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2006 Outback 2.5i Limited 4AT EJ253
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Discussion Starter #1
Many out there have been posting about power steering (PS) pump noise and aeration of the PS oil, which you can observe in the resevoir. Often the culprit seemed to be an o-ring that seals the connection of the resevoir-to-pump (suction) hose. The plastic (or metal) "adapter" that the hose clamps to fits into the PS pump with an o-ring and a single 10mm bolt.

Here's my experience solving a noise/aeration problem that was not due to that o-ring, but another o-ring... inside the pump.

On my gen3 2006 OB the previous owner had replaced the o-ring and hose clamp at the plastic PS pump adapter. I replaced the suction hose as it was original (80k miles) and was dried and stiff. (The aftermarket Sunsong 3403731 hose fit well and seems decent quality). I also used a turkey baster to remove old brown fluid from the resevoir and replace with new Dex3 ATF. About 1.5 quarts over several tries. The aeration on startup persisted so I replaced the suction pump adapter o-ring myself (M2x13) from the "stealership". The problem continued. Heading into Fall, and colder mornings, the problem got worse.

There were no observable leaks at the resevoir, the pump, or below at the rack fittings that I could see after several weeks of checking.

My workaround was to start the car and let it warm up several minutes without moving the steering wheel. This greatly reduced the aeration once I began turning the wheel, suggesting that something in the system needed warming to properly seal.

From a 2005 OB at the salvage yard, as in my 2006 2.5i (non-turbo), I found a Showa FAGA-F-1a branded PS pump. I got the junk yard pump to disassemble and see how hard it would be to rebuild the one on my "daily driver".

There are 7 o-rings in the Showa FAGO-F-1a PS pump, in addition to the suction tube adapter o-ring. Any one of which can deteriorate with time and allow pressure/air to bypass into or out of the pump. I bought a Gates rebuild kit 348827 online. It contains all of replacable parts needed except the bearing: 7 o-rings of various sizes, the main shaft seal (impressively NOK brand), and a 2-piece rubber and plastic "bar" seal for the inner eliptical part. (I don't know how the pump works so I'm just calling it "bar" since it's a strait piece of rubber and a straight rectangular peice of some kind of plastic).

The bearing in the Showa is the same 6203 that is used in the 98 OB pump. I had one sitting around. But any 6203 with seals on both sides should work, for example SKF 6203-2RSJ, NTN 6203-LLU, Timken 6203-2RS (40mm OD 17 ID 12 wide, single ball bearing, sealed). I found the NTN in both the 2005 and 2006 pumps I have. One side was metal shield (facing inward) and one side sealed. Since double sealed were easier to find and because I liked the idea of keeping ATF out of the bearing, I bought the double sealed (those listed above) as a replacement. Incidentally, the shaft seal, which is behind the bearing, keeps ATF from reaching the bearing. I found no seal failures on either of my pumps. Both bearing and bearing cavities were dry.

Rebuilding the pump, replacing all the o-rings, bar seal, shaft seal, and bearing has completely solved the pump aeration problem. Notably, two of the o-rings inside the pump were quite stiff and desicated. Likely one, or both of those could have been allowing air to be drawn into the pump. The bearing replacement is optional but after 80k the bearing was feeling loose and the shaft was already out to replace the shaft seal.

These rebuild kits are quite affordable. If you are still having noise problems after trying the easy things like adapter o-ring and hose clamps, consider rebuilding the pump. It's much cheaper than purchasing a rebuild, and requires only patience, cleanliness, and keeping some parts orderly to reinstall facing the same way they came out. The photos online of "professional" rebuilds show dirty bearing seals. I suspect they don't change out the bearing during "professional" rebuilds. The bearing was $10. I put the shaft in the freezer before pressing on the new bearing. Wish I had a press.


Total cost (ignoring the practice junk pump) about $25. 3 hours time.

Hope this is useful to others.
 

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07 OBW 2.5i 4EAT; Eastern Ontario, Canada
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Here's my experience solving a noise/aeration problem that was not due to that o-ring, but another o-ring... inside the pump.
Great write-up. Appreciated.

