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November 2007 4x4 Tech Questions - Nuts & Bolts

Posted in How To on November 1, 2007
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Confused? E-mail your questions about trucks, 4x4's, and off-roading tech using "Nuts, I'm confused" as the subject and include a picture (if it's applicable). Digital photos must measure no less than 1600 x 1200 pixels (or two megapixels) and be saved as a TIFF, an EPS, or a maximum-quality JPEG file. Also, I'll be checking the forums on our Web site (, and if I see a question that I think more of you might want to have answered, I'll print that as well. Otherwise drop it old-school style with the envelope addressed to the address below. Letters published in this magazine reflect the opinions of the writers, and we reserve the right to edit letters for clarity, brevity, or other purposes.

Write to:
Nuts & Bolts
4-Wheel & Off-Road
6420 Wilshire Blvd.
Los Angeles, CA 90048-5515
fax 323.782.2704

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Question: I have a '79 Bronco that I purchased a few years ago for $350. My wife thinks it's ugly and my friends think I should have just bought a Jeep, but I love it. I have replaced the engine, added a small lift and 35s. I have also upgraded to an Aussie locker, better brakes, homebuilt bumpers, and new seats. My confusion is I would like to make a rollcage to protect my girls, my wife, and myself. What is the cheapest way for me to bend tubing to make a rollcage? When I ask around (local shops, wheelers), everybody says to spend $600 or more on a bender or have a shop do it. Is there a cheaper way to get this done at home? Can you help a cheap dad?
Vince G.

Answer: I understand your situation, but before you balk at $600 consider how much your family's lives are worth. A quality rollcage is an important investment, and not something to skimp on. I would recommend at a minimum using 1 3/4-inch by 0.120-wall tubing, preferably 2-inch diameter for your fullsize 4x4. Though there are cheap "pipe" benders out there they should not be confused with "tube" benders. Pipe benders crimp the tubing in the corners, and this stresses the tubing and makes it weaker. Why not look into a cage kit for your Bronco. I found two varieties from All4Fun Off Road (541.928.8600 and both are under $600. However, they do require truck freight. In my conversations with them I learned that you would still need to trim the height to fit perfectly in your Bronco and do all the welding yourself, but all the tubes are bent and notched to fit your Bronco.

Since your question was helpful and enlightening to more than just a few of our readers, we've decided to award you this month's Tech Letter of the Month with a very enlightening prize, a set of the new 9-inch round HID lights from Pro Comp Motorsports (619.216.1444, These high-intensity floodlights feature a built-in ballast and clear heat-resistant protective lens. Plus the durable ABS housing is rugged and impact resistant so you should be able to see your way no matter how crazy you get off road after dark.

Question: I have a set of 33x11.5 Baja claws on my '94 Mazda B2000. They are starting to cup really bad. What is the best way to get them to stop cupping? I rotate them frequently. Is there any way to save them once they start cupping?
Jason P.
South Dakota

Answer: To my knowledge there is no way to fix severely cupped tires. Have you tried running them in the opposite direction? Since these directional tires are designed to run in one direction only, flipping them around to the opposite direction may just help reduce the abnormal wear. Otherwise it's time to make your Mazda a stunt truck and take it off lots of jumps; this will keep the tires off the ground and preserve them.

Question: I was wondering which would be better for a conversion into an '89 Suburban; a Cummins 4BT four-cylinder or a Mercedes/Dodge Sprinter diesel engine?
Joachim S.
South Dakota

Answer: The Cummins 4BT is a better choice for the swap. This engine was available with a GM transmission adapter from the factory and it doesn't require nearly as many complicated computers as the Mercedes Sprinter engine does. However the Mercedes engine would be a cool swap into a Jeep or buggy if you had the time and knowledge to wade through the electronics.

