Page updated on 06-21-2018

How do I replace steering gear box seal?

Earl Ollila
05-30-2007, 08:39 AM
The power steering fluid all of a sudden poured out of the gear box shaft area on my 1997 4X4 ford F 150. Is it a big job to replace the seal? How do I remove the gear box?

05-30-2007, 09:36 PM
I've not done a steering box on a Ford truck, but many are the almost the same, so I'll throw in a reply in case you don't get something more specific.

First off, call the auto parts to see if they sell only the seal. In the last box I did, they only sell new or rebuilt boxes, not the seals. The dealer may have a seal, but the process to get the old one out and the new one in, without damaging it, may make it easier and more reliable to replace the whole thing.

I'd get a manual too, it could have a proper sequence of the R&R to make it go quicker and easier. Be sure and review it first before buying it to be sure it gives adequate information as some manuals are better than others. You might try some used book stores to get a better price. You'll need a can of new power steering fluid too, although some people will say that auto trans fluid works, it doesn't withstand the high p/s box pressure as well as p/s fluid will.

Chances are you'll have to disconnect the steering shaft at the four-bolt connector under the hood - be sure to note how it aligns, connects up and which bolts and nuts went where when you disassemble this. Don't forget, this is your "steering" and you don't want to mess this up and find out the hard way that you did something wrong. You might try using paint to mark the line-up on both halves of the connector, before you disassemble it, to insure a proper mating upon re-assembly.

Stand by to probably lose power steering fluid when you disconnect the power steering hoses from the box and be sure to note which hose goes into which hole - some may have different size connector nuts to make this foolproof. Use a tubing wrench so that you are less apt to round off these nuts as you might have to replace the entire hose if they become too badly damaged. Working "way down there" can be a real hassle and I've used a small hammer to tap the wrench to knock the hose nuts loose. Working from underneath sometimes makes it easier to get these on and off. Now would be a good time to replace all of the fluid possible by siphoning out the remaining fluid from the reservoir so that it will have fresh supply for the new box. When you attach the hoses to the new box, be very careful to thread in the tubing nuts properly as you do not want to cross thread (and damage) these nuts - move the hose up/down left/right and hand thread in the first few turns. If the threads are damaged, it'll probably leak. No sealant is usually needed as the steel tubes are pressure mated (flare jointed) to the box with a taper fit.

The hardest part is separating the box from the pitman arm as it is usually pressed on. You maybe able to rent a special tool from some auto part stores to do this. Otherwise, it'll be quite a pounding job with a small sledge hammer. *Don't* use a pounding technique to put the arm on the new box because you could damage the seal - tighten it with the holding bolt and use Lock-tite to coat the end threads although the nut probably has a lockwasher. If the pitman arm joint at the steering linkage is worn too much, now is the time to replace it. If a hose looks like it's leaking, now is the time to replace that too. If the fluid "return" hose (usually the larger one) is brittle, I'd replace it because it's just a matter of time before it'll leak. This hose often has a removable clamp binding it to the steel tubing since it is under much less pressure and that makes replacing the rubber tubing cheaper then the high-pressure hose that has special crimped connections.

Tip: Before attaching the pitman arm (after replenishing the fluid) start it up to see if the new one leaks. There's nothing like finishing the job to discover a bad seal in a rebuilt box - after all has been assembled - been there, done that, cussed that.

Best 'o luck

Earl Ollila
05-30-2007, 10:35 PM
Thanks Mike, I purchased a Pitman Arm removing tool for $7.00 and a repair kit (two seals and a snap ring) for $12.00. I did paint the pitman Arm before removal. Has to use some heat. Job all done for $20. Lining up the steering shaft was the biggest problem. The kit gave instructions on assembly. You can save a lot of money using automotive forums. Thanks again

11-08-2009, 12:16 AM
this is my first time here but i wanted to add something ,when removeing a pitman arm or a tierod end after putting on the pitman arm puller or ball joint fork tighten or drive in until tight and hold a small sledge hammer tight against one side of the part and strike the other side with another hammer sometimes this works miracles freeing stuck tierod ends and pitmanarms hope this helps someone. I also reccomend checking the pitman arm nut after a few days or a week to make sure it is tight

11-16-2009, 07:54 PM
Ive worked on Saginaw power steering boxes in early 70's M400 Dodge chassis, and hope the one on 91 F350s is about the same. Its only problem at the moment is being mushy and needing too much management to steer. So I assume the steering box needs to have its bearings adjusted.

And since its 19 years old, its going to get at least the high pressure hydraulic hose replaced; just because....

Add your comment to this topic!