'97 F350 power steering overflows, doesn't work

[texasjohn]

F350, 97, 7.3 diesel crew cab dually has twice now given me power steering problems. About 8 months apart.

Both times it began when I had my steering wheel cut all the way over to the stop to make a tight turn to the left. Am not sure same would occur if turn was to the right. haven't tried.

All is working fine, then it happens

First time...plenty of fluid to begin with, tight turn backing, obviously slow speed, power steering stopped operating, check fluid, cap has blown off and fluid is all over everything, very messy. I was ultimately able to drive it a couple of miles using ARMSTRONG, purchase fluid, took almost entire pint and power returned immediately to the steering wheel. Checked fluid level and for leaks for couple of weeks afterwards, no problems seen, thus I forgot about it. About 8 months passed, driving it a couple of times a week, couple of trips of 300 miles, mostly 30 mile trips.

2nd time...plenty of fluid, tight turn going forward, power steering quit abruptly, straightened out with difficulty and drove into my shop, fluid cap not blown off, but fluid had been pushed out everywhere. Assuming it now low on fluid, sought to add some... it was not significantly low. Started engine again, HOWEVER power steering power did NOT return.

Current assumption is that I need to take to mechanic and have power steering pump replaced.

Anybody have this experience, or see a different resolution?

I did a net search, there are reports of this happening when engine is NOT running and you are moving the vehicle..... but saw nothing reported when engine IS running.

[tractorsanmore]

Probrably needs news p/s pump now as you figured . We have had a few trucks over the years do this kinda thing , usually they blew the pressure hose off the p/s unit . Talked to drivers and most said they had the brake pedal pushed and the steering cranked to the stop and held it there . Only thing I can suggest is don't dehead the steering if you can help it , especially if your foot is resting on the brake pedal .

[texasjohn]

I definitely seldom put the steering into a full turn... but, on the two occasions that the problem occurred, it was necessary... or so I thought...yep, likely had foot at least tapping the brake, although am unclear how this is part of the equation. There must be some connection between loosing power steering and braking, however, because I saw another reference to this combination elsewhere on the net as well.

Have driven it to my local mechanic...15 miles....using ARMSTRONG steering, luckily, it was mostly a straight drive with only three turns....it was still dripping power fluid when I got there...Interesting failure, glad it didn't happen at speed

[Hooked_on_HP]

Does the power steering pump on your truck also operate your power brakes? If so this might have somthing to do with it.
Bill

[ScottAR]

Ford pickups with a diesel have hydro boost brake booster. It uses the power
steering pump for power since a diesel produces zero vaccum. I wore out the
pump on my '99 by overheating it several times manuvering trailers. It was the
original best I can tell and by 170,000 miles it was probably due soon anyway.

[texasjohn]

Scott....thanks for the technical explanation. Educational.

Yep, although I don't use the pickup daily, when I do use it a trailer is almost always following it. both times the problem happened I did have a trailer and was maneuvering it.

Pickup has 330,000 miles on it... so, it may just be time for it to go.

[Chuck K.]

Originally Posted by ScottAR

Ford pickups with a diesel have hydro boost brake booster. It uses the power
steering pump for power since a diesel produces zero vaccum. I wore out the
pump on my '99 by overheating it several times manuvering trailers. It was the
original best I can tell and by 170,000 miles it was probably due soon anyway.

Scott, his truck is not a Super Duty like yours. My 95 Power Stroke had a vaccum pump that supplied vaccum to the brake booster and worked the HVAC motors. So applying the brake and going lock to lock should not be a problem. Based on his description though my bet is the PS pump..

[ScottAR]

I stand or sit corrected... I thought all the vac pump on the early 90's
trucks did was work the hvac controls...