Question: What's the biggest tire I can put on my '85 Blazer? I want to run 37s but I can't afford a big lift kit so I was thinking about a body lift. What's a broke boy to do?
Bobby S.
Clarksville, KY

Answer: Your Blazer is blessed with a solid front axle and is probably one of the most "normal" and easy to lift vehicles ever made. You can easily run a 33-inch-tall tire with no modification, while a 35 will mean you need to trim the fenders a bit up front, or just drive in a straight line. For the 37s you could go with a body lift of an inch or 2, but remember that even though a body lift is cheap, practical, fairly easy, but very time consuming, they do nothing to dampen the weight of the much larger and heavier 37-inch tires and wheels. The added weight of the bigger meats means that you really need a spring and shock combo that can control the added heft so that your ride is controlled, and neither choppy or mushy. Save your cash and do it right the first time, since you'll be doing it again in the long run if you go to bigger tires.

Question: During my deployment in Iraq, we encountered some rain which made the few paved roads really slick. It reminded me of how my 35-inch mud tires at home like to slide all over the place on wet pavement. I've noticed that some other tire manufacturers have some siping on the tread blocks to improve traction on wet pavement. I understand that the sipes can sometimes pick up road debris or cause the tread blocks to tear off in chunks, so I can understand why many people would not want siping in their mud tires. What are some of the other drawbacks and some other benefits to having siping? Since my mud tires unfortunately spend most of their time rolling down paved roads, I'd like to have that additional traction aid. Is there a way to add siping to a tire myself?
1st Lt. Dan Cole
263rd Maintenance Company
U.S. Army
Northern Iraq

Answer: Siping is a great upgrade especially if you live in a place where there is a fair bit of rain. Siping is small cuts that not only add traction on the road, but also help the thicker tire lugs found on many mud tires to flex. I've even seen some rockcrawlers running siped tires for additional traction in big boulder fields. I would look around at your local tire shops and see if they will sipe your tires. Most shops will sipe used tires if they have the tools and the tires are not extremely worn. If you want to do your own siping or tire cutting, look into Ideal Heated Knives (248.437.1510). It is good for both grooving tires and siping, depending on the blade you use. Since you may not be able to get a heated knife in Iraq, try cutting the tires with a sharp knife, but don't cut more than about 1/4-inch deep from the top of the tread. Also most siping is often done across the tread, not around it

Question: I have a problem; I am 15 years old and want to start wheeling when I get my license in another year. I am hoping to make my first vehicle a Ford or Chevy pickup but I need something with good mileage. My dad offered to help pay the fuel in my vehicle but he doesn't think I should buy a 4x4. I need to find something that gets 17 to 20 mpg yet still allows me to go off road. What do you recommend that will satisfy my dad's desire for efficiency and my wish for a 4x4?
Sean B.
Coregory, MI

Answer: I was in a similar position once. My dad offered me a perfectly good Volkswagen Beetle that he was willing to pay the insurance on when I was 16. However, I had been reading 4-Wheel & Off-Road and never saw a Beetle in there so I was determined to get a Jeep. I think your dad has a valid point: Finding a fuel-efficient vehicle will result in more money in your pocket to modify your truck, take your girlfriend to the movies, and buy food and camping gear for a long weekend of four-wheeling. I would recommend either an early diesel 4x4 or a four-cylinder mini-truck like a Ranger, S-10, or Toyota. The diesel truck will probaby be a 3/4- or 1-ton with strong parts.

Also remember these rules for better mileage. Always keep your tires aired up and front hubs unlocked when on the road. Don't speed. Keep all the fluid levels topped off and routinely serviced. Don't carry extra stuff. Leave the Hi-Lift Jack, tool bag, chains, and extra stuff at home unless you're going wheeling. All that extra weight robs fuel. And when you come home from your wheeling trip be sure to clean as much mud and dirt from your ride as possible. It adds weight and robs mileage.

Question: I own an '07 Toyota FJ Cruiser. I would like to know if there is a way to turn off the traction control when in two-wheel drive. I don't like the computer shutting down the throttle after both wheels start to spin.
Randy F.

Answer: I hate all those electronic nannies that act like fun police, ruining all the smoky burnouts, drifting, and other juvenile antics that make driving fun. I understand some people don't know how to operate their vehicles, but I think it should be a choice for those of us that think we do. I spoke to the guys at All Pro Off Road (951.658.7077,, since they are doing a great business with FJ Cruiser products, and they have a simple modification that helps turn off the traction control. So give them a call.

