If you encounter leaks, looseness or wander with a Saginaw Rotary Valve power steering gear, some quick diagnostic steps will prove useful. These troubleshooting techniques require nothing more than access to the steering gear and setting the steering wheel on center with the front wheels pointed straight ahead.
With the steering wheel and column unlocked, you can troubleshoot leaks and the over-center sector/tooth looseness within the gear. When vehicle handling changes, be aware that an aftermarket dropped pitman arm and oversize tires place excessive loads on the steering gear’s sector shaft and sector bearing, and this can lead to a sector seal leak, looseness and tooth backlash. The vehicle will wander from the play.
Note: If the steering gear does not have over-center looseness or any signs of sector backlash, check for other sources of steering wander like loose tie-rod ends, ball-joints, suspension links and wheel bearings. Tire belt separation, wheel misalignment and tire wear can also cause wander.
Once you determine the gear’s needs, you can remove the steering gear for tear down, inspection and resealing/rebuilding. The lengthy, detailed HD video how-to is available at the magazine for free. Take advantage of this comprehensive coverage!
If you encounter gear housing, piston rack or sector damage, you need to find a matching, rebuildable steering gear core—or a rebuilt gear—from a reputable source. This is an example of a gear housing that is severely damaged and must be replaced:
This Saginaw Rotary Valve gear housing has been severely damaged, likely from debris running through the power steering system. The additional metal sloughing from this gear housing wall adds to the damage and further chews up the wall. When a pump fails, the metal debris can also cause this kind of damage to an otherwise rugged Saginaw steering gear. The piston (shown here) shows scoring damage as well. An attempt to rebuild this gear would prove futile, the seals would not hold, and the sector seal will fail from the bypassing pressure. The grooves from wear will tear up the Teflon seals.
More information and history on Saginaw Rotary Valve power steering gear are available at the magazine, click here!