wdwilson10

Hi,

I have a 99 SC300. A few months back I started getting a vibration in my steering wheel when braking. Normally that would suggest rotors, but the vibration appeared to be an up and down, north south 12 o'clock type as opposed to the east west hand position vibration usually associated with rotors. Anyway, I took my ride to a guy that does work for me on my other rides. He test drove and determined it was the front rotors. So i went to autozone and got front roters. once installed the vibration got WORSE. So, took back rotors, got new ones, put them on. Problem went back to original vibration. Next stop, rear rotors. same mechanic put them on and vibration was still occurring. This time took both new rear rotors and rotors that were replaced on car to machine shop to check condition. Found out old rotors were actually in good shape, so put them back on SC. Vibration still there. So, now mechanic thinks problem might be driver side front lower control arm, after performing simulated road condition test with 2 by 4. Well, as you guys probably know the lower control arms are expensive. I want to make sure this is the problem before proceeding further, with new mechanic of course. And Im not 100% convinced it is the control arm. Ive never had a control arm issue before so I have no experience in diagnosing this type of problem. And also Im concerned the braking might still be causing the problems, either with the calipers or brake lines. just not sure at this point. Any help on this would be greatly appreciated. This SC is in great condition overall with on 117,000 miles on it, but this problem is driving me nuts. sorry to be so long winded but I wanted to be as descriptive as possible. Thx

turbodremz

iTrader: (18)

I had a vibration/bouncing issue also. Replaced my LCA bushings and voila, I can run my 15x3.5" skinnies and jam the brakes and its smooth.

IIRC the MK4 Supra LCA are slightly cheaper, but they are a direct fit.

wdwilson10

Thanks, Turbo. how were you able to determine that the control arm was the problem?

eknine9

iTrader: (8)

One way to test control arm bushings is to go in reverse and step on the brakes, if there is a clunk when you come to a full stop its bushings, just switch back and forth between drive and reverse and listen for a clunk upon coming to a full stop.

wdwilson10

Thanks, eknine9. I performed the test you recommended. Did not notice a clunk. also jacked up car and did 12-6 o'clock push and pull test to check tire play. there was none. also did 9-3 to check tie rod, just in case there was any play that way. No play in tires at all. Got under car and did visual. Didn't notice anything. So, after that, took car to sears to have a mechanic friend of mine test drive the car. He seems convinced its the rotors and not the control arm. I told him I replaced front rotors twice already, but he said he's had to replace new rotors a couple of times before, so its not that uncommon for rotors to be bad out the box. I respect his opinion. he solved a difficult car problem for me on another vehicle, its just I feel Im going in circles about this.

SexCoupe

iTrader: (6)

Just cause someone fixed a problem on a previous car doesnt mean he is the god of cars if you changed the rotors twice and still had the same problem its not the rotors my question is did you change the pads? if not you need to change the pads and see if there is a difference if nothing changes next needs to be control arm bushings. there is no way to diagnose the bushings besides removing the control arms

turbodremz

iTrader: (18)

Sorry for the late response, but seems eknine9 beat me to the answer. But I also did a visual inspection of the bushings and could see where they were falling apart. But with the cost of the urethane bushings, still might be a good idea to change them. Worst case replace the entire LCA assembly to update the ball joints too. Since were on the subject, I also started with the brakes like you did, pads also and it didnt work. But be sure to check your tie-rods also, they can allow some shifting while braking.

Who claimed to be god of cars? Kind of a rude comment considering I had the SAME problem and only suggested what to look at. And there are several ways to diagnose the control arm bushings without removing them.

wdwilson10

Thx, Turbo. I was going to get at coupe for the juvenile remark but you beat me to it. If he had took the time to absorb my comment, he would have seen that I am still not convinced about it being a rotor problem anyway, as the vibration feel is more jerky than typical rotor steering wheel shake. I'm definitely going to need to look at everything to get it diagnosed correctly. Thx again

t2d2

iTrader: (8)

Have you considered driveline stuff? I can't remember which one it is, but I've seen something in the transmission mount / differential mount / center bearing family be associated with braking vibration.

