Rear lower link frame attachment point

[Zandoz]

I am having a hard time coming up with an idea for the lower link attachment point brackets. The problem is that the center of the rod end will be around 2-1/2" below and 4" out from the frame rail. The body will be channeled completely over the frame, with a gap of about 1" between the frame and the flange on the bottom of the body. If possible I'd prefer a double shear arrangement. Also, if possible I'd prefer a bolt-on solution.

So far, all of my ideas have shared 2 things...a 3/8" plate fastened to the side of the frame, and extending below the frame and body...and all have been exceedingly ugly.

Any ideas and pics will be greatly appreciated.

 

[old round fart]

Cover it up with a step?

 

[bobs66440]

You can do something similar to what I did. I made a double shear bracket and welded it to the stock location on the frame to bring it out past the body. Mine isn't terribly attractive either, but with the car finished, the pipes on and everything going on it really isn't that bad I don't think. At least I haven't heard anybody say "Oh my god, look at that horrendous bracket!" Of course it's black and kind of gets lost. On a lighter color car it may not be so good...

I was planning on hiding it with a step as mentioned, but it turned out the car is low enough that I can just step right in. And the step would have been too close to the body to be useful. If I ever decide to add one, I will have to have it swivel or slide out somehow far enough to be able to use it.

 

[fletcherson]

You can do something similar to what I did. I made a double shear bracket and welded it to the stock location on the frame to bring it out past the body. Mine isn't terribly attractive either, but with the car finished, the pipes on and everything going on it really isn't that bad I don't think. At least I haven't heard anybody say "Oh my god, look at that horrendous bracket!" Of course it's black and kind of gets lost. On a lighter color car it may not be so good...

I was planning on hiding it with a step as mentioned, but it turned out the car is low enough that I can just step right in. And the step would have been too close to the body to be useful. If I ever decide to add one, I will have to have it swivel or slide out somehow far enough to be able to use it.

I don't think it looks bad at all. It is a machine and function is king. As long as the bracket is well made as yours is, it's just part of the car. That's part of what makes these things cool, seeing the works, so to speak.

 

[Zandoz]

Unfortunately a step will not work in this case. The center point of the rod end is only about 3" ahead of the rear tire, and is almost directly under the bottom edge of the body. If it extended out past the body a bit farther forward, I'd definitely be going with a step of some kind.

I've been playing around and came up with an idea I think will work...but there is one point I'm not sure of. My idea is to use a 3/8" plate bolted to the side of the frame rail, with a wedge shaped spacer cut from a heavy piece of channel welded to it. On the face of the channel, I'd use use an "off the shelf" Z-shaped link bracket to get the double shear.



I've seen 3/8" radius rod brackets, some extending 6" or more below the frame, with no other gusseting. Is that really sufficient for a rear axle?

 

[fluidfloyd]

Unfortunately a step will not work in this case. The center point of the rod end is only about 3" ahead of the rear tire, and is almost directly under the bottom edge of the body. If it extended out past the body a bit farther forward, I'd definitely be going with a step of some kind.

I've been playing around and came up with an idea I think will work...but there is one point I'm not sure of. My idea is to use a 3/8" plate bolted to the side of the frame rail, with a wedge shaped spacer cut from a heavy piece of channel welded to it. On the face of the channel, I'd use use an "off the shelf" Z-shaped link bracket to get the double shear.

View attachment 10665

I've seen 3/8" radius rod brackets, some extending 6" or more below the frame, with no other gusseting. Is that really sufficient for a rear axle?

Bill...Looks good to me. I like the double shear solution and it appears you will be using a hi misalignment spherical bearing at that end. Bolting it to the frame should be just fine too. I assume you will run the bolts completely through both sides on the frame rail and use a though bolt and nut assembly. If so I would put in a crush tube to stiffen the vertical wall of that frame tube. Would also weld in that tube so has to not have any stress risers appearing from the drilled holes. Just my .02 cents worth. Have fun.

George

 

[Zandoz]

Bill...Looks good to me. I like the double shear solution and it appears you will be using a hi misalignment spherical bearing at that end. Bolting it to the frame should be just fine too. I assume you will run the bolts completely through both sides on the frame rail and use a though bolt and nut assembly. If so I would put in a crush tube to stiffen the vertical wall of that frame tube. Would also weld in that tube so has to not have any stress risers appearing from the drilled holes. Just my .02 cents worth. Have fun.

George

Yes, I am planning on welded in anti-crush tubes. For rod ends. I'm planning on 2" Currie Johnny Joints for rod ends. They give a slight bit of cushioning over a conventional heim. My only question is if that 3/8" plate is sufficient without gusseting.

 

[fluidfloyd]

Yes, I am planning on welded in anti-crush tubes. For rod ends. I'm planning on 2" Currie Johnny Joints for rod ends. They give a slight bit of cushioning over a conventional heim. My only question is if that 3/8" plate is sufficient without gusseting.

I think 3/8" will be fine. Looks like you are on the right track. Have fun.

George

 

[Bucketman]

I would say if your going with a triangulated rear suspension to be careful. I was going in that direction but after building a model out of wood and checking the angle of the differential at different points on its radius I gave that idea up. Then I listened to the experienced guys on here and went with simple.
This one only changed about 1/2 degree in 5 inches of travel. Still not perfect but closer than my triangulated design. It can be done, and it works great but I didn't have the design ability. Oh and Bobs66440, I would be showing people that bracket. It is well designed, and well fabricated. Good job! I like your T-bucket.

 

[Zandoz]

I would say if your going with a triangulated rear suspension to be careful. I was going in that direction but after building a model out of wood and checking the angle of the differential at different points on its radius I gave that idea up. Then I listened to the experienced guys on here and went with simple.View attachment 10675
This one only changed about 1/2 degree in 5 inches of travel. Still not perfect but closer than my triangulated design. It can be done, and it works great but I didn't have the design ability. Oh and Bobs66440, I would be showing people that bracket. It is well designed, and well fabricated. Good job! I like your T-bucket.

The triangulated configuration I'm using comes directly from the Ford Fox body Mustangs, Cougars & Thunderbirds...via Granatelli Motorsports racing control arms. When I made the decision to go this route, the numbers tipped the scale...around 3 million of them. If they didn't work it would be common knowledge by now. And the configuration is obviously going to be better than a hairpin & buggy spring set up.

Having said all that, I did model the suspension travel in my CAD system. .19 degree pinion change over 5-13/16" travel. Apparently Ford hit somewhere near the sweet spot with their control arm lengths and angles...which is what I was hoping for.

 

[Bucketman]

.19 is about as close to perfect as it gets. It is the best system for rear suspension out there. I wish I could have made mine work.

 

[Zandoz]

.19 is about as close to perfect as it gets. It is the best system for rear suspension out there. I wish I could have made mine work.

Well in this case it's not my doing....I have to give credit to Ford's engineers. A lot of folks complain about the Fox body suspensions, but most of the problems are due to control arm flex and spongy bushings, not the suspension geometry. Is it the best design out there? No, far from it. But for street use it's not bad.

 

[Bucketman]

I was talking T-buckets, for street use. However all opinions expressed are my personal opinions and, in no way, should be confused with the actual truth. lol