Building a custom hybrid front axle

Building a custom XJ front end.
Hybrid Dana30/Dana 44 axle, locking hubs, and high clearance steering.


Part 1 - What and Why?

OK - here's how this whole mess came about.

I wasn't happy with handling of my XJ with the lift somewhere in the 7 to 8" range. Control arm angles are too steep, and the stock steering is way past its safe and effective limits. Here's the evidence.








There were also other problems. Despite setting the front CV shaft angles properly, with the new Detroit Locker up front, the vibrations were so bad that both my mirrors vibrated loose and fell off, smashing to pieces while I was driving. Not good!. Also, with the pinion rotated up, I had almost zero caster, and this made the steering worse. Imagine steep control arm angles, steep steering linkage angles, a full time locker, zero castor, not to mention the worn tie rod ends, and 2 badly worn ball joints!! Something had to be done. I decided I needed:

1) Locking hubs

2) New stronger steering linkage with improved angles

3) To address the suspension geometry

4) Some way to regain caster while retaining proper driveshaft angles.

But how to get all this, and at what cost? Options include a custom built front axle, some kind of long arm coil suspension, Warn hub conversion, and more. Ultimately I rejected all of these options for the following reasons:

1) I'm cheap, and all of these would run into the thousands of dollars.

2) I like to design and build my own stuff, and I like to document it too.

3) I had just installed the 4.56 gears and Detroit Locker, which cost me a pile, and I hadn't even wheeled them yet. The climate where I live is such that there would be almost zero chance of my selling them and regaining my money, or anything like it, and besides, I wasn't ready for the emotional cost of dumping a mod I had long wished for, finally gotten, and never really tried out.

So - that left me having to work with what I had, but getting what I wanted, and all at a reasonable cost, and labour I could do myself.....easy eh?

After much research and contemplation, the Jeep Wizard himself came to my rescue with inspiration and knowledge. Paul Weitlauf was an enormous help, and his very own XJ D30 upgrade formed the basis on which I would base my plan. You can read his article at: http://www.outdoorwire.com/4x4/jeep/tech/axle/xjupgrades/index.htm

Here's the plan:

1) Remove the XJ's steering knuckles, and replace with early Chevy 1/2 ton 4x4 (K10) open knuckle Dana 44 parts - this would give me locking hubs and the basis for high clearance steering.

2) Build my own high clearance steering linkage from DOM tubing and parts sourced from the local race shop, R&D Performance.

The issues with this plan are:

1) You can't just bolt the D44 parts to the XJs knuckle yokes, you first have to cut off the XJ's knuckle yokes and replace them with a knuckle yoke that will accept the Dana 44 steering knuckle and balljoints. Luckily, a CJ Dana30s knuckle yokes will both fit on the XJ tubes, and take the D44 balljoints.

2) BUT - the "throw" of the CJ knuckle yokes is different so custom length inner shafts are needed.

3) A custom seal will be required on the inside of the passenger side of the diff, as the stock seal is in the disconnect housing and will not work (too large - the original disco shaft is HUGE at this point)

Read on to see how I overcome all this and more!


Part 2- Definitions

Before I go into detail with my project, it's appropriate that we set agree on some common terminology for the front end, as there are some different names in use for the same parts.


Parts Definitions (list in order from the inside of the axle out)

1. Knuckle yoke - the yoke welded onto the end of the axle tubes, either houses the balljoints (XJ,YJ,MY,TJ,ZJ) style or takes the balljoint stud (CJ,Scout,1/2 Tons etc.) Sometimes called the "inner knuckle" or "C".

2. Balljoints

3. U-Joint

4. Stub shaft - the "short" outer part of the axleshaft on the outboard side of the U-joint.

5. Knuckle - the bit attached by the balljoints that does the steering (some call this the spindle, I imagine because in cars the actual spindle is fixed to it).

6. Caliper bracket / dust shield (if not part of theknuckle) e.g. in Ford F-150 the caliper mount (sometimes called caliper stand) is all cast as part of the knuckle. In early 70's Chevy 1/2 tons, the caliper bracket bolts onto the knuckle.

7. Spindle - The round part that bolts to the knuckle and on which the wheel bearings seat.

8. Rotor - The front disc brake rotor.

9. Hub - The metal body that attaches to the rotor, houses the wheel bearings, and through which the spindle and stub shaft pass.

