andy here, using mcmarks computer ...
quick question:
putting back together my 911 front end and got the nut for the hub as tight as it goes, wheel still spins freely.
shouldn't there be some drag ???
how tight is tight enough ???
Andy
Bearing races fully seated? Correct bearings? Got the washer in there under the nut? There should be plenty of adjustment beyond tight, although the wheel "might" still move even when the bearings are too tight. The Cap'n
Tight enuff is when you can move the big washer in there with a screwdriver....not wedge it around, but not sloppy, either.
It's a "touch" thang.
Andy...you know better.....rollerbearings were invented so there would be minimal drag. If you feel drag, the bearing is bad.
RTFM
QUOTE (Cap'n Krusty @ Jan 21 2006, 03:36 PM) |
Bearing races fully seated? Correct bearings? Got the washer in there under the nut? There should be plenty of adjustment beyond tight, although the wheel "might" still move even when the bearings are too tight. The Cap'n |
Since you've convinced yourselves there should be drag....tighten the mfer until you feel drag and see how long the bearing lasts. It's a taper bearing and the tighter you make it, the more you force the rollers into the race....lubrication won't last long..
You might want to Google frictional coeficients for roller bearings.
QUOTE (SLITS @ Jan 21 2006, 03:57 PM) |
Since you've convinced yourselves there should be drag....tighten the mfer until you feel drag and see how long the bearing lasts. It's a taper bearing and the tighter you make it, the more you force the rollers into the race....lubrication won't last long.. You might want to Google frictional coeficients for roller bearings. |
Ah allus went wif the method of tightenin until thar ain't no slop when ya wiggle the top and bottom uv the rotor/wheel. But then agin, Ah'm ignernt.
manual says tighten to 10 lb/ft, rotate wheel back off till you can just move the washer..
Real world says rotate wheel while tightening the nut till you feel it( feel resistance from tightening the bearing), back it off, and drive the car for a bit, then recheck bearings.. check bearing not by turning the wheel but but rocking the wheel in Z axis.. ie hands at 0 and 180 try and wobble the wheel.. you should barely feel movement
Sorry Andy....of all the wheel bearings I have tightened, I have not felt the drag like you are talking about. I run them up tight and back the nut off 1/4 turn, check for looseness (movement of hub in relation to spindle). If I *feel* it moves to much I tighten it about 1/16 - 1/8 of a turn and do it again.
I also have not exerted sufficient force on the spindle nut to "lock" the bearing to the point where it won't turn.
My technique has been to snug up the wheel nut very tight, while also using a big screwdriver against two temp. lug bolts to spin the hub as I tighten. This keeps the rollers from dimpling the races. Usually, the wheel will barely turn once fully tight like this. I then back if off completely, then tighten it down WITH MY FINGERS until I can't feel any wiggle in the wheel.
Alfa manuals (very similar front end design) have you tighten to 35 ft/lbs, then back off, then retighten to 7ft/lbs.
If you can't feel any wiggle in the wheel, it's tight enough. If you can't spin the wheel freely as well, it's too tight.
QUOTE |
Real world says rotate wheel while tightening the nut till you feel it( feel resistance from tightening the bearing), back it off, and drive the car for a bit, then recheck bearings.. check bearing not by turning the wheel but but rocking the wheel in Z axis.. ie hands at 0 and 180 try and wobble the wheel.. you should barely feel movement |
QUOTE (hmeeder @ Jan 21 2006, 08:22 PM) |
Truly, you want to feel the tiniest bit of "click" when rocking the car on the "z axis." |
I'm with Slits,
Been doing it that way for over 40 years.. Not 1 problem.
Twystd1
QUOTE (Twystd1 @ Jan 22 2006, 01:24 AM) |
I'm with Slits, Been doing it that way for over 40 years.. Not 1 problem. Twystd1 |
Holy shit I sound old...
40 years...yada...yada..yada.....
Hell....Emotionally i'm bout 16..... I think...crap...oldtimers just hit again.....
What was I saying....????????????
Twystd1
QUOTE (Twystd1 @ Jan 22 2006, 04:31 AM) |
What was I saying....???????????? Twystd1 |
I rotate the hub or rotor whilst tightening the pinch nut, until it's tight enough that you can't move the thrust washer, and then back it off enough that you can just move the thrust washer whilst prizing it with a screwdriver.
I had to throw in "whilst" a couple times. They use it in the Haynes manual, which is where I learned the above technique about 26 years ago, and I've never roasted a bearing.
If the bearings are new then you can tighten em down so they don't move but if they are used then I found you can't ususally.
Use JP's Porsche method and you'll be fine.
I too have been using this method since shoot 1969 so its works.
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