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Techline: Answers to all your 4x4 Tech Questions

Posted in How To: Tech Qa on December 13, 2016 Comment (0)
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Big Truck Braking

Regarding the lifted AEV Ram, what kind of upgrades to the brakes would you do to maintain the factory tow rating? Or would an upgrade to the trailer's brakes be sufficient?
Greg Rowell
Via facebook.com/fourwheelermag

AEV (aev-conversions.com) states that the factory tow rating of the vehicle is retained with the lift and tires. However, you could always upgrade the brakes of the truck if it was a concern. Companies such as EBC (ebcbrakes.com) offer aftermarket pads, as well as slotted and dimpled rotors to improve stopping performance and heat dissipation. The EBC Extra Duty Light Truck, Jeep and SUV and Yellowstuff brake pads are available for many different 4x4s. The EBC BSD rotors are also available for popular 4x4 models. These rotors are manufactured from a unique material known as discalloy and feature blade gas slots. The slot design is said to help to remove hot gases from the braking zone more efficiently than a unidirectional slot. Ultimately, this helps keep the pads flatter and the brakes cooler. Brake wind noise is also reduced.

If you are towing heavy, it’s always a good idea to regularly inspect the brakes on your trailer. They often go unmaintained for long periods of time. If only one axle on your trailer is braked, you can always add brakes to the second axle for more stopping power. Triple-axle trailers generally have brakes on all three axles already, but inspecting them regularly for proper function will ensure that you can always stop on a dime.

Banged Up JK

I have a question about the front-end damage on my ’07 Jeep Wrangler Unlimited four-door. I was involved in an accident with my Wrangler. I rear ended a car and since have had issues with the insurance company’s body shop and my insurance. I parked my winch bumper in a car trunk, the body shop says they can fix the visible damage, but I tried to explain that there are electronic issues arising from the accident. They feel the clicking noise in the front end is in my head. The Jeep has a clicking noise, like a broken U-joint. I also had a light come on saying the air bag system had been turned off and the wet road braking system wants to come on persistently. I can turn the system off, but it will turn itself back on. While on dry roads, the brakes pulse. The body shop says these issues are not related to the accident. Normally, I would ask the dealer what the causes of the issues are, but I choose to not deal with the dealers here. They lack competent people. I had a new EVAP installed at one dealer and had to take it back three times before they almost got it right. I also had to rebuild the transmission at about 31,000 miles. The Jeep was bought new at the end of 2006 and has about 45,000 miles on it now. It has never been off-road. Any thoughts on what might be wrong?
William Roberts
Via email

It’s hard to say what the exact problem is without seeing the Jeep and knowing exactly what was damaged in the wreck. If the clicking is consistent, it’s likely a wheel bearing, steering U-joint, or driveshaft U-joint. Try inspecting these areas for slop or damage. Realistically, if the Jeep is not lifted, none of these parts should be worn out yet. Another possibility is that the front brake pads could be loose and rattling in the calipers. If the clicking goes away when the brakes are applied, you might want to take a closer look here. A little bit of anti-squeal paste liberally smeared on the back of the brake pads will go a long way in keeping them from rattling, clicking, or squealing. If a tire made contact with the other vehicle during the impact, you should inspect the suspension brackets on the axle and frame. A broken or severely cracked mount could be rattling under there.

The ESP stability control system on the Jeep JK Wrangler can be a bit finicky if the alignment is not perfect. Make sure that the steering wheel is set straight when you are driving straight down the road. If the wheel is off to one side when driving straight, the ESP system becomes confused and will apply the brakes and pull throttle, thinking that the tires are slipping and the Jeep is sliding sideways. Prolonged driving with the steering wheel not properly aligned will set off the dashboard lights you have mentioned.

How to Magazine

How did you get into this line of work?
Cody Perkins
Via Instagram @cappaworks

Everyone has a different story about how they got into automotive journalism. For me, it was kind of an unexpected accident. I failed typing in junior high. I nearly failed every English class I ever walked into all the way through high school, but I loved 4x4s and trucks of all types. I read about them and the adventures they could take you on all through my teen years. I started college on track to be an engineer because that’s what my engineer dad recommended. I could understand how mechanical things worked, came apart, and went back together. I was especially good at coming up with the best chronological steps to attack a problem and develop an operational procedure that worked and made sense. I eventually found an English professor that understood my writing style in college. I wanted to write the same way I would talk to someone, as if we were sitting around a campfire. She encouraged me to make the grammatical errors I needed to tell the story. All through college I spent more time tinkering with my truck than I did studying.

On a trip to Washington to attend my stepsister’s wedding, I saw one of the many off-road magazines I regularly read sitting on a table in the hotel lobby. It had an editorial by David Freiburger titled “You Wanna Work Here?” Needless to say, I stole the magazine and spent the next few years working toward an English degree. When I finished college, I began sending my resume and writing samples to all of the 4x4 magazines. I honestly really wanted to be a part of Four Wheeler at the time. The Top Truck Challenge was starting to take off, and it sounded like a great event to be a part of. I knew a lot about 4x4s, how to fix them, how to modify them, and so on, but I had no connections in the industry. So I got a job at the local 4 Wheel Parts Wholesalers store to get my foot in the door. I became an assistant manager in less than two years and eventually lined up an interview for a staff position at 4-Wheel & Off-Road. My first interview was with David Freiburger. He didn’t hire me, but I didn’t give up. A few months later I had an interview with the then-new editor of 4-Wheel & Off-Road, Cole Quinnell. He hired me, and I began my journey.

