I was all set to continue to test Satch’s patience and launch into another installment of Conditioning The Shark when I found that the foam on the flaps of the car’s heater box had deteriorated. A sudden need to follow my own advice arose, and I was faced with the decision of whether to yank the heater box and re-line the flaps. This dragged the evaporator installation to a screeching halt.
So it’s wheel bearings on the tii this week.
This repair also caught me by surprise. Maire Anne and I had planned to go up to see some friends in Vermont last weekend. I wanted to drive Louie, the ’72 2002tii that I bought in January after it had been sitting for a decade in Louisville. You may recall that I resurrected it and drove it home by the skin of my teeth (the subject of my book Ran When Parked). I shipped down new calipers and flexible lines because I was told that the brake pedal didn’t slow the car down, but I re-used the rotors because even though they were ancient and pock-marked, new rotors appeared to be unavailable from any source other than Walloth and Nesch in Germany. I got the brakes to the point where they were functional enough for the drive home, but I certainly wouldn’t have wanted to do any canyon-carving in the car.
But what does this have to do with wheel bearings? Well, prior to the weekend in Vermont, I was test-driving Louie and poking and prodding him to see if there was anything I needed to fix, and I heard a new clunk coming from the left front end. I jacked up the car and didn’t find anything amiss in the left ball joint or strut, but when I checked the wheel bearings by holding the wheel at 6:00 and 12:00 and rocking it, the left front was noticeably loose. If I recall, my friend Dave Gerwig, who’d spent a weekend with me working on the car in Louisville, had called my attention to the play in the left front wheel bearing then and there, and at the time I deemed it good enough. But with the additional thousand miles on Louie from the trip home, then nearly another two thousand from the romp down to the Vintage and back, it now needed attention.
I tried to tighten it by moving the castellated nut one notch (see below), but that would’ve clearly over-tightened the wheel bearing. It had to be replaced.
Wait—what does that have to do with rotors? On a BMW of the tii’s era, the front rotor is actually behind the front hub, which means that in order to change the rotors, you have to remove the hubs, which means that you have to—ta-DA!—take off the wheel bearings. (See? I get there. You just need to trust that my associative processes haven’t turned to oatmeal.)
So I elected not to drive Louie to Vermont, and instead ordered a set of wheel bearings. Then, knowing that this would be the perfect time to replace Louie’s ancient pockmarked discs as well, I gave another look at the availability of tii rotors, and was thrilled to find that although they’re still listed by BMW as back-ordered, they are now once again available through the aftermarket. Centric makes them (part number 120.34002). They’re sold by Rockauto and Amazon for about $80 a pair, shipped. It looks like they’re even cheaper through CARiD, about $70 shipped.
I opted for Amazon because I have a Prime account that could get them to me quickly, and the Amazon option allows for an easy return if what arrives are not actually the correct ten-inch tii rotors and are instead the standard 9.5-inch standard 2002 discs. (They were, in fact, ten-inch tii rotors. Happy days.)
Back in February, Louie and I made it home from Louisville on a wing and a prayer, with my having replaced the calipers and flex lines but no other brake parts. Since then, however, I’ve also replaced the master cylinder, the rear wheel cylinders, and brake shoes. Now I had new rotors on the way. Although the front pads still had a lot of meat left on them, it was false economy to leave the pads as the only part of the braking system not to be replaced, so I ordered new pads as well. After all, the calipers needed to come off to pull the hubs and rotors to get to the bearings, so it’s the perfect time to do pads as well. See? I can be smart.
The hub layout on a car like the 2002 is such that there are inner and outer bearings, each running in a race that’s pressed into the hub; the inner bearing is protected by a pressed-in seal, the outer bearing by a dust cap. The hub assembly—hub plus rotor plus bearings—slides onto a spindle that protrudes at a right angle from the strut, and it’s held in place by a castellated nut, so named because it has notches in it like the crenellations in the parapet of a castle or the top of a rook chess piece. One of the notches is lined up with a hole that’s drilled through the end of the spindle, and a cotter pin is used to secure the nut.
So let’s replace some front wheel bearings.
If you’re also replacing pads, it’s easiest if you first bang the pins out of the caliper before you unbolt it from the strut. Note that the original brake pads and shoes on a vintage car may contain asbestos, so wearing a dust mask is a wise precaution when dealing with brake components.
