Starting a project need some help Quadra track AMC 20

I am building an amc quadratrac amc 20 rear out of a standard AMC 20 rear....I know most people will say "why would you do that!".....just humor me.. I will need very specific measurements from the diff housing to the brake flange to know the proper length I will need to make my new axle tubes. Pictures would be awesome if you have the time. Thank you in advance for the help!!

 

I don't have the measurement you need, but will follow your progress with interest. I have installed a TH400/quadratrac in a coil sprung Land Rover project and uses the Rover offset rear axle. I think the measerment you need is very close to the same offset as a narrow D44 used with a D18 T/C in our early CJs. I believe the T/C offset for both the D18 and 20, and the BW quadratrac are the same.
-Donny

 

Thanks Keys5a, I will post pictures and Info As I make progress. Yeah I'm sure someone on here has the measurements I need or can at least point me in the right direction. There is a guy on ebay selling a housing for a q-trac amc 20.....I suppose I could see if he would give me the measurement. The 20 I have now is centered but in nice shape....new brakes/posi...etc. And I just picked up a super cheap set of brand new I piece q trac axles. Once I get the diff done I can run a d18 t-case with a warn overdrive (the reason for this project)

 

Ok...so a very kind eBay member that was selling a q- trac rear sent me some measurements. (from diff housing to outside of brake flange) He said Pass side was 9.000" and driver side was 21.250. Can anyone confirm or deny this??? how much play do I have with the splines and how far they can slide into the spider gears.

 

I'll crawl under mine tomorrow and measure it unless someone beats me to it

 

That would be awesome! Thank you so much!

 

I hope you are retubing this with at LEAST 5/16" wall dom tube. Otherwise you are asking for at least one bent tube.
I've re-tubed a bunch of 20's because people spent money on them then mangled the tubes and carriers. The tubes done only bend upwards but can bend forward when crawling up something then sliding backward. Watched it happen.
Plus the carrier is very thin where the tubes are pressed in. I've seen the carrier stretched and distorted bad enough where even with new tubes they could not be trued. Don't even get me started on the small axle bearings and crush sleeve for pinion bearing preload.
I know you have parts for it. At least upgrade to heavier axle tubes.

 

Nick.... totally believe you and have heard the same from many others. But I just don't get how me and my buddy been beating the tar out of out 20's for over 15 years. And mine had a v8 35's and a welded diff and 2-piece axles. I guess we were just lucky. M thoughts For this project are..........( I know you probably wont like this but I am just going to cut the tubes and sleeve them with a tube, heaviest I can use without rubbing the axle on the inside. Once its welded in I'm going to build a truss. I have alloy usa one piece axles and new bearings/seals & stuff to put back in. This is more of a daily driver with 29" tires rather than my wheeling rig, so I anticipate it lasting at least another 15 years before I have to do something else to it or replace it.

 

Couldn't get really great pictures as it's sitting under a 61 Wagon body in the back corner of the shop.





Had to take measurements from the back of the flange to the housing as I have backing plates etc already installed but I came up with 8.5" on the right, 21" on the left so seems to coincide with the measurements you got given the thickness of the flange.

 

Awesome! Thank you so much for the info and the pictures. It is very helpful. My axles should be here tomorrow. I hope to start working on it ASAP.

 

Well....I got the rear out and disassembled.....As you can see, I don't have much extra room, so the wife's car must sit out for awhile...the most annoying part was pulling the hubs of to remove the backing plates. After that everything went smoothly. My axles came today and now I'm almost done. I was actually really surprised at how heavy the axle tubes were. It took a long time to cut through them with the tubing cutter but the end result was worth the time. (very nice cuts) This is actually starting to seem too easy.........The amount I had to cut of one side to give me the correct length was the exact amount I needed to make the other side long enough. It worked out really well. I sleeved the entire axle tube with 3/16 wall tubing. I thought this would strengthen things and help my keep everything straight also. While I had the welder out I welded the tubes to the housing to eliminate the "spun tube" syndrome these axles are prone to having. I think it should be pretty stout when I'm done. I was also thinking about building a truss, but I'm not too sure I need one.


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might as well truss it. you already went this far.

 

I like your plan. Is this on straight? Now do you fill it in with weld and grind smooth?

I think the M20 gets a somewhat bum rap on the strength of the axle. it seems like if you use sense and it is built it for what you use it for, it will last fine. But add lots of power, big tires, etc and they just were not made for it.

 

Yeah It was just tacked temporarily... I will true everything up and weld all the way around. By using the tubing cutter and the fact that the inner sleeve had to be pressed in it kinda naturally wants to go together nicely. I will probably not grind the weld smooth unless It interferes with the U-bolts or perches. If had a good Dana 44 with the correct gears and offset I would run it, but I don't. I have tons of parts for amc20's and one thing I don't have is horse power and big tire so I think it will be fine.

 

Has anyone ever put grease fitting on the axle to lube the bearings?

 

Tapered axle 44 housings came stock with them.

 

cool! So , would you recommend adding them to an amc 20?

 

I wouldn't. Too much chance forcing grease past the seals creating various other problems.
I hope you plan on using some kind of alignment bar and pucks to align the tubes/housing ends/axles with the bearing saddles in the carrier.

 

Yeah I wondered the same thing about pushing grease. Not sure what I'm going to do yet. I really done feel like pulling it apart to grease it but I don't put that many miles on it so it won't need it that often. And as far as pucks and bars go.....don't worry, I have a top secret method that will align everything perfectly!

 

I've been building custom axle housings for 21 plus years with and without proper equipment. There are only a few ways to get it right so the differential side gears, pinion gears and shaft, axle bearings, axle shaft, and housing hold up.