When I was at the helm of the magazines, I always felt motivation, commitment, and genuine interest in the topic outweighed experience every time. You can teach someone to take better photos or improve their writing, but you can’t teach enthusiasm. You either have it, or you don’t. I like to think my first magazine boss, Cole, felt the same way. I think he already knew I had no idea how to turn on the computer in my new office, but that I would figure it out. He left me alone for several days while I poked and prodded through my first email address and Microsoft Word. That was nearly 20 years ago. Today, I can’t even imagine doing anything else.

Injection Advice

I have a mostly stock ’82 CJ-7. It has the stock drivetrain including the Dana 30 front axle, AMC 20 rear axle, Dana 300 transfer case, and T-5 manual transmission. The engine is a swapped-in 4.0L from a ’93 Cherokee, but it has a carburetor on it. If I don't shift the transfer case to low range on steep hills, the engine stalls and dies. I have already replaced the Weber carb jets for the biggest ones in the kit. This helped a bit. I've seen carbed Toyota 22Rs climb up hills I can't do without using low range. Is it something to do with the carb floats at certain angles? What do you think? Since going EFI would probably cost me the same as swapping the engine, what do you think could be a good swap regarding mpg? I use the Jeep primarily as a daily driver and also some good weekend warrior fun. Could you recommend somewhere to look for a complete EFI kit if it exists? I have absolutely none of the factory 4.0L EFI parts, just the intake manifold.
Daniel Pineda
Via Instagram @cappaworks

The sputtering and stalling problem you are experiencing is likely caused by over fueling, not a lack of fuel. The reason I believe this is because your Jeep will run fine at the higher engine rpms produced by the low range gearing. The engine is better able to ingest and burn some of the excess raw fuel, then spit the remainder out the exhaust at a higher rpm than at idle. Plus, the Jeep seems to be working fine at higher rpm, where fuel consumption would be far more than at idle. It’s a very common and well-documented problem with carburetors. Because of different carburetor designs, some work better than others for trail use.

The carburetor float bowls vent to the top of the carburetor intake. If the hill is steep enough or the trail is rough enough, it can cause the fuel to slosh out of the bowls, through the vent, and down the intake. This causes a rich condition, engine stumbling, and stalling. There are cheap tips and tricks you can employ help alleviate the issue, such as extending the float bowl vents and lowering the float bowl fuel level, but none of these tips will compare to the performance of a fuel injection system.

An EFI kit or swap will be a lot less expensive than a complete fuel-injected engine conversion. There are many people who have successfully swapped factory 4.0L injection into older 4x4s. Because your 4.0L originally came with fuel injection, the components can be sourced from a wrecking yard. Mopar (mopar.com) offers a complete bolt-on MPI fuel injection kit for the ’81-’90 AMC 4.2L. The kit is based on production components from a ’95 4.0L. It’s an expensive kit, but you may be able to adapt it to your engine. Perhaps a better and more affordable route is to use a Howell Engine Development (howellefi.com) fuel injection kit. The company offers bolt-on GM-based TBI fuel injection kits for many different older V-8, V-6, and inline-six engine applications.

Kubota Diesel Swap

I am scrounging the Canadian countryside to revitalize my ’48 Jeep CJ-2A. The next parts I need to pick up are the 60-inch-wide Dana 44 front and rear axles.

What four-speed manual transmission do you recommend? The engine will be a turbocharged Kubota diesel that will mate to a GM bellhousing. I plan to use my original Spicer 18 transfer case.

Thanks for the inspiration to breed life back into my flattie!
Tactical Ordinance
Via Instagram @cappaworks

Sounds like a really cool conversion. It’s sort of difficult to recommend a transmission for a Kubota diesel in a flatfender because I don’t know anything about the Kubota engines, such as where the starter is, how the exhaust is routed, oil pan design, and so on. I’ll go ahead and assume your engine has the same starter location as a GM V-8, given that it uses the same bellhousing. You’ll need to watch for starter clearance around the front driveshaft, and you may need to clearance the bellhousing if it’s a 360-degree style bellhousing. Compact gear-reduction starters are a great way to increase clearance in this area. Unfortunately, just about every engine and transmission configuration is a tight fit in a flatfender. You’ll generally be better off with the more compact four-speed manual truck transmissions like the T-18 and SM420. Larger transmissions like the SM465 take up a lot of space and will hang down far below the framerails, even if you suck it up into the body.

I think the T-18 with a 6.32:1 First gear is probably a better swap than an SM420. It seems to fit up to the Spicer 18 better and allows for a longer rear driveshaft. However, it will require more adapting to make the swap. You might also consider the RTS overdrive transmission from Herm the Overdrive Guy (hermtheoverdriveguy.com). It only has a 3.25:1 ratio First gear, but you may not need the incredibly low First gear ratios of the T-18 and SM420 with the low-revving Kubota diesel engine. The Overdrive gear of the four-speed RTS transmission will be nice to have with the diesel if you don’t have an overdrive unit on the back of the Spicer 18 transfer case.

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