Material for links and brackets

[Motorcitydak]

Coming from the off road world, we over build everything to the extreme. The suspension links on my truck are 2.0 0.250 wall and 1.5 0.250 wall DOM tubing with 1/4 thick brackets. I am building a 3 link rear for my PT car. What should I be using for these? I am thinking 3/16 cold roll steel for the brackets on the axle. What about tubing for the links? Also I would prefer to run heim joints at both ends and 1/2 inch grade 8 bolts by using 3/4x3/4 joints and hi misalignment spacers just to give me a wider mounting area. After doing a lot of work on Stropes calculators, it looks like I will not see more than more than 7000# compression or tension on any of these bars. In case you want some more info, it will be in my '68 Charger with a weight of around 3000#, 400-500hp/tq, 315 tires, 3.00-3.50 gear w/ truetrac and a Moser ford 9 inch full floater axle.

[E.rodz]

I have used thornbeck bros. products to build link bars they are top notch quality and great prices to. they can be found @suicidedoors.com also speedway automotive is a great sorce for brkts. and ends. hope this helps.

[Bryce]

I am running 1.25" x .120" DOM tube for my 3-link.

that is what most drag car 4-links use.

The compression loads in the upper link will be the most critical.

[Motorcitydak]

The upper link is under tension under acc. The Strope calc has been showing around 4-5000# of tension during 1g acc.

The 1,25 .120 wall DOM is what I was considering using, I just wanted to see what you guys had to say.

[Bryce]

the compresion loads come from braking. Since there is a single link. Depending on your link lengths I would guess a buckeling failure mode due to the compression in the upper link. Just run some calculations to determine wall thickness. Use wikipedia to get some equations. I would think you can achieve more than 1G in accel?

[JRouche]

For brackets and tabs 3/16" steel is about the most common you will see. I did use some 1/2" steel for the upper "coilover" mounts. Shockwaves actually but the bracket sees the same loading. Everything else is in 3/16" steel.

For the links it sounds like you have that covered.

For the ends. If you can swing not much more money I would look at a johnny joint type end. Everything I have read (no experience from me though, I have QA1 spherical bearings) shows they are the ends to use. Many manufactures suppling a variation of them.

For a car Currie http://www.currieenterprises.com/ces...nnyjoints.aspx
sells some nice ones. Not like the massive ends you are used to from the offroad trucks and buggies.. JR

[Motorcitydak]

I have some JJ's on my truck rite now. They seem to be OK but I am probably going to run these for the ends. I have these on my steering rite now and they are great after over a year now. Plus that is an awesome price for a pair of ends complete with spacers, tubing adapter and jam nut

http://www.ruffstuffspecialties.com/...-rh-p-338.html

[19,69camaro]

I just saw your other posts for you 3-link build. I am also in the process of building one myself. As for an alternative for johnny joints check out UMI's roto-joints I just got mine the other day and they look top notch and I havent heard a bad review from the f-body and mustang guys who use them http://www.umiperformance.com/catalo...roducts_id=388

[Motorcitydak]

Cool man, thanks for the heads up. I had not seen those before. I ended up getting the rod ends from ruffstuff tho. They do not have any sort of rebuildable bushing in them like a jj or those roto joints would so there will be no cushion between the axle and the chassis



Ill update this with what I ended up doing for my build. I used 1.25 OD 0.125 wall DOM for all 3 links. The lower mounts on the chassis side are just the stock leaf spring mounts drilled to put the mount holes where I want em. The axles mounts are made from 1/8 cold roll. I laminated the pieces at the mounting location to make it 1/4 thick total. The upper chassis mount was a little more tricky because it had to mount rite at the floor which is obviously not strong at all. I built the mount in a same way I did the axle mounts. Then I threw in a 1x2 0.120 wall steel tube going from frame rail to frame rail. I mitered the ends 5 degrees a side to make it 10 degrees total. This will force the tube even harder out towards the frame rails when the mount is under load. Basically it just means that the mount will never have a chance to fail.

Sorry about ALL the pics, just wanted to show you guys every step I took to build the mounts

[19,69camaro]

Don't worry we like pics. Those are some serious axle mounts I dont think you will ever have a problem there