After reading the post, I checked the pump on my 07. I couldn't find any SHOWA marking, but there was a label on the side showing "ASI 34401 AG0 3B". A Google search for ASI 34401 provided numerous images of the same (visually) pump as mine with the same label. Looks as if there's more than one pump used in the 3rd gen 2.5s, (SHOWA and ASI) and raises the question whether the same Gates kit etc., would apply.

https://parts.subaru.com/ lists 34430AG0119L as the power steering pump part number covering most Outbacks 2005-2009. However, http://opposedforces.com/parts/ lists 34430AG03B. When searched on the part.subaru site, it too lists a wide range of 3rd gen Outbacks. Again, hints at more than one pump (brand) used in this generation.

And to round it out, here's a catalog that includes Subaru power steering pump seal kits. It too shows two kits depending on the year range (page 102).

Just raising this to suggest there might be a different kit depending on the pump supplier.
 

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2002 Subaru Outback LL Bean H6
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My 2002 LL bean h6 has a similar problem. Did you need any special tools to complete this?


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2006 Outback 2.5i Limited 4AT EJ253
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Discussion Starter #4
My 2002 LL bean h6 has a similar problem. Did you need any special tools to complete this?


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@Josh: I was kind of trying not to get into the procedure of the rebuild in this post, as that is a whole other (important) topic and I haven't made enough good photos of the steps yet. I will try to do that.

Aside from standard metric wrenches and sockets, a bench vice, and some spray cleaner (I used brake cleaner), I used a plastic dead-blow hammer to knock the pump a little trying to wedge it out of the mounting bracket (a very tight fit even with all the bolts out). I also used that hammer to remove the old bearing from the shaft and (with large sockets) reinstall the new bearing and then install the bearing/shaft assembly back into the pump housing. One other tool I found very useful was a small curved forcep (a 90 bent pick would work well too) to adjust the "back plate" into alignment. Basically the back-most inner plate (with 2 o-rings on it's back) drops into the pump housing and then you need to spin it so the metal dowel is exactly at the bottom of the pump. A pick with both straight and bent ends would work well.

One trick I would like to perfect before I do this again is some kind of sticky way to hold o-rings in place while they are on peices that must be inverted for the install. Some of the o-rings could easily drop off when putting in the "back plate" or putting on the final rear cover. Needless to say, if any of those o-rings move on install the pump will likely fail to work properly. I got by using engine assembly lube (like Permatex 81950). One could also install the back-plate while holding the pump housing above it. That way at least those two o-rings would have gravity on their side during install. There is no easy way to do that installing the rear cover as many small vanes of the pump would fall out.
 

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2006 Outback 2.5i Limited 4AT EJ253
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Discussion Starter #5
Great write-up. Appreciated.

After reading the post, I checked the pump on my 07. I couldn't find any SHOWA marking, but there was a label on the side showing "ASI 34401 AG0 3B". A Google search for ASI 34401 provided numerous images of the same (visually) pump as mine with the same label. Looks as if there's more than one pump used in the 3rd gen 2.5s, (SHOWA and ASI) and raises the question whether the same Gates kit etc., would apply.

https://parts.subaru.com/ lists 34430AG0119L as the power steering pump part number covering most Outbacks 2005-2009. However, http://opposedforces.com/parts/ lists 34430AG03B. When searched on the part.subaru site, it too lists a wide range of 3rd gen Outbacks. Again, hints at more than one pump (brand) used in this generation.

And to round it out, here's a catalog that includes Subaru power steering pump seal kits. It too shows two kits depending on the year range (page 102).

Just raising this to suggest there might be a different kit depending on the pump supplier.
@plain: Thanks plain for the excellent input as always. I realized I did not include the part number found on the two pumps I was using as reference. They have a similar white label, that does not include "ASI" but simply the bar code and "34401 AGO 3A <serial number>". The "SHOWA" is cast into the front of the pump housing on the high-pressure output. You can see it at the top left front of the pump, just partially behind the pulley. Looking at the online images of the ASI pump, they appear to have exactly the same casting as the SHOWA's I'm looking at. I just searched "showa asi" and what do you know, Showa's US subsidiary is called American Showa Inc...ASI.

