Brake Warning Light Strangeness

[Kelraine]

My brake warning light seems to be feeling a bit left out and has started coming on - it's always when the car is cold, and it comes on while the brakes are on and goes off again when they're released.

After a few minutes it stops happening.

Any ideas? I'm hoping it's something simple like a bad connection to a bulb..

[P4UL T]

May just be the bulb on its way out, try changing it

[Tony9r]

As Paul says, more than likely a temperamental bulb... I've got one that can't make it's mind up whether to work or not :winky:

[Kelraine]

I've had a look - and the brake fluid level is down to 'Min'. The light is coming on while driving and sometimes when braking, so I suspect it's right on the edge.

Is this likely to cause the light to come on (and not stay on?) - I'm going to try topping the level up, and if that doesn't work I guess it's time to visit a dealer. <Shudder>

[IanCornwall]

I've had a look - and the brake fluid level is down to 'Min'. The light is coming on while driving and sometimes when braking, so I suspect it's right on the edge.

Is this likely to cause the light to come on (and not stay on?) - I'm going to try topping the level up, and if that doesn't work I guess it's time to visit a dealer. <Shudder>

I had a duff float on my resevoir (not on a Lexus though that was a Ford) and when I parked on a hill it told me that I had run out of fluid, or when I cornered hardish then the light came on as well

similar symptons and if your resevoir is low I bet that is it

[Tony9r]

I've had a look - and the brake fluid level is down to 'Min'. The light is coming on while driving and sometimes when braking, so I suspect it's right on the edge.

Is this likely to cause the light to come on (and not stay on?) - I'm going to try topping the level up, and if that doesn't work I guess it's time to visit a dealer. <Shudder>

Yes, low fluid level will make the light come on :winky:

[Chippy 01]

My brake warning light seems to be feeling a bit left out and has started coming on - it's always when the car is cold, and it comes on while the brakes are on and goes off again when they're released.

After a few minutes it stops happening.

Any ideas? I'm hoping it's something simple like a bad connection to a bulb..

Your brake fluid is getting low, but for a very good reason. Word of warning here, DO NOT top it up. Check the condition of your pads and discs first.

The level is designed to drop with brake wear. New stoppers all round, and a full reservoir is the starting point. As they wear the fluid level will drop accordingly. When your light starts to appear, then is the time to definately get them looked at.

When your fluid is cold, (as with most liquids), it shrinks slightly. (Quick tip- Get your petrol first thing in the morning. The cold overnight weather means you get more juice for less dosh)

When you pump your brake pedal, a little more fluid is pumped to the calipers thus lowering your reservoir level. Result light on. Release brakes, the fluid is drawn back, turning the light off. Do this a few times and the fluid warms up under pressure, and expands a little. Result no light.

If you top the fluid up, and at a later stage you find out that you need new pads or discs, resetting the calipers will cause the reservoir to overflow. Not a nice thing to clean up afterwards. (Don't ask me how I know this)

Check your handbook. The indicator light is most likely called a Brake Wear Warning Light, not a Low Fluid Warning Light.

NOTE:- The same light will also come on permanently after the first push of the pedal, if one of your brake lights have failed.

Phil.

[JS820]

Phil, you are very right. And it's better to check brake pad and disc before making any change.

[Kelraine]

Yeah, I'd come to this conclusion - all the pads are fairly worn (probably a couple of thousand miles left in them). I -have- topped up the fluid and it made the problem go away.... I noticed a warning about overflowing fluid in the IS200 help section (on changing brake pads) - I'll make sure I draw off some fluid before I put the new pads on (in the next few days by the looks of things).

Interesting though - like you said, the fluid contracts slightly in the cold which is why it seems to do it first thing in the morning.

It would be nice if the handbook mentioned that this was a possible cause..

Oh yeah, while we're on the subject of brakes, has anybody changed the brake fluid on a GS? I get the impression that you need some Special to Type equipment to get air out of the system.. is this true, or can it be done with the kind of gear you can buy at Halfords?

[Chippy 01]

Oh yeah, while we're on the subject of brakes, has anybody changed the brake fluid on a GS? I get the impression that you need some Special to Type equipment to get air out of the system.. is this true, or can it be done with the kind of gear you can buy at Halfords?

