Hi everyone,

I had a chance to have a close look at the steering configuration in a 2wd Hardbody the other day, and it seems that the design would solve the weak centerlink problems in the 4wd Pathfinder.

I've searched through all the Nissan forums that I know of, and I can't find any discussions about this other than basic "they're not the same" comments. I've learned that the idler arm is the same part number between early 2wd and 4wd, so it seems that the centerlink ends are the same diameter at least.

Does anyone know if it's reasonable to swap 2wd D21 steering into a 1988 4wd Pathfinder? I know there are several custom centerlink solutions, but I'd prefer using as many off the shelf parts as possible to be able to keep trail spares and stuff.

Thanks!

Well if you wanted to swap an entire 2wd steering system I'm sure you could. The center link and tie rods are different. Only thing which would stop you is the over all length between the center link and tie rods.

Found it, the knuckles are different on the 2wd HB. They mount the TRE lower and cannot accept the CV shaft, 2wd Pathfinder knuckles are the same as 4x4 stuff with a dust cap in them.

The hydraulic lines on the 2wd boxes that I saw had screw in hydraulic lines instead of banjo bolts. The 94' 4wd Pathy box that I put in my 91' 4wd HB had banjo bolts that mounted in a differnet location, so I had to go back to the salvage yard and get the hard lines from the Pathy. Just something else to consider.

Thanks for the responses. I'm just spitballing here, so I hope you'll forgive me if this is full of craziness (and probably confusing).

I was hoping to just use the D21 linkage (centerlink, ITRs, adjusters and OTRs) in a WD21, not the pump or the knuckles.

According to the Courtesy diagrams (I've attached links below to each diagram), the D21 OTR mounts to the bottom of the steering knuckle (nut facing up), and the WD21 OTR mounts to the top (nut facing down). I don't know if I could mount the D21 OTR to the WD21 knuckle (with the nut facing down) and then use the adjuster to compensate for the shorter length, or if this would cause bump-steer problems. The D21 diagram appears to show that the ITR is mounted to the CL an inch or so inside of the CL ends, and the WD21 ITR is roughly at the same spot as the outer CL ends. Again, bump-steer problems? Dunno. Overall, the D21 tie rod seems longer than the WD21.

Things I don't know:
- Are the overall CL mounting lengths the same between the D21 and WD21?
- Are the D21 and WD21 outer tie rod ends the same size and bolt taper?
- Are the outer tie rod positions similar *enough* on the knuckles between the D21 and WD21 to not cause massive bump-steer or binding?

I hope it's clear what I'm shooting for here: the D21's design mounts the ITR horizontally through the center link, unlike the WD21. As a result, there isn't the same upward twisting force on the center link in a D21, and it might solve the age-old WD21 problem of the center link rotating upward and contacting the frame under high stress or a suspension lift (and often bending the tie rods). It's basically the same as some of the custom heim setups I've seen around, but much cheaper and "technically road legal."

Anyway, sorry again for rambling. Maybe I'll have to take my camera out to the junkyard next time to get some pictures of both setups.

WD21: http://www.courtesyparts.com/betasite/images/wd21/wd21_485-1.gif
D21: http://www.courtesyparts.com/betasite/images/d21/d21_485-1.gif

Looking at those pics it looks like your best bet would be to use the 2wd CL and inner TRE's and then have that go to pathfinder outer TRE's. Not sure what that would exactly take, couldnt be too hard though.

For bump steer, the most important part is that the tie-rod is paralell to the arms. Having them the same lenght is also good. Just like the relationship between a trac-bar and drag link.


I was trying to figure out if I was right on the height or not. In those IPB's the Pittman has the same part-number. But that cant be right becuase the tapers are clearly reversed. So, are those part numbers or just labels?

quote:

I was trying to figure out if I was right on the height or not. In those IPB's the Pittman has the same part-number. But that cant be right becuase the tapers are clearly reversed. So, are those part numbers or just labels?

I *think* they're part numbers, but that's a good point -- the CL mounts to the pitman/idler from the top in a WD21 and from the bottom in a D21, so the bolt taper would be reversed. To make this work, I'd have to swap the pitman and idler to a D21 as well... which is confused by the part numbers.

Guh.

Anyway, thanks again for the comments.

