Gunnar's axle beef insert-fab and install

[gunnar]

So this is the easy way(sort of) to do this mod. There is a catch to what tube I'm using however, this size tube is too big. The Chromoly tube I got from McMaster-Carr measures .438 OD, this idea would work much better with a .433 OD tube. Although the axle can be bolted together, the fit on the C's are very tight, and the bearings on the end of the housing are in my opinion not tight enough. They don't fall out, and the C's seem to provide enough "squeeze to hold them in, but I really don't think these should be sold until proper tubing is located.

McMaster tube P/N 89955K75 .438" OD X .272" ID

I will continue anyway, just to show the process.

First, I measured how long I would need the tubes, anywhere from 50 to 51 mm is long enough. You dont want to touch the diff carrier bearings, but you do want to get it long enough so the screws going through the holes near the diff put pressure on the tube to hold it:



Here is a pic of each end of the tube, the bearing seat is on the right, the central portion of the tube is turned down a few tenths of a millimeter, leaving a small ridge for outer race contact:



Here is the plastic bearing seat that must be removed:



Bearing seat removed and ready for install. Take care not to damage the inner wall the bearing sits against:



Here is a closeup of the space needed between the tube and the diff bearing. This tube is about 50.3mm long, a 51mm tube will be closer to the bearing, but will just fit. Anywhere from 50 to 51mm will work:



Using either half of the housing, place both tubes in so the bearing is sticking out a small amount:



Loosely bolt the housing halves together using the four diff bolts:



place a bearing in the end of the housing, and push down on a flat surface so the bearing pushes the tube in, and the bearing is flush with the end of the housing:



After both tubes are put into the right position, tighten the diff bolts, and install the C's onto the housing:



Remove the bearings, and using a #39 or 2.5mm bit, drill through the hole in the housing and into the tube. Take great care to keep the drill straight and square:



Holes drilled:



Tap to 3mm:



Screws installed:




After the C's are attched, there is a small gap in the housing from using these larger tubes:



In order to reduce this gap, and to provide more strength, two more holes will be drilled for screws. I marked a spot for the front half hole:



Rear half hole already drilled:



Tap both holes:



Completed assembly. Use M3X6 screws for these central holes:




Pull everything apart and clean up any chips remaining:



Close up of C holes:

[Code454]

This is a great idea i have thought about doing similar idea but just with aluminum but this would be way stronger definetly interesting and it will work for sure its also a good way to get some more weight in your diffs and not in the tires
Cody

[gunnar]

Here is the weight of both tubes, 1.7 oz. These are undrilled, so the actual weight will be slightly lighter:

[Code454]

thats a good amount to take off your tires

[C*H*U*D]

Originally Posted by Code454

thats a good amount to take off your tires

I'm thinking the same thing....I'm going to do this mod to my 1.9" scaler so that I don't have to add so much to the wheels. I really don't want to try and stuff so much lead in there when the tires are small to begin with.

Thanks Scott! I'll be firing up the lathe next week

[Szczerba]

great idea!

[Sharkey]

good work, and a great idea. ive got some solid 1/2" aluminum and access to a lathe, might have to give it a go.

[JLF]

Great mod idea!

Just when I think everything has been thought of already... Comes something Ive never seen before!!!

[Slyp Dawg]

I haven't heard of anyone having axle breakages, but then again I haven't been following it at all. still, I might give this a shot just to get some more weight on the axles, and the extra beef never hurt anyone (who wasn't looking for less unsprung weight, anyway)

[Manning]

That should make them bombproof. Excellent thinking and execution. I'd do this mod if I had a lathe......

But, I just got done doing something similar, a ghetto fab version. Had some K&S brass tubing in .438 or 7/16" laying around, and cut pieces to fit between the bearing seat that you dremeled out, and the rib near the diff bearing. IIRC, one side was 28mm, the other was 33. Should strengthen it a bit. We'll see.

[gunnar]

Originally Posted by Sharkey

good work, and a great idea. ive got some solid 1/2" aluminum and access to a lathe, might have to give it a go.

