4x4 power steering conversion questions [LONG w/LG PICS]

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4x4 power steering conversion questions [LONG w/LG PICS]

Post by FORDification »

When doing a power steering conversion on a 4x4, I've always heard that using the integral power steering box from a '78-'79 pickup would make the conversion a bolt-on deal. However, I'm finding out that it's not exactly true. Therefore, while I was at the shop today for a few minutes I snapped a few pictures, and hopefully someone can shed some light on this subject.

OK...here's a picture of the manual-steering box mounted on my '69 F100:

Image

...and here's a similar view of the '78 F150's PS box mounting:

Image

First of all, you can see how they differ. The manual steering box is located much farther forward to the front, actually dead center on the front crossmember, with the Pitman arm facing backward, whereas the '78 PS box is farther back, almost against the Panhard bar bracket, and has the Pitman arm facing forward. Also notice the spacing of the bolts between the two...they're not the same, meaning some drilling would be necessary to mount the PS box in the same relative location on the '69. However, that's not going to be easy, since the inside of the frame rail of the '69 is boxed, and there's a curved section right where it needs to be mounted. Here's a shot of the '69 setup, looking down on it from the driver's side:

Image

And finally, here's a shot of the inside of the '69 truck's framerail. The yellow arrow is pointing to the forward mounting bolt/nut.

Image

OK. Now, to mount the '78 box on the '69 in the forward location (where the factory '69 MS box is currently located), I'd have to drill new holes. However, because the front crossmember is there, I have no access to the backside to put a nut. If I was to mount it there, I'd also have to flip the Pitman arm around 180 degrees to face rearward.

On the other hand, to mount the PS box in the rear location, where it was mounted on the '78, I do have access to the backside of the frame, but the framerail boxing is curved, meaning that some modification would have to be done to create a flat surface for the nuts.

Unfortunately, I neglected to look at the inside frame rail of the '78 after I removed the box to get an idea what the factory did, but I'm guessing it's a flat area there instead of the curved brace that the '69 frame has in that spot.

Anyway, at least we now know that it's not quite the easy bolt-on we've thought it was. So which direction should I go? I'm not really a mechanical-engineering genius, but I do know that there's the Ackerman principle to consider here...would changing the location of the steering box have any affect on this? The way I'm looking at this, the easiest way would be to simply cut out the curved frame brace on the inside of the '69 frame and weld in some flat steel instead...however, I'm open to any suggestions. Any insight into this would be greatly appreciated. :D
____| \__
-O-----O- Keith
'67 F-100 2WD SWB ~ '69 F-100 4WD SWB w/7" chop ~ 1975 F-250 Ranger XLT Supercab Camper Special
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re: 4x4 power steering conversion questions [LONG w/LG PICS]

Post by heep70 »

This has came up before. I didn't stay up to speed with the findings. I know that the F100 had issues with the crossmember being in a different place making it an easy install for PS.

It would be cool to flip the steering arms on the knuckles to allow the tierod to be behind the diff like on the F100 2xs. Or even mount the gear behind the axle (in the f100 2x location) and do the cross over drag link and leave the tie rod up front.
Greg

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re: 4x4 power steering conversion questions [LONG w/LG PICS]

Post by FORDification »

So the F250 front crossmember is in a different place than the F100's? Farther forward or back?
____| \__
-O-----O- Keith
'67 F-100 2WD SWB ~ '69 F-100 4WD SWB w/7" chop ~ 1975 F-250 Ranger XLT Supercab Camper Special
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re: 4x4 power steering conversion questions [LONG w/LG PICS]

Post by 460 crew »

My f250 is 15in from the bottom of the frame horn up front to the beginning of the crossmember and it is 4in wide.

here is a pic of the original manual steering on the 67-77.5 4x4 F250
1970 4x4 Crewcab build and 12v cummins conversion
http://www.fordification.com/forum/view ... 22&t=17179
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re: 4x4 power steering conversion questions [LONG w/LG PICS]

Post by FORDification »

Cool....thanks for the pics, 460 crew. I can use those for future reference.

I went back to the shop to get some more pictures and measurements on this, so I could do some planning, and found that I do have access to the framerail under the front crossmember after all, via an access hole on the bottom:

Image

(I guess it helps to actually crawl under the truck to look for things like that, huh?) :roll:

Anyway, I also posted this question to the folks at Pirate4x4 in this thread, and was given some good advice, which I'll repost here for future reference:

1) I can use the early Bronco power steering box, since it's mounted in the same position as my '69's MS box. I did some checking though, and to get one of these outright from Jeff's Bronco Graveyard is a whopping $800! Nah, that's OK...and unlikely that I'd actually find one of these rare setups anywhere.

