Bump Stop Check Walk-Thru With Pics

jjvw said:
Yes.
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Ha! I take it that's "yes" to both questions. There's nothing simple, is there. As the Subaru tuners would say, stay stock, stay happy.

Anyway, I might go for it, with another check to see what's rubbing afterwards. Seems like 15x8 wheels with 4.75" backspace are less common, but Black Rock has some steel wheels in that spec with a decent load rating. Classic look too: Black Rock 997581247 Type 8 Series 997.
 
If it helps, my 10.5" wide 33s are on 3.5" backspacing. No washers on the steering stops and no rubbing on the frame.
 
fuse said:
I've been thinking I could get some more clearance for the tire sidewalls by replacing my 5.5" backspace wheels with 4.75" backspace wheels. In theory, an extra half-inch of offset should be enough, but some extra space can't hurt. Moving the wheels out by 0.75" seems like a relatively minor change.

That way I'd be able to keep both the uptravel and the turning radius. You guys have more experience with this stuff than I do, though. Is that something that might work? Should I expect any other clearance issues if I move from 5.5" to 4.75" backspace?
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Are you planning on going to a larger tire?
 
toximus said:
Are you planning on going to a larger tire?
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No. I'm planning to stick with the 31s. I see all the hassle everyone on here goes through for 33s and 35s, and I figure I can do without that. And if I'm honest, I don't need bigger tires for anything I'd do with the Jeep in the near future.
 
What a fun day it has been. Luckily most things have gone fairly smoothly so far.

I got to step 10 where you take the shocks off and put the tires on to check clearance in the wheel well. I noticed something that I don’t like...

The bottom of my track bar at the frame side mount is coming in contact with my axle! Well the truss on my axle that is.
D5A5E562-8A97-4EE5-BBB4-40FEC5CE91FD.jpeg


Is there something I’m missing? Is something not centered?
It basically takes me from 2 hockey pucks to 3 hockey pucks for a bump stop.
 
Schwifty Rich said:
What a fun day it has been. Luckily most things have gone fairly smoothly so far.

I got to step 10 where you take the shocks off and put the tires on to check clearance in the wheel well. I noticed something that I don’t like...

The bottom of my track bar at the frame side mount is coming in contact with my axle! Well the truss on my axle that is.
View attachment 106345

Is there something I’m missing? Is something not centered?
It basically takes me from 2 hockey pucks to 3 hockey pucks for a bump stop.
Click to expand...
Bummer. That's why you do the bump stop check, though.

If the bump stop cup lines up with the middle of the axle pad, I'd guess things are pretty well lined up.

Maybe some of the experts here have some ideas to get the truss past the track bar. Adjust control arms?
 
Pull the axle back a bit. Trim away the enormous truss. Some of both.

These are the things we learn by cycling the axles. :)
 
fuse said:
Bummer. That's why you do the bump stop check, though.

If the bump stop cup lines up with the middle of the axle pad, I'd guess things are pretty well lined up.

Maybe some of the experts here have some ideas to get the truss past the track bar. Adjust control arms?
Click to expand...

You are exactly right! And I've put it off this long I'm lucky nothing else broke.


I know I don't have all adjustable control arms. It looks like I've only got adjustable front lowers and RE non adjustable front uppers and rear lower
 
jjvw said:
Pull the axle back a bit. Trim away the enormous truss. Some of both.

These are the things we learn by cycling the axles. :)
Click to expand...

I’ve been trying to wrap my head around the angles and control arm adjustments but a lot that I find involves a shop computer. An angle finder is coming in tomorrow and I’m ready to start pulling the axle back a bit.
The truss is from what I understand is unnecessary but would hate to have to cut into it.

I’ll have to see what I can get away with I only adjustable front lowers and take it from there.
Sure wish I had a nice rolling floor jack. I’ve got wood blocks bricks and 2 bottle jacks moving around all over!
 
A regular rolling floor jack makes the whole process easier and much much safer. I've tried it with a couple bottle jacks and didn't like what was happening when the jack can't move along with the load.

As far as the angles, the only one I pay attention to is the pinion. Everything else is by eye and by tape measure.
 
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jjvw said:
A regular rolling floor jack makes the whole process easier and much much safer. I've tried it with a couple bottle jacks and didn't like what was happening when the jack can't move along with the load.

