Newbee questions on bumps and limit straps

[Willwater]

I have been working on doing my own cut ant turn on an84 f150. I am pretty much done but ran into an issue when cycling to figure out travel. I did the cut and turn using the pie cut method. I am running deaver 5.5 inch coils and built axle pivot brackets that lowers the pivot point 1.5" so that I could get the full lift out of the coils but only have to cut and turn for 4 inches.

The problem I have is that with the passengers side beam at full stuff and the drivers side at full droop the passenger side axle hits the bottom of the window in the beam. I foresaw this to some extent and ported the window as much as I feel comfortable taking out of the beam. As it sits not I will have to lower my bumps 2" and limit strap it 1.5 up from full droop to keep this from occurring. This leaves me with only about 14" of travel. I could cycle 17 pretty easy if it wasn't for this issue.

My question is do those of you that are running big travel numbers just assume that your truck will never see this condition because you are running them as go fast rigs and won't be expecting them to articulate like this? Or did I screw up the geometry somewhere I am in Oregon and building the truck primarily as a sand rig, but will also see some mud running and snow wheeling. At the dunes we spend some of the time doing what we call sand crawling where we run trails along the edges that have steep climbs off cambers and ravines. It cycles the suspension very much like what you would expect in a rock crawiing situation. I am a little concerned about that axle hitting as I am sure it wouldn't take many times before it will scour and weaken the axle.

So what do you all think? Thanks in advance. This site has been very helpful in me pulling this off.

[hobbyturnedobsession]

Did you clock the diff?

[otter]

Can you post up some pictures of the port job? Would help to see how much you cut.

[otter]

Did you clock the diff?

This too. With the pie cut you need to clock the diff.

[Willwater]

I did indeed clock the diff. It isn't enough to really make much difference in the shaft clearance. It is was less than 1/8" to get the drivers side shaft to line up with the spindle bearing. I will grab some pictures of the window porting when I get back to the shop and post them.

Thanks again.

[Willwater]

Here are the pictures of the porting in the passenger side beam.

[ChaseTruck754]

Yeah, I personally wouldn't want to cut any more than that.

[hobbyturnedobsession]

Nope and make sure to plate around the base.

[ChaseTruck754]

Hard to tell for sure from the pics, but looks like he did plate already. Can't say for sure though.

[hobbyturnedobsession]

Oops good call Steve.

[Willwater]

I plated it when I cut the beams. I massaged it just a little bit more today and think I may be able to pull 15" of travel out of it. I am going to strap it at 15" and paint the axle shaft white to see if it is hitting. If it hits I will just shorten the limiting straps. Got the truck basically back together today. Just gotta finish putting the front clip back on and it will be ready for a test drive. Won't have limiting straps until next week so I don't get to really test it out until the following weekend. I am pretty stoked to try it out.

I still would really like to know what if anything I did wrong, that I can only pull 15 without the axle hitting but I am just going to run it and not worry about it.

Thanks for the help guys.

[Rmc]

15 is still alot bro with functioning 4wd. Don't discount your efforts. Clocking the diff means opening up the bolt wholes into slots to orient the axels shaft at a new relationship to the port of the beam. I personally think its alot of effort with out the correct tools to do it. I suppose a dremmel and some ambition could get it done but at the gain of possibly 1-2 inches of additional travel? You may think of clearancing the ac box and moving some stuff around on the top side. It could be just as beneficial to your goal of 16 inches but less work. Agian I have no idea how yours is set up but look at the whole and don't get consumed but a small detail, it may help.

[ESHALLBETTER]

15 is still alot bro with functioning 4wd. Don't discount your efforts. Clocking the diff means opening up the bolt wholes into slots to orient the axels shaft at a new relationship to the port of the beam. I personally think its alot of effort with out the correct tools to do it. I suppose a dremmel and some ambition could get it done but at the gain of possibly 1-2 inches of additional travel? You may think of clearancing the ac box and moving some stuff around on the top side. It could be just as beneficial to your goal of 16 inches but less work. Agian I have no idea how yours is set up but look at the whole and don't get consumed but a small detail, it may help.

He clocked the diff already if I read correctly.

Willwater - from ride height, how much of your travel is bump and how much is droop?

[AussieRod]

The problem I have is that with the passengers side beam at full stuff and the drivers side at full droop the passenger side axle hits the bottom of the window in the beam. I foresaw this to some extent and ported the window as much as I feel comfortable taking out of the beam.

