Dissapearing Brake Fluid

[whysub]

I parked my 1995 LS400 up for a few hours last Saturday-I came back and drove off. Approaching the junction at the top of the road, the brake pedal felt really spongy and had a lot of travel-usually the pedal is firm and just needs a slight touch to stop.

Driving with a bit of caution on the motorway and a few miles of B road showed that when needed the pedal travel was nearly to the floor, but if I released the pedal and reapplied it, it made it a bit firmer for a second or two. Then the brake warning light came on a mile or so from my mates house. Checking the resevior at his house showed it was well below the minimum mark. Topped it up (with the engine running) and the brakes felt much better again.

Driving the 12 miles home from his, the brake pedal again went spongy and the warning light came on a few miles from my house, but, despite the pedal travel, the brakes worked with no drama (although I did slow right down). However, on checking the resevoir again, it was below the minimum level again. Can't see any leaks-all the wheels are dry inside and out, as is the resevoir and engine bay, so what's happenning to it?

I had rear brakes rebuilt in January which included new discs, pads and brake shoes. A couple of months ago I had a new front suspension spring changed, and the garage gave the car a check over too.

[Ruud]

It's obvious you have a leak somewhere.

Get the car up on a ramp or axle stands and have a good look underneath. Follow all brake lines from front to back, check under the master cylinder etc etc.

I'm sure you'll find it :)

[lexynik]

it sounds like a big leak - get someone to pump the pedal with a full reservoir and look underneath for a puddle

[whysub]

I've been away for the last couple of weeks (biking around Czech Republic, Poland and Germany) so only just looked at the car. Filled the resevior up (with the engine running) and, although the brake pedal was a lot firmer, it was still somewhat spongy. repeatedly applying the brakes shows the fluid level dropping, but there are no leaks to be found anywhere. No puddles, nothing wet or with any sign of being wet.

So I am now stuck as to what it can be-anyone have any further suggestions or can recommend a good garage near Braintree in Essex that can check this problem out for me? I miss driving it a lot!

[SteveLS400]

I've been away for the last couple of weeks (biking around Czech Republic, Poland and Germany) so only just looked at the car. Filled the resevior up (with the engine running) and, although the brake pedal was a lot firmer, it was still somewhat spongy. repeatedly applying the brakes shows the fluid level dropping, but there are no leaks to be found anywhere. No puddles, nothing wet or with any sign of being wet.

So I am now stuck as to what it can be-anyone have any further suggestions or can recommend a good garage near Braintree in Essex that can check this problem out for me? I miss driving it a lot!

Hi

I would Google for a brake specialist in your area. No point in going to a general mechanic.

[whysub]

Hi

I would Google for a brake specialist in your area. No point in going to a general mechanic.

Thanks for the tip-found one near me and will ring them on Tuesday to see what they can do. i remember reading somewhere once that the brake fluid can leak into the servo, but, after yet anotjer look, this doesn;t seem to be the case.

I had the rear brakes rebuilt by a main Lexus dealer, but driving it the 40 odd miles to them to check it over is a bit of a risk!

[SteveLS400]

Hi

I would Google for a brake specialist in your area. No point in going to a general mechanic.

Thanks for the tip-found one near me and will ring them on Tuesday to see what they can do. i remember reading somewhere once that the brake fluid can leak into the servo, but, after yet anotjer look, this doesn;t seem to be the case.

I had the rear brakes rebuilt by a main Lexus dealer, but driving it the 40 odd miles to them to check it over is a bit of a risk!

Hi

I was intrigued by this problem. I found the following links which may throw light on it

http://www.hotrodders.com/forum/wheres-my-brake-fluid-going-139083.html

http://www.corvette-nation.com/corvette-forums/viewtopic.php?t=381&sid=1e847ac0fed18bdca123b146fab69704

http://www.honestjohn.co.uk/forum/posts/?t=53556

http://www.british-cars.org/mgb-technical-bbs/dissapearing-brake-fluid-2010022313220627240.htm

The general view appears to be that the fluid is leaking into the booster/servo where its either collecting or finding its way down the vacuum hose and being burnt off.

The solution looks like a master cylinder rebuild/renewal. If this is the case at least we've learned something, unfortunately at your expense.

[SteveLS400]

OK, maybe we didn't learn anything new

http://www.lexusownersclub.co.uk/forum/index.php?showtopic=34848&st=0&p=368822&hl=master%20cylinder&fromsearch=1entry368822

[lexynik]

interesting links - i had brake fluid disappearing once and being burnt off in the engine on an old rover sd1 years ago ! all i can say is the smoke was very very white and very very noticable

[whysub]

Thanks for the links-all very interesting and, apart from a lack of white smoke (or any smoke) from the exhausts.

Seems like when the garage call me tomorrow, I have some idea about what the problem could be. I'll check out cost of a rebuild kit too.

Thanks again for all the links.

[whysub]

lo and behold, the local brake specialist has failed to contact me, despite promising three times to ring me back. Since then, work and other committments have meant that the car has been left.