Question: I am in the process of building a rad rock buggy. I don't have much money or tools, but I have a lot of time. I am running a 4.3 Vortec out of my mom's old Blazer that started on fire (cigarette, Pabst BR, the dog, long story). I am having a problem getting the oil pan to clear my Dana 44 that I converted to eight-lug to match my Eaton rear axle. I need to know which one of the vehicles that used this engine will have the shallowest or shortest oil pan. I really want to get my buggy going because I have a hot date with the girl up the road in a month or two and she seems to be into the buggy thing. She drives a really cool Forward Control Jeep, and I think she likes me.
Brian E.

Answer: There are two basic factory oil pans, steel and aluminum. If you have a steel pan you need to replace it with another factory steel pan, and the same goes for the aluminum. However, there are also differences in the depth depending on whether the pan is from a two-wheel-drive or a four-wheel-drive. The four-wheel-drive is very shallow at the front, but very deep in the rear and uses a small sump, where the two-wheel-drive is shallow the whole length, but not as shallow as the front of the four-wheel-drive. You'll most likely be better off with the two-wheel-drive version of the aluminum pan since yours is a Vortec engine.

Question: I was told that my new four-door Jeep JK has lockers (it's not a Rubicon model), but it seems like I get a lot of wheel slippage climbing hills. It makes it to the top OK, but shouldn't a real locker really lock, not spin?
Henry D., MD

Answer: You're right on. A real locker does lock, not slip. What you have is a system known as Brake Traction Control, and theoretically it could be called a locker, but it isn't. A locked or a spooled differential allows both tires on one axle to turn at the same time and rotational speed, regardless of traction, even if one tire is in the air. Brake Traction Control (BTC) and all of the various names for the same system from different manufacturers control traction by applying the brake on a selected wheel to force the power to the other wheel through an open differential. That's correct, you have an open differential, which on an ordinary vehicle means that if one tire is in the air or slips due to lack of traction, the other tire remains stationary and you are stuck. Now enter the magical BTC; by sensing wheel speed (since the vehicle has an Antilock Braking System) the computer knows that one tire is spinning faster than the other and clamps the brake down on the spinning tire proportionally to transfer power to the nonspinning tire which has traction, and up the hill you go. However, the drawbacks of this system are numerous, even though the technology is slowly catching up with the design parameters. While the engineers can make wonderful graphs and models to show the bean-counters why this is a good system as well as convince the marketing people that stupid consumers will be able to use this instead of a real locker while the lawyers all nod in liability-proof agreement, the fact remains that for the system to work (regardless of the threshold parameters), the tire without traction has to slip while the other tire remains still for the BTC to engage, hence a loss of traction and even more spinning. The way to drive these rigs is counterintuitive-as you have to give the vehicle more power to make the other tire pull, by breaking the spinning tire which forces the other tire to spin. Early versions (and some current ones) from various manufacturers are simply hideous, as you have to keep gassing the rig until it hooks up and lurches over an obstacle, and hopefully not over a cliff. As far as we're concerned, they aren't lockers.

Question: I have encountered a slight dilemma concerning my choice in wheel size for my '04 Super Duty diesel 4x4. When I bought it new in 2004, I put a set of 16.5x12 Weld Mountain Crusher wheels on it. Now I'm finding it very difficult to find tires that fit them. I've been running 16.5/36/16.5 Cepek Fun Country Kevlar for the past couple of years. Do I need to opt for new tires and wheels this time around?
Tony A.

Answer: The 16.5 wheels and tires are quickly becoming a thing of the past. Though these wheels and tires have been around for a long time, the new 17-, 18-, and 20-inch wheels are quickly replacing them, and they are better wheels. The 16.5 wheels often do not have the small safety bead that helps keep the inner bead in place, thus they are more likely to lose a bead when run at low air pressure off road. I do, however, like the military surplus Humvee wheels that are 16.5 and double bead locks, but otherwise I wouldn't spend any more money on 16.5s. There are a ton of great tire options for 17-inch rims and I would recommend you upgrade to them.

