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How To Convert A Front Axle – The in’s and out’s, the oops and the gotcha’s!

 

How To: Convert a Front Axle

 

Our Project Land Cruiser has seen more swaps, mods and changes than we ever thought it would. Every time we thought it was at a point where we could leave it alone and simply enjoy it, something bigger, better, faster or stronger came along. Call it evolution, call it envy, call it keeping up with the Jones’, call it masochism – it is what it is and that’s just the way we are.

It all started when we decided that our beefed-up, Birfield-impregnated FJ40 front axle just wouldn’t be strong enough to handle 35″ meats (reliably that is), not to mention our prototype steering just wasn’t cutting the mustard. It was now time to install an axle up front that would be cheap, tough, easy to maintain, easy to find parts for, and easy to repair on the trail.

This isn’t an instruction set for converting axles, nor will we go into details on why we chose our ’78 Jeep Cherokee Dana 44 front axle, except for the fact that the spring puches were the same width as the stock FJ40; it’s not that type of article. What we will cover, are some questions you should ask yourself and all of the little gotchas that we ran into when swapping out axles, even on a rig that’s relatively barren of gadgets that would make the install tougher (e.g. anti-lock brakes, coil-sprung suspension, anti-sway bars, sensors, etc.).

Before you decide to convert a front axle, here are some things to consider:

  1. Axle width – will you have to cut and axle down, or can you go with a standard width?
  2. Axle width 2 – If you are thinking of going to a wider axle up front, will the local terrain be an issue? (e.g. are the trails too narrow?)
  3. Steering – will you have a problem with the tires rubbing against the frame, shocks, shock mounts or spring at full lock?
  4. Spring purch location – will the spring purch / spring buckets (spring mounting points) be in the same location, or will you have to modify the axle and / or the spring locations?
  5. Brake lines – will you have to modify your brake lines to make them fit? Will they need to go from metric to standard (or vice versa)?
  6. Steering components – will you have to change from a front-to-back steering system to a cross-over steering system, or something different?
  7. Wheel bolt pattern – can you reuse your rims, or will you have to modify your axles to accept the bolt patterns? Or do you have the bling-bling left to buy 5 new wheels (no 22 inch spinners aloud!)?
  8. Condition of axle to be swapped in – will the axle have to be completely rebuilt? Is the housing straight and true?
  9. Gear ratio – will the gear ratio match that of your rear axle, or will you have to install new gears too?
  10. Strength & Size – What type of wheeling do you do? Do you need a big ol’ Dana 60, or will a 44 cut it and save precious ground clearance?

This isn’t an exhaustive list of questions, but some to at least get you pointed in the right direction. Ask fellow wheelers what works for them. Contact a reputable 4-Wheel Drive company that has years and years of experience such as Stage West 4-Wheel Drive Center or All Pro Off Road. These folks have forgotten more about building and wheeling rigs that most of us will ever know. Ask their opinions and thoughts, but most importantly, do lots and lots and lots of research. It will be worth it in the end.

After we received our front axle from Stage West 4-Wheel Drive Center, we enlisted the help of Tucson Differential to build the innards to our specifications. With a fully assembled axle, it was time to start the process of fitting it to our Cruiser. Swapping an axle requires some patience, a checkbook, a good set of tools and a good mechanical mindset.

Tools you should have (aside from the standard wrenches, sockets, etc.):

  • Welder
  • Angle finder / gauge
  • Torque wrench
  • Hub socket
  • Brake line tubing bender
  • Brake line double-flaring tool
  • Large drill bits (1/2″ to 7/8″)
  • Torch (we did our swap without one, but…)
  • Reciprocating saw
  • Upper-ball joint keeper socket
  • Large C-Clamps
  • Drill press
  • Heavy duty hand drill with large chuck
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By Rick Webster

 

Page 2, How To Convert A Front Axle – The in’s and out’s, the oops and the gotcha’s!

