Front airbump install

My front suspension setup has been pretty much unchanged for two years at this point...and like XJ's tend to do, once you wheel 'em hard for a while, you need to fix some spots on the unibody that have been a little "overstressed".



The passenger side spring used to be vertical, and the bumpstop used to point towards the ground. Likewise, the driver side isn't doing so well either:



That one is bent the other way, towards the shock. These things happen when you've got limited uptravel, stock bumpstops, and attempt to jump your rig.

Basically both bumpstop towers got bent, and also my "temporary" hockey puck bumpstop extensions pretty much outlived their usefulness too.







These pics are at full flex in the front:



They also highlight another problem...with the axle bumpstop extended 6", when it flexes, your target area for the frame bumpstop to hit moves over quite a bit. So it hits off center and causes issues like seen above.

Unrelated, but equally important...my Rusty's trackbar bracket, which I've had since early 2003, has started to shit the bed.



So...step 1. Remove the stock bumpstop towers by cutting through the factory stitch welds, and breaking the few spot welds loose.

Cleaned a few pounds of dirt out of the inner fender. I also like that the Rusty's piece decided to break about half a year after I welded it fully in place.



These guys are going to be the new bumpstop towers:



Radflo 2" air bumps. They will be held in via set screws (thanks Skullver for the idea).



My McMaster order came today. Those set screws, plus this stuff:



B16 grade 1/2" threaded studs, and 4" round UHMW. The round stock came in 3" lengths for $9 each.

A big complaint with air bumps is that they're noisy...the metal end coming in contact with a metal bump pad makes a nice clank as you go down the trail. Rubber doesn't work well either because it's too sticky - if the pad hits sideways, like when flexing, it tries to grab the piston and yank it sideways, which shortens the seal life. So I went with the UHMW as a compromise:



Threads right into the spot where the hockey puck bolt used to go, with no exposed bolt head, and gives a slippery yet somewhat forgiving surface for the air bump piston to strike. It's also shorter than the puck stack so it won't move as much when flexing.

Of course, 4" round would fit perfectly inside the spring. These don't fit. I checked McMaster again and they give a tolerance of +0.1875/-0.0 on the diameter, and sure enough they measure just over 4-1/8". I'm going to bring them over to the machine shop tomorrow and have them turned down to 3.75" just to give a little more room.

Mocked up the placement of the driver side bump:



The square plate will be trimmed down to match the curve of the factory spring seat, and I'll plate the vertical face with some 1/8" stuff. That picture is 2" below ride height.

From the front:



I'm testing it all ugly-like to make sure the air bump will stay in contact with the pad through the whole range of travel. Here's full flex, as much as I can do on jackstands anyway:







Should leave me with at least 1/2" of shock travel in even the worst case scenario.

Got one almost done yesterday...







Approximate ride height.



New springs...Rusty's 6.5" vs. Rusty's 4.5". I wanted something a bit stiffer up front so this should work well...and also make up for losing the coil spacer I had up there previously.



Now I get to do it all over again today.

do you have any trouble with the bump fully extended at full droop getting into the coil? I have done a few of these & noticed with body roll the bump would hit the coil. Your set up looks pretty good & like how you plated around the upper bucket:thumbup:







Approximate ride height.



New springs...Rusty's 6.5" vs. Rusty's 4.5". I wanted something a bit stiffer up front so this should work well...and also make up for losing the coil spacer I had up there previously.



Now I get to do it all over again today.[/quote]

hellbilly04 said:

do you have any trouble with the bump fully extended at full droop getting into the coil? I have done a few of these & noticed with body roll the bump would hit the coil.

Click to expand...

I don't know, to be honest...in the limited amount of movement I can get with jackstands, a highlift, and a floor jack it doesn't look like it will be a big issue. But we all know that stuff gets flexed in weird ways on the trail.

Holy crap that is serious fabrication there. Awesome stuff.

It'll never work.

Looking good, as usual for your stuff. The UHMW is a great use. Depending in how long I keep my polished turdy I might have to borrow that idea.

Good ideas are meant to be borrowed.......even modified and improved upon. :thumbup:

XJEEPER said:

Good ideas are meant to be borrowed.......even modified and improved upon. :thumbup:

Click to expand...

That's some wisdom. :cheers:

I keep telling myself I'm going to do some write ups on stuff I've done for my own XJ and friends rigs, but I never get around to it. I tend to get ideas in my head that are a little bit out there and say "eh, why not." I'm sure people could get ideas, or at least a laugh, out of some of them.

Due for an update, let's hear how they work? I'm at a crossroads here........

Uh oh. Shoulda gone full coilover

yeah I really need these on mine now

Bryson said:

Uh oh. Shoulda gone full coilover

Click to expand...

more like full air shocks!!!

now all i need is time and a few REALLY expensive parts and i will be 60/60, full hydro, air/ linked front and rear.

hijack over, air bumps look killer

Sorry for the delay folks...as you can see from the pics, there have been just a few changes.



Got some flex shots in today.





No issues at full droop.





Full compression.





Goatman mentioned that if you're fully compressing the bumps on flex, it's not going to be stiff enough for any kind of hits when going fast...I guess this is a good start. Driving around some more I can notice when the bumps engage but it's not a real abrupt change...just sort of a seat-of-the-pants thing. Once I get it on some good access roads (or the JV lakebed ) I'll have a better idea what I want as far as tuning...and that's easy enough to change.

very stupendous Timmay sent me a picture on AIM yesterday to show me the new toob, and it had 2 creepys and 2 iroks haha. some VERY nice changes!! hope it all works out good for you sir

Looking good. Is that all 1.5" tube you're using?

vetteboy said:

Once I get it on some good access roads (or the JV lakebed ) I'll have a better idea what I want as far as tuning...and that's easy enough to change.

Click to expand...

if you use them on the lakebed, you just hit a bomb crater...

the 'roads' to the trails however... irate1:

Fair enough.

I hit a badass railroad crossing at 60 MPH tonight and it felt good.

A week from Wednesday and I can try the same thing on the dirt.