48/49 B1B - cherokee rear axle swap

[Frank's 49]

I have seen several comments/posts discussing installing a jeep rear axle in a B1B.  My questions are "just how difficult is it", It welding required, or is it "bolt on", Do I need to modify the drive shaft, and will the brake lines connect-or do I have modify something there also?  Can anyone point me to more specific procedures on this forum? 

[NiftyFifty]

It's not a real hard job, but Welding is absolutely necessary to weld on the new spring perches, you will very likely need to add a piece of line to plumb in the new distribution block, and as far as I know 1/2 tons don't(??) need to modify the driveshaft, but 3/4 and up I know you do.

 

should be lots of topics on this subject with a forum search, not sure anyone laid it out in step by step or not though

[Jeff Balazs]

On my 52 B-3-C (116" WB) the driveshaft was a direct fit up. Since yours is an earlier model the rear U-joint may not fit as it is.

Jeff

[Frank's 49]

Thanks for the replies.  

 

[wayfarer]

The process for the truck should follow the same lines as the car...

 

[bosworth]

Frank;

I changed the rear axle on my 52 B3B to a 96 Jeep Cherokee axle with a 3.55 gear ratio.  I was able to find 1.75" perches on line and had to locate square "U" bolts. perches came from a Jeep web site, U bolts from Stengelbros.net I used 5U116S, but found them to be a little tight, had to do a little grinding on the purches to get them to fit. I used the origional bottom plates which are also the shock mounts.   I followed advice found on this site for finding and properly positionsing the perches.  Cutting the old purches off in not very difficult,  I then ground the welds down smooth.  Be careful not to grind to much, the axle tube isn't all that thick.  Positioning the new purches is fairly critical.  Before I cut the old ones off I determined the angle of the pinion shaft.   Once I had the purches properly located I tack welded them in place.  I had a pro welder complete the weld as I didn't trust my welding skills for this critical weld.  I found that the drive shaft and universal joints matched up perfectly with the Jeep Dana axle.

[NiftyFifty]

If you have a local spring shop, most of them can just make you new U bolts, that's what I had done when I swapped in mine from a 91 YJ, and they had the spring perches in stock too, and I don't love by a metropolis by any means...more like a 2 horse town.

[Darkrider]

Hmmm thought it was a direct bolt up...What is the spring pad width on these trucks then? I am also considering an axle swap to my one ton to a newer one ton axle to gain better gearing and e brake especially if i end up doing an automatic transmission swap.

[wayfarer]

...direct swap between two completely different vehicles that are 50 years apart...?

It has been reported by one of the forum members that the rear axle wms to wms is 62¼".

I have a list (in no way is it complete...!) on my website of various axle measurements. http://www.qualityengineeredcomponents.com/?page_id=1023

[bergy]

In a previous postI had mentioned-I think...?..that a neighbor had a 99 keep Cherokee.I was unsure of axle width compared to my 53 b 1/2 ton. Looks like it will work.So,now my question is-with the 218 engine ,original4 speed- with that new rear -what kind of road speed with the 6.50 x16 tires .? Thanks in advance.

 

 

 

[wayfarer]

As listed on my website, this is my favorite number-crunching link:

http://ctny.audiworld.com/mark/s4/gears/gear_calc.html

[Darkrider]

Does anyone actually know what the ratios are and what model the stock 4 speed transmission is?

[lonejacklarry]

I'm a little confused (OK, a lot confused) about axle widths.  According to the charts listed my '54 Dodge pickup should be 62 1/4" WSM.  Also, the often cited Explorer is listed as 59 1/2" WSM.  That means that each side will be 1 3/8" narrow with the Explorer.  The Cherokee is about 1/2" wider WSM.

How does one handle the difference?  Wheel offset?  Spacers?   Or let it go as it is close enough?

Thanks,
Larry

 

[wayfarer]

If you are keeping the stock wheels then look at the amount of clearance behind the tire/wheel and decide if the loss/gain will be a problem.

[lonejacklarry]

21 hours ago, wayfarer said:

If you are keeping the stock wheels then look at the amount of clearance behind the tire/wheel and decide if the loss/gain will be a problem.

I'm going to have tubeless tire wheels that are stock looking with stock hubcaps.  They are going to be custom made so should I handle the loss/gain with offset or a slightly wider rear wheel or does it make a real difference?  I'm thinking same offset but with a wider wheel assuming the clearance is there.

[wayfarer]

You have plenty of options if you are making new wheels and the 'hoop' should be chosen based on the potential tire sizes. For future reference, I would however, check the clearance with a stock wheel so that you'll know what you have if you needed to use one.  Personally, I like the look that a fair amount of offset provides.

Also, keep in mind that depending on the tire used on any particular hoop width, you will have some sidewall extending past the rim.

[lonejacklarry]

Thanks very much for the advice!