35 Rear Axle

[LeroyM]

Hey guys,

I have a guy who has a 35 rear axle that I'm thinking about getting for my Model A since I'm collecting parts for a V8 conversion and want a heavier rear axle. The 35 rear axle doesn't have the radius rods on it though. My question is can I use Model A radius rods on the 35 rear axle?

Any help would be appreciated.

Thanks.

[av8paul]

Originally Posted by LeroyM

Hey guys,

I have a guy who has a 35 rear axle that I'm thinking about getting for my Model A since I'm collecting parts for a V8 conversion and want a heavier rear axle. The 35 rear axle doesn't have the radius rods on it though. My question is can I use Model A radius rods on the 35 rear axle?

Any help would be appreciated.

Thanks.

Don't use the A wishbones. Keep looking for 35,6 and early '37 bones. The A's are too weak.

[Karl Wolf]

You can also use 46-48, They are robust and shorter... Karl

[LeroyM]

I'll look for a set but will the Model A radius rods bolt up? I have a spare set of Model A radius rods and thought if they bolted up I could try and reinforce them some how.

[hotrod30a]

I think you would be better off finding a pair of 35-36 bones. They are stronger and less hassle than model A bones. There is a reason why they ditched the A bones back in the day and went with the later model suspension parts.

[thunderbirdesq]

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You don't state whether you're planning on using a torque tube or converting to open drive. If you're planning an open drive conversion, you should DEFINITELY look for later radius rods and beef them up or consider adding a torque arm. NONE of them were designed to take the rotational forces of locating a rear axle. That was a job for the torque tube.

Also, not sure if you're planning on welding on new spring perches on top of the axle like an A rear, or moving the rear crossmember back to use a spring behind setup, but the '35-'36 radius rods also contain the perches for those rears.

One thing is for sure, don't bother with the A radius rods, they are just folded sheet metal.

[Flathead Fever]

‘35-‘36 rear radius rods have the spring hangers built into them, there are no hangers on the rearend housings. No other radius rods will work because you won’t have any spring hangers. A lot of times the ‘35-’36 radius rods are missing because they are worth more than the whole rearend. They make brackets that weld to Ford 8-inch and 9-inch rearends that except the ‘35-‘36 radius rods so you can run a buggy spring with a modern rearend. It’s a neat way to give a modern rearend a somewhat more traditional appearance. I Have seen these radius rods sell for $400.00 on ebay You need to inspect them for severe wear in the shackle bushing holes before buying a pair.
　
The spring is centered over the rearend on a Model A, on later rearends the spring is behind the housings so it will not line up with the Model A cross member. I’m not sure what the cure is for that problem. I have seen some V8 rearends with the Model A spring hangers welded to the axle housings.

[Andy]

Personally, I would get some spring hangers made that would bolt to the flanges on the housing ends so as not to warp anything. The 46-48 bones are a good choice and would not interfere with the spring hangers. Years ago I built some hangers to put a 36 rear under a 32 using the stock 32 spring. The new hangers just bolted on. the car has been on the road for maybe 15 years.

[LeroyM]

I'm planning on cutting off a set of Model A spring hangers and bolting them to the 35 axle and then welding them on so that I can have it bolt up to the Model A crossmember and also use the Model A shocks in the rear. I'm also keeping the torque tube since it's closed drive behind the 39 transmission I have.

What I want to know is will the Model A bolt pattern for the radius rods bolt to the 35 axle? Worse case I could split the seams of the Model A radius rods and reinforce them with new steel in the center and weld it back up if I had to. Has anyone done this?

[LeroyM]

I went out to the garage and did a quick measurement on the distance between the bolts on the radius rods where they bolt the the axle. I come up with about 3 1/4" to 3 1/2" between the center of the bolt heads. I'm thinking the radius rods should work because guys have bolted later style hydraulic backing plates to the Model A's and still used the Model A radius rods right?

[thunderbirdesq]

I don't think many folks bother with reinforcing A rods because later, stronger rods are still quite plentiful and cheap. Heck, I just sold a pair of late 40's ones for $50 not too long ago.

I'm not sure if the A rods will bolt up or not, I've never messed with A rears much, other than yanking them entirely for a V8 model.

[LeroyM]

If I can find a set of later radius rods I''ll get them but I'm trying to decide If I should get the 35 rear or not since it doesn't have the radius rods on it. 35 to 41 rears are pretty much the same right other then the carrier bearing in the 38 and up?

[Bassman/NZ]

Your problem is not so much worrying about radius rods, that can be got around in several different ways, but rather has this rear got a ratio that will suit you?

[Charlie Stephens]

I think the later rear end will be too wide if you run fenders. Better measure.

Charlie Stephens

[Andy]

The A radius rods will bolt on and are fine for the app. After all, they are stock to the car!!!
The 35 rear is the same strength and has the supported pinion as the later rears.
The torque tube and driveshaft are different and will not interchange with you A stuff. The banjo center is longer on the later rears so you can't just shorten the 35 to match the A length. I think it is a 1/2" diff. The A driveshaft can have a later coupling welded in to match the pinion shaft. In a 35, it will be 10 spline so you would need the end off the 35 shaft.
The 35 and 38 and 40 are all the same width. 42-48 are wider and don't fit an A as well.
I would just bolt on the spring hangers so not to secerw up the seal in the housing or warp the housing. The seals are a PITA to change.

[LeroyM]

I haven't seen the 35 rear yet but the guy tells me that the driveshaft and torque tube is still there with it and that it still has gear oil in the banjo. I'm told that it came from a car, what's the chance of the ratio being 3.54 or 3.78?

I know that the later rears have longer torque tubes and driveshaft but why wouldn't I be able to just shorten the 35 torque tube and driveshaft to the the Model A driveshaft and torque tube length?

[thunderbirdesq]

Most likely a 4.11, possibly 3.78.

The '35 driveshaft is a tapered tubular type, much better suited to building headers out of than shortening. If you want to use that Torque tube, you'll need to use a '34 straight tubular driveshaft and shorten it. I would just use a shortened 37+ TT and solid driveshaft.

[Andy]

As stated, You can shorten and use the A shaft by adding the 35 splined section. They are tubular like a 32-34 shaft. Shorten the 35 torque tube or add the 35 end and shorten the A tube. The A tube will not bolt to the 35 center. The A uses a different attachment to the trans if you are keeping the A trans.

[Jason M.]

I chose a 35/36 diff for my AV8. I used 46/48 radius rods, they where very easy to adjust and required only a minor heat and tweak to align with the 34 torque tube. 35/36 and 37/41 rods will require significant shortening where the 46/48 parts are the perfect length and require no other mods than the heat and tweak. Plus they are CHEAP and plentiful.

This photo is BEFORE the rods where modified and you can see how they only need a little work. The rods where heated and bent upwards and out to align with the radius rod lug which was also relocated to match the location of the radius rod eyes.

[LeroyM]

I went and got the 35 rear today. Was about a 2 hour drive each way. I scratched off some of the grease on the bottom and the number on the rib is 9 3 7. I believe that is a 4.11 ratio?

Does anyone know what most of the Model A rear ratio's were?