Power steering pump replacement notes
12-30-08, 03:57 PM
#1
Power steering pump replacement notes
Hey guys-
I just replaced the P/S pump on my 94 LS400 this past weekend, posting my notes so it might help someone.
- Car has about 230K and previous owner replaced the P/S pump at about 130K.
- Pump was making a whining noise, it was very noticeable by my "poor man's stethoscope" - touching a screwdriver tip to the reservoir and the handle to my ear. I repeated touching the drivebelt tensioner, and then on the alternator; to see if one of these was making the whining. The sound was there but much quieter at these locations.
- I confirmed it wasn't anything timing belt related by unhooking the drivebelt and starting the car - the whining went away.
- With the drivebelt slackened, I played with the pulley on the P/S pump. I couldn't detect any roughness or play, on the contrary it seemed to turn smoothly. The pump was not leaking nor was it losing fluid. It made me wonder about doing the repair, but with about 100K on this pump (and I just bought a new alternator!) I figured it made sense.
- Bought a used pump from a 93 LS and rebuilt this. Bought a pump seal kit and a replacement bearing, replaced all the seals per the lexls and lextreme instructions online. Also replaced both the "longer" and "shorter" straight pins because they had developed some notches. FWIW I measured the o-ring that fits on the feed from the oil reservoir, looks like OD 15mm width 1.5mm. If any of you need to replace just this, consider giving this a try.
- Make sure you replace all the o-rings on the vane assembly. There are two on the side front plate. I almost missed the small one. You should end up using everything in the rebuild kit.
- Getting the last plate of the pump vane assembly (called the side rear plate) in place was more difficult than I had planned, it dropped out on disassembly but with the new o-ring it was a snug fit
- I had planned on using my idle air control valve from the pump that was in place. Took the pump off fine but couldn't remove the IACV. Gave up and plugged the hole with the recommended hex bolt, believe this was 14mm x 1.5, wrapped teflon on the back threads, torqued to the same torque as the IACV...hopefully that's ok
- Remember to get a replacement seal washer set for the high pressure feed, a replacement didn't come with my rebuild kit
- Installation was pretty straightforward, although there wasn't room to fit a torque wrench on one of the mounting bolts and the high pressure feed. If/when I do it again I'll torque the high pressure feed in place before mounting the pump to the engine.
- The screen at bottom of the new reservoir looked fine, but I decided to try putting an inline filter in place on the low pressure return line. I tried a Cardone, it fits inside the line. This didn't work at all, when I started the car, the pump was screeching and the steering wheel was shuddering when I tried to turn it. I think it was blocking the line because the fluid level in the reservoir dropped below the screen with the engine running. When I stopped the car, the reservoir quickly filled with frothy P/S fluid. I removed the inline filter and the problem went away.
- I capped the IACV input ports on the air tube and manifold.
- Seems to be working fine, after a few days of use. The whine is gone. I don't notice any difference in steering feel at idle. Pleased with the result so far!
Hope this helps-
Rob
I just replaced the P/S pump on my 94 LS400 this past weekend, posting my notes so it might help someone.
- Car has about 230K and previous owner replaced the P/S pump at about 130K.
- Pump was making a whining noise, it was very noticeable by my "poor man's stethoscope" - touching a screwdriver tip to the reservoir and the handle to my ear. I repeated touching the drivebelt tensioner, and then on the alternator; to see if one of these was making the whining. The sound was there but much quieter at these locations.
- I confirmed it wasn't anything timing belt related by unhooking the drivebelt and starting the car - the whining went away.
- With the drivebelt slackened, I played with the pulley on the P/S pump. I couldn't detect any roughness or play, on the contrary it seemed to turn smoothly. The pump was not leaking nor was it losing fluid. It made me wonder about doing the repair, but with about 100K on this pump (and I just bought a new alternator!) I figured it made sense.
- Bought a used pump from a 93 LS and rebuilt this. Bought a pump seal kit and a replacement bearing, replaced all the seals per the lexls and lextreme instructions online. Also replaced both the "longer" and "shorter" straight pins because they had developed some notches. FWIW I measured the o-ring that fits on the feed from the oil reservoir, looks like OD 15mm width 1.5mm. If any of you need to replace just this, consider giving this a try.
- Make sure you replace all the o-rings on the vane assembly. There are two on the side front plate. I almost missed the small one. You should end up using everything in the rebuild kit.
- Getting the last plate of the pump vane assembly (called the side rear plate) in place was more difficult than I had planned, it dropped out on disassembly but with the new o-ring it was a snug fit
- I had planned on using my idle air control valve from the pump that was in place. Took the pump off fine but couldn't remove the IACV. Gave up and plugged the hole with the recommended hex bolt, believe this was 14mm x 1.5, wrapped teflon on the back threads, torqued to the same torque as the IACV...hopefully that's ok
- Remember to get a replacement seal washer set for the high pressure feed, a replacement didn't come with my rebuild kit
- Installation was pretty straightforward, although there wasn't room to fit a torque wrench on one of the mounting bolts and the high pressure feed. If/when I do it again I'll torque the high pressure feed in place before mounting the pump to the engine.
- The screen at bottom of the new reservoir looked fine, but I decided to try putting an inline filter in place on the low pressure return line. I tried a Cardone, it fits inside the line. This didn't work at all, when I started the car, the pump was screeching and the steering wheel was shuddering when I tried to turn it. I think it was blocking the line because the fluid level in the reservoir dropped below the screen with the engine running. When I stopped the car, the reservoir quickly filled with frothy P/S fluid. I removed the inline filter and the problem went away.
- I capped the IACV input ports on the air tube and manifold.
- Seems to be working fine, after a few days of use. The whine is gone. I don't notice any difference in steering feel at idle. Pleased with the result so far!
Hope this helps-
Rob
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