What we had to do to get the axle mounted:

 

U-Bolt Flip Kit (Stage West 4-Wheel Drive Center, $145)

We chose to install a U-Bolt flip kit during our installation and we highly recommend you do the same thing. This will save an inch or so of precious ground clearance and protect the nuts and threads of the U-Bolts from being munched by rocks, tree stumps and the likes. Installation for the most part was a piece of cake. The U-Bolts gave us a fit as they spread open when we slid them up the axle tube. This meant we had to use C-Clamps to squeeze the U-Bolts together to get the flip kit to slide over them.

Difficulty rating: 4
Time To Install: 2 hours
Special Tools Required: C-Clamps, Torque Wrench
Notes, Hints, Tips, Gotchas: N/A

 

 

 

Shock Mounts (Home made, $1.75)

We got a series of different shock mount tabs and brackets from our friends at Stage West, but in the end we decided we would weld Grade 5 bolts (we cut the heads off) to the front of our U-Bolt Flip Kit plates. This would accomplish a few things…

1) It gave us the flexibility of mounting our shocks in a near perfect, straight up & down position.
2) It would keep the shocks out of the way of steering components
3) We didn’t have to weld on the axle tube itself and risk cooking the seals, or weakening the axle tube.
4) Installation and removal of the shocks is a piece of cake.

Difficulty rating:

3
Time To Install: 3 hours
Special Tools Required: Welder, drill press (If you want to cross drill the threaded shank for cotter pins)
Notes, Hints, Tips, Gotchas: We chose Grade 5 bolts because they’re plenty strong and aren’t as brittle as Grade 8. We’d rather have the bolt bend slightly, than sheer off. Also, before you assemble and weld, we suggest that you drill a small hole through the threaded portion of the bolt so that you can use a castle nut and cotter pin to secure the shock.

 

 

 

Brake Lines (Local auto-parts store, $35 (plus $40 in flare-tool rental))

When swapping out axles, you may have to contend with converting your brake lines from metric to standard or vice versa. Our calipers had a standard fitting, yet our master cylinder and remaining lines were metric. There are a number of options to convert; yet we chose to modify. We ultimately converted the brake lines after the proportioning valve (T-Block) to minimize the amount of fabrication. Aside from spending an hour or so in the parts store, installation was tedious, but easy and can likely be done by just about anyone.

We chose two 5’ sections of brake line. One was metric (which had the same fittings as the T-Block) and the other was standard (which had the same fittings as our calipers). Using a tubing cutter, we cut one end off of each tube and swapped out one fitting per tube. What we ended up with was two tubes; each having one metric fitting and one standard fitting on opposing ends.

Using a coat hanger, we mocked up the bends of the brake lines for each side and then bent the brake tube to match. Lastly we flared the ends of the lines so we could attach our lengthened stainless steel brake hoses to the calipers.

Difficulty rating: 5
Time To Install: 1.5 hours
Special Tools Required: Brake line tubing bender, brake line double-flaring tool, welder (to mount T-Block bracket to axle)
Notes, Hints, Tips, Gotchas: Take your time with this part and make sure you have quality tools. Take many, many measurements and mock up the hard brake lines with stiff wire or a coat hanger before you start bending.

 

 

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By Rick Webster

 

Page 3, How To Convert A Front Axle – The in’s and out’s, the oops and the gotcha’s!

Axle-Side Steering Components:

This is where it may get tricky, depending on what you choose to do. In our minds, logic dictated that if we were going to go through the work of swapping out an axle, we’d spend the extra time and money on components that would be durable and strong. Here were our choices:

 

 Severe Duty Tie Rod and Drag Link (Stage West 4-Wheel Drive Center, $85 each)

1 1/4″ inch O.D. X .250 wall 4130 Chrome-Moly seamless tubing. This tubing was small enough it wouldn’t interfere with the frame at full compression, but large and strong enough to handle big meats on rocks.

