AGR pump installed; air leak? Please Help!

Hello,

I installed my new AGR 809156 power steering pump yesterday to improve my steering performance and reduce system noise. I flushed and filled the system with fresh Amsoil Synthetic PS fluid. I noticed when bleeding the system with the engine off a "sucking" sound when moving the tires back and forth, followed by fluid level fluctuation and large bloopy bubbles. It took a very long time ( 2 hours) to preliminarily bleed the system, even with a vacuum pump. When I started the engine for a final bleed, everything seemed ok, all was quiet and smooth as butter. When I took it for a test drive, the pump became very noisy and I could feel vibration in the steering wheel. I stopped and noticed the fluid was extremely foamy, indicating I hadn't gotten all the air out.

So, I bled again........ same problem. The pump started smooth, but after one minute of driving, the pump became louder and louder. Bled again, same result. What interesting is the fluid level doesn't drop, so I can't have a fluid leak.

Can I have an air leak? I noticed a little play in the high pressure hose at the pump; the fitting is tight, but the hard line out of the fitting seems loose. Can this connection leak air? Are there any other areas in the steering system that can leak air and not fluid?? Please help, I don't want to ruin my new and expensive AGR pump, and I hope I don't have to change the rack...

Thanks so much,

ERUSH

...You probably already have this, AGR instructions for bleeding the pump with "Eliminating Air in the Power Steering System"...
http://www.explorerforum.com/forums/showthread.php?t=240227&highlight=agr

Thanks for the reply Tbars!

I followed the instructions provided to a 'T'. I am in the process of rechecking the connections, but my high pressure line still has play in it at the connection to the pump. I assume there should be no play?

Are there any other sources of air-without-fluid leaks?

...For future readers, which vehicle is this on (specs), and have you contacted AGR themselves?

...Does it make noise right away or after say a 15 minute drive on a highway? Details of what is happening before it makes the noise may help solve it...

..After driving and you hear the noise, did you check your fluid and find bubbles or what makes you think it's air getting in?

If fluid level has not dropped, no fluid has moved through the system. This normally indicates a large bubble in the system reservoir or pump. Until this passes, no fluid will circulate through the system.

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...Have you been doing this by yourself or did you have someone knowledgeable helping? I had help watching the fluid as it is very important to watch it or you may still have air in the line..

..I have seen connections suck air and not leak..Have you disconnected the lines and checked the fittings to see if there was a seating problem? I've also seen bad fitting "fittings" before..

That high line will seem loose from what I was told. I had the same question after finding it not so tight. That O-ring that fits in there may be the culprit.

...For future readers, which vehicle is this on (specs)

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1997 Explorer XLT, 4.0L OHV, 4WD

...Does it make noise right away or after say a 15 minute drive on a highway?

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While Idling in the driveway, the pump is silent and smooth, even when turning the wheels. I drive 200 feet out of my driveway, and the pump whines like a pig caught in a fence My guess is the increase in rpm stirs the system up, or introduces air from a leak somewhere...

..After driving and you hear the noise, did you check your fluid and find bubbles or what makes you think it's air getting in?

Click to expand...

After my short test drives after bleeding, and after I notice the pump noise and steering wheel vibration, I found foam in my reservoir, but no drop in fluid level. This phenomenon leads me to believe that I have an air leak and not a fluid leak. As stated above, idling in the driveway yields no noise nor vibration, even after idling for about 30 minutes.

...Have you been doing this by yourself or did you have someone knowledgeable helping?

Click to expand...

My dad came over to help, and he is quite knowledgeable since he used to build circle track cars back in the day. We both agreed before starting the engine that we had all the air out---no bubbles in the reservoir, no fluid drop after cycling the wheels (the level dropped considerably when moving the wheels for the first time).

..I have seen connections suck air and not leak..Have you disconnected the lines and checked the fittings to see if there was a seating problem?

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The only lines I disconnected where the return hose and the high pressure hose. The rest of the lines are pretty rusty, so I didn't touch them. I am going to disconnect my high pressure line and see if I can get a better seat.

That high line will seem loose from what I was told. I had the same question after finding it not so tight.

