Tie Rod Ends and their replacement
Thanks to Hugo Teufel & Michael Davis :
Tie rods, and tie rod ends, are important parts of the SHO's steering. Unfortunately, the OEM tie rod ends are not known for being long-lived. There have been a number of reports of spectacular and catastrophic tie rod end failures, primarily when SHOs are making slow-speed, sharp-angle turns in parking lots. The National Highway Transportation Safety Administration looked into Ford tie rod end failures but, apparently, came up with nothing conclusive. (It is rumored that in April of 1994, The Wall Street Journal ran a piece on NHTSA's investigation.) Because of the short-lived nature of tie rod ends, Gary Morrell suggests replacing the tie rod ends by 60k. Vadim of the SHO Shop suggests that, in particular, the '89 to '91 SHOs should have the outer tie rod ends replaced.
The maintenance and concomitant condition of the inner and the outer tie rod ends are related. The joint has a very strong torque load when turning, and when the grease from the outer tie rod end is gone, the result is extra pressure on the inner tie rod. This probably adds to the premature failure of inner tie rods, and the primary symptom of this combination is the "clunk" in tight parking lot turns. The reason for the clunk is because the 'de-greased' outer tie rod resists turning, returns a torque (moment arm), which will hold the inner tie rod against the side of the socket, such that when the torque is then decreased, the inner tie rod will snap back, or "clunk." After several times of the rod snapping back, it is bound to give, and do so catastrophically. When this happens, you'll be calling for a tow to take your disabled SHO to a mechanic, or your home, for repairs.
Short of catastrophic failure, bad tie rod ends will affect your car's alignment, prematurely wearing out your suspension and steering, along with your tires. Bad tie rod ends affect the car's "toe." Gary Morrell has written a very good piece on alignment, posted on the FAQ. Rather than reiterate the importance of "toe" to alignment, we suggest that you read his piece.
When looking at your tie rods, it is best to get both tie rod ends on both sides checked out (or check them out yourselves) when you are thinking of replacing them. The price for all four tie rod ends (parts alone) is approximately $100. If you are going to replace tie rod ends, it is not recommended that you use tie rod ends from a bone yard. One never knows were they have been. Besides, new replacements are not expensive, especially relative to other maintenance parts. Also, you may as well do the tappet adjustment while you are there, using that same logic about installing the struts and springs.
Technical Service Bulletins to look at on tie rod ends include: TSB 96-1-1 "New Torque Specs For Installing New Design Tie Rods"; TSB 93-13-2, June 1993, "Tie Rod End (Inner) - Replacement Procedure"; and TSB 91-17-4, August 1991, "Tie Rod End Service Tips".
The Outer Tie Rod End: A bad outer tie rod end will sound like a bad shock or spring when you push down on that corner of the car. It has been described sometimes as making a soft "huunngh" sighing kind of sound, and sometimes as a "clunk", when turning to the left at slow, parking lot speeds, and when driving slowly on uneven roads, or when turning the steering wheel while the car is stopped. A good way to check the tie rod ends is to jerk on the wheel hub and see how much play you are getting in the tie rod end ball joint. You should check the outer tie rod ends whenever you have your car up on a lift.
Outer tie rod ends go from $18 to $35 at aftermarket suppliers such as Autozone and Pep Boys and are manufactured by Moog, Dana and TRW (Part Number: ES2513R, Moog, and #133207, Auto Zone). The difference between the Ford ends and the Moog/TRW ends are that the Ford ends have sockets lined with rubber and thus are not designed to be greased, while the Moog/TRW ends are metal to metal and have a grease fitting. The rubber tends to wear out, giving the car's steering a loose feeling.
Replacement is fairly simple and takes about 30 minutes. Take the cotter pin out of the bolt holding the crown nut at the wheel. Remove the crown nut. Hit the tie rod end with a hammer and it will pop off the spindle. Loosen the holding nut on the inner tie rod shaft. Count the number of turns it takes to take the end off. Put on the replacement outer tie rod end and turn it on the same number of times. Tighten the locking nut -- you should get a new one with the tie rod end. Then reattach to the spindle, tighten the crown nut, and put in the cotter pin. Be sure to tighten it to get it to where you can get in the cotter pin; don't loosen it to get the crown nut to align with the hole in the bolt. (BTW, the manual recommends you replace the crown nut that holds the tie rod spindle in the steering knuckle.) If the tie rod end has a grease fitting, grease the ball joint.