SexCoupe

iTrader: (6)

Fellas i apologize if it sounded like i was attacking you or your friend it was sarcasm i should have put a smiley or something but even after reading it it doesnt sound like i am bashing aka being rude to anyone i am saying someone who has fixed your car before doesnt mean he will be right every time including me i said "just cause someone"not "just cause your friend" wdwilson..you said you respect his opinion about bad rotors out the box and you feel like your going in circles which sounds to me like your leaning towards another set of rotors .....the bushing thing if they arent nearly destroyed completely you cant tell by wiggling your tires you cant tell by going in reverse and braking and also prying on them doesn't work so whats left? you can barely see the rubber its best to remove them my first SC i could tell by bouncing on the car but nothing when wiggling tires or going in revers.may last 2 SCs i couldnt tell until i removed the arms

wdwilson10

No one said he was right about EVERYTHING, coupe. I mentioned he helped with a serious problem I had before. that is why I asked for his opinion on this matter. And, yes, I do respect his opinion, BUT, it is obvious that I'm still unsure about the problem. I'm not leaning towards replacing the rotors again. If anything, I'm leaning towards replacing the control arm. I just want to be certain before I shell out the loot for it. That's why I opened this thread in the first place; to get some insight from those that may have experienced this problem before. What I, or anyone else, don't need is somebody being a clown, making baseless assumptions, or making snide remarks. I'm well aware that the tire tests I performed aren't sufficient in and of themselves to diagnose the problem thoroughly. That was just something I did because I could. Anyway, If you have something helpful to add, I appreciate it, otherwise... move on

SexCoupe

iTrader: (6)

i recall adding plenty thats helpful ...sensitive are we?good luck with your ride be easy

wdwilson10

Not sensitive. Just giving you the response you deserve. Simple as that. Oh, and thx

tibby12

When you changed your rotors out, did you happen to change your pads too?? Sometimes the pads will wear an uneven way and create somewhat of a vibration when braking. My first thought would have been rotors also but since you have replaced them twice its clearly not a problem. To me, a lca wouldnt vibrate the steering wheel just when braking, Ive replaced multiple control arms due to clunking noises when braking, not vibration. Im new to sc cars but been a Chrysler tech for 3 years now. Id still put my money on pads or caliper problem. Maybe one of them is sticking and not applying proper pressure?

Ali SC3

iTrader: (10)

at 112k your control arms are definataely suspect. couple that with they have been sitting around likely for a long time with that kind of mileage and it can be a definate possibility. also don't forget the ball joint is part of the control arm so replacing them with the toyota units is not a bad idea as maintanance, with every SC, you change the bushings or the whole arm at some point, and the lower supra arms is a great idea cause its much easier than trying to remove bushings, you get a little sportier feel, and they will last longer (the bushings are completely filled in vs the half filled in "luxury" SC bushings that fail for that main reason), best is you also get a new ball joint before it ever has a chance to fail.

I am not positive its the problem, but its never a bad idea and its known to go out on these cars all the time around that mileage. at 140k, I had a noticeable clunk. I just changed the bushings.. and now I am wishing I had just done supra arms cause the aftermarket bushings sort of squeak sometimes and I sill have the original ball joint, so If you do go down this path just replace the arms unless you really want and have to have poly aftermarket bushings. the supra arms price and performance is hard to beat.

also the test I used is take a prybar, and try and pry the lower arm towards the front of the car or the rear of the car, not up and down, also be careful what you are prying off of or on. it should not move side to side when you do this at all, if there is flex in the bushings they are shot, and this is what can cause play as when moving there is more force on your suspension than you or I can apply with a prybar, so if you didn't take a large breaker bar or prybar to it you really won't see it as bad.
Mine looked so good still that I was unconvinced they were bad until the mechanic pry bar'd it and made it move, and I realized while they looked okish on the outside they were actually on the verge of failure.

Also to throw it out there, I have had the same type of symptoms you described on another car and it was a blown shock. not all of them but one of them was bad enough it would just vibrate up and down when breaking instead of dampening like its supposed to, almost felt like you were dragging that wheel along when braking, so check out all 4 shocks while they are at it.