Seeking professional or experienced help here... I've got a banjo rear end thats open drive. I have the wishbones split but still being mounted in the general area of their original location towards the center of the car. They will -not- be mounting directly in line with the front U-joint. I just can't make that work with what I have. Of course I will be adding a torque arm. And the questions begin.... 1) Does the arm need to be mounted solid to the rear end. Or can I put a rubber bushing at both ends? 2) Assuming I can use a rubber bushing at the rear mount on the axle, does the pivot need to be directly in line with the rear u-joint? 3) Because the front of the wishbones do not mount in line with the front u-joint, should the front mount of my torque arm intersect with the front u-joint, or with where the wishbones are mounted?
It can be bushed at both ends. A threaded end will help to set the pinion angle. It can be mounted anywhere within reason on the rear. The front end should be inline with the ends of the bones to eleminate pinion angle change. I would mount the torque arm end to the top of the right bone. The arm should go on the right. There are reasons to do it this way.
I used Urethane bushings, they deflect a bunch. I think a rubber bushing at one end and a heim at the other would be fine, or just make both bushings outta a harder Durometer material UMHW perhaps. Pivot should be higher than the Ujoint to triangulate the system, mine was 5 or 6" higher My arm was as long as the Wishbones and mounted as closely to the bones as in "if I ran a broomstick through the rodends from right to left it would also skewer the rod end on the front of the TA"
Ok.......makes sense. Here's a stupid question...the original and uneducated plan was to mount the rear of the bones solid to the rear end. I know that that definitely does NOT work if you mount the front of the bones out on the framerail, and causes the rear end to twist. However, since my bones are mounting very close together at the front, will there be an issue solid mounting the bones to the rear end? Or am I writing a death wish, and should absolutely make that rear mount non-solid?
They can be mounted solid but it is no advantage. You loose the ability to tune the pinion angle to stop vibration. I would use the heavy 4-bar type ends.
I thought the pinion angle on the banjo was set by heating the bones and moving them up to the mounts that you have.
The advantage is I don't have to re-fab the ends of the wishbones and can just make a few plates to weld on the rear end to bolt the bones to. I know pinion angle is going to be finalized once it's all welded on, which isn't a big deal because all these brackets will be tacked until the motor is in. My main concern with all of this stuff is I don't want anything to bind or bend. *edit* What I mean by solid mount is in the attached crude illustration....I think you think I'm talking about a solid rod end instead of adjustable. Here's another one....panhard bar with this setup, yes or no?
great topic. there some really good and lengthy past posts about this same thing. i think this is the link to one of those posts: http://www.jalopyjournal.com/forum/showthread.php?t=184446&highlight=torque+arm+wishbones i'm glad to see it come up again because i'm in the same boat. my plan was to use a tie rod with heim joints at each end, mounted to a bracket on the rear end center section and at the front x-member near the wishbone mount. does anyone see a problem with using heim joints at both ends? why is it recommended that the torque arm be mounted on the right side? is it because of the way the rear end wants to twist under load? thanks.
Eric, if you do it like the drawing you will probably need a panhard bar. Sure you can get away with it, but you are probably going to get some side to side sway in the spring shackles, if you are using a transverse spring. If you'll notice, all the Pete & Jakes style ladder bar set-ups are meant to incorporate a panhard bar. What you have drawn out is essentally the same set-up, but with an added link (torque arm) to absorb the strain that would normally be put on the wishbones under launch. Add the panhard bar and set your pinion angle correctly before you weld on the wishbone brackets, and I think you'll be fine.
I kinda thought it was like a ladder bar setup but that I might be missing something. Part of me wanted to just use a ladder bar but I don't think I'd like the look with everything exposed. I'm using an A rear spring. Panhard bar it is. I think I've got the room... Thanks again for the advice guys. Off to the garage...
My take on the torque arm... It's all rigid mounted and tied together up front with a Model A wishbone ball. If you want any more details, let me know. Neal
With Neals way OR by mounting the fronts of the wishbone arms to the torque arm, you will eliminate all conflict between different parts of you suspension. All rear mounts can be hard, the single front moving joint can be bushed, adjustments can be provided as with some types of front hairpins to allow adjustment of pinion angle. Why have 2 or three front pivots?
. Here is another shot... The torque arm is made out of the end of a Model T axle and the tube from a Model A front wishbone. The radius rods were made from 35-36 rear forgings, 40 front wishbone tubes (they are 3/16" wall), and a Model A wishone yoke and ball to tie it all together. Hope that helps. Neal
I'd seen yours before Neal and really like it. I probably should have followed suit with the model A pivot, but live and learn. I will mount the torque arm to the right wishbone, seems like a pretty logical place. And there will really be no need for bushings....I will make the TA bolt on, for ease of assembly. Thanks again for the reassurance. Here's what it looks like now. Rear mounts tacked, and there will be two more plates on the inside of the bones.
The Jalopy Journal
