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January 2005 4x4 Tech Questions - Techline

Willie Worthy | Writer
Posted January 1, 2005

Send Us Your Tech Questions

Address your correspondence to:
Four Wheeler
6420 Wilshire Blvd.
Los Angeles, CA 90048-5515.

All letters become the property of Four Wheeler, and we reserve the right to edit them for length, accuracy, and clarity. The editorial department also can be reached through the Web site at Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.

Question: Is there a company that can help me put disc brakes on a Chevy 1-ton rearend?
James Limmer
Brandon, Florida

Answer: Several companies offer kits to do this. They include: TSM (Dept. FW, 4321 Willow Creek Rd., Castle Rock, CO 80104, 303/688-6882); Desert Fab Motor Sports (Dept. FW, 564 N. Idaho, No. 4, Apache Junction, AZ 85219, 480/980-2681,; and Off Road Unlimited (Dept. FW, 2102 Kenmere Ave., Burbank, CA 91504, 818/563-1208,

Question: I own a '94 GMC Jimmy and love it to pieces. However, I've replaced four fuel pumps and now it needs another one. Do you have any suggestions other than a bad ground?
Katie MacIver
Dover, New Hampshire

Answer: I had to kind of chuckle when I read your letter, as I just helped a neighbor with the same problem on a '94 Chevy. Replacing the fuel pump on this fuel-injected vehicle involves dropping the fuel tank. This is not a fun job. Anyway, you're on the right track when you think about proper grounds. You should also check whether the pump is getting the proper amount of voltage. Lower voltage means the pump motor may be overheating, though this isn't usually the case with a DC motor that is submerged within the tank. One other thought is that there may be a problem in the fuel-return line. If there is a restriction reducing the flow of unused fuel back to the tank, then the pump could be doing more work than it's designed for, thereby shortening its life.

Question: In "Willie's Workbench," (July '04), you discussed making high- and low-beam lamps all burn at the same time on GM four-headlight systems. I have the same question with regard to the Jeep XJ Cherokee two-headlight system. I can wire it so the low beams stay on with the high beams, but I don't know if that is OK to do. Do you know if the lights or wiring will get too hot if I do this, or of any other problems that might arise with both filaments on? I sometimes do as you described-momentarily hold the high beam flasher to get more light.
Martin Goetsch
San Dimas, California

Answer: I've been told that if you wire your XJ this way, you will overheat the bulb and shorten its life dramatically. However, my CJ-2A has an MB grille with the small 5-inch headlights containing 12-volt halogen sealed-beam bulbs. I wired the low and high beams on separate circuits so I can use both. While it doesn't get a lot of night driving and probably doesn't have a total of four hours of high-beam usage, they are still working. I say, try it, knowing that it could cost you some headlight bulbs, and let us know how it works.

Question: I'd like to ask you about wheel spacers and the different materials they are made from. I have been seeing more and more high-dollar rigs using wheel spacers-and aluminum ones at that. So, what is the better material-aluminum or steel? On the cover of the May '04 issue of Four Wheeler there was a photograph of a '00 Dodge Durango using 2 1/2-inch billet-aluminum spacers. I use the steel spacers myself, and they are pretty heavy. I recently saw a Chevy Avalanche on the cover of another magazine using aluminum spacers. Steel is stronger, but heavier, while aluminum is a softer material and lighter. If the guys who own these $100,000 rigs are willing to run billet-aluminum spacers, are they good enough for my 3/4-ton Chevy 4x4?
Paul Herrington
Rosepine, Louisiana

Answer: The aluminum wheel spacers seem to work just fine. There are several companies offering them, so I suggest you do some research into their quality. Just because they're made out of aluminum doesn't mean that they don't have the necessary strength. There are, however, several things you need to keep in mind if you choose to use spacers. A couple of things will change, including the steering and scrub radii, which can lead to faster tire wear. Because you're moving the center load point of the tire outward, you're putting more leverage on the hub and spindle. If your rear axle is of the light-duty type with a flanged axleshaft, you're putting more load onto the axle bearings. Whether this will cause a problem or not depends on just how you use your truck, and the amount of load you carry.

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