Will rear upper spring perch relocation cause additional height?

jazngab

Done but not quite finished
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So I'm considering having a shop relocate my rear upper spring perches. I have my pinion rotated quite a bit and my bumpstops aren't aligned very well and theres a good bow to the springs. In fact, the bump stops pop out often when articulating due to the angle it meets the lower perch. My concern is if they straighten out the rear springs, it will add additional lift and cause increased rake. At that point I'll be chasing the front springs to match the height. For those that have had this done, did you find that additional ride height was added to the rear? If I can anticipate it, then I would consider switching to a shorter rear spring at the time of installation instead of going higher in the front. FWIW, i'm on 2" BDS springs now with a UCF extra clearance skid and traditional SYE.
 
Depends on how you do it. There can be an increase, decrease, or no change to the ride height.
By that statement, I’m guessing there’s more than one way to do it? Here’s a pic of the job done on a TJ by the shop. Not sure if it tells the story. Which is the way to do it that maintains ride height?

DE8BB5D9-2ED3-4705-A150-4DFD1A637C66.jpeg
 
If the distance between the spring perch and axle pad remain the same, the ride height won't change as the spring rate and vehicle weight haven't changed. I believe what JJVW maybe referring to is altering this distance. Some of the bolt on correction kits for example reduce the distance and add ride height as a result.
 
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If the distance between the spring perch and axle pad remain the same,
Therein lies the challenge. Since the spring perch in stock form is tilted a fair bit, there is no way to accurately measure the distance between perches at ride height and then duplicate that by simply measuring the same distance when the perch is flattened out. That is due mainly to the spring reacting slightly differently when compressed with an angled upper perch and then again with a flat perch.
 
By that statement, I’m guessing there’s more than one way to do it? Here’s a pic of the job done on a TJ by the shop. Not sure if it tells the story. Which is the way to do it that maintains ride height?

View attachment 267958
The way to do it that maintains the existing ride height is to put the spring seat in a position relative to the frame that maintains the existing ride height. You're gonna have to take some measurements for reference. 😉
 
I used these. Didn’t need to adjust up or down. Ride height remained the same. Probably luck more than anything, but it worked out perfectly…

I welded a nut to the top of the plate. Machined up an aluminum spacer and bolted the jounce bumper cup to it. That way it is basically the same setup as O.E. bump stop wise…

B28FBBDD-B688-436B-A709-C8FA81B0EE40.jpeg
 
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I used these. Didn’t need to adjust up or down. Ride height remained the same. Probably luck more than anything, but it worked out perfectly…

I welded a nut to the top of the plate. Machined up an aluminum spacer and bolted the jounce bumper cup to it. That way it is basically the same setup as O.E. bump stop wise…

View attachment 267964
That's the same ones the OP shows in the picture. Also happens to be the ones I bought...
 
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I got quoted $650 for parts and labor for this particular job. Does that seem like a fair price? This would only be second job I’ve outsourced for the TJ (the other being the regear) considering I don’t weld.
 
I got quoted $650 for parts and labor for this particular job. Does that seem like a fair price? This would only be second job I’ve outsourced for the TJ (the other being the regear) considering I don’t weld.
people get paid to do this?!?!

@Squatch we need to have a talk...
 
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I got quoted $650 for parts and labor for this particular job. Does that seem like a fair price? This would only be second job I’ve outsourced for the TJ (the other being the regear) considering I don’t weld.
If you have no other way to accomplish this I would say to go ahead with it. Meaning if you don’t have a friend with a welder. You may end up finding a place to have it done for $100 or so less if you wait long enough, or look long enough. Or you could just bite the bullet and get it done now…
 
I got quoted $650 for parts and labor for this particular job. Does that seem like a fair price? This would only be second job I’ve outsourced for the TJ (the other being the regear) considering I don’t weld.
If that is the only task you are having done, that is more than a fair price for a clean job. To do it cleanly, the rear of the tub has to be lifted up to cut the perch loose from the frame and not butcher it. To lift the rear high enough, the grill snubbers have to be pulled along with the entire body mount under the grill. If you don't, when you lift the rear you will bend the front fenders over the tires.

If you also want the shop to deliver a specified ride height, there is some trial and error that has to happen. That is time you are paying for. Be aware that there is no difference in anything after the job is done except a lighter wallet and your feelings are hurt less.
 
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If that is the only task you are having done, that is more than a fair price for a clean job. To do it cleanly, the rear of the tub has to be lifted up to cut the perch loose from the frame and not butcher it. To lift the rear high enough, the grill snubbers have to be pulled along with the entire body mount under the grill. If you don't, when you lift the rear you will bend the front fenders over the tires.

If you also want the shop to deliver a specified ride height, there is some trial and error that has to happen. That is time you are paying for. Be aware that there is no difference in anything after the job is done except a lighter wallet and your feelings are hurt less.
We’ll that’s where I’m torn. Do I “need” to have this done? I understand that driving it this way as it is now has no effect except for the bowed spring being an eye sore. Do I just suck it up and deal with the bump stops being off angled? Will they still do their job as is? They are the extended type bump stop from the jounce cup, which is why they keep popping out when pressure is applied at that angle. Can they be extended from the lower perch with a puck like the fronts and shorten the length of the upper bump stop instead? I’d hate to spend a chunk of money on something unnecessary.
 
We’ll that’s where I’m torn. Do I “need” to have this done? I understand that driving it this way as it is now has no effect except for the bowed spring being an eye sore. Do I just suck it up and deal with the bump stops being off angled? Will they still do their job as is? They are the extended type bump stop from the jounce cup, which is why they keep popping out when pressure is applied at that angle. Can they be extended from the lower perch with a puck like the fronts and shorten the length of the upper bump stop instead? I’d hate to spend a chunk of money on something unnecessary.
Yep, just raise the lower and split the bump stop between the upper and lower perches.
 
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