2) I can't mount the '78 box in the forward location and just flip the Pitman arm around, since it'll steer backwards. (Duh...what didn't I think of that?)

3) I could use the 2WD box and do a little fabricating, but we already knew about that option from the 4x4 power steering tutorial on this site. However, I didn't realize that wildhorses.com has some custom brackets that will make it go much smoother....or you can buy the entire kit with pump, brackets, steering box, steering shaft couplers, hoses, etc., which ranges between $700 and $850 for everything.

4) The best idea yet....and the least expensive....is to just mount the '78 box in the same location as the '69 MS box, but swap the spool with one from a 2WD F100/F150 box to change the steering direction. About all that would be necessary is the drilling of a couple holes in the frame to mount the box, and of course rotating the Pitman arm around 180 degrees. :thup:

Now that sound easy enough, right? So...option #4 will be the option I'll be attempting. Not sure when I'll get around to it, but I'll keep you all informed about how it goes. And of course, I'll be taking lots of pictures, 'cause if this goes as easy and painless as I'm thinking it will, it'll be the subject of a new tutorial and will answer one of the most frequently-asked questions here. :hd:
____| \__
-O-----O- Keith
'67 F-100 2WD SWB ~ '69 F-100 4WD SWB w/7" chop ~ 1975 F-250 Ranger XLT Supercab Camper Special
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Post by averagef250 »

The early bronco PS boxes aren't too hard to find and usually in the $100-$300 range used in good shape. They made a gazillion early broncos and alot of them were beat into the ground and cut up for parts. Atleast around the NW, parts are very easy to find for the EB's.
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Re: re: 4x4 power steering conversion questions [LONG w/LG P

Post by heep70 »

FORDification wrote:So the F250 front crossmember is in a different place than the F100's? Farther forward or back?
That was what whomever posted about the differences in the F100 and the F250. I don't know that for a fact and I can't remember who stated it either. I will search around for it.
Greg

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2000 Subaru Outback limited.
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2010 Polaris 800RMK Dragon 155"
2013 Polaris Pro 800 RMK 163"
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re: 4x4 power steering conversion questions [LONG w/LG PICS]

Post by heep70 »

Read this. http://www.fordification.com/forum/view ... t=steering

bumpside-smitty was the one who mentioned the problem.
Greg

1971 F250 "Highboy". SOLD to "Highboy_Firefighter_71"
2000 Subaru Outback limited.
2000 F250 4X4 PSD SuperDuty Crew.
2010 Polaris 800RMK Dragon 155"
2013 Polaris Pro 800 RMK 163"
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re: 4x4 power steering conversion questions [LONG w/LG PICS]

Post by zakt »

There is also a (4) bolt box that came on the F250/F350
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re: 4x4 power steering conversion questions [LONG w/LG PICS]

Post by hardtailjohn »

Wasn't there something posted one time about a shop down in the Phoenix area that could put the new guts in your '77 power steering box to make it steer the right way??? I thought I read about that somewhere. Maybe the outfit that Greg had his steering box rebuilt by, could offer an opinion on this? I emailed them once, but never got any response back.
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re: 4x4 power steering conversion questions [LONG w/LG PICS]

Post by FORDification »

Well, you can get a shop to do it for you, but from what I understand it's really not that hard to do yourself, using the guts from a 2WD box. So I'll be attempting this in the fairly new future, and will be sure to post the results. I'll be taking pictures of course, and if it works OK (and I don't make any embarrassing mistakes) I'll do a write up on the entire PS conversion.

So does anyone have a decent picture of an installed F250/F350 4x4 power steering box that I could use for the visual aid?
____| \__
-O-----O- Keith
'67 F-100 2WD SWB ~ '69 F-100 4WD SWB w/7" chop ~ 1975 F-250 Ranger XLT Supercab Camper Special
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re: 4x4 power steering conversion questions [LONG w/LG PICS]

Post by 460 crew »

Keith I have pics of the 77.5-79 box on my 77 stock if you need some of those. Also pics of the frame bare where it mounts. Also have pics of the 2wd box mounted on my highboy. PM me with what you want for pics and your email and I'll send you a bunch you can pic through. :wink:
1970 4x4 Crewcab build and 12v cummins conversion
http://www.fordification.com/forum/view ... 22&t=17179
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Post by averagef250 »

Steering boxes are pretty simple to work on. Factory shop manuals covers everything completely.
1970 F-250 4x4 original Willock swivel frame chassis '93 5.9 Cummins/Getrag/NP205/HP60/D70
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