Vibration Under Braking

MattyBlue · August 30, 2011

Hello all, hope all is well.

Just asking for advice on a braking problem i`m having on my IS200. Basically the car was fine, running like a dream but it needed some new front discs. I bought a set of Mintex discs and pads from eBay and fitted them myself. I took my time while fitting, cleaned the hub surface off, cleaned as much grime as possible of the caliper, tightened the wheel correctly, etc.

Anyway now i get this juddering though the steering wheel when braking gently from around 40mph. If i put the brakes on harder it seems to ease off and also it doesn`t seem to do it all the time (maybe only when it`s warmed up a little).

What could be the cause of this?

I have read many posts on this issue and the responses have been varied so i thought i`d just ask for advise. The calipers sticking seems to be something that has come up a few times, but the discs don`t seem to be getting hot and i`m able to touch the surface after a drive without losing a layer of skin. Before doing the new discs i had new tyres fitted all round and the wheels where re-furbed, balanced and the tracking/allignment done (about 1 month before).

It only seems to have started after changing the front disc/pads.

I have just replaced the rear pads to see if that made a difference and it doesn`t seem to have done. Next i`m going to strip down the discs one side at a time and refit.

Could it be that the discs just weren`t cast right and are slightly warped, they where sat in the garage for around 8 months before i fitted them. Also after fitting them i wen`t on holiday for a week and they weren`t half rusty when i got back (the inner and outer circumference seem pretty rusty too!

Does anyone have any suggestions or know of any good places i could take it in the North-West area. If i have to get new discs fitted, fair enough, i just wan`t my braking smooth again...

Regards,

Matty

is200 Newbie · September 24, 2011

Hi Matty

I have the exact same problem ... i have changed the front discs as they did need doing anyway and put brembo discs on and a set of Mintex pads. I cleaned all the parts in the caliper up also when doing the work and noticed one of the slide pins in the caliper housing was a bit pitted and sticking (the one with the rubber seal on the end) - this was very hard to get out but i managed to free it and get it out. it was rusted and pitted but i managed to clean it up as best i could without scratching the hell out of it (still a bit pitted but a lot cleaner) and i re-greased all the pins before putting all the parts back together. This was fine for around 2000 miles and then i noticed a vibration when braking at 40.

i have cleaned the calipers again this weekend to check for any obvious problems - pistons were ok - pads / disc from what i can tell are ok (should be as they are new) but when i came to checking the slide pins i noticed they were hard to get out again and dry so this afternoon i have ordered a new set of pins from Lexus as i am sure this is the cause of the vibration. I will let you kno wthe outcome of this when i manage to re-fit them.

is200 Newbie · October 5, 2011

Matty

Slide pins changed on both sides of the car - top and bottom slide pin / caliper boot and bushes.

This has stopped the vibration at low speeds. It made sense thinking about it that this was more than likely the cause as one pin was a bit "sticky" and another was a bit pitted hence making the braking uneven and vibrating as they were not moving freely.

Job took an hour and cost £61 for all the parts.

Hope this helps

is200 Newbie · October 24, 2011

Hi Matty

I posted the remedy a bit too soon previously but have managed to resolve the issue with vibrating now

I popped the caliper pistons out at the weekend (all 4 of them) - none were seized but i think some may have been sticking?. All pistons were spotless so i cleaned them up and re-inserted them into the caliper and bled the brakes. I put a bit of WD40 in the rubber dustcap and left them overnight after testing to see if all the pistons were working. Just done a 10 mile drive and the brakes are spot on.

Saved just under £600 on a set of new ones from Lexus