78 ln9000 power steering

Bigblueford

New member
I have a 1978 ford Ln9000. Power steering pump keeps forcing fluid back out the top. Do you think this is caused by bad seals and power assist cylinder? The power steering pump isn't whining. Thinking maybe fluid is blowing right past seals it cylinder. I figure I asked for some expertise.
 

Truck Shop

Well-known member
You are not over filling it are you? What color is the fluid? Sometimes when the pumps get worn they wont make any noise but the fluid expands or foams
because of heat. What is the truck used for? Are you doing allot of constant turning? Just some Q's

Where I work we change out two power steering pumps and filters a month, sometimes more. Our trucks have drop axles which are lifted when backing up.
When the axle goes up the steer axle weight goes to 15,500 lbs. And if the dock is hard to back up to and the driver does not get lined up the best he can,
the steering fluid gets real hot. Every time the pump over heats a little more life goes out of it. Dry steering is the worst thing on pumps. The newer TRW
aluminum body pumps can't take much hard work. Your's should be a cast Vickers depending on engine.

Truck Shop
 

Bigblueford

New member
It's a 1978 ford ln9000. Big cam Cummings. Dump truck. Not overfilled. If cap is off motor off as soon as you start engine it blows the fluid right out
 

Truck Shop

Well-known member
Just for grins remove the return line to reservoir and plug the reservoir. Refill and run return into bucket start and see what happens.It will push fluid at a rapid rate
out the return line. If it does not push fluid out the reservoir then it probably is running straight through the assist. Is the reservoir and pump one unit? If so that
is a Saginaw system and I had an International with a DT466 that pulled the same stunt, It was the pump.

Truck Shop
 

Truck Shop

Well-known member
If your truck is equipped with a remote reservoir there will be two hoses connected to it one is the feed hose to power steering pump. The other hose is the
return hose from the assist. Remove the return hose from assist to the reservoir at the reservoir. Plug that fitting the return hose was attached to on the
reservoir. Your plugging it so you can refill the reservoir with fluid, and run the return hose into a bucket. This is to see if it stops pushing the fluid out the top.
Note the reservoir will run dry pretty fast only run engine a few seconds.

Truck Shop
 
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