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Answers to Jeep Questions

Posted in How To: Tech Qa on February 8, 2017 Comment (0)
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I have a ‘04 Jeep Wrangler Rubicon and need to mount spare gas cans. Can you point me in the right direction?

Paul Forslind
Via email

Fortunately, you have one of the most modifiable 4x4s in the world, a Jeep Wrangler. So you have lots of options when it comes to increased fuel capacity and driving range. If you are looking for a simple and inexpensive way to add a 5-gallon fuel can to your Jeep, companies such as Smittybilt (smittybilt.com) offer universal fuel can mounts. The Smittybilt Jerry Gas Can Holder (PN 2798) carries a standard 5-gallon steel can. It features universal mounting options and is lockable to prevent theft.

Rotopax (rotopax.com) offers several different convenient fuel containers and mounting options. These include 1-, 1 3/4-, 2-, 3-, 3 1/2-, and 4-gallon containers. They are keyed to fit together for secure and rattle free mounting on roof racks, body panels, spare tire mounts, or nearly wherever you can fit them.

Daystar (daystarweb.com) offers a 2-gallon Cam Can. Model-specific and universal brackets are available to mount the Cam Cans on nearly any flat surface or spare tire mount. They can also be stacked if you need more than one.

Companies such as AEV (aev-conversions.com), Fab Fours (fabfours.com), Garvin Wilderness Products (wildernessracks.com), Rock hard 4x4 (rockhard4x4.com), Smittybilt, and many others offer swingout spare tire carries with the capability of carrying fuel cans. Bolt-on rear cargo racks are also available.

The other option is to forgo the fuel cans and simply increase the size of the fuel tank. Genright Off Road (genright.com) offers replacement aluminum fuel tanks with increased capacity for many different Jeep applications, including your ’04 Wrangler. The Genright Extended Range tank increases fuel capacity to 24 1/2 gallons. A 31 1/2-gallon Safari tank is also available; however, it is designed for the ’05-’06 Wrangler Unlimited.

Air-Clunk

I have an all-Jeeps question. My wife's ’15 Grand Cherokee Overland with Quadra-Drive II and Quadra-Lift air suspension elicits a loud hammering noise when the Select-Terrain is placed in the Rock position and the air suspension is placed in its maximum height position. The noise occurs when traversing over the smallest bumps and stones. Other than being incredibly annoying, are there any other mechanical issues that we should be concerned about when driving in this setting?

This Grand Cherokee will only see mild off-road terrain. It was purchased for touring and confronting severe weather driving conditions. The 10.8 inches of potential ground clearance may be overkill for our current needs, but I appreciate the other benefits of the air suspension.

We have a highly capable ’05 TJ Rubicon built for rockcrawling and off-road exploration. Throughout the TJ build, I followed guidance from a 2005 Jp article that I picked up during one of my Iraq tours. I've been a reader ever since.

Rory Travis
Colorado Springs, CO

Thanks for sticking with us over the years! The Quadra-Lift air suspension on your Grand Cherokee has many advantages. It gives the driver the ability to lower the vehicle for easier entry and exit as well as for loading and unloading cargo in and out of the back. You can raise the vehicle for more ground clearance off-road or in snowy conditions, as you have noted, and you can bring it down for improved on-road handling in the curves, less highway wind resistance, and slightly better fuel economy.

Unfortunately, the noise you hear coming from the suspension on your Quadra-Lift-equipped Grand is not unusual. It’s very common, especially with the air suspension on the fully raised setting. What’s happening is that the air struts are topping out as the suspension bounces along and cycles over rough terrain. The increased ride height decreases the amount of droop travel the suspension has. When you select the Rock setting on the Selec-Terrain knob, the suspension is automatically raised to the highest Off-Road 2 setting. You can diminish this noise by manually lowering the Quadra-Lift suspension to the Off-Road 1 setting or even to the standard ride height if you don’t need the additional ground clearance, while taking advantage of the other drivetrain parameters afforded by the Rock mode. Both of these suspension settings will offer more droop travel so that the struts do not top out as frequently.

Because the noise from the struts topping out is so annoying and rough, we generally avoid using the Off-Road 2 setting, unless the extra ground clearance is absolutely necessary. However, if the noise doesn’t bother you all that much, it really won’t do any harm to the suspension if you simply want to maintain the extra clearance over terrain that doesn’t require it.

Go-Kart JK

After many years of wanting a Jeep, I finally purchased a ’11 two-door Wrangler Sport. There are two items I feel I have to improve. The harsh ride and go-kart handling feel. Without breaking the bank, is there a bolt-on kit that will either eliminate, or at least improve the go-kart handling and the harsh ride. Can the ride and handling be improved with good shocks alone or is there more that needs to be done?

Pat Story
Blythe, CA

Congratulations on your new-to-you Jeep purchase. The ’07-current Jeep JK Wrangler is an extremely fun and capable vehicle. Of course, it does have a few handling quirks that are sort of inherent when you consider the vehicle capability, ground clearance, durable solid axles front and rear, and overall chassis and suspension design. The Wrangler is not a crossover SUV, and was never really designed to compete in that market.

Many new JK Wrangler owners feel like the vehicle is a little bit darty and twitchy. When driving several different types of vehicles back to back you notice it more easily. However, most of us learn to adapt to the sometimes-twitchy handling of the Wrangler. After driving the vehicle for several months, it’s less of an issue.

