Violent Juder When Braking

[TMB]

My pride and joy is a 99 LS400 that is in A! condition, full service history, a beutiful car.

My problem is that whenever I brake I get a judder from the front, felt through the steering wheel.

I have had three complete new sets of disks and pads from Lexus in a year. each time they are changed the problem goes away for about a 1000 miles and then returns.

I brake gently and drive sensibly and I am at my wits end about what to do next. The Lexus centre says no fault, the car passes the rolling road MOT test.

Tried 4X4 specialist who just keep telling me to change the disks, my pockets arent that deep to do this every month.

Any ideas or suggestions would be highly appreciated.

[steve2006]

Hi,

Does sound like warped discs again but may be worth going to someone with the necessary equipment to test the discs run out with a micrometer.

Discs do warp but generally this is caused by prolonged heavy braking and then keeping the brakes on when stationary when they are still hot or poor preparation i.e cleaning of the hub flange when fitting the discs.

I assume they have a warranty with the Lexus dealer if so reapproach them 1st or they may not honour the warranty if another party has been involved.

The other thing to consider is were the pads replaced each time the discs were replaced?

Cheers

P.S. Welcome to LOC

[dlayen]

i have read here somewhere that the is suffers from this at times because the calipers are seized.

[Gord]

Try checking the calipers (sticking), or getting service kit for them from lexus

[TMB]

Hi,

Does sound like warped discs again but may be worth going to someone with the necessary equipment to test the discs run out with a micrometer.

Discs do warp but generally this is caused by prolonged heavy braking and then keeping the brakes on when stationary when they are still hot or poor preparation i.e cleaning of the hub flange when fitting the discs.

I assume they have a warranty with the Lexus dealer if so reapproach them 1st or they may not honour the warranty if another party has been involved.

The other thing to consider is were the pads replaced each time the discs were replaced?

Cheers

P.S. Welcome to LOC

Been to Lexus, they argue it must be caused by excessive braking also, I cant disprove it but I KNOW I dont brake violently or hard and I am the only driver of the car. I have done all the sane things, each time new discs and pads, from Lexus, balanced the wheels, tightened the nuts in the right order to the right torque. Lexus just want to fit new discs and pads again, circa £460. like I say third time in a year and only 5,800 miles driven.

Something is causing this and it isnt braking, or at least not hard braking, calipers and pistons all check out, there is no history of any accident in the car. (suspected it may have been in a bang and something out of align, but no)

I am almost at the point of giving up on it if it cant be fixed will probably auction it with a declared defect and never buy another Lexus which is a great shame because it is a superb car but I cant afford £2k a year on brakes.

[GoldfingerLS]

if all pistions in the front callipers are ok (all 8 of them in total), then after pads and discs were changed the 1st time and problem re-appeard the questions which would come to my mind are:

1. how were the new brakes bedded in ? were the brakes bedded in properly ? this is very important. a lot cases of "warped discs" are not warped. its the uneven deposits of pad material which become imprinted in the disc surface and the next time the disc heats up they become hot stops. Soon after they will become hard spots which can then only be removes with machined skimming.

2. Is the hub onto which the disc is mounted ok ? any excess play / runout ?

3. Could it be a suspension component e.g. control arm ball joint or bush etc which has excessive play ?

Its very unusual for this to happen.

Let us know how you get on.

Thanks

[steve2006]

Lexus may argue that it has been caused by excess braking but under the sale of goods act is it not also up to them to prove this is the case.

I don't know who manufactures the discs for Lexus but surely they should be returned to them for examination.

Another point arises here in that if the brake discs have warped due to excessive use ( define excessive) I would have expected the brake fluid to have suffered also ( easily tested).

[Redsteve]

Hi there TMB,

my car was also suffering from brake judder until yesterday.

I took it to a small, family owned tyre and exhaust fitter and asked him to balance all four wheels for me.

All the wheels already had weights on them but, when they were re-balanced the fitter told me that it was almost impossible to balance wheels as wide as mine (standard LS size) without putting weights on the inside edge of the rim (near the tyre) and also closer to the centre of the wheel rim.

I have done about 50 miles today and my brake judder has gone!

I hope you can get yours sorted as easily as mine was.

Let us know how you get on.

Redsteve.

[Mark W]

Must be something to do with the discs and not other (eg suspension parts or hub) as you would experience all the time - not only after ~ 1000 miles

You might want to read this - Particularly page 2

http://www.powerbrake.co.za/downloads/tech_01_judder.pdf

Rgds

Mark

[Redsteve]

Must be something to do with the discs and not other (eg suspension parts or hub) as you would experience all the time - not only after ~ 1000 miles

You might want to read this - Particularly page 2

http://www.powerbrake.co.za/downloads/tech_01_judder.pdf

Rgds

Mark

That is a really interesting read, it sure does dispel a few myths.

I will be trying my hardest to adjust my driving style to prolong the life of my pads and discs.

Thanks for the linky.

Redsteve.