I finally got around to replacing the stay bushings on my car, and wanted to do a quick writeup on what all was involved. First off, a huge thanks to the author of this page. The Google translation is a little rough and he already had a custom press ready to go, but it was the only howto I could find on the procedure. "Bushing" translates to "silent", btw. This page was also an excellent resource, so thanks to those folks as well!
This part appears to be set up exactly the same and shares the same part number on all 2003-2014 XC90s, regardless of engine or how many powered wheels you have. This may also be applicable to the S60, S80, and V70, but I'll let others pipe in on that. It's the blue piece here in the subframe diagram. There's another stay that attaches to the rear of the hub, so this isn't the only "stay" on the rear.
I'm guessing you should plan on them lasting 10 years or 100,000 miles, but naturally your mileage may vary. Mine is a 2004 with 150,000 miles and they were somewhat spongey and had cracks forming. If you're having trouble with toe in the rear, this is a great place to start looking.
They're easy to find if you know where your fuel filter is (just to the front of the right rear wheel). Just find the fuel filter, and look about 6" behind it. Same position on the other side.
If you're wondering if this needs to go on your todo list, they're easy to check! Just grab the fork arm bolted onto it and try twisting and pushing on it. You shouldn't be able to manipulate a good bushing by hand. If you're able to move it at all or you see cracks or tears like on mine, it's probably due for a change. Lifting the rear like you're changing a tire will also put stress on it and make any damage very obvious.
The good news is it's not too difficult to do yourself and for the most part only requires simple hand tools. It's very accessible. However, unless you already have bearing pressing tools it does require a fair amount of preparation. On the upside, the parts needed to build your own setup can be had for less than $60.
Here's the parts I used for my custom jig. I found this lot at Home Depot, but places like Lowes will probably also work:
- Southland 511-208HN - 2" galvanized steel pipe coupling - $10
- Southland 511-207HN - 1½" galvanized steel pipe coupling - $7
- Southland 568‑001HN - 2" galvanized steel close nipple - $4
- Simpson Strong-Tie BP 1/2-3HDG - 3" x 3" Galvanized Bearing Plate with 1/2 in. Dia Bolt - $4 each (buy 2)
Note: While the 1½" coupling is not strictly necessary, I highly recommend getting it. You can press the new bushing in with the close nipple, but the thin edges mean it loves to move around on you. Using the flat end of the coupling is a much more foolproof approach. I completed one side with the close nipple, but the other side is off center by about a centimeter because the bushing collar collapsed a bit just as I got to the home stretch and I couldn't get the nipple to seat flat any more. I'm guessing I'm lucky I got as far as I did so I'm officially recommending using the coupling instead.
I originally tried a 3/8" nut/bolt/washer combo from Home Depot but after giving it the beans the threads gave up almost immediately. I then went to Fastenal and tracked down some bolts that had the key characteristics I was looking for:
- 7/16" diameter. A 1/2" bolt just barely doesn't fit through the bushing, so I went with the next size down.
- Grade 8. I'm guessing the first bolt died because it was a plain-Jane steel bolt, nothing special.
- Fine thread. The more threads being engaged, the stronger the hold.
- Length. It's really hard to find an 8" 7/16 grade 8 bolt!
I was also able to find a tall nut. Again, more threads in the nut means less opportunity for failure. The downside to using grade 8, however, was that they don't sell bolts with threads along the entire length of the bolt. Grade 8 bolts generally only have a small threaded section to maintain strength. This meant I had to buy three bolts that ranged from the minimum length I'd need to the maximum, with enough overlap between them to fit the nut and just swap them out as they bottomed out.
These had to be ordered and I picked up from my local Fastenal spot about a week later:
- 18892 - 7/16"-20 x 6" Grade 8 bolt - $4
- 18894 - 7/16"-20 x 7" Grade 8 bolt - $5
- 18896 - 7/16"-20 x 8" Grade 8 bolt - $9
- 37889 - 7/16"-20 Grade 8 high nut - $2 (I grabbed a few extras too)
- 33859 - Washers - $0.25 (I grabbed 6 but only used 4)
The bushing part number is 31277893 and run about $10 each. I also bought replacement bolts. It turned out to be unnecessary since the old ones were in good shape, but bolts are cheap insurance. Their part number was 985063 and they were $5 each.
