Coil springs bump stop

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Matt77

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I'm new at this so those of you that helped so far thank you.

I measured from the bottom of my coil spring to just below the top perch pad. And came up roughly with 3.5". So that's my lift???? Plus I have a 1" body lift. I'm assuming that's the bushings between the rear bumper and and body as well as front bumper and body? IS This correct????

So if I was replacing the front coil springs would I get a 4" spring??? Is a half inch that much????

And is the lift height what I use to determine how to order new top and bottom perch pads/bump stops????

I'm trying to get all this guys, thanks
 
Jerry Bransford said:
Stock coil spring heights are 8" in the rear and 12" in the front. Spring heights taller than that is how tall a suspension lift is.
Click to expand...
So do I have to take the springs off first to measure them? I'm a newb man. Lol I wasn't really sure. Or do I measure them while they are still on? When I measured the spring while it was on, it measured 15.5" that's the front.
 
Matt77 said:
So do I have to take the springs off first to measure them? I'm a newb man. Lol I wasn't really sure. Or do I measure them while they are still on? When I measured the spring while it was on, it measured 15.5" that's the front.
Click to expand...

No, you dont have to remove them. If you measured 15.5" that means you have 3.5" of lift. Spring heights can vary depending on your set up. Weight of bumpers, winches, hard tops, ect... add up. Are you looking to replace a damaged spring or at new springs all around?
To measure for bump stops remove the spring and cycle the suspension. Use an appropriate sized bump stop to avoid any interference.
 
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Matt77 said:
..


And is the lift height what I use to determine how to order new top and bottom perch pads/bump stops????
Click to expand...

The bump stops are intended to stop up travel and keep parts from crashing into other parts. The correct amount of bump stop extension has nothing to do with the amount of lift the Jeep has. Tire size and shocks are most often the determining factors.

To determine the correct amount of extension for your Jeep, put the frame on jack stands. Remove the coils and soft jounces from the cups. Move the axle, tires on, through it's entire range of motion. Typically, the front needs to be extended to prevent the stuffed tire from hitting the steel fender (ignore the flexible flare) at full flex. The rear typically needs to be extended to prevent the shock from over-compressing. Also, check the front track bar against the diff cover at full bump. Certain combinations of track bars and diff covers do not fit well together.

The first point of interference is what you need to extend the bump stops just enough to keep that from occurring.
 
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Matt77 said:
I'm new at this so those of you that helped so far thank you.

I measured from the bottom of my coil spring to just below the top perch pad. And came up roughly with 3.5". So that's my lift???? Plus I have a 1" body lift. I'm assuming that's the bushings between the rear bumper and and body as well as front bumper and body? IS This correct????

So if I was replacing the front coil springs would I get a 4" spring??? Is a half inch that much????

And is the lift height what I use to determine how to order new top and bottom perch pads/bump stops????

I'm trying to get all this guys, thanks
Click to expand...
It takes awhile to get all this, NooB here too. Take your time, read the forum
Step one is determine lift height like you are doing.
Remember the higher, the costlier.
Post pics as you go along
 
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KCsTJ said:
It takes awhile to get all this, NooB here too. Take your time, read the forum
...
Click to expand...

Cycling the suspension sounds daunting. But if you installed your lift, then you already know how to remove the coils and move the axle around. Things become very clear once you do it. I've cycled mine for various reasons at least a dozen times. It's the single best thing to understand when it comes to modifying your suspension.
 
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06lj said:
No, you dont have to remove them. If you measured 15.5" that means you have 3.5" of lift. Spring heights can vary depending on your set up. Weight of bumpers, winches, hard tops, ect... add up. Are you looking to replace a damaged spring or at new springs all around?
To measure for bump stops remove the spring and cycle the suspension. Use an appropriate sized bump stop to avoid any interference.
Click to expand...
 
jjvw said:
Cycling the suspension sounds daunting. But if you installed your lift, then you already know how to remove the coils and move the axle around. Things become very clear once you do it. I've cycled mine for various reasons at least a dozen times. It's the single best thing to understand when it comes to modifying your suspension.
Click to expand...
I bought my jeep with the lift already. I don't know what cycle the suspension means. Can you break that down a little more please? Sounds like a pita.
 
Cycling the suspension is just a term for taking the axle through its full range of motion. It is done to measure for the correct shock length, appropriate bump stops and to ensure you don't have any steering components that hit the axle when the suspension in compressed. Its not a difficult job although it can be a little time consuming. A good set of jacks stands and a floor jack are a must.
 