First off, check your discs as well as the pads, and remember that the fronts are taking the brunt of the braking. If in any doubt, change them.

As far as my experience goes with other older cars and bikes I have had in the past, changing the fluid is a fairly straightforward procedure. Although a little time consuming.

Remember that two sets of eyes are better than one, so if possible get a friend to help.

I would recommend getting an EZI-BLEED kit of some description, though. These can be found at any good Motor Factors. The tube to the catchment jar will have a one way valve of some sort, and it really helps no end.

The way that I was taught, was to start at the caliper nearest the reservoir, and work your way to the farthest.

Attach the bleed kit tube to the bleed nipple, open the bleed nipple a little, and pump the brakes.

Pump slowly.

If you go too hard, you might blow the tube off of the nipple.

Keep topping up the fluid in the reservoir as the fluid is pumped out into the jar. When the fluid changes from the dirty old stuff to the nice clean stuff, close the nipple, take off the tube, clean the area, and move to the next wheel.

This can be done on your own, but it involves a lot of getting in and out of the car. With two people, one can stay in the car while the other checks the condition of the exiting fluid, and keeps the reservoir topped up.

Without the EZI-BLEED kit, it is a two man job. The nipple has to be closed again after every depression of the pedal to prevent air getting into the system on the return stroke, and then re-opened for the next stroke. Open-pump down-close-release-open-pump down-close-release-etc-etc-etc

I hope this is of some help. Others with more experience will no doubt chime in if I have missed something or got it wrong.

Phil.

[Speedy Duck]

My brake warning light seems to be feeling a bit left out and has started coming on - it's always when the car is cold, and it comes on while the brakes are on and goes off again when they're released.

After a few minutes it stops happening.

Any ideas? I'm hoping it's something simple like a bad connection to a bulb..

My brake warning light seems to be feeling a bit left out and has started coming on - it's always when the car is cold, and it comes on while the brakes are on and goes off again when they're released.

After a few minutes it stops happening.

Any ideas? I'm hoping it's something simple like a bad connection to a bulb..

Did you sort out what it was?

My 4 year old GS300 is doing exactly the same. I've booked for Lexus Bham to look it over for £47.00 odd!

[dave1]

Had same thing....new pads resolved this .

[Kelraine]

Well, I don't think it was the pads - the RAC guy told me they were worn, but when I took them out they looked to be only 20-30% worn.. However, the discs were really badly worn (big ridge round the outside) - to I replaced both the front pads and discs, flushed a load of brake fluid through the whole circuit and the problem has gone away.

The brake fluid level warning is -very- sensitive. Once you've replaced the pads/discs you need to turn off the engine and pump the brake pedal 40 or so times - then make sure the brake fluid is topped up to the 'maximum' line.

Hope that helps.

[jamesc]

Well, I don't think it was the pads - the RAC guy told me they were worn, but when I took them out they looked to be only 20-30% worn.. However, the discs were really badly worn (big ridge round the outside) - to I replaced both the front pads and discs, flushed a load of brake fluid through the whole circuit and the problem has gone away.

The brake fluid level warning is -very- sensitive. Once you've replaced the pads/discs you need to turn off the engine and pump the brake pedal 40 or so times - then make sure the brake fluid is topped up to the 'maximum' line.

Hope that helps.

Hi. I'm having the same problem with my mkII gs, but I also have a brake wobble and suspect my front discs need replacing. I've had the car for 4 years and the discs were replaced by Lexus Glasgow under Lexus warranty and then again under Lexus parts warranty as the first set only lasted about 10 months (approx 2500 miles).The car has now done 8000 mls on these discs and I was thinking about replacing them with Mintex discs and Lexus pads. Has anyone got any thoughts about this combination.

[Kelraine]

That doesn't sound good... they should last a lot longer than 8000 miles. Is it possible you've got a sticky caliper? I'd get somebody to have a look at it - you don't want to trash another set of disks.

I'm using 'Black Diamond' pads and disks - I went for the drilled and grooved 'combi' disks but would probably just get the grooved ones next time (the drilling makes them a bit noisy under heavy braking). I'm very happy with them.

Would be good to hear what people think of Mintex.