1996 LS400 total loss of brake fluid

[Howplum]

I've been fiddling with a friend's car that has been standing for 3 years, and noticed that the fluid reservoir is empty. I pumped the brake pedal, but there was no improvement, so there must be a lot of air in the system. After pumping I noticed a small damp patch just forward and inboard of the rear offside wheel. It appears to be coming from above the subframe. All the hoses seem fine, as do the visible brake pipes. The car has not been run for 3 years, so I'm ruling out master cylinder/servo issues. I am wondering if there will be an issue if air has got into the ABS mechanism, if there is one. I am thinking of filling the system and bleeding all 4 wheels so that I can at least move it. I have access to a pressure bleeder, if necessary. Any thoughts?

[amazighman]

2 hours ago, Howplum said:

I've been fiddling with a friend's car that has been standing for 3 years, and noticed that the fluid reservoir is empty. I pumped the brake pedal, but there was no improvement, so there must be a lot of air in the system. After pumping I noticed a small damp patch just forward and inboard of the rear offside wheel. It appears to be coming from above the subframe. All the hoses seem fine, as do the visible brake pipes. The car has not been run for 3 years, so I'm ruling out master cylinder/servo issues. I am wondering if there will be an issue if air has got into the ABS mechanism, if there is one. I am thinking of filling the system and bleeding all 4 wheels so that I can at least move it. I have access to a pressure bleeder, if necessary. Any thoughts?

Standing for 3 years isn't going to do the brakes any good.

Fill up with fresh new fluid and bleed, if any leaks are present you ll find them then

[Howplum]

I mentioned ABS because I normally work on Mercedes-Benz of a similar age, and if air gets into the ABS device then it can be difficult to sort out. Hopefully Japanese engineers have used a different, more user-friendly, system. Still, nothing ventured, nothing gained.

[steve2006]

The rear brake pipe which runs across the rear subframe is a common failure due to corrosion and this, given the time the car has been stood, is probably why the reservoir was found to be empty. I also would not recommend pumping the brake pedal with no fluid in the master cylinder as the seals may be damaged due to lack of lubrication of the fluid. Pre formed brake pipe sections are available from Lexus but it would probably be cheaper to have the section made.

[Howplum]

On 9/30/2019 at 9:06 PM, steve2006 said:

The rear brake pipe which runs across the rear subframe is a common failure due to corrosion and this, given the time the car has been stood, is probably why the reservoir was found to be empty. I also would not recommend pumping the brake pedal with no fluid in the master cylinder as the seals may be damaged due to lack of lubrication of the fluid. Pre formed brake pipe sections are available from Lexus but it would probably be cheaper to have the section made.

That sounds logical. I have made several replacement rear brake pipes for Mercedes, which seems to be one of their weak points. Hopefully the Lexus one is easier to get at.