I have read a lot of the old posts on this topic and am looking for a little advice. What has worked best for you. I think last time I just lucked out on everything working well, so I want to make sure its perfect this time. Here are a few questions? The rear end is positioned at ride height and I understand that the lower bars should be parallel with the ground. The airbags will be positioned behind the rear end. 1. On my last 4 link I welded to the center of the 10 bolt that was in the truck. I have a new one, has anyone had any issues welding to the GM center, I know some guys use nine inch rears so they can weld to it easier, but since its a chevy truck, I would like to keep it all chevy. 2. Upper bar angles. Is this angled enough? Do you think the rear end would walk from side to side? Option #1 In your opinion would this work better? Option #2 3. Angle for upper bars in relation to frame Should this be more parallel with the ground, like the lower one will be. Thanks for the advice
if you weld it to the cast housing you better use a nickel alloy and gusset the hell out of it or it will break off, you would be better off welding it to the axle tubes.
yes welding it to that cast will be a nightmare, ive seen it done before and its never a good outcome. have you thought about adding a crossmember farther up, notch it for the drive shaft, this is the setup on my daily driver, sorry about the bad pics
The only way to weld your bracket to the cast center section it to take it completely apart and get it up to around 1500-1800 degrees. It will be a total penatration at that heat but it will be jacked on the inside. So like said before... weld it to the axle tube.
Do not weld to the center section!!! Yea, some people will tell you it CAN be done, but dont! I've been doing bags, and 4-links since 1994 you can go to my websight and look under suspension. That might give you a few ideas. If you have any questions let me know. www.insanedesigns.com P.S. Damn, that is one beefy crossmember you got going there!
Thanks Guys, I am going to play around with the layout tomorrow, the frame is from a 56 chevy truck, if anyone has any pics of thier trucks with a triangulated 4 link I would love to see it.
I think you would want your uppers close to parallel like the bottoms. Mine have a slight angle to them. If you mount on the axle not on the housing, and mount onto the top of the frame, not the side...that should take that extreme angle away and get you closer to where you need to be. im sure you mounted it sideways off the frame for clearance issues. I did mine on my 52, so it was a little different, I would stay away from welding to the housing also... Good luck...
Looks like you have plenty of room on the outside of the frame why not run a parrallel setup with a Panhard bar?
What if you made a heavy gage plate that used the top row of bolts on the rear of the center section that you could weld the upper link brackets to?
Man, that is not good, you can see why the OEM's dont weld onto that cast stuff, they cast in attachment points if they need mount points which is a luxury you dont have. The alternative with the finer angle is just not satifactory either. Parallel with panhard has got to be the best choice in your situation. Do it right now and you will never need to revisit it later.
Option #1 will work IF you move the lower attachment point (on axle) out towards the end. You want at least 40 degrees total . Add top & bottom angles. Later, Mark
I just called DTS who built my Dana 60 to ask about this exact same thing. They told what everyone else is saying don't weld to the cast pumpkin. DTS told me to make a bridge piece to go from one axle tube to the other up over the pumpkin to accomplish the same thing.
triangulated four bars work best if the convergant bars are at right angles. Many shops are supplying the brackets to work at lower angles because of situations like this and they will work. There will be a tendency for body sway the lower your angle is and the more compliant your linkage is. If you do opt for the low angle situation, measure very carefully to make sure both bars are the exact same length. Then build a new set of non-adjustable bars to replace these. I use 1x2" 0.120 wall box tube for my beams and 2" 0.125" DOM sleeves on either end and modified energy suspension bushings. This way the only thing compliant is the bushing itself and no chance the bar could twist. The offroad guys do the same but use Johnny joints (huge spherical rod ends) and no bushings to eliminate suspension compliance. Inverted triangulated works also. Where the upper bars converge on the frame like the post earlier. And you can have the upper bars parallel and the lower bars converge on the axle or frame. This is much less popluar and there is a ton more acceleration and braking loads put into the lower bar because of the angle between the axle and frame.
I would suggest rebuilding the rear part of that frame. It looks poorly done and is way over-kill. Those corner tubes are unneccesary and clearly in the way. After that, look at reversing the top bars so that the uppers run from outer axle to inner ch***is. Keep the lowers level and parallel. If you don't intend to race it ( I wouldn't with that ch***is) and you don't have a clear understanding of suspension geometry, you will be much better served by a parallel and level 4-bar with a panhard bar. I have another solution for the rear cover axles using a 3 link and panhard I can post pics of, if you are interested. I am installing it in an '69 Opel GT now. It's modeled after the '92 and up Camaro suspensions.
I agree with alteredimage. Parallel four bars of the same length and a panhard bar to keep the axle centered. You don't have enough angle outward if you weld the upper brackets to the axle tubes and as stated don't weld to the cast center section. Good luck, The FOGGER
think about going with a wishbone effect (forward mounts are closer together) like the picture above if you do not have the room to go with a standard triangulated 4 bar (rearend side of the mounts are closer together) look that way you get a better triangulation.
looks to me like the parallel 4 bar and a panhard bar would work really well here instead of worrying about how to engineer the triangulated set up for this car. What limits the triangulated set up here is the frame layout, in my opinion.
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