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Rebuilding a Power Steering
Pump (Saginaw Type)

Starting in 1968, AMC began using Saginaw power steering components. The first cars to get them had 6 cylinders while V8’s began using them in 1972. These pumps are a big improvement over the Eaton units they replaced which are prone to leaks between the reservoir and the pump housing.

These pumps tend to be trouble free but can develop a few problems that require a tear down to repair. Those problems are a damaged reservoir (which causes a leak around the pump body if that area gets distorted), leaks around the hoses and the pump body, and sticky pressure relief valves (which causes either a chirp noise at low speeds or a loss of pump pressure).

The rebuild procedure is very simple (see Tips to make sure your rebuilt pump lasts for a long time prior to heading to the store for parts). You'll spend most of your time cleaning parts. Here’s what you'll need to get before you get started:

• A 1x2 block of wood
• A hammer
• Assorted box and socket wrenches (deep drive)
• A small flat blade screw driver or pick to remove o-rings
• A large flat blade screw driver to remove the pump cover retaining ring
• A small pin punch or large finishing nail (also used during pump cover removal)
• A torque wrench that will measure up to 35 ft/lbs.
• A pump rebuild kit (I purchased mine at AutoZone for about $10).
• Fresh power steering fluid
• Parts degreaser (Grease cutting dish soap and warm water works well if you’re willing to scrub.)

If you have a press-on pulley, you'll need a removal/installation tool set. Your bigger auto parts stores will usually have a loaner you can borrow.

Before you begin disassembly, I want to warn you about the reservoir on these pumps. They are stamped sheet metal (thinner than a valve cover) and are very easy to bend. Never hit them directly with a hammer. If your reservoir is badly distorted, you can get a new one from a GM dealer (you should take your old one along to make sure the return hose tube is in the correct position) or an AMC parts supplier.

Speaking of reservoirs, Saginaw changed the design of them midyear in `71. The old reservoir is round with a long filler neck. The new design is tear-drop shaped with a very short filler neck. This is the only difference between them.

Disassembly

1. Drain the pump.
2. Remove the pulley from the pump. You'll need a special tool for the pressed on pulleys. The bolt on have a nut you need to remove.
3. Remove the shaft key (pressed on pulleys may not have one).
4. Remove the brackets.
5. Remove the studs on the back and the union for the pressure hose. Turn the pump so the shaft faces up and tap on the pump housing to remove the flow control valve and spring. Remove the o-ring from the hose fitting.
6. Clamp the pump in a vice clamping on the area around the shaft seal and tap around the edge of the reservoir with a block of wood and a hammer to remove the reservoir. Only clamp hard enough to hold the pump in place.
7. Remove the o-rings from the pump body. There are 4 of them. A large one around the body and 3 on the back where the studs and hose union attach to the pump. Make sure to hold on to the 3 in the back. There are two sizes and you may need to match them up if you are unsure of which ones to use.
8. Rotate the retaining ring on the pump cover until one end is near the hole at the top of the pump body. Insert a punch into the hole to push the edge of the retainer clear of the pump body and pry the retainer out. There is a spring behind the plate so be prepared to catch it. Chances are, you'll need to tap on the pump body some to remove the plate.
9. After making sure the key is removed from the shaft, tap on the end of the shaft until the pressure plate, ring, rotor, and thrust plate assembly can be removed. One or both of the dowel pins may come out with this assembly. Separate all of the parts (the pump rotor has 10 vanes in it that will likely fall out so make sure you take it apart over the bench).
10. Remove the two o-rings in the pump cavity and the shaft seal.

Inspection

Clean all of the parts and either air dry or wipe them dry with a lint free cloth. Lightly coat any machined surfaces with power steering fluid to prevent flash rust.

Check to make sure the flow control valve moves freely in its bore. If it doesn't check for burrs. These can be corrected with emery cloth.

Make sure the screw in the pressure relief valve is tight. If it isn't, tighten it. Make sure not to damage any machined surfaces.

Inspect the pressure plate, ring, and thrust plate for scoring. A polished finish is normal.

Make sure the pump shaft turns freely in the bearing in the pump. If there is any side to side looseness or the bearing is scored (or loose in the pump body), replace it with the one in the rebuild kit. I had to use a cold chisel to remove mine.

Make sure the pump vanes move freely in the rotor and check the pump shaft for any cracks.

Assembly

Note: All parts should be lightly lubricated with power steering fluid during assembly.

1. Install the pump shaft oil seal using a 15/16 inch socket to drive it into place. Lubricate the rubber lip with power steering fluid.
2. Lubricate the o-rings that go in the pump bore and install them.
3. Install the dowel pins.
4. Install the pump shaft.
5. Install the pump ring. The arrow on the side should face the open end of the pump bore and the smaller set of holes fit over the dowel pins.
6. Install the pump vanes making sure the rounded edges face the pump ring.
7. Install the pressure plate making sure the spring groove is facing up.
8. Install the pressure plate spring.
9. Install the end plate. Force it down enough to install the retaining ring and install the retaining ring.
10. Install the large o-ring around the pump body.
11. Install the stud and union seals. Make sure to match the old ones up with the new ones since two different thickness’ were used.
12. Place the reservoir in position and gently tap into place using the wood block and hammer.
13. Install the flow control valve and spring.
14. Install the studs and union (make sure to replace the o-ring on the union first!) and torque to 35 ft/lbs.

Installation and Break-In

1. Reinstall the brackets and pulley and install on the car (make sure to connect the power steering hoses as well!). Fill with fresh power steering fluid, start car and let idle for at least 5 minutes.
2. Support front end of car so wheels are not contacting the ground. Turn the wheel to the left and check for leakage.
3. Stop car and recheck the belt for proper tension.
4. If needed, refill the reservoir to its proper level.
5. Turn the wheels back and forth from stop to stop until there is no evidence of foaming in the fluid. Do not hold the wheels at the stop for any length of time or you will overheat the pump. Air going through the system will make noise. This is normal.
6. Once all of the air is removed, check the fluid level in the reservoir and recheck for leaks.

Tips to make sure your rebuilt pump lasts for a long time [top]

• Prior to removing the old pump, flush the power steering gear box out with new fluid. The simplest way to do this is to remove the return hose from the pump and place the end of it in a milk jug. Use a rubber stopper or a cap to seal the hose fitting on the pump so it can hold fluid. Fill the reservoir and have a helper start the car. With the engine idling, add fluid to the reservoir until it comes out clear in the milk jug. Make sure the pump does not run out of fluid or damage to the pump may occur.
• If you find metal shavings or other debris in the pump or the fluid flushed out of the steering gear box, you should rebuild or replace the gear box at the same time. A rebuilt steering gear for my American cost $149 in 1999.
• Replace the power steering hoses. They are cheap (the pair for my American was around $30) and can be a source of leaks and debris in the future.
• Inspect the steering coupler (its the rubber circle between the steering gear box and steering shaft). I know this doesn't affect the pump but if it is cracked or falling apart, a new one will improve the road feel of the car and remove some of the slop from the steering.

Last Updated 01/05/04 09:37:24 PM