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Air bump adjustment in bump can

MtnYota

Mean Dad
Joined
May 21, 2020
Member Number
971
Messages
96
Loc
Ben Lomond, Ca
In the perfect world the bump can would be positioned so that the bump is completely compressed at the position you want full bump, and the airbump lip would be seated against the can. Now for the question, can you rely on the pinch bolts alone to secure the bumpstop position in the can? IE weld the bump can on high and lower the bumpstop to the desired location. OR is the clamp force not enough to rely on? I was thinking about using some shaft collars as added reassurance that when the bump fully compresses and the force spikes that the bumpstop cannot move upwards, but I may be overthinking it.

What say irate?
 
I wouldn't trust just the pinch bolts alone to hold the can in position during a bottoming out event but with a collar taking up the space I don't see a problem.

Another thing to note about the bump cans..... If you overtighten the bolts it ovals out the bumpstop and could possibly bind them up.
 
I have cut some tubing to slide on the bumpstop to space them down 1" or even 1.5" before without an issue. Only problem is finding some 2.25x.120 tubing. SO what I did was slid a piece of 2" tubing in the can and cut 4 pieces of plate the 1" x 1" then I welded those onto the bottom edge of the bumpstop can to space it down. I raced the truck with that and never had an issue or worried about it. Could even weld pieces of plate over those to keep them from wanting to bend outward.
 

You could get a sleeve like this to space it down BUT i would really just weld the cans on in correct spot
 
Not just no to pinch bolting them for friction positioning other than fully seated but don't try. The pinch bolts will crimp out of round and will distort the bump body, probably damaging the body and/or piston when it cycles like that, or even locking up the bump. If in doubt, weld the cans a bit high on the chassis and get/make spacer rings to position the bumps. Don't tighten the pinch bolts past "keep the bump from falling out".
 
What say irate?
put them in the right place to start. the cans are thing and ive replaced multiple bodies that the owner use a impact to tighten the bolts on. the pinch bolt is to keep it from failing out.
Screensho (1).jpg
 
The bump can's I have worked with don't have much room for adjustment anyway. After going through too many do-over cycles I will be building adjustability in to the can mounts going forward. Or even better:

 
The bump can's I have worked with don't have much room for adjustment anyway. After going through too many do-over cycles I will be building adjustability in to the can mounts going forward. Or even better:

why do you need adjustment in the bump can? im not smart, so maybe im missing something but setting the rig at bump, mount bump can, weld out.
 
why do you need adjustment in the bump can? im not smart, so maybe im missing something but setting the rig at bump, mount bump can, weld out.
Various reasons. One, you could be an idiot like me who welds them on in the wrong spot in the first place. Two, and more importantly, if you were smart enough to build adjustability into the suspension (control arm length, control arm brackets, etc ) then dialing in the suspension will also change the optimal bump stop location.
 
so i did the standard bump can that is open top and bottom. instead of using a air bump right away i used some 2 inch scrap DOM and made replica air bumps with a rubber 2 inch bump installed on the end. my thought process was lets try this with scrap and then this winter after i get all the bump pads worked out move to the actual air bumps. as you see in the pic i may need to bend the pad because it looks like i should line binding.

and to combat the fact i cant tighten down bumps that tight i was gonna weld in a lip at the top and put a spacer so the can can not move to far up.

over thinking too. but works for me. plus i had rubber bumps.


bump pic.jpeg
 
McMaster-Carr cut a round of this and weld it in the proper place and youll be good to go.

i hope thats not the pad you plan on using. it will bend, ive seen 3/16" plate dent. the bump will slide on the pad, its just the way it goes with a solid axle. also pull the rubber off and set everything up metal to metal.
 
3/16 for sure will bend. I am using that as the temp piece. Need to add another part so it does not bend for sure.
I wish I would have thought about notching frame and recessing in there. I just welded up. And used some bracing. Much better idea.
 
I wouldn't recess a pinch bolt style can into a chassis. Done that before, a little welding heat distortion, and it's nearly impossible to spread the can enough to get the bump in, and a few years and some weather/rust/whatever, and it's nearly impossible to spread the can enough to get the bump out. Much better off to keep it to itself and not enclose it in too much.
 
McMaster-Carr cut a round of this and weld it in the proper place and youll be good to go.

i hope thats not the pad you plan on using. it will bend, ive seen 3/16" plate dent. the bump will slide on the pad, its just the way it goes with a solid axle. also pull the rubber off and set everything up metal to metal.
by going metal to metal, make that my no shit it will stop point.
 
well that changes my setting for sure i may have F'ed up a bit. at least i still have the micro cells in the shock bodies. hahahaahahah
 
well that changes my setting for sure i may have F'ed up a bit. at least i still have the micro cells in the shock bodies. hahahaahahah

focus on vertical travel, check articulation to ensure there are no issues. if you bump to articulation you will be leaving a lot of vertical travel on the table because your bumps are inboard quite a bit from the shocks
 
i think i may have done a happy mistake then. at ride height my bump is really close to the amount of shaft showing give or take a tiny bit. and i can always adjust the bump pad up or down till i get it right.
bump at ride height.png
 
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