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May 2002 4x4 Truck Repair Questions - Techline

Posted in How To: Tech Qa on May 1, 2002 Comment (0)
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Techline
Four Wheeler
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Los Angeles, CA 90048-5515.

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CJ-7 Divided by 360 Equals V-8
Question: I own a 1979 Jeep CJ-7 with a 258ci six. I have a spare 360ci V-8 in my garage. Would this make for an effective swap? My Jeep has a T-18 transmission. I use it mostly for sand and mud running.
Omar Esquivel
Via the Internet

Answer: In my opinion, one can never have enough horsepower or enough cubic inches. This is especially true for running in sand and mud. So what you're suggesting makes good sense. This swap is fairly easy, as for starters, the six and the V-8 share the same bellhousing, so you don't need an adapter to mate the engine to the transmission. But it is important that you use the flywheel from the 360. This is because all AMC engines are externally balanced, so the flywheel must match the engine, or be rebalanced to the engine. Naturally there will have to be some changes, such as different motor mounts and modifications to the wiring. The radiator used to cool the six would be marginal for cooling an additional 100 cubic inches, so a new one is in order. Mepco, in Midvale, Utah (800/388-5337), has some heavy-duty units at a reasonable price that will bolt right in.

Bigger Brakes?
Question: I own an '88 Chevy 1500 four-wheel-drive truck. I would like to do some performance modifications, but need to improve the braking system first. I had the brakes checked by three different shops, and have changed pads and fluids, but the brakes are still sub-par. Are there any enhancements that I could make?
Rod Mull
Shillington, Pennsylvania

Answer: Summit Racing (800/230-3030, www.summitracing.com) offers some really nice Autospeciality Power Stop Rotors that are said to run up to 200 degrees cooler and last up to five times longer than other rotors. Heat is the biggest enemy of brakes, so combining these cross-drilled rotors with some quality brake pads most likely will be the hot (or is that cool?) ticket to better braking.

Also, you might want to invest in some quality stainless-steel flex lines. These aftermarket lines will limit any swelling that may have taken place in stock lines and give you a much better pedal feel.

If you're going to stick with 15-inch wheels, that's about the limit of what you can do-aftermarket rotors and upgraded brakelines. If however you opt for the 17-inch wheels now coming into popularity, you have a few options with several companies offering bigger rotors and more powerful calipers to grip them. For a look at what's possible, you might want to check with Stainless Steel Brakes (800/448-7722, www.stainlesssteelbrakes.com) or Baer Brakes (602/233-1411, www.baer.com).

How Much Should It Cost?
Question: I have a 1972 Ford F-250 that has been sitting for three years. I'm thinking I might like to restore it. But my uncle said I should just sell it because it would cost too much money to restore it. What do you think?
Meredith Hess
Via the Internet

Answer: Only you can answer this question, especially because the verb "to restore" takes on several different meanings. To me, it means to return something to original, "as-new" condition. To some folks, however, it might just mean getting the vehicle running so that it is usable. Obviously the costs for those two definitions will be quite different from one another.

Whichever you choose to do, a lot depends on the condition of the truck when it was parked. Does the engine need rebuilding? That could amount to anywhere from $500 for a home rebuild of just rings, bearings, and a cheap valve job, on up to several thousand dollars for a semi-performance engine. Most likely the tires are in need of replacement, so add that to your bill. Wheel cylinders and calipers will need to be rebuilt, and so might the master cylinder. And you might need new brakelines. While you're at it, you might want to go to new shoes, pads, and have the drums and rotors turned. You have to consider the condition of the transmission and the rest of the drivetrain, and don't forget the steering components. Then there is the body's condition. Is it a total rust bucket, or don't you care what it looks like as long as safety isn't compromised?

What you need to do is sit down and start pricing out the parts that you think the truck will need for a full restoration and another list for just getting it running. Then you can make up your own mind whether it really is worth the money and the work. Keep in mind the amount of time it will take to do all this. When all is said and done, perhaps your uncle is right. Then again, half the fun of owning a vehicle is fixing it up, as long as you recognize that you're unlikely to ever get your restoration/rebuild money back out of it.

A Clunk in the Night
Question: I have a Ford F-350 crew-cab longbed 4x4 with 4.30:1 gears with a V-10 and 8-inch Fabtech lift with 5-inch springs in the rear. When I come to a complete stop, I feel a clunk in what I assume to be in the rear U-joint. I also feel the clunk right when I take off. Is this axlewrap? If so, what can I do to fix it? I have already lowered the driveshaft in the middle about 1 1/4 inches. Would it help to lower it more? I know traction bars would probably fix the problem, but I really don't like the way they look. Any other solutions?
Michael Auth
Via the Internet

Answer: I doubt that what you're hearing is axlehop or axlewrap. When you come to a stop, the braking action causes the pinion on the differential to point slightly downward and then as you accelerate, the pinion will move slightly upward. This causes the driveshaft to change length at the slip yoke. Most likely the noise you're hearing is the driveshaft binding on the slip yoke and then releasing quickly. The noise is enhanced by the driveshaft tube acting as an amplifier. Most likely it is caused by improper driveshaft angles. As you know, your truck has a two-piece rear driveshaft with a carrier bearing supporting the two halves. This is necessary because one long shaft would have a tendency to whip at high speeds. I think that if this is indeed what is happening, the solution probably is to lower the center mount to a point where the slip yoke doesn't bind. How much lower? Only trial and error will find the answer. You also may want to play with the angle of the rear pinion. Sometimes a synthetic grease on the slip yoke will cut down on the friction and will stop the clunk noise. Sometimes it even takes a replacement slip yoke and shaft to do it.

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