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How to Buy a Willys Flatfender Jeep

Tips and tricks you can use when shopping for an early GPW or Willys MB, CJ, or M38 flatfender Jeep.

Christian HazelWords and Photos

We're amazed at the popularity explosion early CJ Jeeps are currently enjoying, specifically the WWII-era Willys MB and Ford GPW, early Willys CJ-2A, CJ-3A, and Korean War-era M38 Jeeps. Known more affectionately by their nickname, flatfender or flattie, these early Jeeps have long been a crowd favorite for modification, but now a new movements has taken hold with an increasing number of off-roaders enjoying them in mostly stock form. So, assuming you're not going to automatically throw all the factory parts away for new aftermarket "upgrades" in no particular order, here are some things to look for and consider when shopping for a flatfender.

Flatfender Dash and Interior

It's not very common to find an early Jeep with an unmolested dash. Over the decades since they left the factory, many get butchered with holes chopped for radios or CBs, various wiring switches, and non-factory gauges. To some it's no big deal, but if you're planning a restoration or want a purer throwback feel, consider a candidate that hasn't had its dashboard butchered, that still retains the factory large-diameter steering wheel, and that still has the factory seat frames. Aftermarket or custom cushions and seat covers can be easily added, and replacement steering wheels are available, but flatfender dashes don't unbolt like later CJ-5 and CJ-6 models, so if the dash is butchered and you dislike the additional holes, you'll be doing some sheetmetal repair.

Flatfender Taillights, Tailgate, and Tow Hitch

Like the dashboards, the back end of these vehicles oftentimes get butchered to the point of no return. It was common in the 1960s and 1970s to open up the back of the tub and insert car taillight assemblies. Or, perhaps simple trailer lights or later-model CJ taillights get added. Tailgates on models that have them are another item that can be damaged or lost over the years. Not all replacement tailgates are stamped with "Willys," so if you see a blank center bar in the tailgate it's probably an aftermarket reproduction. Finally, the rear tow hitch is a nice thing to have, but it can often interfere with the Jeep's off-road departure angle, so may have since been removed. There's bracing that runs from the top of the hitch to the top of the framerails and rear crossmember, so if you want the factory implement/tow hitch and are planning on adding one, remember you'll need these parts to make it structurally sound.

Flatfender Windshield Glass and Frame

There are all sorts of different flatfender windshield types, with kick-out glass, fixed glass, central vents that open, vestigial vents that are sealed shut, and so on. In many cases you can transplant windshields across the various flatfender models, so if you've got an early split CJ-2A frame with lollipop vent brackets on your CJ-3A and want a period-correct restoration, you can swap it without too much fuss. But nowadays original windshield frames are becoming a bit scarcer and more expensive to buy alone, so if the vehicle you are shopping for doesn't have a windshield frame bolted to it, either be willing to accept an aftermarket frame or factor the increased cost of a used windshield frame that's appropriate for your vehicle into your purchase negotiations.

Flatfender Dana 25 Front Axle Considerations

Flatfenders have a Dana 25 front axle with teeny 8-inch drum brakes. You want to give the housing a good look because the axle tubes can get bent with hard off-roading and they're just not making new Dana 25 housings anymore. Additionally, these Jeeps didn't come with locking hubs from the factory, but by now almost all will have been upgraded with some form of locking hub. If yours have a vintage old-school variety like Cutlass or Warn or even Sears, make sure the hubs lock and unlock. If you see an axle that's still wearing the original drive flange on one side but the flange is missing on the other it can often be a sign of internal axle damage. This particular 1948 CJ-2A had the passenger-side drive flange removed and when we got it home and pulled it apart it quickly became apparent the reason for the flange removal was an exploded inner and outer axleshaft.

Flatfender Rear Axleshaft Considerations

Regardless of which axle is in the back of the flattie you're looking at, once again give the housing a good eyeballing to see if it appears bent. The earliest MB and GPWs have full-float rear axles and 4.88 gears, some with or without a limited-slip depending on the branch and theater of service. And many CJ-2A have a rather oddball Dana 41 that doesn't have great parts availability. It's not uncommon to see either of these axles cobbled with scrounged or makeshift repairs to keep them going, so before you get your new purchase up to road speeds make sure you pop the diff cover and inspect the internals for any signs of damage. On our 1948 CJ-2A the Dana 41 had apparently suffered some issue, with the lemon-shaped diff cover having been braze-welded back together. Later CJ flatties have a Dana 44 rear with a coarse-spline pinion and 10-spline axleshafts. On any early flatfender rear axle with the exception of the WWII-era full-floaters, you'll also want to check the two-piece axleshafts to make sure the nut that holds the hub to the tapered shaft hasn't begun to walk off. The nut should be good and tight and the keyway should be in good shape and without damage. Hopefully you won't find an old nail or chunk of wood wedged in the keyway to gingerly get the Jeep down the road.

Flatfender 134ci Go Devil Four-Cylinder Engine Issues

As with any engine in prospective vehicle purchase, the first thing you should do is pull the dipstick to check the oil condition. Many of these engines didn't have an oil filter on them, or they run an external oil filter with lines that can be damaged, so bearing condition should be carefully listened to if the engine runs when you're checking it out. Black and gritty oil is often a sign of a poor running engine with carbon or bearing issues. On our '48 CJ-2A, the oil was white milkshake, indicating a bad head gasket or a cracked block. We rolled the dice on a bad head gasket and, after carefully soaking the head stud nuts in penetrating oil for weeks, got them to budge without snapping the studs off in the block. Many aftermarket head gaskets for these engines have inferior fit and finish, so we got a NOS one from a local source.

