up to be bad. I don't believe most alignment shops will consider the bushings bad, but you no longer have a stock suspension and by lowering the geometry is no longer by design. Throw in those massive brakes and the bushings become the weakest link.

The only other concern is did you bed in the pads to the rotors when everything was brand new?

Improper bedding can also cause the feeling of warped rotors.

You can always have the brake shop check your run out and verify if they are warped. Otherwise, these are probably the two most likely problems.

TXGS

Thanks for the info. I'm not sure about bedding the brakes when they were new. If they weren't bedded properly does that affect the pads, the rotors or both?

RMMGS4

iTrader: (5)

Did the Rotora Instructions recommend bedding the brakes when new? There should have been reccomendations how to do it.

Basically you are breaking in the rotors by imbedding the brake pad material into the virgin rotors. It's important to have the rotors get very hot and then spread an even layer of pad material across the rotor, by repetitive hard braking 10 + times, without ever coming to a complete stop.

If the rotor was super hot and then you braked hard and came to a complete stop for a few seconds, that would cause an uneven deposit of pad material to the rotor where it stopped. This uneveness can cause a pulsing effect when braking after that. This is why it is important to bed the rotors evenly when they are new. Once the rotors bed, It will be difficult to remove any un-eveness. Even if you turn the rotor,it's not the same as bedding a new one.

Do a search and you should find more info than I could ever explain.

UptownGS

interesting.... very informative...!!!

rominl

iTrader: (4)

if the setup is done right, i don't think it's going to have much effect unless you have very worn bushings. it's all about balance. i have had ap racing 6 pistons on my gs400 since 2002 with 30k miles, i never ever had any vibration or warpage until my bushings worn out. so imho unless bushings are worn having big brakes shouldn't have negative effect. my sc430 has stoptech as well and also no problem

you have to make sure you bed in the pads and break in the brakes correctly, otherwise you will get noise and you can get warppage easily

in your current situation, since you already warpped the rotors before, even you surfaced it, you NEED new pads, or if you can find a way to make the pads flat again. otherwise, with not flat pads, they are going to damage the rotors again. so you need to make sure both rotors and pads are fixed at the same time. and then you need to break in the system

RMMGS4

iTrader: (5)

There ya go, in a lot of ways Henry is saying the same thing as me. AND he didn't even read what I posted, OBVIOUSLY !

rominl

iTrader: (4)

nah i read everything yoi posted, otherwise i would have posted even more info. but i was mainly talking about this you said:

"Stock bushings even in good shape are just not a good combo with 6 piston BBK"

which i dont' think is true

TXGS

Thanks for the info guys. I think I'll purchase new pads and have the rotors resurfaced and install the new stuff together and follow the "bedding" advice. Greatly appreciated!!!

RMMGS4

iTrader: (5)

If I wasn't clear I meant that if you have a lowered car , with coilover, sways, STB, that put's a lot of force on the bushings, so I'm just saying the BBK is just one more thing that will add to the overall problem. All the forces on the suspension eventuaqlly have to get transmited to these bushings.

I have less than 50k miles on my car and I have 6 piston AP Racing.

I changed the bushings to Daizen anyway. Come over and check the old bushings out, they don't look bad at all.

But now my brake warped feeling is now 100% gone. You know I was about to order new rotors from Todd for a while now. Glad I waited.

So this is why I am commenting on the BBK with OEM bushings not being ideal. Of course there are many other possible factors affecting this.

All I know is my warp is gone and the only mod I did recently was change bushings.

RMMGS4

iTrader: (5)

I think if you do this the problem can go away. But you will need to run a few K miles to verify if the warpage comes back again.

At that point , I would start looking into replacing with Daizen bushings.