John Cappa
Former Editor, Four Wheeler
Photographers:
Ken Brubaker
Most factory Saginaw-based power steering systems found in early GM and Jeep vehicles hold about a quart of fluid. Hitting the trail with larger tires and traction adding devices can put a huge demand on the system and cause it to overheat and fail. There are many different aftermarket power steering upgrades available, but since our power steering pump and steering box worked fine for our needs and appeared to be in good shape, we decided to simply increase the fluid cleanliness and capacity on a budget. For this garage mod we used several easy-to-find items that you can get online and at your local auto parts store. These mods can also help make your at-home ram-assist system work more efficiently and reliably. It only takes an afternoon to keep your power steering system running cleaner and cooler.
This GM Saginaw-style P pump with a built-in reservoir is extremely common on several models of 4x4s. On the street, the cap seals fairly well. Off-road it can be quite a leaker. Overfilling the reservoir to compensate for the fluid needs of a ram-assist steering system exacerbates the cap-leaking problem.
You really don’t need all that much to double your power steering fluid capacity and make sure the pump and box are circulating clean fluid. Increased fluid capacity and clean fluid leads to longer power steering system component life.
To stop fluid from leaking out of the pump cap, we simply replace it with an extension made from a 1 1/2-inch fuel-filler hose, a Pro-Werks weld bung kit (PN C73-731), and a couple hose clamps. Avoid using radiator hose; the power steering fluid will degrade it quickly.
Our underhood clearance was tight, so we placed a locked tape measure under the hood before closing it. This measurement gave us an idea of how long our power steering filler neck extension could be. A wad of clay on top of the cap can also be used to check hood clearance.
After cutting the hose, we clamped it all together. The Pro-Werks bung has the same 1 1/2-inch outer diameter as the factory power steering pump fill tube. Even a short extension will help keep sloshing fluid in the reservoir. The extension gives us the ability to add an additional 1/4 to 1/2-quart to the system.
Since the Pro-Werks bung has a sealing O-ring, we decided to drill a small vent hole in the aluminum cap. This will keep the system from becoming over pressurized when the fluid warms up.
Unfortunately, we used this remote hydraulic oil filter mount and small filter because that’s what was in stock at the time. However, we think you’ll be better off with NAPA remote mount (PN 4764) and filter (PN 1622). The filter is larger and holds nearly a quart all by itself. You can also use a Wix remote mount (PN 24764) and filter (PN 51622).
The remote filter mounts have two inlets and two outlets with one on each side to simplify installation. We threaded common 1/2-inch brass NPT fittings into the aluminum mount to route the power steering hoses in the directions we needed. The remote filter is plumbed in on the low-pressure return line of the power steering system.
Mount the filter below the power steering pump so that it doesn’t bleed into the reservoir when the engine is off. Also, attach the filter mount so the oil filter faces up to avoid a mess when changing the filter in the future. We attached ours to the inner fenderwell just above the steering box.
Once you have the mount and hoses all set, you can remove the filter and fill it with fresh power steering fluid prior to refilling and bleeding the system and checking for leaks. We more than doubled our power steering fluid capacity with these additions.