On a car from the 02’s era, the caliper is secured by two 19-mm bolts—actually, we’re talking wrench size here, not bolt size!—plus the 13-mm bolt and nut holding the brake-line bracket to the strut. Remove those and set the caliper on the control arm.
Next, pop off the dust cap to expose the castellated nut.
Remove cotter pin and then unscrew the nut from the spindle. It shouldn’t be on tight, but if it is, a 24-mm (15/16-inch) wrench can loosen it. Withdraw the thick spacer that’s behind the nut.
Pull the hub and rotor assembly forward and off the spindle. The outer wheel bearing will slide off along with the assembly. Lay everything on a piece of cardboard or a paper towel.
Take the castellated nut, the spacer, and the dust cap, clean them, and put them somewhere where you won’t skitter them across the garage floor. Fish the outer wheel bearing out of the hub and throw it away.
Take a paper towel and clean the spindle. Inspect the two flat surfaces. The bearings themselves do not actually run on these surfaces, they serve as the seating surfaces for the rings in the centers of the bearing assemblies. If these surfaces are badly pockmarked or gouged, the inner bearing rings may not sit firmly on them, allowing the entire bearing to wobble. If that is the case, and if, after replacing the bearings and adjusting them, there is still substantial play in the wheel, the entire strut housing may need to be replaced. Fortunately, this is extremely rare, and usually comes only from catastrophic bearing failure (which is why, when you feel play as I did that can’t be adjusted out, you replace the bearings).
To remove the inner wheel bearing, you first need to pry the seal out of the back of the hub. You’re replacing it, so don’t worry about destroying it. A long screwdriver rocking on a fulcrum point like the handle of a hammer usually does the trick. With the seal out, withdraw the inner wheel bearing and throw it away.
Give the inside of the hub and the bearing races a quick cleaning with a paper towel so you can see what’s what. You should be able to see the smaller outer bearing race pressed into the front of the hub, and the larger inner race pressed into the back. If you look inside the hub from both sides, you should see two notches behind each race that allow you to bang them out. Using a hammer and the drift of your choice (e.g., an old screwdriver, a beat-up quarter-inch ratchet extension, or even an actual drift punch), and working on one race at a time, knock it out by banging alternately on the portion of the race visible in the notches. Then move on to the other race. It doesn’t matter which one you do first.
If you are replacing the rotors, now is a good time to take the old ones off. On a 2002, they’re held on by four 8-mm Allen-head bolts. This is one of those times where owning air tools and an impact wrench makes it so easy that it’s almost not fair. If you don’t have air tools, you may need to clamp the old rotor in a vice to hold it still. Draw the bolts and their lock washers out, then pull the rotor over the hub. If it’s been on there for 40 years, you may need to persuade it with a few smacks from a hammer.
Spray everything down with brake cleaner and clean it thoroughly. (Some fraidy cats like Satch refuse to use carcinogenic compounds, preferring milder toxins like Simple Green or kerosene to clean parts.) Then, as you did with the spindle, inspect the surfaces that the races sat in; I’ve never seen one ruined, but it’s not uncommon to see some gouging from the races being banged in and out. If gouging in one area is pronounced, you can take off the high spots with some Scotch Brite, but don’t go nuts and risk not having the race fit snugly.
Open the package with your nice new bearing. It contains the bearing and the race. It doesn’t matter whether you select the inner or outer bearing first. Withdraw the race and set the bearing down on a clean paper towel.
Take a new race and place it in the hub. Begin gently tapping it in with a rubber hammer or a hammer and a wood block or a hockey puck, then stop and look at it carefully to determine whether it’s going in cocked, which it almost always is. If it is badly cocked, it can gouge the mating surface, so you want to correct it as quickly as possible. Gently tap on the high side until it is going in level, then continue tapping until it’s flush with the top of the hub.
When the race is flush with the top of the hub, switch from a block of wood to using a socket whose diameter is just slightly smaller than the race. You’ll have to figure this out by trial and error, as the exact outer diameter varies socket to socket, but I used a 1-13/16-inch socket on the larger inner race and a 1-3/8-inch socket on the smaller outer race.
When the race is fully seated, you should hear the sound change from a ringing to more of a thud as you’re tapping it in, but you should also check by turning the hub over and carefully examining where the back of the race is visible through the slots. Be certain that there is no space behind the race.
