Folks that have done the rear spring conversion....

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Dec 29, 2015
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For folks that have done the conversion, using the 4Runner/FJ upper spring isolator, does it bolt up to the upper spring perch? Or is it just held there by the spring? I'd like to run them with the OME trim packer, but wondering what would keep the trim packer from falling out if the rear flexed enough to drop the spring slightly? I'm thinking it would never flex that much, especially with the KDSS sway bar attached, but figured I'd check.
 
Just sits up in there.

Your shock would bottom out on flex, plus I am thinking the packer would go over the isolator like the spring? So if you were all maxed our it wouldn't go anywhere and the isolator would do its job.
 
It's just held there by the spring pressure. From what I understand the shocks are what limits the downtravel of the axle so the spring cannot shift slightly
 
Thanks guys. I'll give it a go. I'm using the caster wheel method now - but it's creeking something awful, so gotta get it out of there. If the spring sits up there just on its own pressure, is the isolator even needed? I would think the bump stops would keep the spring/shock from bottoming out, so not sure what purpose the isolator serves.
 
The shocks do limit the travel, which is a slight concern when you start doing a long travel rear suspension. It could be possible to flex the axle so that it spits out the spring.
 
I think it prevents vibrations and stuff from getting transmitted to the chassis

So if I just put a rubber spacer up there, it should do the same, I would think?
 
I am not a vehicle engineer so I don't know if if the conical part is super important to the vibration damping or not. But I think it has to get cut to install the helper bags so maybe a rubber spacer would be fine. Maybe @THeGeNTLeMaN can provide some input here since I think he has the helper bags.
 
The shocks do limit the travel, which is a slight concern when you start doing a long travel rear suspension. It could be possible to flex the axle so that it spits out the spring.

Luckily (or not), I won't have to worry about long travel suspension, since KDSS won't allow it :/
 
I am not a vehicle engineer so I don't know if if the conical part is super important to the vibration damping or not. But I think it has to get cut to install the helper bags so maybe a rubber spacer would be fine. Maybe @THeGeNTLeMaN can provide some input here since I think he has the helper bags.

I have some rubber spacers in there now, so I'm going to just try removing the caster and see what happens. I think all the creeking is coming from the spring rubbing on the caster itself.
 
I am not a vehicle engineer so I don't know if if the conical part is super important to the vibration damping or not. But I think it has to get cut to install the helper bags so maybe a rubber spacer would be fine. Maybe @THeGeNTLeMaN can provide some input here since I think he has the helper bags.


The conical section is to help keep the spring in its place and centered. That setup he is running was originally mine and i did have to cut a couple of sections off of the isolator but still had a healthy amount of cone structure left. I think just a rubber spacer without anything to help center the spring could be a problem.
 
The conical section is to help keep the spring in its place and centered. That setup he is running was originally mine and i did have to cut a couple of sections off of the isolator but still had a healthy amount of cone structure left. I think just a rubber spacer without anything to help center the spring could be a problem.

There ya go - ruining my cheap way out! :) I may just bone up and do it right, with the isolator. I just hate spending so much on a couple pieces of rubber :/
 
If you only want to have to do it once, do it right.
 
If you only want to have to do it once, do it right.

Ha! You would think I would have learned that lesson by now. I've done everything 2 or 3 times on every vehicle I've owned... :)
 
Has anyone ever tried to wrap the first few coils on the top of the spring with some fuel or vacuum line to help insulate it from noise or vibration when using the caster method?
 
Has anyone ever tried to wrap the first few coils on the top of the spring with some fuel or vacuum line to help insulate it from noise or vibration when using the caster method?

That's not a bad idea either. Just wondering how long before it would just wear through.
 
That's not a bad idea either. Just wondering how long before it would just wear through.
not long... youd be better off placing some thick rubber floor mats or other type of pad up under the frame mounts to and use some adhesive bonding agent to hold them there to isolate the springs from the frame, hose like that is not desinged to take any type of abuse or constant wear.
 
I just gave in and ordered the FJ spring seats. Ordered some 10mm trim packers too, since I won't be able to use my current rubber spacers up top with the spring seat.
 

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