How do I know if I have too much play in the front wheel bearings?
Are there any web-sites that detail how to adjust them?

Thanks

 

With the car on the floor, rock the top of the wheel in and out toward the center of the car. If there is any play, your wheelbearing is loose.

Any manual should cover how to adjust that. It is very simple. Take the wheel off, remove the grease cap on the hub (rubber mallet and / or channel locks). There is an allen head bolt that holds a 'nut' on the spindle shaft. Open, adjust tighter (but make sure your rotor still turns fairly freely). You may need a few iterations to get a feel for it. It also helps to move the adjustment all the to loose, then too tight and back it off from there...

George

 

And of course, you fasten that allen head bolt, re-install the grease cap and your wheel. Test if it rotates freely and lower car. Test for play...

George

 

This has been a puzzler for me also. Mechanic and manual concensous has it that proper adjustment is determined by cheking the tension on a washer that sits just inside the axle nut. It seems to be a developed sence of feel (not unlike a developed feel of resistance when checking valve clearence). You should be able to move the washer with the tip of a screw driver, but it should not be loose. This adjusts the preload on the bearings, too tight will generate excessive heat and cause premature bearing and race damage.

With that said, you might still feel some movement in the wheel when the bearing is adjusted properly. The results of the prescribed adjustment sure seemed too loose for me. I took my car to the same Porsche shop for DE tech, and one week they said that the bearings were too tight, two weeks later a differant mechanic (at the same shop) tightened them cause he said it was too loose.

It all is a little too subjective for my comfort level at 120+ mph.

 

There should be no play in the front bearings (or the rears for that matter, but that's a different story). This can be achieved while still having the washer free to move. But, be careful how you put the screwdriver in there - it's easy to bend the cage for the outer roller bearing, which will ruin the bearing. Also, you're not supposed to lever the screwdriver, just push it, when checking the motion on the washer.

There is a torque spec for the allen bolt on the nut that holds the front hub on. Failure to follow the torque spec can leave you with a nut that is distorted.

I don't like to use channel locks to remove the dust cap. Use a muffler clamp (2-1/4", I think) around the ridge on the cap and some levers. (Of course, there is always the factory tool....) The caps look awful after they've been chewed on by the channel locks. Be prepared to wrestle with the cap, if it's original.

Proper wheel bearing adjustment is important - too tight, and you'll wreck the bearings; too loose, and your brake pads will get pushed back too far and you'll have a low brake pedal.

 

Since it sounds like you do your own work, you might want to consider getting Bentley's 911 SC Maintenance Manual. Although it lists for around $120, you can find it on the web for around $75. (Full disclosure notice: I provided review and input for the second printing of the the book) Of course the Factory manuals are an option, however, for the SC you'll pay around $350 for the 6 volume set (If you do most of your own work, the Factory manuals, IMO, are worthwhile to own).

 

Adjusting my front bearings for the first time, and have an issue...one side seems perfect...I can barely move the washer with a screwdriver, and there is no play at all when attempting to "rock the wheel". However, on the other side, when I am still able to move the washer a bit, I do have the very slightest bit of "play" when rocking the wheel. I tightened it up just a tiny bit till I no longer have any play in the wheel, but now I can't move the washer. I'm unsure about which is 'right', and need some advice. One other thing...the bearings have only 50K miles on them, and I don't think they're worn or anything like that. Thanks...Keith

 

i wrapped duct tape around the cap prior to removal with the channel locks. no scratches, no knicks, no cuts and the feel of a blade! scratch that last blade part i got carried away.

 

KC, the only way to check the end play is to load the bearing by putting the wheels back on the car. Youe are better off with it a little loose than too tight. It takes a while to get the feel of where it should be. You'll get there. LOL.