So my original "base" rack decided to start leaking on the drivers side from the boot. This is about 8k miles after a rebuilt AV6 transmission was installed. Because of the AV6 "upgrade" I bypassed the speed-sensotive pressure modulator with an unrestricted hose, thus it was in "full-bypass" all the time (basically I had stiffer steering all the time) which was not a problem.

I did the "add fluid every week" thing until i sourced all the parts. I decided to go with a Type-S steering rack and scored a 93k mile takeout unit from a 2002 TL Type-S. To day I scored was an understatement, as it was in "like new" shape, as in perfect physical and mechanical condition with amber fluid, inner and outer tie-rods in good to excellent condition and zero corrosion on anything.

I sourced new Type-S lines and hoses and reservoir from Rockauto and a new aftermarket pump from Amazon.

I decided to install the new pump to "test it" on the old rack and system. It definitely seemed to move more fluid (as observed looking into the reservoir when running) and it generated more heat into the pressure line compared to the original pump. The strange thing Is with the new pump I didn't notice as much of a leak from the rack, almost like it "sealed up" with the new pump. Drove it for a week and only had to add a very small amount of fluid, which could be attributed to the pump replacement.

In the meantime I ordered a new seal kit and Honda bearing for the original PS pump and rebuilt it for a spare. Afterwards the compulsion to "try it out" was too great so I swapped it back in. I noticed immediately that it produced less heat and less recirculated volume (the swirling in the reservoir while running was noticeably reduced).

After only 12 miles I noticed the rack was leaking once more, so I went ahead and swapped all the new parts in.

With the new rack in place I noticed the original pump was making more noise than it had with the base rack in there. I drove it a little and the noise didn't subside (not really a loud whine, just that you could hear the pump a little under load) so I swapped back in the new pump. Immediately I noticed the same increased heat, volume and now the new pump also made a similar (but louder) sound like the original rebuilt pump did.

I also noticed this morning when it was cold out (47f) that the new power steering pump most certainly is putting more load on the engine as it seemed to stumble a little bit like it needed to relearn the IAC positions under idle load.

I will note I used genuine Honda PS fluid only. In all cases the belt is tightened to spec (.5"-.65" deflection halfway down) so there is not excessive strain on the bearing.

So a couple questions:

1) Is the extra heat and volume out of the new pump a good thing or not?

2) Why would the original rack only leak excessively with the old pump (ie, is it a sign the old pump is too "worn")? And is the reduced volume of the old pump good or not?

3) Since the old rebuilt pump makes less noise and heat should I swap back to it, keep the new pump or return the new pump and see about replacing it with a different one?

I will note that the new pump has mixed reviews (as do all non-OEM pumps) but seems "well built" in that it has green marker over every single bolt/nut showing good assembly quality control.

My thoughts are the new pump has either the proper pressure or it is just too high, but I don't have a point of reference to ascertain which it is. I know the steering system has a pressure sensor, but I have gotten no codes with either pump which basically doesn't help one way or another.

I may attempt to vacuum bleed the power steering system tomorrow. I am on short time with the new pump as the return window closes tomorrow so I need to decide one way or another if I am sending it back.

As a side note the rack swap went pretty well overall. I noticed the new rack grommet sits about 1/4" below the oriignal base rack and as such I had to use some mastic "filler" to seal the rack grommet to the grommet in the body. It was windshield sealer "rope" so it is well suited for the task. The high pressure hose I used was the Carquest brand so I know it was a quality hose. The rest of the lines are Susong lines and hoses. The only bolt I couldn't get out was one of the three bolts for the passenger side reinforcement bracket, so I can validate you can do the swap with that bracket in place.

 

Well I figured I might as well follow up here...

Today I decided to take the next step and flush the power steering system with Lubeguard synthetic Honda fluid as a "hail-mary" of sorts. I really was not expecting much since at least 85% or more of the fluid was brand new Honda PS fluid from sealed bottles with only a very small portion being fluid left over in the rack from the doner vehicle.

I used a bottle and a half of Lubeguard Synthetic Honda PS fluid (32oz bottles, so about 48oz or so) to flush the system with the engine off and by rotating the steering wheel back and forth with the front tires on cardboard. I basically disconnected the hose to the pump, used a vacuum evacuator to remove the fluid from the reservoir, used a big funnel with a short section of hose hooked up to the pump inlet and filled rhe funnel. I then rotated the steering wheel back and forth and when the reservoir was near full I drained it again, topped up the funnel and repeated until the fluid in the reservoir was the same shade as what I was adding to the funnel. Afterwards I hooked everything back up properly, topped up the reservoir anc started the engine. I got a bunch of air noises from the pump as it purged itself, and a bunch of foamed fluid in the reservoir. I shut the engine off, topped up the reservoir and let it sit for about 10 minutes to allow the air to separate out of the fluid a bit. Restarted the engine and topped up the reservoir.

End result is better than I expected. The new pump is basically silent now. It also seems to be running cooler.

At this point I am done and satisfied that the new aftermarket pump is operating properly and the system is purged of all air and has synthetic fluid in it and it operates as it should.

I will add that I believe the original pump is just worn at this point and with the increased tolerances it just does not produce the same volume of fluid that the new pump can. Is that a problem, probably not as there was never a check engine light or code set in regards to power steering pressures, so I am confident it would work for its intended purpose, but, considering how hard it seems to get a "good" aftermarket pump I am just going to run the new pump and keep the rebuilt original as a spare.