Difficulty rating: 4
Time To Install: 1 hour
Special Tools Required: N/A
Notes, Hints, Tips, Gotchas: Measure 15 times before your order your tie rod / drag link, and make sure that the place you order your tie rods and drag links from factor in the length of the heim joints / rod-ends. We had to cut our drag link down by 4” because we forgot to ask them to factor in the heim joint difference, which meant we also had to go buy a ¾” X 16 pitch tap to run the threads in deeper.

Machined Steering Knuckle & Heavy-Duty Studs (Stage West 4-Wheel Drive Center, $110, plus shipping) 

In order to convert our steering system to a cross-over type as described above, we enlisted the help of Stage West 4-Wheel Drive Center to mill our passenger-side steering knuckle to accept the cross-over steering arm.

Stage West uses a specially created jig to level the knuckle, mill and plane the top of the knuckle and then finally drill and tap the knuckle to accept the studs and steering arm.

Aside from re-assembling the steering knuckle to the axle, We only had to install the heavy-duty threaded studs as seen in the picture.

Difficulty rating:

7
Time To Install: 3.5 hours
Special Tools Required: Special castleated socket to remove the upper ball joint keeper, torque wrench, big friggin’ rubber mallet, Torx bits, hub socket
Notes, Hints, Tips, Gotchas: Installing the knuckle isn’t for the beginner. This isn’t a technically difficult install if you’re familiar with the inner workings of axles, but it is time-consuming and requires some special tools. Be sure to buy the tools in advance (especially the upper ball joint keeper socket and the hub socket for your particular axle if required.)

 

 

High-Steer, Cross-over Steering Arm (Stage West 4-Wheel Drive Center, $150)

The high-steer, cross-over steering arm allowed us to mount the new steering tie-rod, drag link and heim joints up high and out of the way of rocks. It also allowed us to create a steering system that didn’t connect the drag link to the tie rod as seen in some stock applications. This is a very strong and tried & true method for steering conversions.

Difficulty rating: 3
Time To Install: 1.5 hours
Special Tools Required: Torque wrench, 3/4” drill bit, HD drill with large chuck
Notes, Hints, Tips, Gotchas: Make sure you put thread locking compound on the studs, but ONLY where they thread into the steering knuckle.

 

 

3/4” Heim Joints with High Deflection Washers (Stage West 4-Wheel Drive Center, $40 each plus $15 per set of high-deflection washers)

We chose to use heim joints for their extra strength and durability given the slung weight and size of our tires. This would also give us greater joint life (as compared to tie-rod ends), tighter tolerances in steering components, and greater strength in the joint when the axle is fully articulated.

Moreover, Stage West supplied us with a full set of high-deflection washers (see upper right picture), which allows the heim joints to articulate further than flat washers would allow. You’ll want to use these on the drag link because it will articulate much further than the tie rod.

 

OPTION – FJ80 Tie-Rod Ends (All Pro Off Road, $34 each) We had the option early on to use FJ80 heavy-duty tie-rod ends instead of heim joints. There are three upsides to this choice: 1) They are super heavy-duty and are already cut to 23mm threads, which means they’ll likely bolt into any Toyota Application. 2) They’ll slide right into place with our new heavy-duty pitman arm (next page). 3) They’re nearly half the price of heim joints.

Ultimately, we chose to use heim joints for some more strength, and because slowly but surely we’re converting our entire project Land Cruiser to standard thread components.

Difficulty rating: 1
Time To Install: .5 hours
Special Tools Required: 1 1/8” socket, large adjustable wrench, torque wrench. 3/4″ drill bit, heavy-duty drill
Notes, Hints, Tips, Gotchas: We had to drill out the holes on the steering arm, the driver side knuckle and the pitman arm to accept the larger-than-standard heim joint bolts. We had to use a heavy-duty worm-drive drill with a large chuck to drill through the knuckles, given the size of drill bit.

