SAGINAW P type Power Steering Pump REBUILD - Tech Questions

[Fat 454]

Hi all, can anyone with re-build experience on these pumps help with advice on any of the following please -
For context I am re-building a P type pump from a '91 K2500 4x4 OBD, with a 350 vortec and serpentine drive belt. Appear to have lost pressure in the steering system ( replaced pitman arm, checked steering box, new hoses etc. etc. )

Is the pump rotor outside face ( between the vanes ) supposed to be smooth, or grooved ? ( rough "wear" grooving, not clean machining rings ) ?
I pulled this one down and found lots of gunk on the magnet, and thought the rotor was galled, however when I stripped another pump to compare, it looks the same ( maybe both bad ? ) Evil bay seems to show both smooth and grooved - any thoughts ?

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Inside of the rotor cam is unmarked, and vane edges are polished also. Assume that is where the hydraulic seal is made :


Next, assume the flow control valve works under pressure, as I have cleaned the gauze filter screen, but cannot blow through it. Assume thats how its meant to be ( ie. not blocked ). I can't get the filter nut off, as cannot hold the circular plunger valve body. Assume there is a factory tool for dissasembly ( j wrench with peg to hold in one of the bleed holes ? )

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The Reservoir on this ( '91 ) model has a mid mounted return line ( top ), whereas all the other ones I have located the return at the base ( lower ). Are they OK to interchange ( the high mount one has a much longer steel return line and it has been partially crushed, so an concerned it may restrict flow ...

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Finally, any tips for getting the ( tiny ) rotor shaft retainer snap ring off ? The newer box had a circular section ring ( top ) that popped off easy, but the older one ( bottom ) has a flat ( piston ring section ) snap ring. Its too small for regular snap ring tools, and the square section wont pop over the land. Its driving me crazy !!..


thanks for any help

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[Fat 454]

Here is the cam body showing smooth internals :

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And general assy. parts showing the vanes etc. All appear in good shape ?

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[Fat 454]

Apologies if this has been covered before - did a good search through, but most threads seem to be on general diagnosis and swapping out re-man boxes. If there is a tech sticky please direct me over - thanks.