'72 250 - replacing PS pump

[rgnprof]

This car has been sitting for a little while, and I have finally pulled my bad power steering pump and have a new one on order. Any advice on putting the new one on? Like, how do I flush out all of the old fluid? Bleeding instructions?

Anyone done this job?

Thanks, ryan

[Tom Drew]

Is the return hose in good shape? Is the gasket on the reservior cap sealing?
I followed this procedure for flushing and it solved the foaming problem:

Flush Power Steering Fluid Exchange

You'll need a helper. The steps are rather simple.

1. Lift front tires off the ground.
2. Disconnect the ps return line at reservoir, drain ps reservoir.
3. Plug open connection at the reservoir.
4. Secure the return line to a generously-sized container (at least one gallon). If needed, add a length of hose.
5. Fill reservoir with new fluid.
6. Line up your bottles of new fluid for quick pouring.
Here comes the fun part...
7. Have helper turn car on, and immediately have him go through full range of steering motion (left and right) all the while you are trying to keep the reservoir filled. Shut off car after about 3 quarts are run thru the system.
8. RE-CONNECT RETURN LINE.
9. Clean up mess.
10. Top off fluid.
11. SLIGHTLY CRACK BLEEDER FITTING ON TOP OF BOX WITH CAR RUNNING AND HELPER TURNING WHEELS UNTIL ALL AIR IS EXPELLED AND FLUID STARTS TO COME OUT.

The front tires must be off the ground so the system is unloaded, otherwise a lot of fluid is forcefully pumped out. The return line must be secured to prevent a big mess. Keep at least a couple quarts of ps fluid on hand. The helper must know what they are doing.
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[rgnprof]

Tom,

Thanks for the details! One point of clarification - my understanding is that the power steering reservoir cap only has a gasket if it is bolted directly on to the pump. Mine is not and I just went out and checked and there is no gasket currently. Of course, I could have easily lost it at some point over the years though... Any thoughts?

ryan

[Tom Drew]

I am not familiar with the power steering reservoir on the six cylinder engines. I know on my car ('72 280SE 4.5L V-8) the reservoir cap has to make a tight seal otherwise it will suck air into the system and the fluid will foam. Anyone else familiar with the 114 chassis system?

[rgnprof]

2 follow-up questions: Currently, I have the pump removed - so both the high pressure and return lines are just 'hanging' there. Is there any way to flush out the old fluid from the steering box before putting on the new pump?

Also, any fluid recommendations? In the past, I've always used Dexron transmission fluid, but I know some recommend power steering fluid. My original manual says to use Dexron - but that is 40 years ago!

ryan

[Mike D]

No need to separately flush the steering box and it wouldn't do any good unless you use a pressure style bleeder.

Dexron is the accepted fluid. The specs actually call for type "F" but Dexron III will do.

[Tomguy]

Ryan, like you found in an old post of mine,

Mine calls for ATF too. I dont think there was such a thing as "Power steering fluid" in the 70's. I used ATF for ages. I switched to PS fluid for 1 reason: The ATF was not as viscous as PS fluid in the really cold temps and it would groan more, and it would be tougher to turn.

I bled mine in a similar fashion to what Tom Drew did. I pulled my old pump off and drained as much old PS (ATF) fluid I could by turning the wheel from lock to lock. Then I attached the new pump and pressure hose & blocked off the return on the pump and put my return hose into a gallon jug. Put in new ATF, bled as Tom Drew suggests - except I didn't have my wheels off the ground, but I didn't see any negative impact on that myself.