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Chris said:
And as I mentioned above, this article covers how to adjust your bump stop accordingly and cycle your suspension:
How to set your bump stop on a Jeep Wrangler TJ
Click to expand...
We'll instead of cycling the suspension I have most of the bump stops still in place the ends are rotted off. Can I use what I have left to just get new ones?

Also is there supposed to be anything on the bottom part of the perch pad? Or is it just a flat pad?

I'll get some pictures
 
So I have the bump stop towers. The ends have rotted away. Can I just add the end part? Bc it's basically figured out for me. This jeep use to run awesome but 20 years in the Florida sun have rotted away all my bushings etc... is there anything supposed to be on the bottom? Or is that just supposed to be flat.
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Matt77 said:
We'll instead of cycling the suspension I have most of the bump stops still in place the ends are rotted off. Can I use what I have left to just get new ones?

Also is there supposed to be anything on the bottom part of the perch pad? Or is it just a flat pad?

I'll get some pictures
Click to expand...

From the factory there isn't any adjustable bump stop. It's just set the way it is, you can't change it (only add to it), but you can replace the jounce bumper.

Since you vehicle is lifted, you absolutely need to be running the proper amount of bump stop. No one here (seriously, no one) can tell you exactly how much bump stop you need to run, as it depends on more than just the amount of lift and tire size you're running. In order to determine how much bump stop you need to run, you need to follow that thread that I linked to above and cycle the suspension so you can determine how much bump stop you need to be running for your lift height, tire size, and a variety of other factors.

If you don't properly set your bump stop, you will crush your fenders, steering, differential, or other components next time you are off-road and decide to flex out your suspension. The bump stop is there (and has to be set correctly) to ensure that you don't end up damaging things.

Every TJ will require a different amount of bump stop based on many variables. But the only way to determine how much you need to run is follow that thread I linked to above.

If you just replace what you've got there right now, it may or may not be enough. The only way you'll know for sure is when you do (or don't) crush your fenders when you're off-roading.

Now if you're not planning on doing any off-roading, I suppose you could never bother setting the bump stop at all and likely be just fine in most cases.
 
Chris said:
From the factory there isn't any adjustable bump stop. It's just set the way it is, you can't change it (only add to it), but you can replace the jounce bumper.

Since you vehicle is lifted, you absolutely need to be running the proper amount of bump stop. No one here (seriously, no one) can tell you exactly how much bump stop you need to run, as it depends on more than just the amount of lift and tire size you're running. In order to determine how much bump stop you need to run, you need to follow that thread that I linked to above and cycle the suspension so you can determine how much bump stop you need to be running for your lift height, tire size, and a variety of other factors.

If you don't properly set your bump stop, you will crush your fenders, steering, differential, or other components next time you are off-road and decide to flex out your suspension. The bump stop is there (and has to be set correctly) to ensure that you don't end up damaging things.

Every TJ will require a different amount of bump stop based on many variables. But the only way to determine how much you need to run is follow that thread I linked to above.

If you just replace what you've got there right now, it may or may not be enough. The only way you'll know for sure is when you do (or don't) crush your fenders when you're off-roading.

Now if you're not planning on doing any off-roading, I suppose you could never bother setting the bump stop at all and likely be just fine in most cases.
Click to expand...


I mean does it look like I'm missing alot of the end of the top bumper?
Does the jounce bumper somehow attach to the upper tower part? I think someone on here told me thats what I needed.
Am I missing anything on the bottom pad?
Does this jounce bumper attach to my upper tower bumper?
 
Matt77 said:
I mean does it look like I'm missing alot of the end of the top bumper?
Does the jounce bumper somehow attach to the upper tower part? I think someone on here told me thats what I needed.
Am I missing anything on the bottom pad?
Does this jounce bumper attach to my upper tower bumper?
Click to expand...

In that photo you posted, you're missing the entire top portion of the jounce bumper, so yes, that would be the place to start. The bump stop gets added to the bottom spring perch with an aftermarket bump stop kit, or you can also use hockey pucks as many do.

Anyways, the top portion is just the jounce bumper, bump stop doesn't go on the top. Bump stop sits on the bottom, and based off those photos you have NO bump stop whatsoever, which is not good.

That yellow jounce bumper goes right inside of your upper tower there. It will be obvious once you take it apart.

I run these for the bump top on my bottom spring perches:
https://www.rokmen.com/variable-height-bump-stop-spacers.html

You can adjust them as necessary.
 
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