Braking Over Speed Bumps / Potholes

[Andil]

Hi,

Have an IS200 SE 02 Reg, noticed a problem over the weekend which I can't figure out the reason behind.

Heading towards a junction with a speed bump positioned very close to the give way line, meaning you have to brake over the bump to be able to stop. Brakes applied before the bump, no problem - when going over the bump, I got a knocking sound and no braking whatsoever. Had to take foot off the pedal and re-apply after the bump in order to stop.

However a bit alarming to almost overshoot the junction because of it - and a bit of testing it out on the way home proved it happens over every speed bump and occasionally over potholes, if big enough.

What could it be, anyone experienced this?

[TigerFish]

Sounds like you are going over the speed bump fast enough for the wheel(s) to leave the ground. The abs is kicking in as the airbourne wheels have locked up.

[Andil]

Doubt it, not at 20mph. It happens over potholes too, but never over a flat surface.

[new666uk]

Doubt it, not at 20mph. It happens over potholes too, but never over a flat surface.

What are the shocks like? If they are goosed you could be losing contact with the ground enough to trigger the ABS.

If you watch, you can sometimes see it on the rear wheels on hatchbacks if they are driving along in front of you. The suspension is working 10 to the dozen keeping the wheel on the ground.

cheers

new666uk

[Andil]

Thanks for the replies :)

The front shocks have been serviced recently, (genuine lexus parts) were changed about 3-4 months ago as old pair were very worn (they were original shocks from new) - were changed with new front ball joints at the same time - can't say for sure as to whether the problem was there before the service.

[johern2000]

Thanks for the replies :)

The front shocks have been serviced recently, (genuine lexus parts) were changed about 3-4 months ago as old pair were very worn (they were original shocks from new) - were changed with new front ball joints at the same time - can't say for sure as to whether the problem was there before the service.

Hey, I had exactly same problem, loss of breaking power over a speed bump, I changed my break pad as well, it is not helping, it is until yesterday that i had to break suddenly at speed of 40miles/h, and it happened agian!!! i crashed into the front car, fortunately it wasn't serious, but it will happen when you need to break from high speed in a short distance, it is very alarming, please do ask a machnics to check it out!