Your second point is quite valid as well. Several pumps are spec'd by Subaru. All I can say for sure is that I found a "3A" in a 2005 2.5i and 2006 2.5i. So, going back to Gates catalog online I see this kit is listed only for 2005,2006, and 2007, but not 2008 or 2009 2.5 models. It's not listed at all for the 3.0 H6. So yeah, I guess someone will have to pull apart a 119L pump and measure the o-rings. :) The bar code label is fairly easy to see with the (clean) pump installed on the left hand (passenger) side of the pump housing. At least that is where they seem to be for the early gen3 models. Anyone have a 119L? Is it a Showa/ASI?
 

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07 OBW 2.5i 4EAT; Eastern Ontario, Canada
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I just searched "showa asi" and what do you know, Showa's US subsidiary is called American Showa Inc...ASI.
I like that!
The "SHOWA" is cast into the front of the pump housing on the high-pressure output.
Indeed! I hadn't looked closely enough. So, not two brands.

Leaves the question of whether the 119L and 3B are interchangeable, and, essentially the same such that the Gates kit applies to both.

There was a "foaming" case here not too long ago where, as I recall, pretty well other possibilities were tried without success. Not sure where that went, but now we have this thread to add as a reference.
 

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2000 Outback Limited, Dual Range 5 Speed
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To stick o rings in place a dab of appropriate grease would do the trick, and should wash off when the part is used.
 

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07 OBW 2.5i 4EAT; Eastern Ontario, Canada
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I was kind of trying not to get into the procedure of the rebuild in this post, as that is a whole other (important) topic and I haven't made enough good photos of the steps yet. I will try to do that.
That would be great.

There's a few Subaru power steering pump "rebuild" videos on YouTube, but I didn't see any that are specifically 2005-9 Legacy-based Subarus. If you have any links to relevant videos or other sites, that could help fill in this aspect.

Also, I was wondering: After re-installing the pump, what did you do in regard to refilling the system?
 

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2007 Outback 2.5i
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To stick o rings in place a dab of appropriate grease would do the trick, and should wash off when the part is used.
I used some dabs of bel Ray Marine Grease to hold a saab engine valve cover and it’s brand new gasket in place when you have to turn the valve cover upside down to install it. Heavy grease will do the same for your O-rings.
 

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2006 Outback 2.5i Limited 4AT EJ253
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Discussion Starter #10
@timber @Horse: I thought of grease as well but was concerned with dabs of grease flowing through the PS system. The question is what grease is "appropriate"? I'm not knowledgable about the solubility of grease and ATF. If it didn't dissolve then that might easily plug some of the small diameter ports in the pump, and perhaps end up in the resevoir filter mesh. That's why I used the assembly lube which is (if I understand correctly) meant to dissolve with engine oils, so I figured it was the safer choice. It still might be a poor choice.

Here is a thread on grease not being good inside a transmission. Playing it conservatively, I might take from that that ATF does not (safely) dissolve greases very well. https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2493980.
 

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Discussion Starter #11
@Josh: I was kind of trying not to get into the procedure of the rebuild in this post, as that is a whole other (important) topic and I haven't made enough good photos of the steps yet. I will try to do that.

Aside from standard metric wrenches and sockets, a bench vice, and some spray cleaner (I used brake cleaner), I used a plastic dead-blow hammer to knock the pump a little trying to wedge it out of the mounting bracket (a very tight fit even with all the bolts out). I also used that hammer to remove the old bearing from the shaft and (with large sockets) reinstall the new bearing and then install the bearing/shaft assembly back into the pump housing. One other tool I found very useful was a small curved forcep (a 90 bent pick would work well too) to adjust the "back plate" into alignment. Basically the back-most inner plate (with 2 o-rings on it's back) drops into the pump housing and then you need to spin it so the metal dowel is exactly at the bottom of the pump. A pick with both straight and bent ends would work well.

One trick I would like to perfect before I do this again is some kind of sticky way to hold o-rings in place while they are on peices that must be inverted for the install. Some of the o-rings could easily drop off when putting in the "back plate" or putting on the final rear cover. Needless to say, if any of those o-rings move on install the pump will likely fail to work properly. I got by using engine assembly lube (like Permatex 81950). One could also install the back-plate while holding the pump housing above it. That way at least those two o-rings would have gravity on their side during install. There is no easy way to do that installing the rear cover as many small vanes of the pump would fall out.
@Josh: I'm working on some photos of a tear down of this pump and realized I forgot to include the 10mm hex socket needed to remove the valve access cover/plug. It required a breaker bar with the pump housing held in a vice (wrapped in rags to protect the aluminum housing). One might desire to leave this on except it was one of the o-rings I found to be rather flattened and aged. An impact driver would probably be best as you would likely not need to put the pump in a vice.
 