As far as the angles, the only one I pay attention to is the pinion. Everything else is by eye and by tape measure.
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Such is life, I have to stop and adjust the jack stands and the bottle jacks frequently. 🤷‍♂️

So I’ll measure the angle tomorrow at the axle and the drive shaft and then remove the control arm one at a time and adjust it since they aren’t double adjustable ones.
I’m doing so I’ll be pulling back the axle and providing more clearance potentially.

As long as my pinion angle is higher or level with my front drive shaft.

If I can’t manage to make it work, I could cut into the truss.
 
jjvw said:
A regular rolling floor jack makes the whole process easier and much much safer.
Click to expand...
+1

It doesn't have to be a fancy floor jack or even have that much range for this job.

Schwifty Rich said:
I know I don't have all adjustable control arms. It looks like I've only got adjustable front lowers and RE non adjustable front uppers and rear lower
Click to expand...

If you're only adjusting the lower control arms, you'll be rotating the axle rather than moving it. Whether that works depends on how much rotation you can get and still stay within spec on the pinion angle.
 
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fuse said:
+1

It doesn't have to be a fancy floor jack or even have that much range for this job.



If you're only adjusting the lower control arms, you'll be rotating the axle rather than moving it. Whether that works depends on how much rotation you can get and still stay within spec on the pinion angle.
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After a few things arrived I went back out to the garage to discover I had it backwards. I have adjustable UCA’s not LCA’s.

Adjusting those to pull the axle will move my pinion angle down too much I think.

Time to get dirty and figure it out!
 
Last weekend, I cycled my front axle and thought it might be helpful to see what that looks like on a Jeep that is a ways away from stock.

This is full bump.
20200216_170818.jpg


Make sure the steering, track bar and diff cover aren't colliding.
20200216_170127.jpg


Full stuff each side. Full steering lock.
20200216_141906.jpg

20200216_143658.jpg


Check the shocks
20200216_141921.jpg


20200216_143718.jpg


Look at the body clearances around the stuffed and locked tire.
20200216_142023.jpg
 
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Sooo following this video and these instructions.

The Facts:
2005 LJ w/ rancho rs5000x (RS 55239) with Rancho springs (which will give ~3.5” compared with other LJs)
793FF47E-3A04-4542-800B-C02A21C5A7DF.jpeg



Here is where I am now:

Full droop on both sides.
F44BB0A4-FD6E-49DB-959D-29A55C6F9383.jpeg


full stuff on both sides

B071EB64-9015-4869-8BFA-67EDB6894F55.jpeg


So with no tires I went around and did. Every droop/stuff combo. And full right / full left. Nothing hits. Perfect.
Now out the tires on. Same thing full droop/stuff combos, no hitting.

So do I need any bump stop? From what I understand bumps limit travel to prevent tire to fender damage, shock bottom outs or over stretch. But it doesn’t seem that I have any of that as when stuffed at each combo nothing hits..... (I assume I am missing something and I need some bump stopbut need some help)
 
BlueChip said:
Sooo following this video and these instructions.

The Facts:
2005 LJ w/ rancho rs5000x (RS 55239) with Rancho springs (which will give ~3.5” compared with other LJs)
View attachment 222371


Here is where I am now:

Full droop on both sides. View attachment 222368

full stuff on both sides

View attachment 222369

So with no tires I went around and did. Every droop/stuff combo. And full right / full left. Nothing hits. Perfect.
Now out the tires on. Same thing full droop/stuff combos, no hitting.

So do I need any bump stop? From what I understand bumps limit travel to prevent tire to fender damage, shock bottom outs or over stretch. But it doesn’t seem that I have any of that as when stuffed at each combo nothing hits..... (I assume I am missing something and I need some bump stopbut need some help)
Click to expand...

If the shock is at full compression, then add some bump stop extension so that the jounces are doing their job.

The next question is if the shock travel is closely divided in half at ride height. If not, then a different size shock is needed to achieve that.
 
jjvw said:
If the shock is at full compression, then add some bump stop extension so that the jounces are doing their job.

The next question is if the shock travel is closely divided in half at ride height. If not, then a different size shock is needed to achieve that.
Click to expand...
The shock appears to have more travel left at full compression. I’ll confirm. And might add a 1” no matter what for a safety factor. (Is that crazy or over cautious)

Once I get the springs installed I’ll confirm ride height and travel distances

Thanks. I think I’m almost there.
 
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