Thursday, 14 June 2012

New inner tie rod for the Subaru

Soon after I purchased my Subaru, I noticed that the right side inner tie rod boot (aka bellows) was broken. I put a temporary repair on it, and promptly forgot about it. Well, 8 months later I started to hear a noise when while turning the steering wheel, and I was reminded of my “temporary” solution.

The front of the car is jacked up and put on jack stands, and the right side wheel is removed. You can see my super classy garbage-bag-and-duct-tape temporary fix.






To help remove the tie rod I gave it a shot of PB blaster.

If you have ever separated a tie rod end from a steering knuckle, you know that these parts are close friends and not easily separated. I decided to avoid that hassle and left the tie rod end connected to the knuckle and unscrewed the inner tie rod from the tie rod end.

Tie rods get exposed to a lot of water and road salt, so they tend to be a little stubborn. I put a 17mm wrench on the jamb nut and stood on it to break it free, then unscrewed it from the tie rod end. It’s a bit easier to access everything if the steering wheel is turned all the way to the right (or left, depending on which side you are working on) to poke the tie rod out as far as possible.



Note that the tie rod unscrewed while the jamb nut stayed rusted in place. This will prove useful for copying the alignment setting. If the new tie rod is not adjusted to be the exact length of the old tie rod, we will change our toe setting on the front wheels. This can result in increased tire wear and odd handling.

With the tie rod loose, I set about removing the garbage bag and the old tie rod boot. Since these aren’t being reused, it’s easiest just to carefully cut them off with a knife.

The steering rack and inner tie rod are now exposed.



Before removing anything else, I make sure my new tie rod matches the old one. Old (still attached) tie rod on the left, new one on the right:



Now to actually remove the tie rod. It is screwed to the end of the steering rack, and you might be able to get a wrench in from underneath to unscrew it, but there is a specific tool for tie rods that makes it a bit easier. I made my own tool. All it is is a chunk of pipe with a bolt threaded into one end and a T-handle on the other.



You can see how it works in the above picture. That’s the new tie rod in the end of the pipe (for demonstration), locked in place with the bolt on one of the flat surfaces of the rod end. That giant bolt on the other end of the pipe is used as the handle. The fact that this pipe is notched is unrelated to its purpose - it just came from my scrap heap that way. It could just as well be a straight cut.

My homemade tie rod tool is slid over the old tie rod and the bolt on the end is tightened down.



A bit of turning and grunting, and out comes the tie rod.



At this point I cleaned off the old grease (along with any dirt that entered through the broken boot) from the steering rack.

Remember how we left that jamb nut in place? Well, now we can measure the length of the old tie rod (to the jamb nut) and adjust the new tie rod to the same length.



We can put the new jamb nut in the correct length position, but it will need to come off later in order to install the new tie rod boot. Its position needs to be marked somehow. I thought I would be clever and spray it with a little bit of primer.



…but some of the primer bled into the threads under the nut and it didn’t leave a very clear mark. I used a sharpie instead, but some white-out or something applied with a brush would probably be better.



I practiced positioning the nut and then checked my measurement, and it came out within 1mm of the intended measurement. Good enough.

A quick word on alignments - a lot of people out there think that any time you touch a suspension component you need to immediately rush out to an alignment shop to have your car professionally aligned with lasers and witchcraft, to the tune of $100-200. Really, that’s not the case. Your car can tolerate a degree here or there of imperfect alignment without exploding, which is reasonably attained by marking your alignment settings (as above with paint and/or sharpie) before disassembly. The worst that will happen is your tires will wear marginally faster.

You can actually give yourself a fairly accurate alignment at home, without the lasers and witchcraft. I’ll likely cover that in a later installment.

Okay, with the new tie rod marked for length, let’s have a look at that funny-looking washer that came off the old tie rod (and the new one that came with the new tie rod).



Oh noes! They’re not the same! Well, they’re pretty close. Those two divots on the outside of the old washer were smashed in place when the old tie rod was installed to keep it from rotating - it used to be flat like the new one on the right. What keeps it from rotating are the two fingers on the inside of the washer (broken off during disassembly on the old washer, still present on the new washer) which fit into the slots on the steering rack end:



Now without further ado, let’s get that new tie rod installed. I put a bit of blue Loctite on the threads for a little extra security, but that locking washer should theoretically be enough. I thread it in by hand as far as I can, then break out the tie rod tool to tighten it up the rest of the way.

This is the result:



To make that locking washer do its job, it needs to be bent over so that it holds the edges of the tie rod. I could only access a three of the sides (not the top), but I used a hammer and a punch to fold the edges over that I could get to.



The tie rod is on! It’s now your duty to install the booty.

Old vs. New:



Slather some new grease all over the steering rack (especially the teeth) and inner tie rod. My boot kit actually came with a little packet of grease. How thoughtful.

With the jamb nut off of the tie rod, the boot should slide over the end without too much drama.



It can sometimes be tricky to stretch the boot up and over the steering rack housing, but Subaru provided lots of room here so it wasn’t a problem. My boot kit came with some stainless steel bands to hold it in place, but I think I would just use zip ties next time. They can be more easily tightened down. One for the rack housing end, and one on the tie rod end:



With everything now done on the steering rack end, all that remains is to reconnect the tie rod to the tie rod end. I aligned my jamb nut with the mark I made earlier and put a little tape on it to make sure it didn’t move.



See the section of the rod end with the wrench on it? A new tie rod is pretty stiff, but with a bit of effort you can put 13mm wrench on that section to spin the rod around and thread it into the rod end. A lot of effort, actually.

With the rod end snugged up against the jamb nut, a 21mm wrench tightens the jamb nut against the rod end. You can’t readily use a torque wrench on these parts, but things should be plenty tight. If a steering part loosens while driving, you’re in trouble!

As one final check I cycled the steering full left and right to make sure it moved freely and the boot didn’t pop off. Things didn’t explode, so on went the wheel, out came the jacks, and Bob’s your uncle. Don’t forget to properly torque the wheel nuts.

This job was pretty easy. I wasn’t entirely sure that I had ruined my inner tie rod by driving with a garbage bag instead of a rubber boot, but it was a cheap part and didn’t involve much more work to replace while I was replacing the boot. Nearly everything had to come off anyway to get the new boot on there.

Rubber parts like these usually die at the same time, left and right, so it is generally a good idea to do the both sides at the same time. However, with Subarus the exhaust runs down the right side of the car close to the right side steering rack boot and CV joint boot, so these parts will often wear out long before the left side due to the extra heat.

continue to DIY alignment!

Costs:

$13 - inner tie rod

$27 - steering rack boot/bellows kit

==$40 total

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