So like everyone I am collecting parts for a model A hot rod. I scored a complete 36 rear end with 39 brakes comete with the torque tube and radius rods. Are the 36 radius rods too long to work in a model A frame? If so, it doesnt seem easy to use a different radius rod because of those angled radius rod mounts on the bells. Tried searching but cant find the answer.
I bet you can. Was just reading "How to build an early hotrod frame" by brianangus. Good stuff! "35-36 rear wishbones are prized for their integral spring mounting brackets"
If you intend using a torque tube, it will need to be cut and shortened.... the radius rods front mount will need to be relocated and as the resulting angle will be different you will also need to revise those brackets on the diff bells. 36 are too long to attach back to the torque tube so will need altering . If you are intending splitting the bones the forward attachment points will be changed for a joint of some kind and the angle of the mounts on the bells will still have to be changed... The radius rods will need strengthening if you are intending using an open drive and once the angle is changed the spring behind mounts will not be parallel to attach a spring...but l will****ume you intend adding spring over mounts on top of the housing for your AV8.
I extended my frame 7 and a half inches to accomadate the spring behind rear. Used the model A spring.
Want to use torque tube. Therefore it seems like '36 rear and bones would be a lot of work. Maybe I will pull out the driveshaft and sell off the rest.
Maybe I will pick up one of those original 1932 ford frames that are always clogging up the craigslist classifieds. Then maybe I could use this rear.
The driveshaft is in it? A funny looking tube pinched at the ends? Let me know if you want to cut it loose.
The driveshaft is in it. If I sell the rear end I'd like to keep the driveshaft and definitely the brakes. OJ, I do need to wait a bit before parting with it because there is a chance I could pick up a '32 frame to use with this rear. Won't know for a little while though.
Scott., Just a note, my car has a '32 frame and a '36 rear, (correction, Model A spring) and the '36 wishbones, without changing the spring mounts at all. A Model A rear crossmember was used, moved back to get the rear end to be in the center of the rear wheel opening. The effect is that the car gets lowered about 5-6 inches, in the rear. With a Model A front crossmember, 4 inch dropped front axle and reverse eye front spring you get an even lowering. The driveshaft needs to be shortened and the torque tube the same. You will need to set it up and measure your particular measurement. Also, you can use the hot lick '36 wishbones by just moving the mount on the shortened driveshaft the correct amount. Just for info, nothing is cast in stone!
Scott, This is what it looks like with same diameter wheels front and back. You will get all the rake you want from bigs and littles.
Thanks Tony. So either a 32 frame or I am going to move this piece along to someone else. Did you need a spacer or something for the 36 spring in the A crossmember? Because of the higher arch of the A crossmember and the flatter 36 spring?
Probably got it mostly right if the OP was going to use a 32 frame, but his question was how to fit a 36 rear into a Model A frame...i.e a real AV8!
Hey guys, I think I have a correction! It's been so long I think I have some CRS going on! I just went out to look and Scott you are right! It looks like we used a Model A spring! It has the arched center. So yes it fits right in and yes it fits the '36 wishbone spring mounts. Sorry for the forgetfulness!
Right. So the real question I guess would be if I mount A style hangers to the axle bells and shorten the torque tube an appropriate amount, will the 36 radius rods work as they are or need to be shortened?
You will need to shorten the torque tube, the easiest and logical place is at/near the rear flange where the tube is parallel, so that means the front mount for the radius rods will need moving, I am pretty sure that the radius rods will be too long . However the 36 rear axle is the best width for the A ( later ( 42-28), wider rear ends leave a big gap between the body and the inside of the wheels), you said you want to keep the brakes, so I****ume once again you are wanting to run mechanical brakes. If this is not the case you may well be better off selling the complete 36 rear and finding a 39 with the same wide five stud pattern, same overall width and hydraulic brakes...and much shorter and stronger radius rods. Also you get the later style axles and carrier/differential gears. The 36 radius rods are more sought after for 32 up frames with split rods and spring behind ... but as I said before without strengthening they are not strong enough for use with an open rear as some people have tried.
Hey Scott, Not to take advantage of a situation, but if you need them I have a very nice set of wide 5 wheels on here right now.
I am going to pick up some later hubs and drums to run standard wheels but thanks for letting me know. Hey you could buy my drums and have a set-up that could swap right on to someones 40-41 brakes! [emoji3]
There are a couple of ways to go here. As I see it, you could extend the frame, to use the spring behind 36 axle and spring mounts. This would give you a lower stance and a better ride,but require a slight pie cut on the radius arms to bring them in line with the torque tube mount, then shorten them, or you could cut the arms, at where the tube meets the forging and replace them with 46-48 arms cut to the appropriate length . The 46-48 arms are shorter and have a greater angle where they meet the torque tube. If the 36 arms are used, that angle, being less, causes a misalignment in the torque tube mount. The second is to grind the radius arm mounts off of the axle housings (bells) and use un-modified 46-48 radius arms, bolted to the backing plate fasteners as intended. You could also leave the radius arm mounts alone if you don't mind looking at them. We chose the latter scenario when we built a friends A sedan, left the frame alone, welded spring mounts on top of the axle and mounted it in its factory position, using 46-48 radius arms and a shortened torque tube/shaft. The 35-36 drive shaft is not easily shortened due to its double tapered tube design. A 33/34 is a straight tube and much easier, or a later solid shaft could be shortened as well. Put the radius arm mount where it needs to be on the shortened torque tube and its done.
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