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The line wiggles a bit when I touch it, but the nut connected to the pump is tight... this doesn't seem normal. Could be wrong...

Thanks again for all your help. I'll recheck my fittings and get back to you. I'll call AGR tomorrow morning and get their advice.

Ok.

I removed the high pressure fitting and noticed the end flare was chaffed and burred, and that the teflon o-ring was split. Looks like a new high pressure line is in order...

Anybody out there have similar problems and solutions they'd like to share?

I don't want to give the impression that I'm a total idiot: I read and followed AGR's instructions implicitly, but the system seems to draw air after driving it shortly.

I'll replace the high pressure fitting, bleed again, and report back.

Any other tips?

Thanks again for the discussion and advice. This forum has invaluable resources and advice!

ERUSH

..Just my .02..

...I had good lines before I did my swap but to save myself some headache, I bought both new lines...

...Anything rusted or in bad shape should also get replaced now, or you will be doing this again..

I read the instructions for bleeding the AGR pump, but disagree with some of the instructions.

On quite a few Fords, especially our Explorers, every time the steering wheel is moved without the engine running, air is introduced into the system.

Once the initial bleeding is done, you need to turn the steering lock to lock several times while the vehicle is running. This may need to be repeated several times with intervals of rest in between for any air to settle out of the fluid.

Every time you redo the AGR bleed you are getting more air in the system. At this point you should only turn the steering while the engine is running.

Furthermore, a poor connection in the high pressure side of the system will cause a fluid leak, not air ingestion.

Do several turns lock to lock while driving very slowly down the street. Allow the vehicle to rest 15 minutes and repeat a few times. Over the next week, do a few lock to lock steering turns while backing out your driveway.

my98nnj said:

I read the instructions for bleeding the AGR pump, but disagree with some of the instructions.

On quite a few Fords, especially our Explorers, every time the steering wheel is moved without the engine running, air is introduced into the system.

Once the initial bleeding is done, you need to turn the steering lock to lock several times while the vehicle is running. This may need to be repeated several times with intervals of rest in between for any air to settle out of the fluid.

Every time you redo the AGR bleed you are getting more air in the system. At this point you should only turn the steering while the engine is running.

Furthermore, a poor connection in the high pressure side of the system will cause a fluid leak, not air ingestion.

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I agree. Also, check the fluid level with vehicle running as you turn the wheels. If it drops close to the min level, it can temporarilty dip lower and pull air into the pump from the resevoir when you hit a bump or take a sharp turn. I suspect the resevoir is too small for the aftermarket pumps. Had this problem a year ago driving me crazy until I watched it pull down from full to under minimum. Ended up adding a little over the full line to cure. It has not recurred to date.

Thanks for the replies, my98nnj and RomeovilleIL!

On quite a few Fords, especially our Explorers, every time the steering wheel is moved without the engine running, air is introduced into the system

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Not trying to argue, but how can air be introduced in the system if it is properly sealed?



If I remember my fluid dynamics correctly, a venturi effect may be causing a pressure differential across a weak connection or hose, causing air to be sucked in at the weak spot. Just an academic theory...any mechanical engineers want to chime in?

If it drops close to the min level, it can temporarilty dip lower and pull air into the pump from the resevoir when you hit a bump or take a sharp turn

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I've watched the reservoir while the engine is running; and there is considerably more turbulence than with the old pump. I wonder if this turbulence is introducing air.............

Just called AGR. Surprise, surprise, they said I still have air in the system .

I'm going to replace the high and low pressure hoses this evening and see if this subsides.

Like I said before, I chased this headache for a while before simply adding a little extra fluid. I'm at maybe 1/8-1/4" over the max line with engine off and system cold. Given you are going to end up draining and bleeding when you swap lines, I'd suggest you try a little extra fill first and go around the block a few times to see if that makes a difference. Might save you the cost of new hoses and time of replacing.

ERUSH97XLT said:

Not trying to argue, but how can air be introduced in the system if it is properly sealed?

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It's a FORD issue, very common knowledge around here. Search the forums and you'll find multiple threads about it. Even a brake job or front end inspection where people have moved the steering while the vehicle is up in the air, engine off, has resulted in the famous steering system wobble due to air being introduced into the power steering system. You had the system completely apart, you've got a lot of air that needs to get out.

