How Do You Flush The Brake System?

[LexusPete]

Anyone out there who knows how to perform a brake system flush? I am getting an erratic TRAC light and someone recommended a system flush. I do not yet have a service manual, so I would need some detailed instruction. Anyone who can help, please post the information on this site. Your help will be greatly appreciated. Thank you.

Peter.

[99lsguy]

Pete,

Here's the old fashioned way......

You need another helper... maybe two

The basic Idea is to pump the brakes 3-4 times and HOLD the pedal down.

Then loosen the bleeder valve at each wheel to let old fluid flow out. put a 1/2" clear hose over the valve to flow into clear jug (so you can see it). After the pressure goes down, tighten bleeder valve, let off brake, refill master cylinder with NEW DOT 3 BRAKE FLUID, pump brakes again, open bleeder valve again...

So on until you can see CLEANER fluid through that line.

The idea is to work your way from longest line to shortest: so the procedure is

RR LR RF LF in that order.

They make PRESSURIZED systems so you can make it a ONE PERSON SHOW. They are pretty slick but never used one. I would like to try it though!

IF YOU GET UNDER THE CAR BY USING A JACK MAKE SURE TO USE METAL STAND JACK TOO FOR SAFETY. DO NOT TRUST THE HYDROLIC JACK ALONE. FOLLOW MANUFACTURES INSTRUCTIONS AND BE SURE.

[tansupplyman]

Be sure to bleed air from the TRAC pump system[if that is where the problem originates.

[99lsguy]

PETE AND OTHERS,

Just checked out this website referred my MKTBULLY on the SC300/400/430 forums:

SPEEDBLEEDER.COM

Looks very slick............... :D

[LexusPete]

I appreciate all the help guys, but I have two more question. Where is the Master Cylinder located? And, how do you reset the TRAC code? Bare with me guys, I am a novice auto mechanic ;)

Peter.

[99lsguy]

Pete,

This is not the 1uzfe engine but the master cylinder will look like this and be in this position under the hood.

You should Suction out as much old fluid as possible in the master (use NEW TURKEY BASTER OR SIMILAR - MUST BE CLEAN) ; then fill with clean fluid and start bleeding/flushing.

[LexusPete]

99lsGuy,

You are the heat brother. Thanks for the schematics. One more question? Do you think it necessary to bleed the TRAC motor, or is this redundant? Let me know what you think. :)

Peter

[99lsguy]

I don't know about that....if it has a BLEEDER VALVE. . the same procedure will work for it as the brake lines.

I DO KNOW the BRAKE ACTUATOR HAS BLEED VALVE - this is 99 manual though!

you'll need to bleed this too

I hope we can read these pictures, if not I'll retry

Good Luck

[99lsguy]

Here's the next one.....

[lexs400]

I am trying to bleed the traction system on the 90LS. Based upon the manual pages printed in this post, the traction motor should be run for 20 seconds.

My question is how does one make the traction motor run ? does it run automatically when the engine starts ? or does one have to trick it to run somehow ?

More over There is a manual page stating that the Brake Actuator can be bled as well. Is that part present in the newer lexus or is it present in the 90 LS as well ?

thnx.

[lexs400]

Great forum and great post !

I would like to find out how the traction motor runs. I tried to open the bleeder valve and start the engine but the traction motor didnt run automatically neither did any fluid come out of the valve.

More over on a 1990 LS there is no bleeder valve on the traction accumulator. How does that get bled then ?

thnx.