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Discussion Starter #12
That would be great.

There's a few Subaru power steering pump "rebuild" videos on YouTube, but I didn't see any that are specifically 2005-9 Legacy-based Subarus. If you have any links to relevant videos or other sites, that could help fill in this aspect.

Also, I was wondering: After re-installing the pump, what did you do in regard to refilling the system?
@plain: I surfed the online videos before deciding to buy a junk pump and figure it out myself. Overall I found nothing that was really close so I can't refer to a video here at this time. However, the internals of the honda (and probably many japanese designed) cars are very similar to the subaru, even if the exterior housing has a different shape, and I learned what I could from some Honda rebuild videos before trying my own.

One detail I learned from the videos was about the loose rectangular vanes of the pump. In some pumps they have a rounded side and a square side. In both pumps I looked at here, both sides were curved but one side was gold in color. Gold edge faces out--away from the inner shaft. I am only guessing, but the gold reminded me of titanium coated drill bits. One vane peice even had a small "chip" of gold missing, supporting the idea of a hardened layer added to the wearing surface. I'll try to get a closeup photo of that for my how-to writeup forthcoming.

To bleed the reinstalled pump before first engine startup, I borrowed ideas I had found in this forum regarding hand-turning the pulley clockwise to draw in fluid from the resevoir. Nevertheless, it didn't seem to do much, as when the engine first ran there was the normal several minutes of bleeding the air (along with the noise of aeration/foaming). Also, during assembly, all parts were rubbed with fresh ATF, to help them stick together as well as for pretection during initial startup air bleeding. What's important is that the next mornings there was no noise or aeration. The pump no longer requires "bleeding" each morning.

Based on my experience here, I would reassemble the pump (relatively) dry, so as to be able to invert the pump housing when installing the "back-plate" and it's two o-rings with gravity holding them in place, rather than "dropping" the back-plate downwards into the pump housing (and hoping the two o-rings on it's back don't fall out of place). There's no way to tell if the o-rings stayed in place or not. There is no clear way to know the back-plate is fully seated. It just goes in until the o-rings stop it against the pump housing. (Actually that plate is at the front of the pump. I guess I should have called it the front-plate :p) After complete reassembly, perhaps hand fill the pump with ATF through the suction hose port (at the top of the pump) while turning the pulley clockwise, might allow some semblance of pre-priming the pump. I didn't do that but probably should have tried it as well as trying to turn the pulley after installing the suction line.
 

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Brucey
'17 3.6 Limited
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I had this issue on an 02 bean that still whined even after hose and o ring replacement. Ended up being the clamp on the hose going from the rack to the reservoir.
 

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07 OBW 2.5i 4EAT; Eastern Ontario, Canada
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Here's my experience solving a noise/aeration problem that was not due to that o-ring, but another o-ring... inside the pump.
Been wondering how a weak o-ring inside the pump (not at the outside hose fittings) would allow air to enter. I.e., do the o-rings seal between the pump interior and a potential source of outside air? Looking forward to the photos and discussion to see if the path for air entry to the interior can be identified. (Not doubting the fix; rather it's an academic exercise to better understand this weak point.)
 

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2002 Subaru Outback LL Bean H6
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Started trying to disassemble my old pump and looked around to try and find a rebuild/reseal kit but apparently there’s none available for a Gen 2 H6. So I may just be out of luck unless I get lucky and can find the appropriate sized bearing and seals somewhere.


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2006 Outback 2.5i Limited 4AT EJ253
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Discussion Starter #16
Started trying to disassemble my old pump and looked around to try and find a rebuild/reseal kit but apparently there’s none available for a Gen 2 H6. So I may just be out of luck unless I get lucky and can find the appropriate sized bearing and seals somewhere.