You also want to make sure if it's there that all the oil bath air filter components are intact. Back in the day many of these were tossed in the trash in favor of more modern paper or oil-impregnated aftermarket filters, but these oil bath air filters do work quite well.

Flatfender Transmission and Clutch

Most of the flatfenders you'll be shopping for probably won't have a top. And if it does, who knows when that top was added. Sitting out in the rain is a great way to fill the transmission in these things up with water, so if there's any difficulty shifting the transmission, it is possible the gears, syncros, or shafts are contaminated with rust. We've purchased flatties that had their transmissions completely filled up to the top with water and that wouldn't spin at all. However, hard shifting can also be attributed to worn components in the clutch or clutch pedal, so make sure you take a good look at each component before throwing the baby out with the bath water. For example, what we originally thought was a worn pressure plate between our Go Devil engine and T-90 transmission wound up being a clutch fork with a cracked pivot ball that flexed to the point of not disengaging the clutch all the way. A good, used clutch fork fixed the issue without replacing the pressure plate or clutch disc.

Flatfender Go Devil Four-Cylinder Carter or Solex Carburetor

Man, we're not even going to go into all the different carburetors that were available on these engines and what you should and shouldn't be looking for. Aside from the incredibly rare original WWII-era carbs that collectors clamor over, as long as the carb is functional and makes the engine run we're usually happy to leave well enough alone. Going down the "correct model carburetor" rabbit hole on these engines is frequently an exercise in frustration, as is dealing with some aftermarket replacement carburetors. Some, but not all, of the aftermarket carbs we've used have had issues right out of the box, so bottom line, if the engine you're looking at runs well with a carburetor that clearly isn't original, just take it for what it is and worry about other stuff that's more pressing.

Flatfender Spicer 18 Transfer Case Considerations

We love the Spicer 18 T-case. Even if the flatfender you're looking at isn't equipped with an aftermarket overdrive bolted in place of the PTO cover, or it's sporting a single- or dual-output PTO attachment, the twin-stick Spicer 18 is a plucky, durable T-case. Look to see if the one you're considering shifts smoothly in and out of 4WD and from Low to High. Remember, these are not shift-on-the-fly T-cases, but with some ginger love they can be bumped in and out on a slow roll down the trail. The drum E-brake on the rear output is a nice feature if it hasn't been removed. When in good shape they actually function quite well. One thing we've run into with infrequency is intermediate shaft issues. The intermediate shaft is one point of wear in these early cases and sometimes if they've been rebuilt poorly and reassembled improperly the locking tab bolt can come out, allowing the intermediate shaft to spin in the case bore.

Flatfender Body Damage and Rust Issues

These vehicles were built before fancy galvanized sheetmetal panels and other weather-resistant treatments, so rust and rot can be commonplace. Watch out for body filler and rot, especially in the tub corners down by the seat frame and in the front passenger footwell areas. Another high rot spot are the hat channels underneath the tub in which the body mounts are located. These channels were filled with wood, which absorbs and retains moisture and often leads to premature rotting of the overlaying metal. Another spot is the underseat tool box, which can collect with rainwater and rot out. Make sure you push the passenger seat forward and lift the toolbox lid to inspect the condition of the floor. And finally, give the rear wheel tubs a good look over. Oftentimes these vehicles have been festooned with aftermarket trinkets, rollbars, seats, and other things that get bolted to the horizontal areas of the rear tubs and turns them into Swiss cheese.

Flatfender Ross Cam & Lever Steering Linkage

All flatfenders were equipped with a super complicated Rube Goldberg-esque steering system. Called a Ross Cam & Lever, the steering column connected to a frame-mounted box housing the Pitman arm. A drag link then ran longitudinally up from the Pitman arm to a pivot arm that mounted to a bellcrank underneath the center of the front crossmember. This then actuates two separate tie rods, one to each front steering knuckle. It's a cumbersome arrangement in that there are many points of potential wear, so it's not uncommon to find a lot of slop in the steering system of these vehicles. In addition to looking over the tie-rod ends, have somebody saw the steering wheel as you inspect the bellcrank for wear, the Pitman arm sector shaft for any lateral movement, and the drag link ends for excessive play. Rebuild kits are available for most of these points of wear, though, so don't let a worn steering system be a deal breaker in an otherwise good candidate.

Flatfender Suspension

By now many early Jeep flatfender suspensions have been upgraded with aftermarket parts, but if original you'll find spring packs made up of many thinner springs, rather than fewer thicker springs. These original packs ride pretty nicely and flex quite well, so original springs are a bonus. The shackles, if original, will be the open "C" type with threaded bushing sleeves featuring Zerk grease fittings. The bronze bushings inside can wear, but it's worth replacing them if you're looking to keep things original. If the vehicle you're looking at has been converted to more modern shackles with rubber or poly bushings it's not a deal breaker, nor are aftermarket spring packs. Don't be surprised to find modifications of unusual or questionable design, like these coil springs mounted to act as both a bumpstop and overload spring for carrying heavy loads.

Flatfender Wheels and Tires

There's just no telling what wheels and tires may be on the Jeep you're looking at, but they could be anything from the factory 16-inch tube-type originals to fancy aftermarket aluminum. However, if the wheels are steel and look original, pay close attention to the area around the lug nuts. Over the life of these vehicles different lugs with the wrong taper may have chewed up the steel or cracks frequently spider out away from the lug nut holes. Also, don't forget that, if original, many flatfenders have reversed left-hand lug nut threads on the passenger side to help prevent the lug nuts from loosening as the vehicle is driven forward. So don't automatically hit the lugs with an impact gun set to "liquify."