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Walt Fricke Walt Fricke is offline
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Join Date: May 2004
Location: Boulder, Colorado
Posts: 7,275
Well, Jesse, the tech inspectors don't know what they are talking about, which is a shame as none of this is complicated.

The 911s through the 3.2 Carreras should have the front bearing loose enough that you can just elicit a small movement when the wheel is up in the air and you grab it at 12 and 6 (top and bottom) to shake it. This bearing is not designed to be so tight that there is zero play in the bearing. I believe the difference is between an angled roller (the front) and a roller (the rear). That ought to give an inspector pause if you lay that on him, even if not quite correct.

There actually is a torque spec for the thing which works like a nut on this spindle, but it is in inch ounces or the like, and you'd have to fabricate something to act like a socket, and about nobody has or uses either of those.

The standard instructions you will find in every manual written for these cars say to tighten it up hard. Then, as mentioned you back off (or tighten from a somewhat loose position) until you can just nudge the keyed thick washer from side to side with a screwdriver tip. Ideally, you are supposed to be able to do this with no prying action at all (the stamped metal cage for the rollers is easily bent) but just barely. I afford myself a little careful prying at times. This means there is a little play in the bearings when you get the wheel back on and try to move the top in and the bottom our, or vice versa, which is what is specified. Often you will find that you go back and forth trying it a little tighter, a little looser, but that is easy and not time consuming. When satisfied, you use the Allen wrench to tighten the pinch bolt, smack the cap back on the hub, and you are done with that side.

If I have had the hub off to replace or service the bearings, replace a brake rotor, or for some other reason, I tend to do this a couple of times - tighten, back off, tighten. You are trying to make sure the bearings are set, and you have squeezed out from contact points all the grease you can, so that your final adjustment will be accurate. There will still be plenty of grease around to do its job.

The rear wheel bearings, on the other hand, and the front bearings on the 964s and newer cars, are designed to have the nut and so on keeping things together very tight, to a torque specification which is pretty high. It is a different design of bearing, made for being tight that way, and requiring it. In 911s of any vintage, any wiggle to the rear bearing (via shaking the tire) is an indication that the bearing needs to be tightened, but more often that it is worn out and needs to be replaced. Same with the fronts on the later cars.

I've tended to run my angled fronts a bit on the loose side. This has had no ill effect, and I don't think I have ever replaced one of these bearings on my cars which was so worn it needed replacement. None have run out of grease (even when the grease seal on the inside has failed), or been all blue when inspected, or pitted. But running them to spec is the way to go.

Just not really tight, so there is zero play.

Last edited by Walt Fricke; 07-28-2014 at 04:36 PM..
Old 07-28-2014, 04:33 PM
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