Before you start throwing $$ in hoses, bleed the system with the engine running, lock to lock turns just as I described in my previous post. Might take a day or two, but I think you'll be pleasantly surprised.

my98nnj said:

it's a ford issue, very common knowledge around here. Search the forums and you'll find multiple threads about it. Even a brake job or front end inspection where people have moved the steering while the vehicle is up in the air, engine off, has resulted in the famous steering system wobble due to air being introduced into the power steering system. You had the system completely apart, you've got a lot of air that needs to get out.

Before you start throwing $$ in hoses, bleed the system with the engine running, lock to lock turns just as i described in my previous post. Might take a day or two, but i think you'll be pleasantly surprised.

Click to expand...

+1

Sorry, guys,

I already replaced the return and high pressure hose before I read your last posts. These items weren't that expensive, and I believe they've bought me some peace of mind at least. Brought out the crows feet...man, that's a tight fit by the rack...

I bled and bled and bled and bled and bled for like 3 hours with the engine running and front end raised. At times, I connected my vacuum pump to help speed things along.

Since it was getting dark, and the pump was acceptably quiet, like I described above after a bleed, I went for another drive. No change; the death howl returned before I even reached the end of my circle. I'll leave it alone and drive it to work for a few days and report back.

Another academic theory: since AGR advertises "proprietary modifications to increase pressure and flow", I think the entire system is now extremely sensitive to interloping air (more so than before). The higher pressure within the pump and the system itself will have a greater tendency to keep more air within the fluid, requiring a longer time to purge, even when bleeding with the reservoir under vacuum. Sorry, I'm kind of a geek, and I want to understand the system better so I may repair it more effectively later.

Thanks again for the advice; this is driving me nuts!!

PS System

...I envy the SOHC's Saginaw TC pump... so quiet and smooth...

Update:

I drove it to work today, and I am convinced air is being ingested, either at the rack or by the pump. The pump started quietly this morning, then grew loud and moaned all the way to work. On the way home, it was even louder. No fluid level change and there's what looks like beer foam in the reservoir after each trip.

This thing sounds like a broken airplane super charger

So. Here's my question: where may I inspect/test for rack air leaks? I should note that I've changed the pump once before with a rebuilt Cardone unit, and I never had this degree of bleeding problems. The one I pulled off was loud due to wear, but the fluid wasn't aerated like it is now.

The pump itself could be sucking air from the shaft seal. One other person has experienced the exact same problem---his post is at the following:

http://204.14.93.181/forums/showthread.php?t=47324

Any thoughts?

Again, I really appreciate all your help. I've never had this much trouble with a steering system before.

Regards,

ERUSH

...I think you are at a crossroads..

...Hopefully you haven't damaged the new pump driving it around with all the air getting to it...

...I wouldn't rule out the pump itself but you may be on the right track with the bottom seal...

...I guess we can rule out you have a bleeder screw on your hoses..Maybe we can get Izwack in here to see what he thinks..:scratch:

...Hopefully you haven't damaged the new pump driving it around with all the air getting to it...

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I hope so, too. I don't think the pump is damaged; it starts out quietly and smooth, then air gets in it, then it howls like a Stuka dive bomber.

...I wouldn't rule out the pump itself but you may be on the right track with the bottom seal...

Click to expand...

By "bottom seal", I assume you mean the pump shaft seal? Or the rack seals?

I don't think it's the rack... the old fluid I pulled out when flushing the system never got aerated with the worn pump. This may rule out the rack's seals.

As a matter of fact, I didn't have trouble at all bleeding with the old pump. Old pump out, new pump in, left-right, left-right, done But that was 75,000 miles ago. I have 140,000 miles now.

If this is a pump warranty issue, I hope they take it back, even if it's ruined. A pump defect may have caused its own demise...

I'll PM IZwack and see if he wants to chime in. Thanks for the reference!

Questions:

1) During your bleeding process, (as mentioned by others) did you start the engine and turn the steering wheel lock-to-lock a few times?

2) When the pump is squealing and you are traveling at a low speed, is the steering pressure gone (difficult to steer) or does it still steer like the power steering system is still working properly?