Hi All,

I bought a set of new disks and pads (Mintex) 20,000 miles ago. The disks are now warped (heavy vibration at motorway speeds) and the pads are only half worn. I "cannot believe it" and I really p****d off with this.

Could it be that I have a sticking caliper???????

I'm thinking of using sports disks and pads (preferbaly green stuff, which I have heard about). Can anyone point me to a dealer (non-lexus can't afford the prices) where I could pick up a set of sports front pads and disks please??

Any help greatly appreciated.

Thanks

not good to hear,who fitted them for you.

As they are free floating type you have to take care.

To see if you have a sticking caliper just feel the wheels after a run...they should not be too hot and both the same temp.

When in traffic jams or at traffic lights I always put my auto into N so I'm not holding the car on the brakes thus building up heat.

Putting salesmans hat on I've a set of 3g fronts with 10 grooves and Mintex extreme pads tucked away............

Hi

Yes, I have always put the car in neutral and coasted when coming off motorways while gently using the brakes. Actually, I forgot to mention that the car passed it MOT on Friday, although I have had the problem for the past three weeks. Could it still be a caliper issue???????

Are the disks and pads new and if so, how much are you asking for them??

Ta

I have a set of the new Prolex 3G/Mintex pads waiting to go on my IS200, once fitted i will get pics up and let you know what there like.

MOT wont fail on warped disc's, so long as they stop you its a pass. (thats what i have always been told)

£166 for the discs (10 grooves...brembo castings) £60 for the pads (mintex extreme...fast road)

cough cough dave...T&C



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GSSPORT......

i would look at the calipers myself, also ensure that the surface of the hub is clean when the discs are fitted...

"Warped Discs" is a misnomer...I've yet to see one that has actually developed any kind of distortion around the annular brake area of the disc. However, you can get thickness variation caused by localised heat/stress on vented discs. In the latter case the usual solution of machining the disc to recover consistent thickness only makes the disc more susceptible to the original problem .

Some useful info that may help in your diagnosis:


http://www.powerbrake.co.za/pages/tech_01_judder.htm

http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

yup, ive posted on here many a time, that "warped disc" is not what it really is.....but if you posted it, everytime someone said they had it, youd have a post count of 50 million..........

its all good info though to those that didnt know it

previous mumblings on the topic.........

Here July 25th 2005

Here..Jan 3rd 2005

Here...Aug 19th 2004

It might no be what it really is but thats what we know it as.

When fitting discs make sure hub is perfectly clean, so the disc runs true......'run out', the amount of 'untruth' when disc spins must be on or below spec. allowed.

Otherwise it's not running true from the start, aggravating the problem.

Dave, you should know better than that... If the wheels are stationary (ie at the lights) you will not build up any heat whatsoever. Heat is generated by the conversion of kinetic energy to thermal energy through friction. If there is no kinetic energy (as the wheels are stationary) then there will be no conversion to heat.

What you will do, however, is wear out the brake bands by shunting to Drive and Neutral repeatedly. Better to let the torque converter handle it, as there are no contact parts to wear out.

By doing this, you will make the problem worse. By moving the selector to neutral, you will remove any engine braking and ensure that *all* the kinetic energy of the vehicle is removed using the brakes, rather than the compression of the engine. Thus, you will actually need to brake harder right up until the point at which the car reaches the speed it would attain on the sliproad if you put it in D from a standstill - about 5 mph or so.

Dave's correct...it's the transfer of heat from the disc to the pad friction material that causes the problem. If you've been using the brakes hard and frequently then stand on the brake while stationary, material can be transferred locally to the disc (you can even see the imprint on the surface). Try reading both the articles I posted...

it seems no one reads links.......

read about putting into nuetral on another forum..........

i always do it and have no probs

Hi Everyone,

Thanks for all your comments, they have been very useful.

A couple of questions.

1. I might go for grooved brakes and uprated pads. I was wondering whether this will help getting warped disks???

2. I also hear that they can be noisy, is that true?

3. If the caliper is seized how much would it cost to repair? or should get a reconditioned caliper?

Thanks

Does the MOT not test brake bias? wouldn't a sticking caliper show up?

Matt you're right, I give up too

The car had it's MOT last week and passed. I asked the mechanic about the vibrations and he stated that nothing had showed up, the car was braking fine.

Thank you to all who have provided useful comments.

There are two possibilities for a "siezed" caliper, the caliper pistons, or the sliders. The latter is probably more likely.
Make sure that the sliding pins are free and greased. Replace the pins if they are corroded. Replace the rubber boots if they are split.

Thanks, mate. I'm going to give them a look this weekend.

mot showed brake bias on mine. n/s front caliper holder has seized pin which only seems available as complete carrier. Can't work out why it can't be freed but seems intermittent.

I was able to buy the pins separately from the bracket they slide in.

well then all he has to do is read the MOT cert, if the calipers are at fault it'll be on it, if not move on to checking other components....

was that from lexus, or elsewhere. oh and what did it cost ?

Hi All,

The MOT didn't pick anything up with the brake bias. I have the feeling its the pins (sliders) or a dodgy caliper. I'm certain its not my driving style as I always try to be gentle with the brakes.

It seems you can buy them separately.

I have bought a set of pins for each of the carriers (thats four in total) from lexus. The total came to £24 with VAT. I'm fitting them with weekend at my local garage, to see if it makes a difference.

I have also ordered a set of 3G disks and fast road pads too.

I will let you know, how I get along.

Thanks