After replacing the tie rod, get the car realigned. This is important since the replacement parts may not be exactly the same length as the originals, and even if you have tightened the new tie rod ends the exact number of turns as old ones, your alignment may still be off.
Inner Tie Rod End: Symptoms of bad inner tie rod ends include looseness of steering, severe torque steer, and a "clunk" at full or near full-lock parking lot maneuvers. Inner tie rod end symptoms are worse when the car is loaded with people and luggage. Those who've commented on the condition of the inner tie rod ends have stated that the end was lacking in lubrication, suggesting that the factory either had not lubricated the end or that the end had at some point dried out.
Inner tie rod end wear is more difficult to detect than is outer tie rod end wear. The best way to check the tie rods is to remove the ends from the steering knuckles and push/pull on them towards the steering rack to check for wear. Helm's states that the inner tie rod end should have around 10 lbs. of resistance with the outer tie rod end disconnected.
Replacement of the inner tie rod end is about as simple as the outer. There are a few important points to consider, however. First, there is a rivet that you must pull before you can unscrew the steering rack end, and this can be a little time consuming. Second, the driver's side will be a little more difficult, because you have to hold the exposed teeth with an adjustable wrench.
To remove and replace the inner tie rod ends: Raise the front end and support it with the proper jack stands. Remove the front-end tires and wheels. Remove the outer tie rod end from the spindle and then from the tie rod. Break the bands around the bellows on the inner end (replace them with a hose clamps when you reinstall). Pull off the breather tube. Use the 1 5/16" inner tie removal tool -- a deep socket -- to remove the rod (manufactured by Lisle Tool Corp., available at Sears, etc., and approximately $20). When working on the driver's side, you can use an adjustable wrench to hold the rack when removing/installing the inner tie rods. Unfortunately, you can only access the rack teeth on the driver's side, which makes the passenger side more difficult, and you will have to remove the bellows on the driver's side if you are replacing the passenger side.
Also, when removing the old inner tie rod ends, you will have to use some muscle, given the shear pins in the female threaded part. In the alternative, you may have a rivet that keeps the inner tie-rod from unscrewing from the rack, you should use diagonal (side cutters) snips to pry it up and remove it from the female end. While working on the inner tie rod ends, watch your hands, you could cut yourself on edge of the brake splashguard. Throw a rag over it. Install the inner tie rod ends with 55-65 ft-lbs. of torque. Put in the roll pins; these do not always go flush, but are something to keep the tie rod ends from falling off and they sit behind a collar. You just have to tap them in, not a lot of room to tap, but you can use the side of the snips. Put on the bellows, install the clamps, and put back on the breather tube. A helpful note: if you put a little grease on the old tie rod, it will allow the bellows to slide off easier. Add chassis grease to the ball and socket by lightly packing around the exposed area of the joint.
Note: Ford's "new" design inner tie-rods won't allow installation with the same tool you use to remove the old ones. The ball housing on the new rod is bigger than the hex area behind it so you can't slip a socket over it. There is a two piece tool that can be assembled around the new tie-rod. It costs about $50 and has several end pieces, so it can be used for other applications. Also, the hex is 34mm on the new and 1-5/16 on the old. Ford TSB 93-13-2 sets forth the installation procedure for the new design tie rod ends and states that Loctite should be applied to the rack threads before installing the new design tie-rod ends. The reason for the Loctite is that the new design does not use a rivet pin. The new design inner tie rod ends are less expensive than the old design (approximately $22 vs. $32). You may also want to look at Ford TSB 96-1-1 "New Torque Specs For Installing New Design Tie Rods" if you go with the new design ends.
Again, after replacing the inner tie rod end, get the car realigned.