woodshak Posted December 6, 2004 Share Posted December 6, 2004 Hi All I have a 1991 LS400 and the trac light comes on about half the time. Code 19, loss of accumulator pressure. I have bled the system. I read that some suggest changing the hose and o-rings from the accumulator to the pump. I would like to try this before purchasing a new accumulator. Does anyone know the part number for the hose and 0-ring kit for a 91 LS400? Has anyone done this and can share any tips or steps for changing it? Thank you. Troy Quote Link to comment Share on other sites More sharing options...
wwest Posted December 6, 2004 Share Posted December 6, 2004 With no signs of leakage?? If so that would be a waste of time. Did you remember to bleed the brake system at the Trac pump accumulator and at the abs pumpmotor? What the diagnostic really means is that the Trac brake fluid pressure replenishing pump is running too often. Each time you apply the brakes the Trac ecu checks the brake fluid backup pressure at the accumulator. If the Trac pump has to restart to replenish the pressure fluid pressure on ten sequential brake applications the diagnostic indication will be illuminated. Oftentimes you can just sit in your driveway and count as you apply the brakes and on the tenth one the light will come on. That can be because the accumulator has lost it 3000PSI of nitrogen charge or it could also mean that some small debris is blocking one of the reverse flow check valves open. A complete brake fluid flush fixed mine. If you take it to Lexus to have this done be sure and point out the extra bleed valves, Lexus of Seattle didn't know of them until I pointed them out. Quote Link to comment Share on other sites More sharing options...
woodshak Posted December 7, 2004 Author Share Posted December 7, 2004 With no signs of leakage??If so that would be a waste of time. Did you remember to bleed the brake system at the Trac pump accumulator and at the abs pumpmotor? What the diagnostic really means is that the Trac brake fluid pressure replenishing pump is running too often. Each time you apply the brakes the Trac ecu checks the brake fluid backup pressure at the accumulator. If the Trac pump has to restart to replenish the pressure fluid pressure on ten sequential brake applications the diagnostic indication will be illuminated. Oftentimes you can just sit in your driveway and count as you apply the brakes and on the tenth one the light will come on. That can be because the accumulator has lost it 3000PSI of nitrogen charge or it could also mean that some small debris is blocking one of the reverse flow check valves open. A complete brake fluid flush fixed mine. If you take it to Lexus to have this done be sure and point out the extra bleed valves, Lexus of Seattle didn't know of them until I pointed them out. ← wwest, I did bleed it at the accumulator and the actuator. I have tried it several times. The first couple of times, it seemed to help for quite a while but now it does not seem to help. I have read some other posts that say this hose that leads from the accumulator to the pump sometimes develops small cracks and allows air to get into the system. It is located underneath the accumulator and pump so I cannot visually see the hose very well to determine if it is wet or not. I just figured if I end up replacing the accumulator that I might as well change this hose as well, and thought I would do it first since it would be less expensive. Alldata doesn't seem to list this hose though or any repair info on replacing the accumulator so I thought I would ask the club for advice. Thanks. Troy Quote Link to comment Share on other sites More sharing options...
wwest Posted December 7, 2004 Share Posted December 7, 2004 Hmmmm...... I rather doubt that air, sea level atmospheric pressure, can overcome the 3000PSI of pressure downside of the pump, at the fluid end of the accumulator. I suspect you would see lots of brake fluid leaks long before any air gets into your brake system via any path other than the filler cap. By the by, you can probably pick up, for cheap, an entire Trac/pump/accumulator assembly at your local wrecking yard. Quote Link to comment Share on other sites More sharing options...
woodshak Posted December 17, 2004 Author Share Posted December 17, 2004 Update: I ordered and installed the following for my 91 LS400: 90947-06002 Pressure Hose $31.05 90301-13011 O-Ring Kit $10.08 47970-50012 Accumulator $462.13 Shipping $18.00 Total $521.26 Ordered parts from HoyFox Everything is good so far after test driving it. No trac light and the traction control does work good. I replaced the above parts due to intermitten trac light caused by trac code 19. Quote Link to comment Share on other sites More sharing options...
wwest Posted December 18, 2004 Share Posted December 18, 2004 I paid $100 for a complete Trac/pump/motor/accumulator assembly at Greenleaf wrecking yard in Woodinville. Works. Quote Link to comment Share on other sites More sharing options...
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