Hey All, I'm back to the drawing board after thinking I had my rear suspension figured out a couple weeks ago with this boards help. Unfortunately, I wasn't thinking about the Chevy rear end I have when I decided to go with split wishbones and a "3rd link". I need to know if the third link mounting point on the rear end must be very near the center of the rear end to work properly. The closest I can mount the 3rd link is roughly 9" from the center of the rear end due to the cast iron center section. The front (frame) mount could be just enough off center to miss the driveline. If this won't work, I am considering a 4 link suspension. The questions with the 4 link would be what an acceptable difference in length (top/bottom links) would be? The bones would end up being roughly 39" (front mount to rear mount). The longest upper bar I could fit would be 18" long, set on a max 30* angle from axle mount to frame mount for a total of 60* bwtween the two upper links. The other question is if it is important to have the front mount of the upper link in line with imaginary line between the rear mount of the upper link and the front mount of the lower link as viewed from above? The last question is whether the wishbones from a 1941 ford front end are strong enough to act as the lower bar in a 4 bar suspension? Thanks in advance for your responses!!
i may be misisng something or not understanding the question.. in which case you can probably disregard my post... if you do a 3 link.. i would think the 2 lower links would run parallel to the frame as close to the frame as you could safely go.. and the 3rd link would go driver side mount to the frame to passenger side of axle the longer the link the better in front of the axle. but you may be talking about a total diffrent setup. someone please correct me if im wrong.. john
Sorry, I've seen that setup for a drag racing application. I was talking about a 3rd link used as a torque arm with the two lower links (wishbones) used as locators. Thanks though!
are you trying to keep it traditional? if so i would check out the so ca speed shop catalog and what pete c suggest.
I'm guessing if you have to move that top link away from centre you may be best to run 2 top links, i.e. a 4 link set up. Without seeing your rear end I can't say, but couldn't you make a mount for the centred top link that bolts onto the centre section using the bolts that mate the centre with the housing?
With a 4-link you want the length of the upper and lower bars to be equal run from front-to-rear, when viewed from the side or above, or as close as you can get it. On a parallel 4-link, all four bars would be the same length. On a triangulated 4-bar, the upper and lower bars would be of different lengths. When viewed from the side, both the upper and lower bars would span the same distance, from front-to-rear. When you have unequal length bars (or unequal run) you introduce pinion angle change when the suspension cycles. A small amount, like an inch or two, is ok, but too much is not. A 39" set of lower bars, coupled with a set of 18" upper bars, set at a 60º angle to the axle, would introduce an unacceptable level of pinion angle change on suspension cycle. An 18" bar, at a 60º angle has a 15.588" run.
Suicidedoors.com great builder kits and links. High quality stuff. But for the purest traditionals ya there not into it..
Split bones and a torque arm are a good way to go. You just have to figure out how to get the torque arm attached to the axle, as close to the center as possible. Is the driveshaft yoke on the differential in the center of the axle assembly, or off to one side a little?
The Jalopy Journal
