Bad vibration when I brake

[Rvan]

Hello All;

This problem likely isn't car specific, but I decided to throw it on here anyway. I have a 97 Q45t, and I put all new rotors and pads all around at 105k kms (65k Miles). I noticed immediately, this didn't remedy my problem of vibration when braking... I took it back to the garage that changed my brakes, and told him I still had vibrations... after some arguing, the guy resurfaced one of the new rotors... This didn't help.... I don't do alot of mileage, and decided to just live with it... It progressively got worse, and now at 140k kms (85k Miles) I brought it to another garage, and told him to just change all the rotors and pads again, and use quality parts, he also cleaned and greased the sliders..... Still happening! My question is as follows:

I don't notice any vibration while driving, but now get heavy vibration when braking... What can cause this apart from rotors??? Seems to come from the front. Also, the intensity of the vibration seems to change as I apply more brake pressure. Under hard braking, it almost goes away.

Thanks in advance for any insight.

[LEMHEAD16]

Check in and outer tie rod ends and both ball joints NOW! Trust me you don't want a tie rod end to fail at highway speeds, been there done that.

There are only a few other things that would transmit a vibration to the steering wheel.

1.) Steering rack bushings
2.) Steering isolator (doubtful)
3.) Out of balance and/or out of round tire, although this normally manifests as a constant vibration not a braking induced vibration

My money is on a tie rod end being worn out. Tie rod ends do require a squirt of grease every so often and most owners typically overlook that bit of preventative maintenance.

Cheers

[Rvan]

Thanks very much! The mechanic did change some links because I had some "clunking" in the front end over bumps, and looked around and found everything tight, but maybe it's a different story when under load. I'll have him look at that again.

Thanks again, and I'll keep you posted.

Ryan.

[maxnix]

Need to measure lateral run out of the hubs. Most owners won't pay for it, so most technicians won't do it. If in spec,then start checking uprights and other suspension for out of specification failure.

No maintenance history provided, so we are just guessing here, but doubtlessly something major has been overlooked.

[Rvan]

Thanks Maxnix. To measure this "lateral run out" would I need to take it to a mechanic with an alignment machine? The guy who did my brakes, does not have one, but there is one around the corner from him.

[maxnix]

No, just a dial gauge. The specifications are in the FSM. Read Q45tech's posts as he prefers a more conservative standard. Very easy to accomplish yourself if you have the dial gauge and a stand or mount.

Any maintenance history? Tension rod bearings? Steering rack bushings?

[djwarner]

When I was a lad while riding down the highway, we passed another car with a rear wheel hopping up and down about 2 inches. Apparently it was a combination of out of balance and a blown shock absorber. I couldn't help but wonder what the driver sensed in what otherwise appeared to be a car driving smoothly down the road.

I bring this up because you might be able to isolate your problem by having a friend watch your car from another vehicle during a series of stops. If your vibration doesn't cause a shimmy in the steering wheel, your problem might very well be in a rear wheel.

[Rvan]

Thanks to all... What it turned out to be was Strut Rod Bushings on both front sides. I'm just looking to find some online now.

[Rvan]

I found infinitipartsusa.com thanks to reading here, but the bushing I find there says Bushing W/O Touring.... Mine happens to be a Touring model. Diagram looks right. Does anyone know if the part is right?

http://www.infinitipartsusa.com/partloc ... atalogid=0

[maxnix]

Call them. There is only one steering rack bushing now and of the two ordered, one must be trimmed to fit.

[MAX_POWERS]

What has to be trimmed on bushing? The metal sleeve?

[maxnix]

Only the DS (I think, or its the PS) steering rack bushing is available. So order two and trim one.

For the tension rods, if the bushing is the same size as the G50 non-active, you can use the Z32 polyurethane one from SPL Parts, but it will be a little harsher.

When installing the OEM tension rod bushing, the arrow -> points forward.