Vibration Under Braking: Help Needed With Diagnosis

[ausdrift]

Hi all need some help. Car is r33 with many aftermarket arms/ suspension bits and tires are mid way through their life. I just got an allignment also. When i brake from mid to high speed with mid to high force i get very noticable shaking from the front.

What, specifically, could be the cause of this? Ie exactly what parts/conditions could cause this?

Thanks

[Hadouken]

http://www.mrtperformance.com.au/performance/brakes/1162-brake-model-1

[GTSBoy]

Upper spindle bearings are usually the last thing to get replaced (because they're invisible and people like to pretend that they're not there) and will allow enough slop when worn to cause braking vibes.

[ausdrift]

What is an upper spindle bearing? Oh and front left wheel bearing was replaced recently

[ausdrift]

And while im at it front brake rotors and pads in vg condition and caliper seals etc changed/ rebuilt 20,000k ago

[GTSBoy]

What is an upper spindle bearing? Oh and front left wheel bearing was replaced recently

Picture your front suspension in your mind. Think about which bits have to rotate with respect to which other bits, particularly when steering. The upper spindle bearing is at the top of the spindle, permitting rotation around a (near) vertical axis.

[ausdrift]

Ahh, so the bearing which would attatch at the top of the knuckle? Thats a pain if its the problem. Would that be one which a shop would have to press out, same as a wheel bearing?

[GTSBoy]

Can be fun.

[zebra]

My LHF Spindle is worn 0.015mm and only found that out after replacing the bearings

f**k knows how....but its a pain in the arse...and the wheel moves about a bit

[ausdrift]

How did you find out it was the spindle?

[zebra]

measured it

[phantc_s15]

Could it be tyre related? Quick check is to rotate front wheels to rear.

When I flat spotted my tyres (cold tyres with no ABS at the track) it caused huge vibrations when braking.

[ausdrift]

The latest. After getting screwed around initially with the alignment by shop A, I took it to Pedders who were able to see that Shop A had aligned my car with caster settings of 3 and 10 to get it straight. Quite different from the 6 each side I asked for.

Pedders then showed me that it looks like the LCA bushes may be stuffed (as are the steering rack ones, they saw) as there was clearly something wrong from 1 side to the other there. I will investigate over the weekend, and its booked in with them for further investigation.

[GTSBoy]

Drift damage