Those are part codes, so the actual part number won't be the same.

I like this idea though. Might be a cheaper alternative. I've never seen the 2wd d21 steering in person but it's gotta be better than stock wd21 steering.

I have both a 2wd and 4wd hardbody. The 2wd steering is different. I wont be able to post anything until I replace my 2wd steering and compare everything to the linkage I took off my 4wd for the sas.

OK,

I went to the junkyard today and pulled the steering linkage from a 2WD D21. Then, I pulled the steering linkage from a 4WD D21 and compared the two. Here's what I found:

- The centerlink lengths are the same.
- The centerlink bolt sizes and taper are the same.

The 2WD linkage mounts to the idler/pitman and knuckles from the bottom. When I flipped the whole thing and mounted it to the top of the 4WD idler/pitman and knuckles (the stock 4WD linkage mounts from the top), everything fit and lined up really well! The linkage was parallel to the lower control arm, too, so no bump-steer!

The tie-rods are about an inch shorter on the 2WD linkage, but there appears to be enough adjustment in the D21 tie rods to make up the length when installed in a 4WD.

The only speedbump appears to be that the 2WD outer tie rod end is a slightly different design, and has slightly less throw than the WD21 end. So, at full droop, the 2WD tie rod's "ball joint" is totally extended. If I can get the 4WD outer end to work with the rest of the D21 linkage, I really believe that this is going to work. Even if I have to use the 2WD outer ends, the difference is very slight.

After spending 3 hours hunched in a muddy junkyard under trucks, I truly don't feel like screwing with this any more today, but I'll have more results soon for the surprisingly small number of people who appear to care about this. Also, this whole experiment is concentrated on the pre-1990 models, so I have no idea how it might work on the newer trucks.

The complete 2WD D21 linkage cost $19.00 from the yard (with good boots everywhere), and that's the total cost so far.

I've attached pictures, but they're taken with my very crappy camera phone, so they're probably quite useless. If nothing else, the first picture illustrates the difference in design between the 2WD and 4WD linkage, and why it seems like desirable swap.

S

Any further developments?

Yeah,

After a bunch of work to free up the adjusters, I put the 2wd D21 steering linkage into my WD21 last weekend and did a garage alignment.

Everything fits and it steers fine on the road. However, with this new linkage, the WD21 power steering feels overboosted and really light. It's kind of a numb steering feel in comparison to the stock 4wd stuff. I took it through my personal "testing area" (an abandoned dirt lot with some ruts and hills), and it seems less numb off road.

I'm taking it out on its first trail run with the new setup this Sunday, so we'll see how it holds together. I have the WD21 linkage in the back as a spare, just in case. Ha ha.

I've driven about 30 miles on the street with this setup so far, and it seems like a successful hack. We'll see how I feel after Sunday.

S

OK,

After the first trail run with this setup, it seems to work well. My buddy was in his virgin run with a new truck, so we didn't push things very hard (maybe 3 or 4 out of 10), but I had no steering problems whatsoever in mud pits or on rocky forest trails. It's still pretty numb on the highway, but I'm used to it now and hardly noticed on the 45 minute drive to the trailhead. On the trail at crawling speed, the numbness pretty much vanishes.

I don't have a suspension lift in this truck, but I'm going to do the 3" JGC/torsion lift this coming week, then hit the trail for a 6/10 run next weekend, so we'll see how this hack holds up under stress. My WD21 has heavy 31x11.5x15 LTBs on 7" rims with a lower offset than factory, so it should be a good test. Also, I did some research with a poor counter jockey at an auto-parts store, and found that the WD21 outer tie rod ends are a smaller thread diameter than the 2WD ends, so that won't work. The 2WD OTRs aren't ideal, but they haven't shit the bed yet.

The only sticking point left is clearance between the centerlink and the frame. With the 2WD linkage in place, I only have about 1/4" of clearance between the link and the frame, so if the centerlink rotates upward at all with the exaggerated angles after I crank the torsion bars, it will probably contact the frame and bend a tie rod. We'll see... I still have the stock WD21 linkage in the truck as a trail spare.

So far, so good. Next up on the junkyard hack list is a collection of Saab, Volkswagen and Ford parts to give me a temp-controlled e-fan for less than twenty bucks. Stay tuned.

S