4x4Wire TrailTalk

Securing TJ Springs to Rear Perch

Posted By: Anonymous

Securing TJ Springs to Rear Perch - 12/06/10 07:45 PM

ok here is what I believe I should do.
Drill and tap a hole in the bottom perch.
Is 1/4" good for this?
Drill a hole a little bigger in a 3"x1" piece of flat bar.
Put spring in place and screw flat bar to perch so it holds the bottom of the spring in place.
Good so far?
[Linked Image]

The top perch has a hole in it already.
I guess I drill threw that hole and into the frame then tap it?
[Linked Image]
Posted By: 4x4Wire

Re: Securing TJ Springs to Rear Perch - 12/06/10 08:23 PM

In your picture, note that the top has a concave surface and the bottom appears to be flat.

I would suggest you consider some method that would keep the bottom in place. Flat stock as a clamp may not be sufficient to keep the bottom from shifting.

Rather than 1/4 inch, I would opt for a a 5/16 inch bolt. And, I would go with ny-lok nuts rather than tapping.
Posted By: DamKia

Re: Securing TJ Springs to Rear Perch - 12/06/10 08:34 PM

If you are going to fix one end of the spring, "cone" the other if it gets too loose, otherwise let it hang free. Placing an "edge" of pressure on the both ends of the spring is asking for trouble and will only rip whatever restraining measures you have taken out. There are going to be some impressive leverage forces at play once you start flexing up. 1/4 inch would be OK if you only fix one end, ie, no tension applied to the 1/4" bolt.

Take care when drilling or opening out any existing holes in the chassis as this can weaken the chassis at critical point along its length. Specifically do not drill through to the other side unless you are going to weld a crush tube in place. (example of a crush tube can be found where the steering box mounts to the chassis)
Posted By: 4x4Wire

Re: Securing TJ Springs to Rear Perch - 12/06/10 09:30 PM

Just checked the spring mounting on my JK. The upper is a concave (coned) surface. The bottom is a round base the spring fits over. The height is just above the first coil of the spring.

As I recall my older Jeep Cherokee with a similar spring mounting, upper and lower were concave surfaces with the bottom having a light weight stability clamp.
Posted By: Anonymous

Re: Securing TJ Springs to Rear Perch - 12/06/10 10:05 PM

Thanks for the prompt reply's guys.
I am only wanting to fix the bottom in place, and put a bump stop in the top that came with my lift from Everet.
If I did both that would obviously create big problems on flexing....lol..I imagine some or maybe even a lot of people wouldn't think about that. I did.

I don't want to drill into the frame if I don't have to. Not a big fan of that. Does the top hole go into the frame already??

I just finished driving around looking for a couple bolts. blew more fuel than the bolts would even cost and I didn't even find anything. Crappy little stores out here where I am right now. i will have to wait till I get back home to do it I guess.

Of course anymore input is greatly appreciated!
Posted By: Everet

Re: Securing TJ Springs to Rear Perch - 12/07/10 05:20 AM

No, the hole doesn't go all the way through. I don't believe that drilling through the bottom of the frame with 1 5/16ths inch hole is going to weaken it to where something is going to break. Just look at the stock holes in the frame for comparison. Wow, now that I think of it, they are huge compared to the 5/16ths hole you drill. Also, what I do know is that Dennis has been driving this way for several thousand miles along with several thousand on mine. Furthermore, no one has ever reported that it has ever been an issue as far as I have heard.

But, you do what you think is best for you.

Everet


Everet
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Posted By: DEFBOY35

Re: Securing TJ Springs to Rear Perch - 12/07/10 05:30 AM

i would suggest the 5/16th as a minimum myself. maybe even go to a 3/8th.

next question being how thick is the spring perch material to be tapped to begin with?

i would also suggest for your flat stock to put a bend on each end that will come down around the outer edge of the spring to help clamp it down better.

and just throwing this out there as a in case.... but i assume you know this already, make sure to get the proper size bit to drill for tapping. i have seen on more than one occasion someone wanting to tap a 1/4" hole for example first drill it out with a 1/4" bit and not know why they could not tap it after!
Posted By: Anonymous

Re: Securing TJ Springs to Rear Perch - 12/07/10 05:30 AM

Well then it will be going in the frame if that's how it goes.

And isn't that just common sense???
lol no..no it isn't.
I think I will go for the 3/8
I don't know how thick the bottom perch is but it does not seem that thick..Was going to do a fine threaded tap if I can.

Thanks for the input so far and to come.
Posted By: 4x4Wire

Re: Securing TJ Springs to Rear Perch - 12/07/10 05:54 AM

If that is the way you go, use Blue Lok-tite on the bolt to keep it from vibrating loose...
Posted By: Anonymous

Re: Securing TJ Springs to Rear Perch - 12/07/10 06:03 AM

Ahh yes..Thank You.
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