10. Lockout - The manual locking hub.




Part 3 - Parts you need

First, in order to be able to bolt on the flat top knuckles that are the heart of the system, you need to have the right knuckle yokes on your axle. The right kind are the "older" style that have small holes in them into which the ball joint studs are pressed. Another way of describing it, is that the ball joints point "up", where the body of the ball joint is pressed into the knuckle, and the studs point up and go through the knuckle yoke. CJs, Scouts, Pickup trucks, Full-size Jeeps, and just about every Dana44 front axle has these yokes. However, XJ, YJ, MY, TJ, and ZJ models Jeeps do not - they have the knuckle yokes that hold the ball joint, with the ball joint pointing "down". This doesn't mean you're out of luck if you own a late-model Jeep, just that you'll have to go through the extra step of swapping on the correct knuckle yokes first (not for the timid, but an opportunity to custom set caster), and it means you'll have to use custom inner axle shafts, as the "width" of the correct, older knuckles is different.





Before I start describing parts lists, a couple more "definitions": Crossover steering is where the drag link and tie rod are separate and not connected (otherwise you have an inverted T or inverted Y setup). True Hy Steer is where both the draglink and tie rod are over the springs (in reference to a Spring Over Axle leaf springsetup).

The parts required for Crossover Hy Steer with 5x5.5 bolt pattern are as follows:


Parts required for High clearance steering (this list applies equally well if you already have a D44 front):

1) Flat top knuckles - from '74 - '76 Front open-knuckle D44 axles, found in Chevy K10, Jeep Waggoneer, and narrow track Jeep Cherokee SJ's. The Chevy knuckles are the best choice as the drivers side will already have 3 holes drilled and tapped. I used '76 Chevy K10 4X4.





2) Balljoints - that match the knuckle you use, they are probably all the same (all D44 open knuckle). I used Spicer Ball joints for '76 Chevy K10 4X4. Upper balljoint part # 500-1070. Lower balljointpart # 505-1156.




3) U-Joint. Standard D44 U-joint. Spicer part number 297-x (non greasable) or 297-1X (greasable) or the newer forged joint5-760x. http://www.spicerdriveshaft.com Exotic choices include "high strength" offerings from High Angle Driveline High Angle Drivline-Call Jesse at 530-877-2875, CTM Racing, Landing Page or Ox / Superior.

4) Stub shaft. That matches the knuckle you use.




5) Caliper bracket / dust shield. The Chevy or Wagoneer style are the best. The single piece doubles as a caliper bracket and heavy duty rotor dust shield.




6) Spindle - Again, that matches the Knuckle. You can use the Ford D44 stub axle, but it is 1/4" shorter (I'll explain why in a second) so you won't be able to install the c-clip on the end of the stub axle, which may mean that the seal where the stub axle enters the back of the knuckle/spindle may not be as good. The Ford stub shaft is shorter because the Ford spindle is shorter because the Ford caliper bracket is a cast part of the knuckle, whereas the Chevy caliper bracket is bolted onto the spindle, and is about a 1/4" thick.




8) Rotor - I used the Ford Rotor .....

9) Hub ..and hub assembly which fits on the Chevy spindle fine, but gives me 5 x 5.5" wheel bolt pattern. You can stick with Chevy or Wagoneer hub and rotor for 6 x 5.5" bolt pattern.



10) Bearings and seals. If you go with the mix n match parts like I did, use the Chevy wheel bearings, spindle bearings, and spindle seals, but the Ford inner wheel bearing seal (that fits in the back of the Ford Hub). Actually, they are all the same except the inner wheelbearing seal.

Timken Part numbers:

76 Chevy / 85 F-150 inner wheelbearing: Set 37

76 Chevy / 85 F-150 outer wheelbearing: Set 45

76 Chevy / 85 F-150 FrontAxle Spindle Outer oil seal 722109

76 Chevy / 85 F-150 FrontAxle Spindle Inner oil seal 722108

76 Chevy / 85 F-150 Spindlebearing B2110

Inner wheel bearing seal(fits in back of hub) Chevy 24898 Ford 24917

10. Lockout - The same for the Ford, Chevy and Wagoneer - Warn Premium part number 20990. I used the Warn Ford lockouts that came from the junkyard with my 85 F-150 hubs.