I believe you might be over-thinking this a little bit. The condition you describe above would very likely never happen in any kind of use, unless you hit the side of a mud pit 45 degrees on at 50+ mph, or come off the top of a dune at said speed to find no back on the dune and you hit the bottom directly on the right front wheel. In either case, the axle touching the portal window in the beam might be the least of your problems. Your bumps should be set to prevent beam to chassis contact and full solid compression of your springs and shocks at full stuff, and your limit sraps set to prevent a/ the steering joint on the pitman arm from being overtravelled, b/ the slip joint in the centre uni from bottoming out in the yoke, c/,that the yokes in the centre uni do not bind in rotation at your set droop and d/, that your shocks do not top out.
95% of your usage, the beams will droop and stuff at roughly the same amount in rough going and the minor differences encountered on rough trails will never induce the extremes of the type you described. I've been very fortunate to see in person MOST of the Broncos on this site, and all work equally well with their suspension set-ups. A few even have minor axle contact with the portal window, but its not a major concern, as most have had the window ported and re-inforced and it usually happens only at extreme travel. All are very well built and have travel numbers in the 15" - 17" + range. Keep in mind, its not the amount of travel thats important, its the QUALITY of the travel you have. 12" of properly set-up, well damped travel will easily beat 16" of badly built, poorly damped travel any time. Just my $0.02.

[Willwater]

[
I believe you might be over-thinking this a little bit. The condition you describe above would very likely never happen in any kind of use, unless you hit the side of a mud pit 45 degrees on at 50+ mph, or come off the top of a dune at said speed to find no back on the dune and you hit the bottom directly on the right front wheel. In either case, the axle touching the portal window in the beam might be the least of your problems. Keep in mind, its not the amount of travel thats important, its the QUALITY of the travel you have. 12" of properly set-up, well damped travel will easily beat 16" of badly built, poorly damped travel any time. Just my $0.02.

Kind of what I was wondering thanks for the insight. I do tend to overthink things from time to time. The above scenario will probably happen to me, because I drive like an idiot and the truck is just a off-road thrasher that I 100% don't care about. But your probably right I will probably have a lot bigger problems by the time I get it to that condition. I got the truck for free and have less that $2000 into it including lifting it, shocks, tires and wheels.

I am planning on going ahead and limiting it at 1/2" above when the springs go slack and just run it and see if there are any issues. My center joint clears not problem at that limit and the shaft does not hit the joint. I did lower the bumps 2 inches from stock which basically should let the suspension cycle like a more standard 4" lift that most people seem to be running and keep the tires out of the fender.

I drove it today and the front seems stiff as hell compared to what I expected but I will have to take it for a real run to see I suppose. I bought some new 7100's off a guy that were valved 360/80. Wondering now if that was a little stiff?

[Willwater]

He clocked the diff already if I read correctly.

I sure did. A little less that an eight of inch counter clockwise looking at the front of the diff. Just enough to make the driver side axle line up with the spindle bearing. To clock it to improve contact, it seems to me, you would have to spin it the other direction and would make the driver side axle not even come close to lining up, unless I am missing something. I very well could be.

Willwater - from ride height, how much of your travel is bump and how much is droop?

I think about 5" of droop and the rest is bump travel. Really not sure because when I clearance and measured everything there was no front clip on it so I really didn't know what finished ride height would be.

[Rmc]

The problem I have is that with the passengers side beam at full stuff and the drivers side at full droop the passenger side axle hits the bottom of the window in the beam. I foresaw this to some extent and ported the window as much as I feel comfortable taking out of the beam.

I believe you might be over-thinking this a little bit. The condition you describe above would very likely never happen in any kind of use, unless you hit the side of a mud pit 45 degrees on at 50+ mph, or come off the top of a dune at said speed to find no back on the dune and you hit the bottom directly on the right front wheel. In either case, the axle touching the portal window in the beam might be the least of your problems. Your bumps should be set to prevent beam to chassis contact and full solid compression of your springs and shocks at full stuff, and your limit sraps set to prevent a/ the steering joint on the pitman arm from being overtravelled, b/ the slip joint in the centre uni from bottoming out in the yoke, c/,that the yokes in the centre uni do not bind in rotation at your set droop and d/, that your shocks do not top out.
95% of your usage, the beams will droop and stuff at roughly the same amount in rough going and the minor differences encountered on rough trails will never induce the extremes of the type you described. I've been very fortunate to see in person MOST of the Broncos on this site, and all work equally well with their suspension set-ups. A few even have minor axle contact with the portal window, but its not a major concern, as most have had the window ported and re-inforced and it usually happens only at extreme travel. All are very well built and have travel numbers in the 15" - 17" + range. Keep in mind, its not the amount of travel thats important, its the QUALITY of the travel you have. 12" of properly set-up, well damped travel will easily beat 16" of badly built, poorly damped travel any time. Just my $0.02.

Just to expand on that a tiny bit, pro-2 trucks are only at 16 inches of front wheel travel any they jump 10+ feet in the air regularly. I agree with quality over quantity. If your pulling a solid 15 you have done well.

[shockseals.com]

from experience, binding the axle on the window port will break the axle at the c clip inside the diff...\

I would clean up the porting you did do with a sander so its all smooth and blended nicely.

[Willwater]

I smoothed it all out and shaped it just a little more before I repainted it. Thanks for the tips. I lifted the back wheels as far as I dared with a forklift and it looks like I will have to take a pretty hard hit to get it to flex far enough to hit. Just waiting for limit straps to show up this week and I will go test it for real.