Will my rear suspension work?

I have a few concerns about my rear suspension. I attempted to use stock wishbones shortened to about 22". They are bolted to brackets, that are welded to the rear end. I'm using a stock style rear "A" spring. My concern is that the rather short rear bones, and the "fixed" nature in which they are attached to the rear axle will try to pull the rear spring forward. Meaning the bones will move in such a short arc that the rear spring will try to rotate forward to move. Either that will happen, or the spring and the bones will just fight each other and create a "stiff situation". doing the "jump up and down" test, things barely move. Although I do have an extremely brittle original spring that is pre tensioned way too much. Do you guys think my design will work, or should I send this one to the bone yard?

 

have you cycled the suspension through its arch? how much does it cause the shackles to move from side to side? load the spring by chaining it down to a floor jack and jack up the rear so you can see the stress of the motion, or jack the frame up and and let the sring hang.. if your going for big inches of travel i would say your gonna have a problem, but in hot rod applications you will probably be fine.

 

Take the spring apart and set it up with just the main leaf to see how it acts. I would add a top bar to the wishbone to make it more like a ladder bar. If you ever hook the car up with some horsepower you have a mess.

 

Those bones are going to break at the mounts on the axle. Plenty to read on here. Put a night aside and search rear suspension threads. There's a bit to learn.

Pete

 

Yes, they will break at the axle in time. As the body rolls to either side, or when one rear wheel goes into a dip or over a bump, the axle cannot twist like a front I beam can with split bones.

Your bones seem to be the later 30s early 40s which are prone to break the weak forged ends.


The bad thing is that your frame rails are very narrow and way too low to be able to form a wishbone shape to the trailing arms, which would be better.

 

These were my exact concerns fellas. Thank you so much for taking the time to reply. I was trying to stay in the somewhat traditional realm with my suspension design, but I'm thinking that my narrow frame and super low stance my call for something a bit out of the box. Dare I say 4-link? What route do you guys think I should go? I'm getting ready to finish the floors and I don't want to cover anything up that might fail down the road.

 

After doing a little more searching I found a few pictures of el polacko's work
(of course). I found a 3 link setup he did with what looks like modified bones to keep the look traditional. I really dig this option. thoughts?

 

If you want a similar look, go with Elpolako's three link. Otherwise a four-bar is the only way you'll get articulation with such a low car. If you narrow the mounting points on the axle enough to fit a whole wishbone inside the frame, it will be too narrow to withstand the pressure placed out at the wheels.

 

I was trying to stay in the somewhat traditional realm with my suspension design,

Nice work but Something must be getting lost in the translation.
That looks like a backhalf tubbed set up to me (sans the narrowed housing) & Those need a 4 link set up & coils.

As low as that is, nobody will see the bones and buggy spring anyways.

 

I realize it's not really a traditional build. The frame is scratch built. By somewhat traditional i meant by using modified original parts and not a 4 link and coil overs. The three link looks like a viable option...

 

I'd go three link, convert the lowers to bars that pivot on the back end, Add a hoop about where the square tube cross member is and tie it back to the frame rails to support the front of the third link and you'll be happy

 

My thoughts exactly!

 

Somethings mix well together.
Chocolate and peanut-butter.
Sausage & peppers
Tequila and lime juice.
Short skirts and high heals.
Traditional builds and old parts.
Old technology and traditional parts.

The buggy spring and bones works when most everything is Above the axle centerline. You can fudge and stretch that somewhat with some ingenuity but there's a limit.
When most everything is below the axle centerline , that's where new technology takes over and traditional can no longer bee seen, because its not.

I'm not against you build, it looks like some really nice work. Just don't see the mix working well. Maybe because it hasn't been thought about or done before.

Yesterday I was building lego houses with a 4 yr old. (big fun BTW) He said " I wanna put eyes on this house". I said "houses don't have eyes, when did you ever see eyes on a house? " He said " well I never have - that's why I want to do it "

 

I think I see what you are trying to tell me. My car does not adhere to any strict guidelines so I should probably go with the system that will perform the best. Especially since the components will be nearly invisible. My only reservation is I want to make sure my car stays a hot rot and not a street rod. If I could use that three link setup and make it work well, to me that would be neat. If you're not using super cool original parts, the next coolest thing is modified original parts. Or at least that's how it works in my head...