 

 

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By Rick Webster

Page 4, How To Convert A Front Axle – The in’s and out’s, the oops and the gotcha’s!

Vehicle-Side Steering Components

 

There are a number of ways to convert your vehicles steering, if needed. Our project FJ40 had used a prototype front-to-back steering system with a 4” drop steering bar (S-Bar), similar to the steering on ’82-’85 Toyota Pickup trucks. While this prototype gave us power steering with little fabrication on our stock axle, it posed too many problems and limited steering. While we could have converted our rig at this point to a Saginaw steering solution, our budget was getting very tight and we opted to use a steering box from an ’87 Toyota 4X4 pickup truck. Here’s what it took to get the steering wheel to work with the box, and what it took to get the box to work with the axle.

Toyota IFS Steering Box (Salvage Yard, $75)

We opted to stay with a steering box that would mount in front of our grille and on top of the frame rail. This would give us a bit more clearance and admittedly, we already had a gaping hole in the grille from our last attempt at a power steering conversion. We picked our steering box up at a local junkyard for about 75 clams, grease and all!

OPTION: New (Rebuilt) IFS Steering Box: (All Pro Off Road, $399)

All Pro Off Road offers lifetime replacement warranty IFS steering boxes, which have been thoroughly examined, measured and checked. They also install all new seals and bearing.

Difficulty rating: 9
Time To Install: 10 Hours
Special Tools Required: Torque wrench, drill bits, welder
Notes, Hints, Tips, Gotchas: This is another tough install. You’ll need to measure everything 10 times, make templates and mock it up several times to make sure everything is lined up. Be VERY cautious of how far forward or backward you mount your steering box. If you mount your steering box too far back, the tie rod will hit the drag link upon suspension compression. If you mount it too far forward, you’ll change the steering geometry, not good. You’ll also have figure out if you need to space the gearbox away from the frame (up or out) to get everything to line up. We found that we needed to space our gear box out 3/8 of an inch, so we made our own scab plate and welded it to the frame. Lastly, make note of the angle that the gear box sits in conjunction with the intermediate shaft and check where your bolts can be located. All in all, this was our toughest portion of the installation and with a lot of patience and lots of measuring, we nailed it the first time.

 

Custom Power Steering Lines (Hydraulics Company, $42)

Since we have a Chevy V8 and Chevy power steering pump under the hood, we had to have our power steering lines customized so that they would have standard threads on the pump side and metric threads on the steering box side.

Difficulty rating: 1
Time To Install: .5 Hours
Special Tools Required: Line wrenches
Notes, Hints, Tips, Gotchas: N/A

 

Heavy Duty Pitman Arm (All Pro Off Road, $69)

Since the standard pitman arm on an IFS steering box won’t accept standard tie-rod ends or heim joints, we gave another call to All Pro Off Road and they sent us one of their heavy-duty pitman arms that they have manufactured exclusively for them.

Installation was a snap, but taking the old pitman arm nut off was a chore. The nut and arm was on so securely it took two days of soaking with WD40, a torch (to heat up the pitman arm and expand the metal), a big sledgehammer, a pitman arm puller and an impact gun to get it off.

Difficulty rating:

4
Time To Install: 3.5 Hours
Special Tools Required: Pitman arm puller, Lots of WD40, HD drill, 3/4″ drill bit
Notes, Hints, Tips, Gotchas: Be sure to index the center line of the old pitman arm and the sector shaft with a marker or soap stone. IFS Steering box sector shafts don’t have indexes cut into their splines, so save yourself a LOT of agony by marking this early on. Otherwise you’ll end up with too much steering on one side and not enough on the other. We also had to drill the rod-end side of the pitman arm to accept our larger-than-standard bolts for the heim joints.

 

DD Collapsible Steering Shaft / Intermediate Shaft (Borgeson Universal Company, $80 incl. shipping)

Borgeson supplied us with their collapsible intermediate. We could have used a section of tubing, but figured a bit of added safety would be worth its weight in gold if we ever had a front-end collision.