I would make the center hole .25-.27 At least one guy had some problems using thinner wall aluminium.

Originally Posted by JLF

Great mod idea!

Just when I think everything has been thought of already... Comes something Ive never seen before!!!

I did a different version on my FF-4, but that was for 6X12 bearings and Super 300 axles.

Originally Posted by Slyp Dawg

I haven't heard of anyone having axle breakages, but then again I haven't been following it at all. still, I might give this a shot just to get some more weight on the axles, and the extra beef never hurt anyone (who wasn't looking for less unsprung weight, anyway)

I've broken 5 housings myself, and have seen many others in different posts here. It usually happens from binds.

[gunnar]

Originally Posted by Manning

That should make them bombproof. Excellent thinking and execution. I'd do this mod if I had a lathe......

But, I just got done doing something similar, a ghetto fab version. Had some K&S brass tubing in .438 or 7/16" laying around, and cut pieces to fit between the bearing seat that you dremeled out, and the rib near the diff bearing. IIRC, one side was 28mm, the other was 33. Should strengthen it a bit. We'll see.

Your mod might have a small amount of tube under the C, but to really strengthen it, the C should be bolted into metal.

[Manning]

Originally Posted by gunnar

Your mod might have a small amount of tube under the C, but to really strengthen it, the C should be bolted into metal.

There's about 3.5mm overlap. Hopefully that's enough to help a bit. It's enough for me to rationalize a strength increase proportional to the effort involved.

Agreed, your method is much better, but I'm limited to a hacksaw, belt sander and drill press. I just might give it a go using aluminum tubing since it's easier to work with.

[mr.freeze]

excellent tech gunner
thank you for sharing

[rmdesignworks]

Originally Posted by gunnar

Your mod might have a small amount of tube under the C, but to really strengthen it, the C should be bolted into metal.

Ive been following htis thread from the start,,great tech idea. What about bedding the tube inside the housing like you do with a rifle barrel in a rifle stock?

[Jeep-Power]

wow-- nice work Gunnar.

It goes without saying that the stock Axial inner C mounts are less than marginal. Something with that much torque on it needs more than 2 screws that thread into plastic.

In taking this to the next level, how about cutting off the plastic OEM inner knuckle flange mount (on the axle) and turning down some tube that will replace it and fit in the axle housing(as yours does)? Retaining it in the plastic housing with a few screws, through the plastic housing tubes, that are tapped into the new metal tube will work. This will provide a metal outer bearing housing and an all metal sleeve/mount for the inner C. Basically the same inner design as yours with a larger diameter end that will hold the outer axle bearing & inner C.

It will, of course, require tube stock that ideally has an OD close to the plastic axles' inner-c mounting flange diameter. The section that inserts into the plastic housing will have to be turned down to the 0.433 you mentioned.

just a thought, does that make sense?

[gunnar]

Originally Posted by Jeep-Power

wow-- nice work Gunnar.

It goes without saying that the stock Axial inner C mounts are less than marginal. Something with that much torque on it needs more than 2 screws that thread into plastic.

In taking this to the next level, how about cutting off the plastic OEM inner knuckle flange mount (on the axle) and turning down some tube that will replace it and fit in the axle housing(as yours does)? Retaining it in the plastic housing with a few screws, through the plastic housing tubes, that are tapped into the new metal tube will work. This will provide a metal outer bearing housing and an all metal sleeve/mount for the inner C. Basically the same inner design as yours with a larger diameter end that will hold the outer axle bearing & inner C.

It will, of course, require tube stock that ideally has an OD close to the plastic axles' inner-c mounting flange diameter. The section that inserts into the plastic housing will have to be turned down to the 0.433 you mentioned.

just a thought, does that make sense?

Oh, you mean like this








Super 300's, 6x12 outer bearings, infinite clocking options, no flex at all.

[Jeep-Power]

yeah, just like that! NICE~

Originally Posted by gunnar

Oh, you mean like this







Super 300's, 6x12 outer bearings, infinite clocking options, no flex at all.

[JeremyH]

Very nice work Gunnar!

[Code454]

Oh now that is beef how much does that weigh for the axle?