Nearly all Jeep Wrangler lift kits and aftermarket shocks provide a much firmer on-road ride than the stock suspension. The factory original coil springs and shocks will be the softest-riding components available. If your Jeep has a lift, and a smooth ride is of primary importance to you, you might consider switching it back to stock suspension components. If you want to retain a small lift, but also want a smooth ride, you could consider a spacer lift. Also, a mild lift with properly inflated larger tires can in some cases offer a smoother and less darty ride than stock. Tire, spring, and shock selection will be critical for this to work.

Big Wheel J-Truck

I just picked up a ’79 J20 with a four-speed manual transmission and an AMC 360 V-8 engine. Overall, it runs pretty good. It’s completely stock right now and therein lies the problem. I need wheels and tires. It still has the 8-lug wheels with 9.5-16.5 tires, which are impossible to find. I'd love to lift this thing 3 to 4 inches and upgrade the wheels and tires.

I love the look of the FSJ in the Feb. ’16 issue on page 22 (lower right pic). Do you have any additional specs on this rig? The caption says it has 37-inch tires, but is that right? Who makes those wheels? I'm assuming a brake upgrade would be needed to run bigger tires.

Also, I have the heavy-duty model with a Dana 60 rear axle. My truck currently has a dump box in the back. If I were to throw a new lift kit on it, would I need custom springs in the back to handle the load?

I love the mag. Don't change a thing, except add more FSJ articles.

James Baker
Via email

Most of the ’74-’87 J-trucks have great drivetrains, axles, and other admirable heavy-duty components. The FSJ trucks are robust and easily modified. The J20 8-lug axles utilize a common 8-on-6.5 bolt pattern. There are lots of aftermarket wheels available that will fit. All of the 3/4- and 1-ton trucks of that era utilized the same 8-lug pattern.

Companies such as BDS (bds-suspension.com) and Skyjacker (skyjacker.com) offer complete 4-inch, four-corner replacement leaf spring lift kits for the ’74-up J-trucks, including your J20. The 4-inch lift will accommodate 33- to 35-inch tires with the factory fender flares and 37-inch tires if you cut the flares off.

The truck in question is mine. It is an ’87 J20. It featured the factory Dana 44 front axle and full-floating Dana 60 rear axle, similar to your J20. Both axles have the 8-on-6.5 lug pattern. I installed a 4-inch Skyjacker lift kit, cut the fender flares off, and mounted 37x12.50R17 BFGoodrich (bfgoodrichtires.com) Krawler KM tires on Wheel Pros (wheelpros.com) Moto-Metal 951 17x9 wheels with 4.5 inches of backspacing. My truck had 3.73 axle gears and a three-speed automatic transmission. It also has an AMC 360 choked down with all sorts of smog equipment. It was a bit of a pig on the highway but really fun to bounce around off-road when the NP208 transfer case was put into low range. Your ’79 J20 should have a Dana 20 transfer case and will perform similarly. Although, the ultra-low 6.32:1 ratio First gear in your T-18 manual transmission will give you better control over rough technical terrain.

I never upgraded the brakes on my J20 because they seemed to work fine for me. I also never planned on hauling heavy loads or trailering. There are brake upgrades available, though. Companies like EBC (ebcbrakes.com) offer dimpled and slotted rotors and performance brake pads. Out back, you could replace the drum brakes on the Dana 60 with disc brakes using a conversion kit from a company such as TSM (tsmmfg.com). Don’t forget to remove the residual pressure valve when swapping to rear disc brakes. In fact, you may want to remove the factory proportioning valve and install an adjustable proportioning valve. Companies such as Speedway (speedwaymotors.com) and Wilwood (wilwood.com) offer several different adjustable proportioning valves that can be set to your trucks specific braking needs once installed.

Unfortunately, your concerns about load carrying capacity with the lift springs are not unfounded. The factory J20 leaf springs are designed to carry quite a bit of weight. As a result, they also ride very poorly and don’t flex well off-road. You have to make some compromises when contemplating lift, ride, articulation, and load carrying capacity. The aftermarket lift spring will have no problem carrying a typical load, but if you plan to haul an overflowing bed of gravel, you’ll need to consider other options. To support extra weight and maintain a smooth ride, you may look into an add-on rear air bag setup. I don’t know of any aftermarket kits available for the ’79 J20, but a competent suspension fabricator should have no problem adding them to your truck.

I recommend avoiding the addition of load-carrying air shocks unless you plan to reinforce or replace the factory upper shock mounts on the frame. They are weak and already prone to fail with the stock shocks. Air shocks will rip them off of the frame in no time.

Oil Pan Antics

Would the oil pan off my 258ci inline-six fit properly onto a 232 inline-six? My 258 is toast and I picked up a 232 to replace it. The 232 came from an old postal Jeep and has the double-sump pan that I don't think will work in my CJ-7. Thanks in advance!

James Pugh
Via facebook.com/jpmag

Fortunately, the basic design of the Jeep inline-six had not changed all that much over the years. The AMC 258 is essentially just a stroked 232. Both engines, along with the 199ci inline-six, share the same oil pan bolt pattern. However, the longer stroke of the 258 requires additional oil pan clearance. This is accomplished via dimples in the side of the 258 pan. The 258 pan can be put on the 232, but the 232 pan cannot be put onto the 258 without contact. So you should be good to go. Bolt it up.

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