Pitman Arm: Where the Van meets the Truck

[MadScience]

Is there a difference between the e-series vs. f-series pitman arms when it comes to the hole size for the ball-joint stud?

My van is '99 e-350 that someone put '08 f-350 axles under. They did this mostly by using a welder, even when it came to the drag link:





The inner drag link contains the last of the ball joints that needs to be replaced. While hunting for the proper length drag link, I noticed that the castle nut that came with the f-series part is slightly larger than the one in place on my van. The one in place on my van is likely the one that was on the van before it was converted, but I have no way of knowing. (For anyone worried about the cotter pin, that's from when I tried the nut, it's secure again.)

I'm obviously working on replacing the drag link with a new part. It looks like in the world of 4x4 converted vans this is largely done by mixing and matching pre-existing parts.

I realize that the portion of the stud that mates with the pitman arm is tapered, so is this just a matter of jamming it in there? Or can I (sanely) ream the hole out a bit? Or should I also be hunting for a different pitman arm as well?

I'm likely doing the steering box soon as well, so changing to a new arm would be simple enough at that time.

(edited after I remembered how pictures work here)

[SteelheadJones]

You might find the info you’re looking for on Wandererr-RRORC’s thread. Start at post #217 here.

[MadScience]

Thank you!!

So that at least supports the idea that I could ream/drill the hole out a bit if I needed to. That's probably enough for me to pull things apart and give it a try.

Well, at least once I have a drag link in hand that's long enough. Hopefully the next one coming in the mail will be.

It also looks like Wandererr-RRORC has some sort of an adjustable drag link, or at least the end on the pitman arm side looks like it might be. I may need to resort to that yet.

After glancing at my own pictures I also ordered the track bar ball-joint. I'm sure that thing is super fun to press out and back in.

[MadScience]

I have the proper length drag link now so I pulled things apart and the confirmed what some other research here very much suggested: The van pitman arm has a smaller hole and needs to either be replaced or reamed out to fit the 5/8" shaft and even larger mating taper of the truck ball joint bolt.

If I read things correctly, the truck pitman arms will fit the respective spline count van steering boxes, but are an inch and a quarter longer which will speed up the steering.

In the interest of getting the van back together, I may just grab a truck arm from the local parts store tomorrow and then think about whether I want to ream out the van arm.

[arctictraveller]

You might need one of these

https://www.speedwaymotors.com/shop/...BoC33kQAvD_BwE

[MadScience]

Hah! Thanks for the pointer.

I did get my hands on a reamer, the rough country branded one. (It was the one that shipped fastest.)

I've also learned that a pitman arm is useful if your goal is to break pitman arm pullers. The harbor freight puller I started with just deformed its screw. The Lisle "heavy duty ford" one snapped right off. And I don't have a welder where I currently am.



I'm now waiting for one of the cone shaped pullers to come in the mail.

The second option is to remove or at least loosen then steering gear box and pivot it up so that I can ream the arm while it's on the van. I'd like to at least have a spare arm handy before I try that, so I think I'll wait for that to show up at the same time as the third puller. That would also give me the option of cutting the old arm off.

The third option is to just order a steering box, since I'm pretty sure I'm due for one as well, but then I have to tackle the question of which one to get. There are a couple of all new ones out there now, which may or may not actually be the same ones. I wonder if anyone has any experience with them. Hmm, that might be another thread.

Finally, the frame cross member on my van has been cut some with a torch under the steering box. Which as much as it's handy for this work, I'm not sure I understand why yet. I wonder if they meant to swap the arm, but couldn't get it off and then just welded the drag link. Edit: It looks like they just cut out the OEM drag link mount before relocating it.

[MadScience]

The Conical OTC puller showed up today. As usual, the most burly tool that will fit is the right choice for the van. I thought I might have stripped the threads in the tool, but that was just the pitman arm sliding off the shaft.

I got it all back together with the new drag link and a reamed pitman arm. Unfortunately the roads here are covered in at least a couple of inches of snow, so I'll have to wait a bit before I can properly evaluate steering precision.

I did have to resort to the spare arm that I was smart enough to order along with the larger puller. This is absolutely doable with a hand drill, without even a vice. However it is possible to get off-axis with the reamer, which will cause the castle nut not to sit flush with the top surface of the pitman arm. Presumably that could put bending stresses on the shaft that may or may not be OK.

On my first try I falsely assumed that the reamer would generally follow the existing opening. That was not the case, and I ended up a couple degrees off kilter. On my second try I put the arm on the shaft every so often and made a grease mark to know which direction to correct to. This wasn't terribly hard, and I ended up with a result that sat a bit more flush than the other, unmodified, spare f-series arm I had on hand at this point.

Again, I ended up with the rough country reamer due to shipping times. I thought I had dulled it pretty immediately, but a couple quick passes with a Translucent Arkansas stone cleaned up whatever was going on. The edge then held all the way through reaming the second arm. That stone came out of my ski tuning tools.

[pjpvi]

I had to use one of those reamers a while ago on my old square body Chevy truck project. I seem to remember it took a long time to get it reamed out enough for the larger ball joint to fit properly.

I'm in the east bay if you ever need an extra hand or tools you may not have. Of course, if I'm around. Currently in Baja.

[MadScience]

Thanks for the offer!

I didn't think it took me all that long to ream out the hole, but that may just be perspective. If you think of milling a hunk of metal a couple of minutes seems reasonable. If you think of drilling a quick hole, well, it's not that.