Then do the same thing with the other bearing race.
With both races seated, next comes the fun part: Packing the bearings. There are few things more automotively primal, elemental, and intimate than packing bearings. Use whatever grease you’re comfortable with (he said knowingly). I haven’t found that it matters much. Traditional brown 100% petroleum-based grease, black semi-synthetic, or red 100% synthetic: As long as the package lists “automotive bearings” among the applications, it’s your choice.
Either wash your hands or use a pair of rubber gloves. I’d advise wearing a Tyvek suit, as you’re likely going to get grease on whatever you’re wearing.
Take a good-sized glob of grease and put it in the palm of your hand. Then take the bearing and press it in the wad of grease in your palm, almost like you’re scooping ice cream with a spoon, and work the grease into every crevice around the rim of the bearing. Replenish the grease in your palm as necessary. Do this for both the front and back of the bearing.
Then cram the outer circumference of the bearing into your palm, working the grease into the individual rollers. Be sure that it’s really well packed. Remember: You’re likely giving this bearing the only lubrication it’ll receive for decades. When the bearing is well-packed, put it down on a new clean paper towel. Do this with both the inner and outer bearings.
When we install the bearings, order is important. The overview is that you have to drop the inner bearing in first, then install the bearing seal to trap it in place, then slide the entire hub assembly onto the spindle, slide the outer bearing into place, and trap it with the spacer and nut.
Use a glob of grease to coat the inner bearing race, then set the inner bearing down inside it. Take the inner wheel bearing seal and install it as you did the bearing races, tapping it into place and taking care not to cock it, but only get it flush with the inner surface of the hub; don’t pound it in any farther than that.
If you are replacing the rotors, do that now, taking care to lay them on a clean surface.
With the inner bearing trapped in place by the seal, turn the hub over and coat the outer bearing race with grease. Clean any grease off the rotors. Then slide the hub and rotor assembly onto the spindle, pressing it gently but firmly to get the inner bearing to seat on the spindle. Slide the outer bearing over the end of the spindle and into its race, then slide the spacer over the end of the spindle. Thread the castellated nut onto the end of the spindle; be careful not to cross-thread it. Once the nut is on, spin it on as far as it’ll go by hand, then gently use a wrench on it, as both the inner and outer bearing rings sometimes need to seat on the spindle. It should be very obvious when they’re seated. Do not apply any real torque on the nut. You’re not trying to tighten it.
Next, you need to find the gap in the castellated nut that best lines up with the hole in the end of the spindle. The Internet is full of stories of people who burned out wheel bearings in a hundred miles by overtightening them. I was always trained to tighten the nut by hand, then back it off to line it up with the hole, but Paul Wegweiser pointed out to me that the 2002 factory manual calls for the nut to be tight enough that the spacer can be moved by prying it with a screwdriver. So find the best “tighten it by hand and line up the holes” setting, then go one notch tighter and see if you can move the spacer by prying it with a screwdriver. If you can, use that notch. If you can’t, then back it off one.
At this point, before I button things up, I like to test-fit the wheel, spin it, and check for play. If you do this, take care not to get any dirt into the open bearing (you can gently tap the bearing cap into place). The wheel should spin smoothly and quietly. Grab the wheel at 6:00 and 12:00 and push and pull it. There should be no play, or only a small hint of play.
Finally, put the cotter pin through the notch and the hole, and bend it far enough that it won’t hit the bearing cap. Put some grease in the cap and tap it back in place.
If you’re replacing the brake pads, now’s the time. Then re-install the caliper.
Put the wheel back on. Give it a final push/pull at 6:00 and 12:00 to check for play.
While you don’t absolutely have to do the wheel bearings on both the right and left sides at the same time (it’s not like rotors and pads), it’s generally considered to be good practice to do so.
After the repair, Louie’s clunk was gone, and with the new rotors and pads, he accepted enthusiastic driving with alacrity, and slowed with elan and confidence. (Actually, he had the elan; I had the confidence.) Perhaps Maire Anne and I will plan another trip to Vermont. They have canyons up there, right?—Rob Siegel
Rob’s new book, Ran When Parked: How I Resurrected a Decade-Dead 1972 BMW 2002tii and Road-Tripped it a Thousand Miles Back Home, and How You Can, Too, is now available on Amazon. Or you can order personally inscribed copies through Rob’s website: www.robsiegel.com.
