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September 2002 4x4 Truck Repair Questions - Techline

Posted in How To: Tech Qa on September 1, 2002
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Where To Write
Address your correspondence to:
Techline
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 www.fourwheeler.com. Due to the volume of mail, electronic or otherwise, we cannot respond to every reader, but we do read everything.

Heim-Joint Legalities
Question: Are spherical rod ends, otherwise known as Heim joints, street-legal and/or DOT-approved? I have contacted several suppliers and suspension manufacturers and have received conflicting stories. The suppliers have said their products are not DOT-approved and are for off-highway use only. On the other hand, the suspension manufacturers have resoundingly stated that they are approved. That being said, I suppose if Heim joints aren't street-legal then many of their kits would be for the above-mentioned off-highway use only and might limit sales.

I now come to you for the final word. Are they legal, and can I use them in my dual-purpose (weekday commuting and weekend four-wheel adventuring) 4x4, specifically in the steering components, drag link and tie rod? If they aren't, how does that affect items such as Currie's Johnny Joints and Rancho's poly eyelet for its TJ lifts?
Dirk Kolnsberg
via fourwheeler.com

Answer: Things like this can vary widely from state to state. It's like asking, "Are lift kits, aftermarket wheels or bumpers or hub caps or chrome lug nuts legal?" If you replace a bolt on your truck with one that came from the hardware store and not the dealer, does that make it illegal? First, it depends on where you live, and on whether or not what you're wondering about has been addressed by your state's legislature. Additionally, not every thing we put on our vehicles carries a DOT-approval rating, nor does DOT approve many aftermarket parts. The Specialty Equipment Market Association (SEMA) has gone a long way in protecting the aftermarket by setting standards of manufacturing, but that doesn't mean an aftermarket part has to be SEMA-approved to be technically legal. I am sure that most manufacturers of, say, tie-rod ends, have agreed to meet a certain standard that is within the design of the original factory piece.

This obviously applies to Heim (registered trademark) joints, aka spherical rod ends. There are a wide variety of these joints available both in quality and size. Picking the proper one can be difficult, as most of us don't have the engineering background that enables us to calculate the imposed loads. In this case what we usually do is over-engineer the product and use the largest one available that will fit our application as well as go on the recommendation of the part manufacturer. To make use of a Heim joint, one has to drill out the tapered hole in a steering or pitman arm to a straight hole. Does this in itself weaken the arm, especially if a larger hole is drilled for a larger joint? Hard to say. And are they legal? That would need to be checked on a state-by-state basis.

What I will give you is my opinion on the subject. Standard tie-rod ends have been used successfully for well over 100 years on everything from cars to heavy-duty trucks. They are relatively inexpensive for the job they are subjected to.

I see no benefit to using Heim joints on a tie rod used on a solid axle, but these pieces could, if properly engineered for the usage, allow more angularity on a drag link or on an IFS system. In most instances a Heim joint should be captured on both sides of the joint in a double-sheer mount. Usually that's easy to do when they're used in a suspension bracket, but is more difficult to do with steering components. Another problem is that most of them don't have any provision for lubrication or for keeping road crud out of them. They don't last nearly as long as a standard tie-rod end will and don't have the shock-absorbing ability. On some suspension systems and types, they are the only way that large amounts of wheel travel are obtainable. Sure, they look trick, but does the expense justify the results? Only you can make that decision.

Cracked Case
Question: In the Mar. '02 issue of Four Wheeler, the article on transfer cases stated that the NP231 transfer case is prone to cracking. I have a 231 H.D. in my '98 Dodge 1500. Do these share the same case? Is this the same transfer case?
Mark Douglas
Aliquippa, Pennsylvania

Answer: Yep, the same case, only basic difference I know of involves the width of the chain and the planetary gear case. However, unless you're really abusing your truck, I don't think you have any worries. It's important when building new driveshafts for a lifted vehicle to make sure that the shaft's slip joint has enough travel so that it doesn't bottom out within itself before the suspension reaches full compression. If this happens, the shaft will push against the offset part of the case, using the case and the driveshaft as a stop. This most likely will break the case.

Driveline Vibes
Question: I'm hoping you can help me with some questions I have about putting a suspension lift on an '02 Ford F-350 Crew Cab shortbed. I've been doing some research and I've been told by the employees down at my local shop that if I lift this truck any higher than 4 inches, I can expect driveline vibration at initial acceleration, which will cause problems with U-joints. Is this correct? Is the only way to solve the problem to replace the stock two-piece driveshaft with an expensive single shaft? Also, I'm very concerned about the ride aspect of the lift, because 75 percent of my driving will be back and forth to work. I would like to go with a 35-inch tire and stay as narrow as I can. I'm ordering the truck with the 4.30:1 gear ratio, hoping that this ratio will allow me to have reasonable highway rpm with the larger tires.

Could you please enlighten this mid-life crisis 4x4 enthusiast, and help me from making decisions I will regret? Any information you could send me will be greatly appreciated.
Dave Palmer
via fourwheeler.com

Answer: Yes, you probably will get some vibration. I think that I would experiment with the mounting location of the driveshaft's center carrier bearing before I built a new long shaft. It might be possible to build a special mount and lower the center bearing to a position and angle that puts all the U-joints in proper angularity to prevent vibration. If you have a new single-piece shaft custom-built, it would have to be quite large and thick to prevent whipping motion. But then again, what's $500 for a shaft after you have spent 40 grand on a truck?

Rough Riders
Question: Sure hope you have some advice for me. If not, my chiropractor is gonna drain me dry. I have an '85 Toyota 4x4 pickup, shortbox, regular cab, with a 2-inch softride suspension kit from one of Four Wheeler's advertisers, along with greasable shackles. To my surprise, it rides worse with this kit on it than it did when I had the stock springs in it. It also has 3 1/2 inches of lift rather than the advertised 2 inches. I have close to 4,000 miles on the new springs with no sign of the ride getting any better. I've taken off the overload spring in back and with a load it rides nice but it sags. Empty, it still is awful. The manufacturer won't help me out. A customer-service rep told me the company has been selling springs for 20 years and no one has complained yet, so it must be my fault.

My plan is to take out leaves front and back till I get an acceptable ride. Once the ride is nice, I will install a set of airbags in the rear to help out with the load handling. I expect to get down to the main two leaves in each spring pack before the ride is where I want it. Do you foresee any problems with this setup? Will the 3 1/2 inches of lift (down to 2 once the extra leaves are gone) not allow me to run the air bags? Any advice would be greatly appreciated by a first-year four-wheeler.
Ben Brittain
via fourwheeler.com

Answer: You have found that, generally speaking, a suspension lift that includes new leaf-springs with a higher arch is going to cause a vehicle's ride to stiffen up. That's true even of some suspensions labeled "soft ride," which causes me to ask the question, softer than what?

Yes, you can take out leaves, and as you have found out, the more leaves you remove, the less load carrying capacity you are going to have, and the lower your truck will sit. Yes, you can add aftermarket air bags to regain the weight-carrying capacity.

Where you're going to have problems is in axle control. Most likely you're going to run into a lot of axlehop due to the leaves flexing and rebounding as they try to resist bending under torque loads. What I suggest is that you contact one of the Toyota specialty shops and purchase a complete suspension system with matching shock absorbers. Kevin Grove at Advanced Off Road Research (725 B West Grand, Grand Junction, Colorado, 970/263-4300) seems to have a handle on Toyota suspensions. Not only does he offer springs that provide a fairly good ride quality, but Kevin's systems also articulate quite well, thanks in part to special eye bushings that provide movement without having to twist the spring.

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