Power Steering Rack Preventative Maintenance

Editor Erik Roe

I was looking the Milano over the other day. Sort of checking if any oil leaks or other issues had popped up that needed attention. The only thing I found was a torn steering rack "dust" boot. At first I didn't really think much of it, but than it occurred to me that it is a big job to replace that rack and that it is also expensive, some thing like $400 for rebuilt one. With that in mind, I decided to replace the "dust" boots.

Most rubber components fail with age, almost no matter the use/abuse. Ozone, heat and oil cause the rubber to loose strength and elasticity resulting in tearing or reduced strength. With my car, the power steering rack has never leaked, but the engine rear crank seal, with a 124,000 miles, has started to weep. Since the steering rack is in close proximity to this part of the engine, I am guessing that is where the oil came from that softened the rubber and lead to the small tear. The driver's side was fine, but I replaced both since I was going to do one. Photo 1 shows the old (left) boot and the new one. Note that each has 13 ribs, but that the old one has shrunk up over time, it was much less flexible.

The parts were pretty reasonable and available at the dealer (in stock at RT GT). Two boots (they are identical left to right) were about $47 list (part number 00099-43860-00-00 "Dust Cover").By the way, AROO members get a 15% discount on parts at RT GT. The installation took about an hour.

To install a boot, you have to disconnect the rack from the tie rod end, remove the old boot, by cutting the nylon zip tires at each end, and peeling the boot off like you would a rubber glove from your hand. Fit the new boot, install zip tires and connect the tie rod end. Easy, but there are some details.

You need to ensure that the "toe-in/toe-out" remains the same, since you may not want to visit your local line-up shop for after this boot replacement. Photo two shows taking a measurement from a reference point on the rack rod to the locking nut on the tie rod end. I used my calipers, but as I did the repair, I noticed that the dirt in the threads showed pretty clearly where the nut was located. With a metric ruler, you should be able to resolve 0.5 mm (0.020") which is probably accurate enough. My reference point was the inside vertical edge to the 13 mm hex on the shaft.

With two wrenches, photo 3, you can loosened the nut from the tie rod. The rack rod is free to rotate, you may see the old boot twist some, but that's OK if you have cut the zip ties at each end. Be careful not to run the nut up the rack rod, if you are using the "dirt in threads" measuring technique, just loosen the nut a quarter turn and then use the 13 mm wrench to back the rack rod out of the tie rod end.

Photo 4 shows the rack without a dust boot. Note the ball joint allowing the threaded end to spin freely. Also note that there are two lands where the boot is held to the rack. One is on the rack itself, and the other is about 1/3 the distance from the ball joint to the threads. In these lands are where the zip ties clamp the boot to the rod and rack body.

I put a small amount of grease in the small hole of the boot to ease installation, a bit of liquid soap would work well also. The point is that the fit is snug and without a little lubrication, it is a struggle to fit the boot. Once the small end of the boot is in place, you can thread the tie rod back on and check its position before you start to fight the big end. This prevents any boot twisting when screwing the rack rod back into the tie rod end.

The boot has to stretch a little to fit onto this second, bigger land of the rack body. The temptation is to use a small screwdriver or similar to help fit it up, but there is not alot of room. I laid on my back with my head under the rack and then could manipulate my hands to get the boot onto the rack body. Be patient, as you do not want to tear or force the new boot. I did not use any lube at this end. I was concerned the lube would reduce the clamping force of the zip tie at this end.

Once you have got the boot onto the rack, install the nylon zip ties, use 1/4" wide by 6" long type and cut off the extra after the tie is tight. and you are done! You have now protected your expensive power steering rack from water and other damaging debris. Good luck.