I tried to start the car tonight, but the Battery is flat-so, before I attempt to jump start it, are there any precautions to take, or should i remove the Battery and recharge it first.

I am still having trouble finding ANY garage that will help, and fear a trrip to a main dealer and their prices will result in me having to scrap what is otherwise a perfect vehicle. looked everywhere on the internet for a master cylinder rebuild kit (as I am sure that this is the problem).

[Malc]

lo and behold, the local brake specialist has failed to contact me, despite promising three times to ring me back. Since then, work and other committments have meant that the car has been left.

I tried to start the car tonight, but the battery is flat-so, before I attempt to jump start it, are there any precautions to take, or should i remove the battery and recharge it first.

I am still having trouble finding ANY garage that will help, and fear a trrip to a main dealer and their prices will result in me having to scrap what is otherwise a perfect vehicle. looked everywhere on the internet for a master cylinder rebuild kit (as I am sure that this is the problem).

Can this Benfur chap help at all ...... he's on here somewhere and is said to break LS's !!! and in Dartford area ??

Malc

[SteveLS400]

lo and behold, the local brake specialist has failed to contact me, despite promising three times to ring me back. Since then, work and other committments have meant that the car has been left.

I tried to start the car tonight, but the battery is flat-so, before I attempt to jump start it, are there any precautions to take, or should i remove the battery and recharge it first.

I am still having trouble finding ANY garage that will help, and fear a trrip to a main dealer and their prices will result in me having to scrap what is otherwise a perfect vehicle. looked everywhere on the internet for a master cylinder rebuild kit (as I am sure that this is the problem).

I would try and jump it first but either way you are likely to have the usual issues with resetting security and radio codes (unless your code is disengaged) but you will definately have these issues if you take the Battery off for charging.

You are obviously disheartened and any other issues are likely to :tsktsk: off all the more. The problem you are having finding a willing motor engineer is not unique - many of them can't be bothered to fetch the vehicle. Round here there are a few who do everything possible to help. How competant are you with a spanner? Doing it yourself will save money and provide a sense of satisfaction on completion.

Here is a link for the removal of the master cylinder http://www.2carpros.com/how_to/brake_master_cylinder.htm

You can sign up and ask about the replacement of the seals and/or Google for the answer. I suggest looking on fleabay for seals/replacemnet cylinder and contacting Benfur as previously suggested. If you send him a private message he will get back to you - give him your email address.

[whysub]

I would try and jump it first but either way you are likely to have the usual issues with resetting security and radio codes (unless your code is disengaged) but you will definately have these issues if you take the battery off for charging.

You are obviously disheartened and any other issues are likely to :tsktsk: off all the more. The problem you are having finding a willing motor engineer is not unique - many of them can't be bothered to fetch the vehicle. Round here there are a few who do everything possible to help. How competant are you with a spanner? Doing it yourself will save money and provide a sense of satisfaction on completion.

Here is a link for the removal of the master cylinder http://www.2carpros.com/how_to/brake_master_cylinder.htm

You can sign up and ask about the replacement of the seals and/or Google for the answer. I suggest looking on fleabay for seals/replacemnet cylinder and contacting Benfur as previously suggested. If you send him a private message he will get back to you - give him your email address.

I'm fine with the spanners, it's time that I am short of, hence not running the LS up to keep the Battery charged. Thanks for the tip about benfur-I'll pm him now to see what he has in stock.

[Irish IS 200]

interesting links - i had brake fluid disappearing once and being burnt off in the engine on an old rover sd1 years ago ! all i can say is the smoke was very very white and very very noticable

Aye,

I had this problem on a Cortina about a thousand years ago and I eventually discovered, by accident, that the master cylinder was leaking into the servo and the vacuum from the inlet manifold was drawing it into the engine hence no visible leak. Rebuilt master cylinder cured the problem.

[whysub]

All sorted!!!

Due to work commitments which took me away from home, I've been unble to do anything to the car since the problem occurred in May. I had been let down by no less that three local garages who all promised to come out and look at the car but didn't. Then a friend recommended a garage owned by a former Lexus mechanic who he rated as "a brilliant mechanic".

Finally I had this weekend free, and the garage could look at it on Saturday, so bought a new Battery for it (the old one spent 3 weeks on a Battery conditioner with no effect-it was dead), which is a story on it's own. I put the Battery on and she started first turn of the key. The brakes worked well enough to do a proper emergency stop, although the pedal travel was a bit much. Armed with a fresh bottle of brake fluid I drove to the garage VERY carefully. Funny how much I missed driving in such comfort for the last 6 months.

And the diagnosis? Rotten brakes pipes, both sides, front to back. He said each was perforated in a number of places, which, under braking,misted fluid out in a number of places, but the underside of the car showed no obvious signs of leaking fluid.

Will pick the car up on Tuesday-repairs will cost about £100 all in. The car can't be at all bad, as he offered to buy it should I ever want to sell it. looking forward to getting it back and enjoying the luxury!

[mike213735]

Well done,

Glad you got it sorted for not too much money.

Mike