Juddering Under Braking - Front End Geometry Problem?

[BikerPath]

Hello Celica fans.

I have a problem which I'm not sure how to approach. I have a gen 7 (02) Celica (the lower bhp one). A few months after I got it, I noticed that the steering wheel vibrated under braking. I lived with it for a bit but it got worse and soon most of the plastic trim clips and the foam in the doors were shaken loose/out. I got fed up and changed the discs, pads and calipers on the front (both sides). This solved the problem but 2 months later it happened again. If I do the same repair, but this time spin the new disc when jacked up (without a wheel on), there is a particular spot where the disc rubs against the pads.. its almost like the hub is at slightly the wrong angle compared to the caliper assembly, so the wheel 'wobbles' when driving?? It happens on both sides so I'm not sure whether its another part that's shared between the two wheels, or whether the same problem exists on both sides.

One Toyota garage suggested a full geometry check at around £90 per hr taking 2 hours to diagnose (not including any part replacement). Another suggested a hub check (and seemed very eager to replace the hubs), at the same time replacing discs, pads and calipers again, all of which may not solve the problem.

What do you folk think? Has anyone else had this before, do you think I should go straight in for the full geometry check, get the hubs replaced in the hope it fixes it, get an independent garage to just rebuild the front end, or just get rid of it?

Any help much appreciated!

[edwardio]

Get a geo done anyway, as the car will feel a lot better after (assuming something needs altering).

Also what are your tyre pressures (psi)?

Another thing that may be at fault is a sticking caliper. This will cause the pads to wear unevenly & subsequently the discs, which will cause a juddering effect. Likewise if the disc is not 100% flush when fitted.

[BikerPath]

Get a geo done anyway, as the car will feel a lot better after (assuming something needs altering).

Also what are your tyre pressures (psi)?

Another thing that may be at fault is a sticking caliper. This will cause the pads to wear unevenly & subsequently the discs, which will cause a juddering effect. Likewise if the disc is not 100% flush when fitted.

Thanks for the quick reply. PSI are checked regularly and are at 30 psi all round. Since I had the calipers changed, I'm hoping they're not the problem, but will check. How will I know if the disc isn't flush, like more difficult to put wheel nuts on, visual check etc, or will I know when I get the juddering?

Geo check sound promising. Will it and the mechanic say exactly what parts would need to be replaced/adjusted or is there a risk that its likely to agree that there is a geo problem, but not really give an indication of what parts are at fault? I'll ask the Toyota garage but it helps to have some pre-info :)

Cheers!

[edwardio]

Easiest way to check the seating of the disc is to remove it & turn the hub whilst inspecting it closely. Clean off any dirt etc & then put the dis back on & do the nuts up, then turn the disc & closely inspect where the disc sits on the hub for any differences in clearance.

What discs & pads are you using?

When you had the new calipers fitted was it on the front & did you get new sliders or just the raw caliper?

A full geo will be camber, toe, caster & thrust. This doesn't have to be done at a Toyota garage, but does need to be done somewhere that can do a full geo. They should provide you with a print out before the work is carried out & once it's done.

Be aware though that you may need need track rods if they are corroded too much.

May advice would be to:

A ) Lower the car on lowering springs - the stock Gen7 GT springs are fine (this is the 1 mod everybody can't believe they didn't do sooner)

B ) Upgrade the front brakes (in order of cost) -

Uprated discs & pads (EBC Turbo Grooved & Red or Yellow stuff pads - for example)

Uprated discs, pads, braided brake lines & 5.1 brake fluid

Uprated to Facelift calipers, uprated disc for Facelift & uprated pads to match

Uprated to Facelift calipers, uprated disc for Facelift, uprated pads to match, braided lines & 5.1 fluid

Big Brake Kit

This is basically because the stock brakes are not the best in the world.

[Jamesbelfast]

Any decent garage taht has a dial indicator gauge for testing run-out shouild be able to check the disks and hubs in 30 minutes max.,

You could buy your own gauge for around £25 or so.

[Golden bay NZ]

New calipers? Thats extreme. A common wear problem with most all Toyotas is the calipers need rekitting and sanding rust off the outside of the piston to stop them sticking

Are your mags straight? no steering or suspension joints worn?

New rotors need to be heated slowly, cooled down and heated again with braking o rthey can warp.

[GreyRacer]

You have classic disc ''warp'' imho or badly fitted discs not seated properly on the hubs.

Please note though that the word ''warp'' is greatly missued. Your disc are not actually bent in any way it is a surface problem. A high spot.

When the brakes are applied, the caliper and the brake pads squeeze the disk which causes the car to stop. Remember the brake disc is turning at the same speed as the wheel. If the disc surface is ''warped'', the brake pads will pulsate inside the caliper as they come in contact with this high spot. The pulsating will cause the wheel to vibrate, and this vibration can be felt inside the car in the steering wheel if the ''warped'' disc is on the front of the car. High spots can be caused by normal wear and tear, not running in new discs correctly, cooking them especially when new, mismatched pads and discs. You have already said that you can see where the disc and pads are touching when hand turning. Cheapest fix to try out is a surface skim especially as your discs are new. £30 at most. One other thing is what discs and pads are fitted?

Easy to check if your brakes capilers are sticking. Just spin wheels by hand and get someone to brake for you. If they go on and off easily then no sticking.