Saginaw pump, used on a bazillion models. Notes on how to make the job easier:

1. O ring between reservoir and pump body leaks. Leaks may not be the hoses! If so, the drip will be from the lip on the bottom of the reservoir.
2. Power steering fluid is VERY SLIPPERY. Clean up spills IMMEDIATELY. Its slicker than motor oil!
3. Dont get PS fluid in the eyes, it BURNS.
Take pictures of everything while disassembling.
4. Edelmann PS rebuild kit, # 7910 from Summit Racing. Good parts. Correct fit.
5. MUST have puller tool to remove pulley. Its not extremely tight, just stuck on with rust. Could make one. Remove the nut by clamping the nut in a bench vise and turning the pulley flat with a wrench. My puller tool came from Tacoma Screw Co.
6. CLEAN the outside THOROUGLY so debris doesnt get in pump!!!! ( !! ) Nice shiney clean for painting later.
7. Pry reservoir from pump body with bracket still attached, use wide flat tool such as cycle tire tool between bracket and reservoir. Reservoir is SHEET METAL, be careful to not distort it!
8 There is a magnet inside, DONT LOSE IT. Put it back where it came from, its the FILTER for the system. IF there isnt one, replace it with a 1 inch thin ceramic magnet, NOT PLASTIC.
9. To remove the large internal snap ring, put a thin punch thru the hole and tap it with a hammer.
10. Clean the shaft before pushing it thru the seal and bearing to avoid contaminating the bearing.
11. Remove the shaft and pump parts with the shaft DOWN, not up. Up lets the vanes fall out.
12. The vanes have a shiney side from the force of the rotor pushing on them. Notice the orientation of the vanes when disassembling and put them in the same orientation when reassembling.
Dont try to look for the rounded edge on the end of the vane, both edges are rounded.

13. Parts inside the pump have razor sharp edges, avoid letting them tear up paper or cloth towels- if so, clean the debris out.
14. Clean, clean, clean!! A clean pump is a happy pump. Clean all the sludge out. NEVER let water contact clean dry bright steel, itll rust instantly.
15. When reinstalling the pump in the pump body, put the lower O ring in first, not both.. makes it easier to get the pump in. Whack the pressure plate with a ratchet handle to pop it past the O ring. Lube the O Rings with PS fluid.
16. The end cap of the pump (under the retaining ring) goes in concave out. The 77 Unit Repair GM book is wrong. Press the end cap and spring in with a C clamp and socket over the shaft.
If the end cap wont go into position, the two dowel pins thru the pump arent seated in the holes in the housing.
17. The shaft bearing in my pump was perfect. The kit has a replacement. Didnt need it. The shaft is 0.750" The bearing measured about 0.750 + 0.0005 with calipers.
18. Tap the seal in with a small hammer to start it straight, then press it in using a bench vise and socket. LUBE the seal lips with PS fluid. NEVER run in a new seal without lube for the seal lips!
19. The pump reservoir is a blankety Blank to get back on. Try putting the pump body and O ring in a deep freezer for an hour to shrink the O ring. Lube the reservoir surface with PS fluid before trying to push the pump and O ring in. If necessary, use wood working clamps
to press the assembly together. DONT rely on the fastners to pull the reservoir in place. It may be necessary to push the O ring in with a small straight screwdriver.
20 After assembling reservoir and pump put a few ounces of PS fluid in it, and set the assembly shaft-down on the bench for a few hours to check for O ring leaks!
21. A pulley press tool is not required, the GM manual is wrong. This pulley is on a shear key and such pulleys must be a slight clearance fit or the shear key may not work. The pulley was stuck on because of rust. Polish the shaft. pulley bore and key with 300 grit sandpaper and the pulley will slide on most of the way by hand. Put a little Loctite on the original lock-nut and reinstall the nut. The original nut is a deformed locking type.
22. Clean the outside of the entire pump assembly thoroughly and then paint it. Make sure to paint two things- the inside of the pulley and the crimp on the sheet metal reservoir- both are failure areas due to rust thru.
23. Caulk the reservoir crimp seam with some kind of sealant to keep water out. If that seam rusts thru, it wont hold fluid and the pump may be destroyed.
24. Attach the high pressure fluid hose before fastening the pump in place- not tight, just thread it in by hand- much easier to start the threads with the pump out.
25. Once installed and filled with fluid, bleed the high pressure hose by loosening the nut on the high pressure hose on the steering gear 2 turns and wait for the fluid to start seeping out. The low pressure hose commutes with the reservoir and doesnt need to be bled.
26. Put a 1-1/2" block on the frame beside the PS pump and use a screwdriver on the block to press up on the pump bracket to tension the belt. DONT do what I did and use a crescent wrench handle against the pump reservoir!!! ( I can do some stupid things)

 

Finished, painted pump in operation. The white line is Loctite Marine Sealant, a special (expensive) aerospace type sealant available at Homeless Depot. The sealant keeps water from soaking into the crimp area on the reservoir (at the O ring).

RUST in the crimp seam in the fluid reservoir...eventually that can rust thru and cause a bad leak. That seam is a crevice that collects water. (crevice corrosion)
Pulley puller tool from Tacoma Screw Co. http://www.tacomascrew.com/Products/Pullers/Proto-4053-Pulley-Puller





Page from GM 1977 unit repair manual.

Page from GM 1977 Unit Repair manual.