Any experience installing a 5th gen rack into a 4th gen?

awhitney1

Member
Just wondering if anyone has experience installing a 5th gen rack into a 4th gen. I don't plan to go long travel, so the LC200 rack will be out of the question, and the 5th gen rack seems better built as well.

i've heard with the 5th gen rack, you have to widen the mounting bolts and everything else will fit just fine.

Any feedback on this?
 
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At stock width so therefore stockish travel numbers the LC200 rack should theoretically work well. Minimal bumpsteer I mean.

Its when you try to get a ton of downtravel with long travel arms the geometry gets out of wack and you end up with bumpsteer. Theoretically, I haven't seen anybody actually measure this setup.
 
I've talked to a few people about a LC200 rack with stock width Total Chaos LCA and they don't recommend it.


At stock width so therefore stockish travel numbers the LC200 rack should theoretically work well. Minimal bumpsteer I mean.

Its when you try to get a ton of downtravel with long travel arms the geometry gets out of wack and you end up with bumpsteer. Theoretically, I haven't seen anybody actually measure this setup.
 
just saw this pop up so I figured I would drop my .02 from my lc200/stock width swap.. though I know both of you guys are probably pretty well aware.. but in case others stumble across this and haven't seen my thread.. so here it is..

-Fitment: It is possible to run the LC200 rack with the stock width control arms. You just need to fabricate your own outer tie-rods, which means you're pretty much stuck running a heim joint instead of the factory tapered ball-joint

-Steering Geometry: While it is no question that factory width control arms are signifincatly better for bump-steer compared to long travel arms which exaggerate the bump steer due to additional downtravel gained, not everything is fine and dandy. I have physically measured... and probably will later today, but there is visible bump steer from ride height, to full droop. As far as on-road experience ... I have been running this setup for a few months now.. and will say that there is definitely a different steering wheel feel... but to be honest.. I don't really notice it much anymore.. certain bumps, in particular the un-even ones, will make the steering wheel wander a bit, but the rig tracks straight for the most part. Probably not the best for tirewear ... but it's certainly doable.

The biggest issue I have seen comes not from bump steer, but actually from the slighly different ackermann angel.. I can tell that this is different because when making near-full-lock circles in a parking lot, or during a U-turn, you can hear one of the tires scrubbing out pretty hard. This is very indicative that either the inside or outside wheel is now turning significantly more or less and not following the factory radius. Not a HUGE deal, but it is there.



For my application, this is OK. I'm looking to have some rock-crawl ability wihtout the fear of blowing out my rack or bending a tie rod because I down wrong on a rock. I don't plan on abusing this, it was more of a just-in-case project. If you're planning on doing some fast paced desert whoops sections, I can't tell you how this will react.. maybe it's doable, maybe it isn't... I'm still unclear on whether or not the marlin crawler RCLT kit solved the bump steer issue with their spindles... or if they suffer from the bumpsteer as well.. but they do use the same rack.. so who knows.



to summarize .. here is where I stand..

Pros:
-I will be very hard pressed to bend/break anything in my steering setup simply due to the added beefiness of everything
-I was able to take advantage of the heim joint & 3/4" bolt to do a double-shear setup on the spindle for added security.

Cons:
-not cheap. My project, with no added labor cost, ran me over $1100.
-time consuming... this was by far one of the longer upgrades I performed in my entire build.. and was the furthest from being straightforward. Lots of custom work, fitment, re-fitment, cutting, welding, more cutting, etc.
-added maintenance.. because I am running heim joints on the spindle now.. I have some added greasing/cleaning to do to hopefully keep them alive for as long as possible. I can already tell these will NOT last nearly as long as a balljoint..especially a factory one.. I may need to look into upgrading to a nicer heim joint at some point.. but these also weren't cheap and from ebay..
-impacted steering geometry..like it or not.. it just isn't the same like it was from the factory. Between bump steer and ackermann there is a difference in how the rig steers.


final thoughts... if I had to do it again... I would probably consider spending a few extra bucks to do the cut -down tundra rack instead.. that would at least resolve the bump-steer issue.. the other work would be the same and I think it would have been worth while. I also don't think I would go through the trouble of upgrading to the LC200 rack on a factory width setup if I had to do it again..
 
not to revive and old thread, but figured I would document some more feedback.. doesn't make much sense to me whatsoever but people out there apparently running LT with the LC200 rack with no bumpsteer issues :bounce:



so math is either wrong, or people are just living in the fairytale world. Maybe i'm the one missing something here... but all the "calculated" numbers thus far line up pretty close to what I'm seeing real world on stock width.. I just don't see how keeping the same spindle and increasing trackwidth by 2-4 inches DOESN'T result in added bump steer..

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So - anyone confirm that the 5th gen rack fits the 4th gen or not? I am looking at this now, and it seems that the GX 460 (150 series 5th gen 4runner) rack will fit the GX 470 (120 series - 4th gen 4runner). There are several different part numbers for the 5th gen racks, so I can't figure it out just from those.
 
