Gas Tank Skid Clearance Issues

Figured I'd do a short show and tell on this since I haven't seen many people discuss it.

Recently I installed a Dobinsons rear long travel kit with apache links to get some more flex out of the rear suspension. Love the setup!

With the extra droop this rig was able to achieve I ran into an issue. When flexed out (with my driver side wheel stuffed and the passenger side at full droop) my driveshaft and rear diff were contacting my C4 Gas tank skid. Felt like it was gonna tear the driveshaft to pieces... Since I was at Toyota Jamboree my short term solution was just to chop the skid plate up at camp. This solved the clearance issue but one of the mounts had to go because of it.

I finally got around to adding that mount back to the skid plate.
Here are some photos of the process.

You can see where the driveshaft joint and the bolts were contacting the skid plate here:


Chopped it at camp and continued to wheel for the rest of the weekend:


Got home. Added the old mount back on in order to locate everything:


This was my rough idea for the new mount:


Prepped for welding:


Welded the mount up. Used a cutting torch to and a grinder to cut off the excess material. Painted it black:


The new mount is about an inch away from the gas tank (Although it looks closer from this angle):


Left the edge open for clearance and for additional drainage:

 

Well it works right?

 

I'll preface this with acknowledging that I do not possess the tools or skills to do what you did.

From a structural standpoint, the part you cut out had reinforcing at the edge, that helps provide structural rigidity. The modified version discontinues that (and where they met at the corner provided additional rigidity because you had 3 planes coming together and now you have a single plane).

 

I considered the same thing. I'm not sure if it's as strong as the original design but it's certainly strong enough to jack the rig up on. I know because I did that and saw no flex in the mount or skid.

I will say in the photos above the skid plate was already modified once before. Originally, the mount is bolted in place there. It was later welded in place. This was still not enough clearance. Here are some photos of the first version. This was essentially a bolt delete and minor clearance grinding.



Doing that did not provide enough clearance. So the entire corner had to go.

I'd argue that maintaining a 90 degree angle would mean more for the skid plate's resistance to vertical load. But again, that real estate is taken by the driveshaft when flexed out. This was simply a way to add that mount back in.

Is it as strong as the original design? Maybe not. But for all intents and purposes it is certainly strong enough.

 

I have the same exact problem now. Added extended travel Dobinsons shocks, extended sway links, panhard bar, and ICON overland springs and I started to rub. I took it off for a bit and remounted it with different bolts. I haven't really put it through an off-road session yet, so I might have to do something like you did. I'll document if I need to go further. My bolt was hitting exactly where it was on yours.

 

Yeah no one seems to talk about this issue.

Quick note: Did you do offset upper links as well? You'll need those or you'll crush your gas tank at full droop.

The first thing I did was use a carriage bolt the correct direction lol. This helped a bit but it was still hitting.
Next I used the adjustable panhard bar to make sure the axle was centered and tried welding the bar on and ditching the bolt. Again, it helped but still contacted the skid plate in two areas around the mount.

This (hopefully) is the last version of this skid plate for now. I'll flex it out this weekend on a wheeling trip and know for sure.
I may drop the skids in another year when I do a fluid film treatment and repaint skids. If I see any degradation I'll reinforce this area before painting.

For now adding the mount back and maintaining clearance was the goal.

 

No to the links. I'll keep an eye on that. Thanks! I was planning to do it probably late summer. I have been doing so much to this 4runner the last 6 months, I'm almost at the end. The rear links is one of the corners I cut early on but I want to revisit once I get everything else dialed. Trying to fit 34" tires at the moment. Just got it aligned yesterday and probably cut the passenger body mount on Friday and see how they fit.

 

Heck yeah man sounds like a sweet setup!
If you're undecided on links I recommend ApacheOffRoad. The owner is local to me. Quality stuff and he stands behind his products.

https://apacheoffroad.com/product/a...003-4runner-2007-fj-cruiser-2003-gx470-gx460/

You can see on their website just how close that upper trailing arm comes to the gas tank at full droop.

 

Your issue is most likely due to the fact that you used "extended" upper and/or lower links. With stock/OEM links, the upper link bracket on the axle tube BARELY clears the panhard/trac bar to being with. Longer links will collide on compression and can cause a lot of damage. Those Apache Off Road links are not actually helping you. They might be offset, but it's the length.

 

You may be confusing the issue since we went off topic talking about offset links to clear the actual gas tank.
The only clearance issues I had were between the gas tank skid and the diff/ driveshaft.

I've never encountered any clearance issues with the upper/ lower links and dobinsons track bar.
Everything plays nicely except for the C4 gas tank skid in a very specific point of articulation. Which has now been addressed.

 

All good. Glad you not only found a workaround, but fabbed it up yourself!

What I mentioned is a known issue for the 5th gen 4Runner, though, when you replace upper and lower links. Lots of companies sell extended/adjustable ones, but they can invite problems due to the increased length. Not always and at every angle, but when it does happen, it can collide/do damage in different places - especially with a kit like Dobinsons that really pushes the rear flex. It's a reason that I just did a bushing kit on my upper links and my aftermarket lower links are still stock length (and not adjustable). I'm running King EXTs.

 

Very nice. I haven't seen this problem with my setup but I'll look out for it.
You said it's sometimes between the panhard bar and the upper trailing arm's axle mount?
I'll flex it out and check for clearance there as well. Thanks for the heads up!

Edited: Learned how to spell.

 

@TRDSD Did some research on this.

(For future readers, this is in regards to clearance issues found by others. Not the gas tank skid this thread was prompted by)

Looks like the extended rear links can become a problem if you don't have a lot of lift height and/or don't have extended bump stops.
The higher you lift these things your rear axle moves forward. Effectively reducing your wheelbase.
At 3" of lift height or more extended links become more necessary to put the axle back in the middle of the wheel well.

During articulation, I don't contact anywhere else in my suspension geometry. (luckily)
During a hard even compression, theoretically the extended links could cause an issue between the track bar and the axle side of the upper track arm (specifically the mount on the axle)
I think the reason this doesn't effect me is I have extended rear bump stops. So even during a hard compression I haven't seen this issue.

Thanks the heads up and prompting me to do more research on this. Luckily this combination of parts works out for me!

Loving the increased travel and ride. I just removed my front sway bar to increase front articulation as well. I'll report back if I find any issues when I go wheeling this weekend!

 

This would have been awesome to read 8 months ago.

I forgot to mention above that I did install extended bump stops.

https://exitoffroad.com/product/timbren-abstorseq-active-off-road-rear-bumpstops-kit/

Now I'm rethinking my rear end (AGAIN!) and I'm salivating on the cantilever suspension....

 

Which timbren spacers did you use?

• A25722-90F00 (1/2″ spacer)
• A25723-90AD00 (1″ spacer

My Durobumps don't seem to advertise a total compressed height. Here's the link for the ones I have.

https://durobumps.com/product/3-inch-extended-rear-bump-stops-dbr525lt/

 

Neither actually. I didn't think I needed them, but maybe I do?

Regarding yours: I think it's just 5.25" minus 1". Right?

 

Good follow up! Just something to be aware of.

 

Flexed the rig out thoroughly and no other clearance issues were found. Looks like the gas tank skid plate was the only problem point for this setup!



https://www.youtube.com/shorts/micixzVWqMg