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@Josh: the 34430ae082 is spec'd for your 2002 H6. Lucky for you Subaru details the internal parts for that pump. So at least you have part numbers for each o-ring...
https://parts.subaru.com/a/Subaru_2002_Legacy-Outback-Wagon/49501816__6027933/OIL-PUMP/B12-348-01.html#34430
It gets even better.. a subaru rebuild kit: 34490AE00A
That's a very different looking pump that the one I found in the 2005 and 2006 OB.
 

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2006 Outback Wagon 2.5L
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spleeph, what (if anything) did you use as a guide for your rebuild effort? Or was it basically, "disassemble as far as possible, reassemble with new bearing and parts from rebuild kit?"
 

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Discussion Starter #18
Been wondering how a weak o-ring inside the pump (not at the outside hose fittings) would allow air to enter. I.e., do the o-rings seal between the pump interior and a potential source of outside air? Looking forward to the photos and discussion to see if the path for air entry to the interior can be identified. (Not doubting the fix; rather it's an academic exercise to better understand this weak point.)
@plain: As far as I can judge, without "knowing" how this pump works, the low pressure suction comes into the housing from the top and has open galleys near two of the 7 o-rings: the pressure-valve cap and the smaller rear cover o-ring. I made photos yesterday but still working them into a walk through. Of the 7 o-rings, 5 appear to seal out the outsides, and two seperate internal areas. The largest o-ring seals the back cover. It was one of the "driest" and stiffest coming out of the used pumps. None of the o-rings actually broke. In either pump.

However, I have another theory. One of the internal o-rings appears to also act as a thrust washer. What I mean is that it seals but also appears to alter the depth what I called the "back-plate". How deep it sits when placed into the housing changes when you leave out this o-ring. It appears that o-ring may provide a small thrust to hold the "back-plate" against the turning vane wheel, which in-turn, sits against the rear cover. If that o-ring gets too stiff, and loses flex, perhaps loose play develops on either side of the vane wheel and allows cavitation. To support this hypothesis, the o-rings behind this "plate" have a little larger cross-section diameter than all the others. Maybe 2.5mm instead of 2.0mm. Measuring the depth of the installed "plate" with and without the old o-ring behind it, I saw about 0.5mm change in the space left for the vanes/wheel/rings. This "plate" o-ring is squashed quite a bit in both pumps I looked at.

Admittedly it's all guessing, and it's easy enough to simply replace all the o-rings. If one wants to skip the bearing and bearing seal one could leave the axle/bearing assembly in place. Much of the time is spent dealing with the axle/bearing/seal.
 

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2006 Outback 2.5i Limited 4AT EJ253
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Discussion Starter #19
spleeph, what (if anything) did you use as a guide for your rebuild effort? Or was it basically, "disassemble as far as possible, reassemble with new bearing and parts from rebuild kit?"
@huesmann: Of course I looked through this forum and youtube videos, and found things that were close, but not exaclty gen3. But of course I forgot to bookmark them :( . That gave me confidence to open up mine. But first I figured open up one I don't care about--and bought the junk yard one. I will be posting a visual how-to soon. I made photos yesterday while dissassembling the yard pump again. Like I mentioned @plainOM, the honda's internals are someone similar. The vane-wheel and vanes are very similar. The outer rings that surround the vane-wheel assembly are a little different. There's an alignment/pivot pin that is critical. And the small strips of rubber and plastic opposite of the pivot pin. All the o-rings can be changed without touching the axle/bearing, if you don't feel up for that. One could try just replacing the easy o-rings first, without dumping out the vanes/wheel. My concern is the o-rings behind the "plate" may be the culprit. That requires dumping out all the innards, but you could still leave the axle/bearing in place. They come out through the front, not the back.
 

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Discussion Starter #20
I had this issue on an 02 bean that still whined even after hose and o ring replacement. Ended up being the clamp on the hose going from the rack to the reservoir.
@Brucey: I had read someone had a small leak in a hose. Hence, I replaced the brittle suction hose first and carefully placed the pipe clamps on it. Before and after an engine-compartment wash, I inspected the low pressure and high pressure hoses for leaks but did see anything. Theoretically, the strongest chance for inhalation of air would be at the pump and the same goes for cavitation. Did you see any leakage on those lines before you replaced it? Was there any visual hint there was a break in the line?
 
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