Parts required if you are converting a late model Jeep D30 like I did:

1) Knuckle yokes from a Scout or CJ D30 - Alternatively you could use the knuckle yokes from the donor D44, and either source or have machined a piece of tubing with the correct inside and outside diameters to slip over the D30 axle tube, and into the D44 knuckle yoke. I don't know if the correct sizes are available in common stock, or if it would have to be machined.

2) Custom length inner axle shafts. This is a kicker. Because of the different style of knuckle yoke, the distance between the center of the U-joint and the vertical line through the upper and lower balljoints is about an inch shorter in the CJ yokes than it is in the XJ/YJ/ZJ/TJ/MJ yokes. This means the stock inner axle shafts, even if you have the 297x U-joints will be too long. They can't be shortened because of the design of the shafts. The only way around this would be to use a sleeve of some sort, preferably with the D44 knuckle yokes, that lengthens the axle tube itself the same amount so you can use the stock inner shafts (assuming they take the 297x U-joint, as they will have to, to mate with the 297x jointed D44 stubshaft) or some other length so that a different 297 jointed stock inner axle could be used. Here are some 297 jointed stock inner axle dimensions from the Warn page www.warn.com to help you figure this out if you want to try that: Note that the stock XJ shafts are the same as the Wrangler - Right 32.25", Left 16.63".


INNER AXLE SHAFTS:


I bought custom length D44 front alloy axles with beefed up yokes and machined for full U-joint circlips, from Moser Engineering, that they cut down and splined to fit in my D30 Detroit Locker. http://www.moserengineering.com/moser_interior/mecustomalloy.htm



The STOCK XJ dimensions are:



The Custom Shafts I ordered from Moser (pictured above) specs are:




Part 4 - Doing the work



Step 1 is cutting the stock XJ inner knuckles off the axle, without damaging the axle tube, as it is not being shortened.




Once I knew how far into the inner knuckle I had to cut, it was time to cut all the way around the knuckle.




To make the cut all the way around the yoke, I had to get the ears out of the way.




This is what it looks like when the cut all the way around the yoke is finished, and the yoke is pounded off with a hammer.






Like the other side, I just wanted to get the bulk of the stock yoke and knuckle out of the way so I could make a better cut around the yoke without cutting into the axle tube. The Sawzall worked fine, but the chop saw is fun too!


Here the axle is ready for the new outers



Fitting on the "new" CJ D30 yokes and setting the caster. Note that the axle is clamped in the vice with the pinion angle set for my lift (i.e. the way it needs to sit in the truck) so I can get correct pinion angle AND correct caster. I stuck with the factory XJ spec of 7-8 degrees of caster.



Well, there's a couple of errors in the pic labels. On the D30 the disco housing and pumpkin are NOT nodular iron, they are CAST. I tried welding the reinforcement sleeves to the housings using a 7018 rod, and they cracked as they cooled. I should have used a high nickel content rod.


Here the CJ knuckle yoke is tacked in place.





Here the Chevy brakes, Ford hub and rotor are installed, with full time slugs in place (before I cleaned up and installed my Ford Warn manual lockouts.



The final thing required was to install an inner oil seal in the passenger side of the diff. I bought a stock drivers side seal, then took my air grinder, and hogged out the axle a bit, till I could fit the drivers side seal in there, and seated it in some RTV.



I drove it around for a while with the stub shafts installed but no inner axles, as I waited for Moser to make and ship my custom shafts. I didn't wait long - to my door in 3 days!



Of course, now I have 2 different bolt patterns front and rear. 5x5.5" in the front and 5x4.5" in the rear. I bought a single 5x4.5" to 5x5.5" adapter (1" thick) from http://www.performancewheel.com/

It's a work of art for $50. I carry a 5x5.5" spare, and if I need it on the rear, I just bolt on the adapter first. You can't do it the other way around as a 5x4.5" wheel or adapter won't fit over the front hub.


Part 5 - Brakes



Once the axle was complete, I had to make the new Chevy 1/2 ton brakes work with the stock XJ system. I chose to use AN-4 racing stainless steel brake hoses. The race store I bought them at had all the necessary fittings to adapt them to both the stock XJ hard lines and the Chevy caliper.


This is how it works.


Placement of the 90* caliper fitting is critical as there is not a lot of clearance back there when everything's installed.



Next 3 pics show how the Chevy brakes are superior to the stock XJ.





Part 6 - Reference Material

Here are some pics from some manuals that I referred to during the project, and that may help you with yours.







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