The 18 ½” long intermediate shaft is designed to collapse 6 1/2″ on impact, lessening the chance of chest injury and allowing the driver to maintain control providing the vehicle is drivable. This also prevents binding with an off road vehicle that has some frame/body flex to it.

Difficulty rating:

6
Time To Install: 5 hours
Special Tools Required: Reciprocating or hack saw, welder
Notes, Hints, Tips, Gotchas: Be ready with your measuring tape again… this component seemed like it was going to be an easy install, but it required a lot of measuring, prototyping, tack welding, re-meausring, cutting, and so forth. We also struggled with the fact that our steering column U-Joint’s (firewall side) inner diameter was about a 1/4″ larger than the outside diameter of the intermediate shaft. That meant we had to shim over and over again until we were relatively confident that the intermediate shaft was true and centered in the u-joint before we welded it all up – very time consuming. Be sure to check for proper clearance between the intermediate shaft and your engine’s headers or exhaust manifolds. We had to shim our steering box outward to gain even 1/8” of clearance. The yellow paint on our intermediate shaft is turning brown from being cooked by the headers.

 

 

 

The mistakes we made / The gotcha’s to look out for:

  1. Hard brake lines too long – we made our hard brake lines too long so our braided steel brake lines tend to get bunched up and come too close to the tire.
  2. Steering gear box rag joint – The rubber-inserted rag joint that sits between the intermediate shaft and the steering gear box rubbed on the frame, so we had to ditch it all together and go with just a standard small u-joint. This will likely lead to increased wear and tear on the u-joint, so we’ll have to inspect this on a regular basis.
  3. Tires hit the steering box, frame, springs and shock hoops – Even though we went to a full length axle, the tighter steering radius of the ’78 Jeep Wagoneer Dana 44 means that our tires hit just about everything. We’ll likely have to install 1.5” or 2” wheel spacers to remedy this.
  4. Articulation – our front axle articulates pretty darn well, which is great for off roading, but presented some problems with the conversion. Our bump stops have to be lowered and modified to clear the u-bolts that now point up. We also noted that at full compression on the passenger side, our drag link and rubs the frame. We’ll have to give up some compression on that side to make sure we don’t do any damage.
  5. Be prepared – to do heavy-duty research, beg your significant other for money, and have your rig tied up in the garage for 3 or more weeks. We thought we had everything figured out but still ran into 5 or 6 problems we required more special tools, more time and more money to finish the project.

 The wrap-up

It should be reminded that this article is about converting axles, not swapping. There’s a big difference here as you can see above. This difference is particularly true if you’re changing from a foreign to domestic axle or vice versa, or if you’re converting from IFS to solid front axle.

All in all, the front axle conversion cost us about $1,200, NOT including the built axle itself. We calculated that it would also take the average do-it-yourselfer about 3 full weekends to complete the conversion as well. This isn’t an impossible task at any level, but does require some special tools, tons of research, a lot of patience and measuring everything many, many times. So stock up the fridge with your favorite cold ones and get to work!

 


 

All Pro Off Road
541 N. Palm Ave
Hemet, CA 92543
Phone: 909-658-7077
Web Site: http://www.allprooffroad.com
Borgeson Universal Company
187 Commercial Blvd.
Torrington, CT. 06790
Phone: 860-482-8283
Email: sales@borgeson.com
Web Site: http://www.borgeson.com/
Stage West 4-Wheel Drive Center
6700 Highway 82
Glenwood Springs, CO 81610
Phone: 970-945-5227
Email: 4by4@crimsonwireless.net
Web Site: http://www.stagewest4x4.com/
Tucson Differential
1102 S Venice Ave.
Tucson, AZ. 85711
Phone: 520-750-1309
Email: diffmaster@tucsondifferential.com
Web Site: http://www.tucsondifferential.com/

 

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About Rick Webster

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