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Power steering fluid filter...

Ronmar

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Do all variations in civilian hands use this same filter.... from A0 to A1r
I think they may, they appear to use the same reservoir/filter assembly, and the A0 24P shows P/N 7632 141 102, but part target crosses that back to the same NSN that General disorder listed above. Also crosses to a Fram CH803APL.
 

GCecchetto

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I need to flush my PS fluid. Curios what procedure you all use to do a flush? Would like to use my vacuum/pressure pump to do the flush, but given the hose sizes, connecting to one to force fluid through Is likely going to require some fitting art. Anyway, it's a little bit of an odd layout since both hoses are on the bottom. Thanks
 

GeneralDisorder

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Jack up the front with the wheels off the ground, suck out the reservoir, refill with new fluid, and steer the wheels lock to lock a dozen times. Repeat this process two or three or however many times you like till the fluid you suck out looks like the fluid you put in. It's cheap AW32 tractor hydraulic fluid and the system capacity is small. This is how we do most modern cars because very few manufacturers provide any method to drain the system.
 

GCecchetto

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Jack up the front with the wheels off the ground, suck out the reservoir, refill with new fluid, and steer the wheels lock to lock a dozen times. Repeat this process two or three or however many times you like till the fluid you suck out looks like the fluid you put in. It's cheap AW32 tractor hydraulic fluid and the system capacity is small. This is how we do most modern cars because very few manufacturers provide any method to drain the system.
Thanks. I normally suck out the reservoir, disconnect the supply and return lines from the reservoir, put the return in a bucket, then connect the supply line to my pressure bleeder and force fluid through the system until clean fluid comes out. Reconnect the hoses and fill the reservoir. Done.

I already bought two gallons of AW32 fluid for this but used some of it Sunday when I replaced the cab lift pump reservoir. The PS system is 5 quarts and I’m guessing I have about 6 left, so I think I’ll order one more gallon to make sure I have enough to finish the PS fluid once I start.
 

GeneralDisorder

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Thanks. I normally suck out the reservoir, disconnect the supply and return lines from the reservoir, put the return in a bucket, then connect the supply line to my pressure bleeder and force fluid through the system until clean fluid comes out. Reconnect the hoses and fill the reservoir. Done.

I already bought two gallons of AW32 fluid for this but used some of it Sunday when I replaced the cab lift pump reservoir. The PS system is 5 quarts and I’m guessing I have about 6 left, so I think I’ll order one more gallon to make sure I have enough to finish the PS fluid once I start.
The cab lift system does not use AW32 hydraulic fluid. It uses MIL-PRF-5606H mineral oil aviation hydraulic fluid. AW32 and ATF and all the other stuff that people put in there is part of what causes the seals to fail and clog up the cylinder check valves, etc. 5606H has an ISO 15 VG - it is twice as thin and extremely clean compared to AW32 (ISO 32 VG). It flows to negative 60 F and because of that doesn't tend to clog things up like the alternatives.

The cab latch seals and the air over hydraulic pump seals are the first to go on these trucks. Both of mine have been replaced and when the cab latch was done I think they used AW32 or ATF and the pump seals went away shortly after.

 
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GCecchetto

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The cab lift system does not use AW32 hydraulic fluid. It uses MIL-PRF-5606H mineral oil aviation hydraulic fluid. AW32 and ATF and all the other stuff that people put in there is part of what causes the seals to fail and clog up the cylinder check valves, etc.

The cab latch seals and the air over hydraulic pump seals are the first to go on these trucks. Both of mine have been replaced and when the cab latch was done I think they used AW32 or ATF and the pump seals went away shortly after.
Well then, somebody should revise the fluid capacities section of the LMTV part spreadsheet. Guess I'm sucking that fluid back out. Seems like an undertaking to purge that complete system.
 

GCecchetto

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It's not that bad...... System only takes about three quarts so this $30 gallon jug will do the job. Get two and have enough to properly flush it and some spare on hand.

Republic Oil 5606 Super Clean Hydraulic Oil 1 Gallon 5606A 5606H 5606J https://a.co/d/475npWk
I'm going to call the local aero supply shop down at the muni airport and see if they have it. I'm sure as always that you have the skinny on the best way to flush the system? The seals were just replaced in the cab latch and pump, so I would like to keep them healthy.
 

GeneralDisorder

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I'm going to call the local aero supply shop down at the muni airport and see if they have it. I'm sure as always that you have the skinny on the best way to flush the system? The seals were just replaced in the cab latch and pump, so I would like to keep them healthy.
It's pretty much the same as the power steering - suck all the fluid out of the pump, refill with proper fluid, exercise all parts of the system as much as you can and then rinse repeat till you have changed what you figure to be about 1/2 the capacity 4 times over, or about 2/3 of the capacity 3 times over. That will have changed out approximately 90% of the fluid which is about the best you can really do. Further "suck and fill" cycles will only result in very small improvements of 5%, 2.5%, 1.25%, etc etc. The idea here is to dilute the wrong fluid so much that it's basically irrelevant. Fortunately you didn't put something in there that has incompatible chemistry.

In the aviation world it's known as "red fluid" - they will know what you want. It's used extensively and they will have it.
 

GCecchetto

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It's pretty much the same as the power steering - suck all the fluid out of the pump, refill with proper fluid, exercise all parts of the system as much as you can and then rinse repeat till you have changed what you figure to be about 1/2 the capacity 4 times over, or about 2/3 of the capacity 3 times over. That will have changed out approximately 90% of the fluid which is about the best you can really do. Further "suck and fill" cycles will only result in very small improvements of 5%, 2.5%, 1.25%, etc etc. The idea here is to dilute the wrong fluid so much that it's basically irrelevant. Fortunately you didn't put something in there that has incompatible chemistry.

In the aviation world it's known as "red fluid" - they will know what you want. It's used extensively and they will have it.
Thanks. Fortunately, the only circuit used since adding the fluid is the cab lift. So I'll focus on that first and then move on to the others. The fluid I saw getting pushed back into the tank when I lowered the cab was red, so it's either the right stuff, or power steering fluid which would be totally wrong.

I'm planning to remove the suspension squat cylinders, so I guess I'll get some plugs and get rid of those hoses before I start the flush to limit what I need to flush out.
 
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