Hey all, Hope I’m not outside the boundaries here, but I’ve been thinking of ditch my rear leafs for some truck arms or maybe a 4 link set up like an A body. I had a simple question... sounds like I’ve never worked on a car but everything I’ve touched has either been new 1990+ or had leafs in the rear. What keeps the rear from going way, way down... like 3 feet below the floor, when the car is jacked up? Is it the shocks? I can’t imagine the cool springs are Fixed to the cups Thanks Sent from my iPhone using H.A.M.B.
I put truck arms in my 54 Stude wagon (Conestoga). I used a wishbone to hold center and coil-over shocks to hold it up. Been there for about 6 years now. Not a ton of miles but a fair amount. Happy with the installation and the way it works. https://public.fotki.com/-Mike-/my_studebakers/ Mike
Ok. Does hanging it for a while hurt the shocks then? Also, did ‘60 Chevy trucks have two peice drive shafts? Wondered because the arms are bushed on a cross member that I wonder if necessitates a 2 piece shaft Sent from my iPhone using H.A.M.B.
Choose your shock length, mount points, attach, and look at driveshaft clearance with shocks extended.
As an aside, this was also a popular way to put a full floating HO 72 under a GM A body short track car. It was easy to find a 4.56 or 5.13 center section, and swap between them as needed.
I had thought at one point the arms might be bushed to brackets on the frame rails and more parallel than angled. The panhard isn’t going to allow side to side movement and that way I don’t need a cross member. I also though about a cross member high /in front of the diff on the rear arch like a shock cross member that could take some short 45° angled arms and do it as a 4 link a la perfect pinion angle always, unlike arms. The purpose is for ride quality and ride height, way more than performance. I do push this car through corners sometimes (and grin all the while) but I’m not looking for a Porsche. I’m looking for a Lincoln tow car Sent from my iPhone using H.A.M.B.
If you move the truck arms out to the frame rail they will work like a old set of ladder bars on a gasser ,they are great for going straight but not any good for corners. Truck arms work like early ford wishbones, when one wheel goes up or down it has no affect on the other wheel just like a 32 ford with stock bones. Don't over think this or try to reinvent the wheel
For a road car you will need to allow for one wheel to go up while the other stays the same or goes down, for corners, bumps etc. The usual way to accommodate this is to have the arms meet the frame near the middle if they are long or to be rubber mounted at the ends if it is a 4 link. In any case you will need to use rubber for sound and vibration.
This is what I did. This is my custom truck arm rear suspension using 3/4 ton composite leaf springs. The car is 2900lbs. and puts out 425H.P. It has been on the road for about three years with no worries.
Close to center as you can get convergence at transmission tail. Though experiment.... Take a rectangle sheet of plywood and lift one corner,,, what happens? The nearest corner lifts and the sheet tries to twist. Take a triangle shaped sheet of plywood and lift one corner,,, what happens ? The one corner comes up and leaves the other 2 where they are and free of twisting.
There was a young couple at the Portland Roadster show who have a suspension shop in Oregon that have some serious round tube truck bars for sale for bagged rigs and also have a nice crossmember to go with them Rather spendy but beefy.
Pragmatist that is pretty cool! Then plywood thing makes sense. So that means making a cross member, unless I go 4 link, where two long parallel (to frame and each other) bars are bushed on both sides, and are accompanied by smaller, 45° bars to a cross member in the rear. That would work fine, right? It’s essentially GM A body set up. I haven’t written off truck arms, as I like thier simplicity and effectiveness but there could be driveshaft/exhaust interference that wouldn’t be with 4 link. Might also wait until I can throw another 6-9” of “arch” in the frame rails Sent from my iPhone using H.A.M.B.
Setting up the 4 link isn't bad and welders series makes a really nice kit. You could easily go with P&J style bars and the dipped crossmember too. If you're going to ride around super low then you're not going to need much articulated motion any way. If you were to dip a tire the frame or body will hit before anything else.
Not super low, right now the car is down 3” in the front and 3” in the back and doesn’t look right. Prolly 5” Total on the back. The rear tire will be 2/5 or 1/3 Showing The thing that confuses me about the premade 4 link kits is that there is nothing to weld the inner links too, at least my car. Making a cross member would be no big Deal but I’d like to see the instructions (or perhaps I should say specifications) before buying. I planned to make my own using large grade 8 all thread for adjustment on the top links so I could adjust pinion angle Pain to do this body on. That’s the other nice thing about truck arms. I can make that happen much more easily on my back in the driveway Sent from my iPhone using H.A.M.B.
I googled it and got women’s fashion lol. Enlighten me. And I am not going for much lower than it is now... just better ride (smoother) Sent from my iPhone using H.A.M.B.
https://www.jalopyjournal.com/forum...bid-spatial-recognition-issues.1098087/page-3 There's a lot going on in these pics- everything to set up a 4 link and hold the rear end. It requires measuring and precision, but just once. It won't flop around or move. The 2x2 angle establishes the normal ride height. The small vertical bars control the fore and aft positions. The small horizontal angle controls left/right center and allows upwards vertical movement of the axle for testing. The pipe thru the ujoint straps to the ground adjusts and holds the pinion angle. The solid struts get the coilover angles equal and hold the top mounts in position. The bar's brackets are much easier and stronger with a boxing plate. It can be small or full length. The thru frame sway bar really cleans things up too. I snuck this one thru the coilover crossmember.
When you suddenly lose air in a front tire, if your susp. hardware, frame, oil pan, touches pavement, you may not steer! All four corners of an auto are designed to avoid this.
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