Front End Vibration - Advice needed

[AlanM]

Story so far - Upgraded to UK Spec brakes from Mr T ~5000miles ago. Spot on. Brakes have never been used in ernest during that time.

 

About 2 months ago started getting a vibration at front very like warped disks - took wheels and disks off, rudimentary tests showed no sign of warping in either disk. Bit of play in offside bearing and weeping seal at balljoint but no play in ball joint, cleaned mating faces, put them back together. No improvent.

 

Bit the bullet and purchased upper arm and offside wheel bearing and flange, fitted them - no improvement.

 

Bit bullet again and bought nearside bearing and replaced it just now - no improvement

 

So I am back to the warped brake disk theory although as I said, nearly new, look new (ie no sign of being heated), and radimentary tests with a straight edge show no sign of warping.

 

Should I buy one disk (knowing the way my freakin luck is at the mo, it will be the wrong one) and try it on each side to establish if I do indeed have a warped disk?

 

Has anyone warped a brand new meaty disk without knowing about it, I don't drive vigourously the whole time and find it hard to believe that I would not have been aware of it had I braked to that extent? Would I have any come back on Mr T after this time if a disk has warped through manufacturing defect if that is the cause?

 

Any advice welcome on how to establish the cause before spending more money on disks would be welcome?

[merckx]

Does the vibration only occur during braking or is it there all the time?

 

Can you feel pulsation through the brake pedal whilst braking?

[AlanM]

Only on braking from above 40 ish, feel it through pedal, general through car and to some extent through steering wheel

[merckx]

You could have a little rust or dirt behind the disc on the hub which hasn't allowed the disc to mate the hub nice and true.

 

You can use a dial gauge to measure the "run out" to determine whether this is the case or a disc or a hub is warped.

 

You push the proble against the disc or hub and rotate it to see how much it might be warped.

 

I'm not sure what an acceptable figure is for the front Supra brakes.

 

http://www.ekmpowershop3.com/ekmps/shops/JUSTPARTSBUSS/resources/Image/disc%20run%20out%20check.jpg

[AlanM]

Thanks mate, think dial guage be the way to go, not a problem in my last job but I will try and source one. Pretty sure it is not dirt, took the disks off and cleaned the mating faces with emery and washed them down, so it is looking more like the disk(s) has warped for some reason.

[Terminator]

Toyota advise using all five wheel nuts torqued to 76flb when doing a run out test.

 

The dial gauge needs to be 10mm from the edge of the disk. Max run out allowed is 0.05mm. Test on all five possible positions and pick the least run out for the final position.

[Scooter]

if you get a guage and its is out a bit, you can try mounting/rotating the disk onto the next hole and retrying.......sometimes with the disk in a certain orientation its within tolerance but out on others..........

[AlanM]

Thanks Guys

 

Have arranged to get disks checked at Precision Engineering next Thursday so will be able rule them out (or not) then.

 

One small extra bit of info since I was on last, if you brake very firmly, from any speed (well never tried over 80) there is no vibration at all. Could this make it more likely to be suspension/bushes/top mounts?