Once you have all the parts in hand you'll need to do some prep work to get them ready. The 2" coupling will act as a cup which the bushing will get pressed into, and the close nipple will be the drift. However, out of the box, they won't work as such. I had to use a Dremel with a stone grinding tip and grind the threads down on both.
The cup will need the threads ground down enough for the bushing to plop into it without any resistance.
The drift will need the threads ground down just enough to make it slightly smaller than the bushing. It will need to be able to pass through the subframe hole without any resistance.
Pro tip: use a particle mask. Grinding the threads down takes a while and produces a super fine black dust which you probably don't want in your lungs. Eye protection is probably advisable as well. After listening to an hour or two of the grinding sound you'll probably also wish you had worn ear plugs. Learn from my mistakes
Once you've got all that done, you're ready to replace some bushings. It took me just under 2 hours per side. Put the bushings in the freezer. Doing so will make them shrink ever so slightly which makes pressing them in noticeably easier. It's not required, but they're more likely to go in straight the first time if you do. Also, give the jig's bolt threads and washers a light coat of axle grease.
Before jacking up the back and removing the wheel, remove the bolt from the arm attached to the bushing. The old bolts had a 17mm head and the new bolts had a 15mm. Once that's out, chock the front wheels, jack up the rear, and remove the tire. Undo the 12mm bolt holding the brake line bracket in place.
Now you'll line up your drift and cup. On the side near you, you'll run the 8" bolt through two washers, a steel plate, and your drift. On the other side you'll have the cup, steel plate, two washers, and the nut. Before you torque it down, make sure the cup is seated over the old bushing and the drift is perfectly centered. I used a 5/8" wrench on the head of the bolt to hold it still, and a ratchet with an 11/16" socket on the nut (yeah, I know I have a wrench on the nut in this picture).
Once you're sure everything's lined up properly, start wrenching. You may hear a pop as the old bushing breaks free. It will move slowly thanks to the fine threads, but the ratchet shouldn't require a huge amount of torque. Once you feel it start to tighten up, you've probably bottomed out the nut on the bolt. If you pull off the socket, you should see about an inch and a half of threads exposed. Pull the nut off and replace the bolt with the 7" one. The bushing should pop out before you bottom out on this bolt. Once the bushing is out, check out the inside of the subframe. You'll want to clean up any corrosion in there. Mine were in great shape so I just cleaned it up with a nylon wire wheel.
Apply a bit of axle grease to the inside of the subframe that you just cleaned up. It'll help avoid future corrosion and makes the bushing's journey back in a bit easier. Grab your bushing out of the freezer. Before you set it in place, make sure the bearing's core is oriented correctly. The line in the center should be vertical relative to the arm, like so:
I forgot to do this but I ultimately decided to just leave it as-is. If it weren't a solid bushing I probably would have decided it mattered enough and redid them.
Line it up on the back as straight as you can and push it in a bit so it sticks in place. Grab your 7" bolt and run it through 2 washers and a steel plate on the front, and on the back your coupling drift (not the nipple drift as pictured), steel plate, two washers, and nut.
Make sure the drift is perfectly centered and start wrenching again. If by chance the bushing goes crooked you can either tap it out with a punch and hammer and try again, or use a hammer to persuade it back into line. Once you bottom out the 7" bolt, swap it out for the 6". When it feels like it may be bottoming out, remove the jig. If the steel core of the bushing is pressing up against the front plate, it's time to move back up to the 8" bolt and utilize the cup again. Look inside the cup and get a feel for where it needs to be positioned to be centered on the subframe hole. As you continue pressing, the bushing's shell will go into the cup a bit.
Start wrenching again and stop once you've got a centimeter or so of the outer sleeve still sticking out. Pull off the jig and figure out how much more to press it to get it centered. Once you're satisfied it's nice and centered, bolt up the brake bracket again, reinstall the wheel and lower the car. Once the full weight of the car is on the wheels again, reinstall the control arm bolt. If you can't quite get it to thread, have a family member or two sit in the back seat. If that's not quite enough, have them rock the car while you try to thread it. Loading and unloading the back will move the control arm in and out ever so slightly. Final torquing should always take place with the car's weight on the wheels. Torque to 80nM.
As an afterthought, it may have been possible to use an impact on the jig's nut instead of the ratchet, but I felt that being able to feel variations in the torque being applied was too valuable. It communicates important things like when the nut has bottomed out or when the bushing core is contacting the plate. That said, if you're confident in your impact skills, have at it!
If you have any feedback or decide to make a go of this yourself, please don't hesitate to reply!