FinnLS

Hi all, new to the forum.

I have a problem with my ī98 LS400. I started getting
steeringwheel vibration when applying the breaks just last week.
Itīs worst when going over 60mph (80km/h). At low speeds, the steering doesnīt really vibrate but stopping feels a bit "unsmooth".
And if I do a panicbreak I donīt get that much vibration.

I searched the earlier threads about the issue and I suppose
the first thing to check is those stuck caliper pins. My front
rotors and pads where replaced some months ago by the
dealership so I hope that the new OEM rotors hasnīt been warped...

The question is if worn and warped _rear_ rotors can cause these symptoms?
Or worn out suspension bushings? My car had done 80kmiles and none of
the suspension components hasnīt been changed.
Has anyone really got their rotors warped because of incorrect lugnut torque?

Thanks and hope you understood the english

PureDrifter

iTrader: (10)

vibration while braking is definitely warped rotors.

vibration felt primarily via steering wheel = front rotors warped

felt primarily though seat/floor of car = rear rotors warped.

LSRN

could also be tire wear and balance. I road force balance all my tires.

FinnLS

I just had new tires fitted and balanced on the original rims.
I just wonder if the OEM rotors can get warped so easily ?
The tire shop used airpistol to tighten the lugnutz but then
I asked the nut to be torqued to 103Nm.

The vibration comes through the steeringwheel mainly so
I suppose it´s one of the front rotors then. The weird thing
is that when I break slightly at 65mph vibration occurs but when
I break harder the vibration is not that bad.

Anyone have had problem with those caliper pins? Going the jack the
front up and take a look at the pins.

Thanks

Broker404

I had this for the first couple months of owning my car a little over a year ago, but then it went away and I haven't had it since. Not sure why though..maybe I was easier and smoother with the brakes than the previous owner which evened the rotors out?

Harky

I just replaced all 4 rotors to cure vibration while braking. I bought Brembo blanks rather thatn something unknown thru the local auto parts store.
I did the fronts on one weekend and the rears the following WE. I thought for sure that the vibration I was feeling was coming from the front.
But to my surprise, the vibration did not disappear until after the rears were changed.

FinnLS

Thanks for the replies

Going to clean and regrease the caliper pins today. The procedure itself
seem fairly easy. Anyone done this? If that doesn´t do it I think it´s worth replacing the rear rotors then. The rear one´s are quite worn anyway.

I have had the car since January and this is the first problem I´ve
faced. I just love the ride and don´t wanna spoil it with any vibration.

dfkd

I have the exact issue right now on my 94 LS.

I changed my pads to see if i could cure it with that and found that i have a stuck pin right now. I was unable to unstick the one pin but 2 of the other ones i was able to get out. Only one of mine was actually movable.

Clearly the last person to do those pads did not take care of the greasing. Naturally i greased the hell out of the other ones that i could get out.

I may be looking at replacing the rotor at least on that one side with the stuck pin because if anything could have damaged the rotor it would have been that one. The pin is stuck so far back that i couldnt even get the caliper back in with the new pads.

Currently I cant get that one pin to budge at all. Any suggestions?

steveski

The two caliper pins on the front should slide out once you remove the retaining spring (for lack of a better word). I used a phillips driver to tap them out from the back.

I had the same vibration (steering wheel and floor) and once I turned both the front and rear rotors (and got new pads) it is now smooth like new. FYI the min. thickness on the front rotor is 1" and the rear is .5". FYI, if you go with ThermoQuiet pads they are guaranteed for the life of the car and they will replace them at no charge.

FinnLS

What kind of grease are you using to grease the pins?
I first thought to go for copper paste but suppose that wheel bearing
grease is better? Which brand? And buying new pins from the dealer
could be worth it.

After futher investigation I´m turning towards the rear rotors being
warped. The vibration is defenitely coming through the floor/seat more
than from the wheel.

And has anyone got some good advice on replacing the rear rotors ?
I found that great front rotor DIY by PureDrifter so the rear
should be quite the same? I do have the service manual for
the thing and it does seem quite easy.

steveski

I used simple wheel bearing grease and have never replaced the pins. Remember the min. thickness of the rear rotors is .5" so if you have never turned them, or turned them once then you can probable turn them again. It is easy to measure with a mic.

As for OEM replacements you can hardly beat Brembo. If you have in excess of .5" why spend the money bro when turning each rotor costs less than $10 at your local parts shop.

Removing the rear calipers is just as easy as the front and takes less than 3 minutes. I did all 4 rotors for $32

PureDrifter

iTrader: (10)

rear rotors are easy

take off the caliper bolts (2 big bolts on each side that hold the caliper to the bracket) and then take the calipers off.

then follow my guide for removing the rotors in the front, the rest is the same

TJW98LS

iTrader: (1)

Hehehe, after a trip to Panama City, mine are warped all over =D It doesnt vibrate unless I stay on the brakes for a few seconds.

lexodude

Mine does the same thing, usually stopping from around 60-45 and my steering wheel shakes pretty bad sometimes at around 50, I think i need new rotors also. Is it possible that alignment could be the problem for the shaking at around 50 bc ive had the rims balanced 2x already, i was told that it could be?

PureDrifter

iTrader: (10)

vibration w/o breaking at a given speed is 99% of the time wheel/tire balance.


if it was a lower speed id say it could possibly be the lower balljoints/control arms but its doubtful at 50.