JTJerryls400

Hi all!
Maybe some one can help. I have problem with trac bleeding in my SC400. In service manual it is write that traction system can be bleeded too.

Service manual says:
*************************************************************************
1) ABS bleeding procedure is the same procedure used in
bleeding conventional brake system. On models without TRAC, if master
cylinder is rebuilt or reservoir is empty, bleed master cylinder
first. On models with TRAC, bleed TRAC system first. To bleed TRAC
system, go to step 3).

3) Connect vinyl hose to bleeder plug of accumulator. Loosen
accumulator bleeder plug. Start engine. Operate TRAC pump motor until
all air bubbles have been bled. Tighten bleeder plug to 74 INCH lbs.
(8.3 N.m). With engine running, add brake fluid. Turn engine off.
4) Connect vinyl tube to bleeder plug of TRAC actuator.
Loosen bleeder plug. Start engine. Operate TRAC pump motor until all
air bubbles have been bled. Tighten bleeder plug to 74 INCH lbs. (8.3
N.m). With engine running, add brake fluid. Turn engine off. Clear any
code(s) stored. See CLEARING CODES under DIAGNOSIS & TESTING.
******end service manual*************

And there is problem. HOW OPERATE TRAC PUMP MOTOR ???? When engine is simple running there is no any pressure air or fluid escaping from acumulator. Any... it looks empty...

Second plug on TRAC acuator work fine(when engine working fluid is escaping with open bleeder plug.

Please help.

Lexs400

I'm trying to find the same info without any posts in the forum describing this.
anyone has the info ?

dirkdiggle

iTrader: (1)

anyone ever figure out how to bleed TRAC control correctly??

Lexs400

I tried all the methods out there. Even the dealer never really bled that system. so I suggest leave it alone. just bleed the brake lines.

djl

1. Loosen Trac Bleeder and connect clear drain hose.
2. Start engine and Trac pump will automatically start pumping to build pressure, but since bleeder is open it never gets to proper pressure so it'll pump continuously.
3. Monitor brake fluid reservior carefully to make sure it does not get drained, the fluid will pump out pretty quickly.
4. Close bleeder when all air is out of system and fill reservoir to proper level.

Pretty easy actully, just need to watch brake reservior level.

Good luck,

djl

Lexs400

I had tried that too but nothing ever came out of the trac bleeder valve...

5sp_jzz30

iTrader: (2)

i dont have TRAC ....but the procedure written above seems right from what i have seen before.

Steelwheel

A while back I posted how bleeding the trac system properly helped with trac/abs codes on https://www.clublexus.com/forums/sho...d.php?t=322396

There is a trick to it and the funny thing was that the trac actuator on the right side had tons of air in it but the accumulator had none. The post above describes how the valve on the actuator had to be open before cranking to get it to bleed. The accumulator is bled by lifting the rear tires off the ground and giving gas in drive to initiate (or Lexus shops may use an SST). Good Luck.

Lexs400

[QUOTE=

There is a trick to it and the funny thing was that the trac actuator on the right side had tons of air in it.[/QUOTE]


Thanks for posting this, where would this bleeder on the actuator located at on the LS400 ?
thanks.

Steelwheel

Here is a scanned pic of sc400 manual, not sure if is the same as ls400. This is on the passenger side (RH) around the ABS stuff. The actuator bleed only required the bleeder open before cranking and did not require the rear end jacked up. The trac pump/accumulator on the left side is done separately and requires the activation of the pump so the rear has to be jacked up. Good luck

Lexs400

I bled the actuator today. didn't see any bubbles. yet the pedal is still soft spongy. i'll try trac pump next.

Steelwheel

trac problems may not cause the pedal to be spongy, mine was not spongy at all, very good braking even though the trac system needed to be bled. If you are spongy, could need overall brake system bleed. Just make sure the resevoir stays full while bleeding, if it gets low just once it will inject air in your normal brakes requiring full bleed again. You may already know this, just speculating.

Lexs400

thanks for the input. you do have a good point. See the brakes were perfect untill one day i was getting the pads replaced at a shop and the mechanic let the calliper hang in the air. that caused the already old rubber brake line to rupture and it leaked almost all of the fluid. From that day on the pedal is spongy and the braking effect is literrally half of what it used to be. I bled the brakes (literally using all methods) atleast 5 times since then but no use.

cali108

iTrader: (1)

That pic is of the actuator? I cant find the The trac pump/accumulator, Where is that?

cali108

iTrader: (1)

Still trying to bleed my trac acumulator (drivers side by the Master Brake Cyl) I loosened the bleeder, connected clear hose, the rear wheels are off the ground, start the car, step on the throttle still no fluid coming out, is there a way to electrically jump the pump on the trac accumulator? Should I clear the codes maybe that's causing the pump not to turn on?

please help thx