Just wondering if anyone has experience installing a 5th gen rack into a 4th gen. I don't plan to go long travel, so the LC200 rack will be out of the question, and the 5th gen rack seems better built as well.

i've heard with the 5th gen rack, you have to widen the mounting bolts and everything else will fit just fine.

Any feedback on this?

I have confirmed that this will work. Just finished installing a rack and all tie rods from a 2021 into my 06 4Runner. No fab needed. It was actually not too difficult. The 11mm diameter 4th gen bolts work just right in the 5th gen rack, despite the fact that the 5th gen bolts are 14mm, because of how the bolt holes in the 5th gen rack bushings are laid out. The 5th gen outer tie rods have the same taper and use the same castle nut as 4th gen. The only difference of any significance is that the fitting ends on the high pressure hose are different between the two gens, but so far I’ve seen no leaking and I did not use a thread sealant. I’ll of course be keeping an eye on this for any future leaking. I got an alignment yesterday and had no issues with that. I’ll do a separate thread and more detailed write up at some point but wanted to report my findings.
 
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I have confirmed that this will work. Just finished installing a rack and all tie rods from a 2021 into my 06 4Runner. No fab needed. It was actually not too difficult. The 11mm diameter 4th gen bolts work just right in the 5th gen rack, despite the fact that the 5th gen bolts are 14mm, because of how the bolt holes in the 5th gen rack bushings are laid out. The 5th gen outer tie rods have the same taper and use the same castle nut as 4th gen. The only difference of any significance is that the fitting ends on the high pressure hose are different between the two gens, but so far I’ve seen no leaking and I did not use a thread sealant.

Any update on this install? What are the details from your last sentence concerning the high press fittings? How did you make the different fittings work?
 
Would the outer tie rod on a 5th gen fit on a 4th gen?

The outer tie rod from the 5th gen bolted up perfectly to the 4th gen spindle. I measured before I did the install, and if the taper isn’t the same on the 4th and 5th gen, it’s so close there’s no practical difference. But, you can’t mix and match 4th gen and 5th gen outers and inners. The shaft diameter of the 4th gen outer rod itself is smaller than the 5th gen, so the outers and inners will only mate with their gen.

Sorry for the slow reply—haven’t been in the site in a while.
 
Any update on this install? What are the details from your last sentence concerning the high press fittings? How did you make the different fittings work?

Thanks for asking/prompting. It’s been a little over 4,500 miles now since the swap. I haven’t noticed any issues at all. Bolts are all still in tight, alignment has held, it’s driving correctly, nothing has fallen off while driving down the road, etc.

On the fittings, I took a chance that the o-ring from the fifth gen (I think it was the fifth gen) would be in sufficient compression between the fourth gen fitting and fifth gen rack, despite the fitting ends being different. I put it all together like that. When I was under the car changing oil within the last couple hundred miles, I noticed what appears to be the slightest PS fluid leak and assume it’s from the connection at the high pressure fitting. I guess it could have been residual fluid from the swap that I just didn’t wipe off well enough but I kind of doubt it. But it was a small amount and there wasn’t any noticeable drop in the fluid level in the pump. So I’m going to keep driving it like it is and keep an eye on it. Ideally I think a larger o-ring would sufficiently solve the issue, but I’m okay with running this way just to have seen how it would work with no modification of the different fittings and the swap as a whole.
 
Further updates here: I’m now about 8,000 miles into the swap. I definitely have a leak at the high pressure line fitting onto the rack. I am going to have to take the line off and try a bigger o-ring or either stack two o-rings together. I haven’t tracked the rate of loss but I’ve dropped below the fill marks on the reservoir a twice now. Yikes. I will report back once I fix this with how I fixed it.

Still no issues with rack fitment and operation. That part has been a great success.
 
Further updates here: I’m now about 8,000 miles into the swap. I definitely have a leak at the high pressure line fitting onto the rack. I am going to have to take the line off and try a bigger o-ring or either stack two o-rings together. I haven’t tracked the rate of loss but I’ve dropped below the fill marks on the reservoir a twice now. Yikes. I will report back once I fix this with how I fixed it.

Still no issues with rack fitment and operation. That part has been a great success.

Would it be possible to use a 5th gen line as well?
 
Would it be possible to use a 5th gen line as well?

Sorry for the slow reply—I concluded that the 5th gen line can’t be used, but can’t remember exactly why at this moment. I think there were physical differences in the routing of the hard line that made it unworkable.
 
Update: I’m around 5,000 miles after having fixed the leak at the fitting of the high pressure line into the rack. I simply used a bigger o-ring. I just used one, not a stack of them. In retrospect, I wish I went with an even bigger o-ring. I just measured the ID of the fitting and went with that size as the OD of the o-ring, but I should have plussed-up for the fact that there’s a little more space where the o-ring sits than the ID when accounting for the threads. Nevertheless, the problem seems to be fixed.
 

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