Question: At what point should one consider an extensive axle swap before investing in what is already there? I've got a '96 short-box Ram. While the BFG Mud-Terrains continue to hook up everywhere, the 33 inches they offer is getting old. My buds with Jeeps on 35s are leaving me for dead. I am thinking about a set of 35- to 37-inch rubber. I think I have the necessary lift already and I'm not at all opposed to cutting the body up if it means keeping the center of gravity low. But I don't know whether to swap in a D60/70 combo from a 3/4-ton truck first, or work with the D44/Corp. 9.25 that came on the truck. I don't want to put a pile more money into the axles in the form of gearing and lockers, only to break everything and have to then do a swap. Some sources suggest that 1/2-ton gears are good up to 37 inches, and others warn to keep under 35 inches. I know that vehicle mass, tire size, engine size, driving style, and terrain all contribute to breakage
Zac V.
Petawawa, Ontario, Canada

Answer: Your 1/2-ton stuff is very tough, but 37s will be pushing them to their limit. Thereare certain thresholds of axles, and a stock 1/2-ton axle is OK with 35s. When built with custom chromoly shafts and lockers they can live up to 37 or 38, but that is dependent on the driving style, terrain, weight, and so on. Unless you are a 110 percent positive that you will never go larger than 37-inch tires and you will never drive aggressively, I would take the step up to larger axles. Follow your lan, keep it low, trim the body to fit, and get those bigger axles under there.

Question: I have a '99 diesel Ford Super Duty 4x4 with an automatic transmission that was replaced by Ford on an earlier recall program. This replacement automatic transmission occasionally leaks automatic transmission fluid but only when the truck is in four-wheel drive! Sometimes the volume of lost fluid is so great that the automatic transmission will start slipping. If I replace the lost transmission fluid-normally about 5 to 6 quarts-and drive in two-wheel drive this stops all further leakage. I can drive thousands of miles in two-wheel drive, pulling heavy loads and in hot temperatures and it never has leaked a drop. The repair shop has suggested pulling the automatic transmission and replacing the seals on the automatic-transmission fluid pump. However, I suspect the pump seals are not bad if the automatic transmission does not leak fluid while in two-wheel drive! Have you heard of similar fluid leakage problems? Could this be an overheating problem related to the use of four-wheel drive, which puts a heavier load on the transmission and causes the fluid to be lost?
Ronald M.
Florence, AL

Answer: That is a pretty crazy situation you have there. My first suggestion would be to take your truck to the local pressure washer and get it spic-and-span clean underneath. Then take it off road and when it starts leaking, crawl underneath and figure out exactly where it's leaking. I spoke to Brian Thompson from Brian's Truck Shop (870.422.3673, www.brianstruck, where they specialize in Ford transmissions, and he said that the transmission should not care whether you are in two- or four-wheel drive. Any line pressure increases due to being in four-wheel drive would also be seen in two-wheel drive. In the end we came up with only two scenarios. First, you might have a broken bellhousing. If it is cracked, the additional twisting of the drivetrain while in four-wheel drive may be causing a leak. However the second scenario is more likely. You are heating up the tranny considerably more when driving off road. Do you have big tires, yet still have the factory axle gearing? If so, this is putting more strain on the transmission, and if you are going slow but working the tranny very hard, you are probably not getting enough airflow to cool the transmission, thus the overheated fluid is getting pushed passed that seal. I would recommend a few things once you determine where the leak is coming from. Change your gear ratio in your axles to better turn the bigger tires, get a bigger tranny cooler or add an additional fan to help cool the gearbox, and get that pump seal replaced. Brain is just up the road from you in Arkansas and would gladly help you out if you're interested.

Question: I have an '87 Samurai that won't run smoothly, and is multicolored and rusty. I think the carb might be plugged and the battery is dead. Do you want to buy it?

Answer: Nope. Thanks for writing.

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