Think I found my Vibration- now I need a hub

[Kurt peterson]

I'm almost done with a suspension and A/C upgrade on my '87 930 and when I was putting the the LF caliper on I noticed way too much run-out in the rotor. I've had a rather annoying steering wheel vibration at 65 mph and up) in the car since I bought it 7 years ago (and I see others on the board have the same problem). Not serious but still annoying. Two sets of new tires, one set of new wheels, ball joints, new rotors, 2 sets of bearings......still there. Enough history.

Got the dial indicator out and found .030 run-out. Of course my first swear word was addressed at the new rotor, thinking it was warped, and the thought of a further slow down in my 2 week project (already in it's third month).

Took the rotor off the hub and measured the run-out of the hub and it's about .011. Moved it to the RF and the measurements were the same (glad it isn't the strut/spindle). The other hub has less than .001 run-out so I know it's the hub. Checked to verify the bearing races are fully seated (they are). I can't imagine the hub has always been this bad, but the vibration has been worse for the last year, accompanied by a pulsing brake pedal.

Anyway, now I need a new or used hub. I found someone selling a set in the used parts forum, but he wants to sell both. I haven't priced out a new one (not available from our host) but I imagine the cost will make me sick.

Anyone out there have a used hub for sale that will fit my '87 930? Not sure if the 930 hub is different from the base 911.

Either way, I'll update everyone how the suspension and A/C upgrades work out.

[Oh Haha]

Hey Kurt. Good news,maybe!!
You should put a message on the Rally Sport website or try calling Monk's. Someone local might just have one handy.

[Zeke]

The spindle can't have any effect on runout. You were correct and wise to check the races first. I had a bad hub, too. I use it now on a dead strut for various operations having the wheel ass'y off and up on the bench in a big vise. Pretty handy.

One of the parts dismantlers will gladly sell you one hub. The Turbo hub PN is 930 341 065 01

[Johnathan]

Kurt, Forgive the stupid question, but how did/do you measure the run out on the hub/rotor?

Thanks.

[Huh]

yes please I too would like to know how to measure run out.

[rusnak]

Kurt, I can shoot a picture of my 911 hub to compare with yours. I was wondering also how to measure hub run out. I've had problems getting accurate measurements on my wheels and rotors due to all the variations (hub, races, spindle moving, etc), and I was thinking about making a jig or buying one of those wheel balancers.

[Kurt peterson]

Success!!

Picked my car up from the alignment shop tonight in our lovely 95F heat after having the alignment set as the last step in my much longer than expected Winter project. Included in the update were:

- Polybronze bushings front and rear
- 31mm rear and 22mm front Sander engineering torsion bars
- New front ball joints
- New tie rods
- New upper strut mounts
- New front HD Bilstein struts and rear Sport Bilstein shocks
- front ride height 25" rear ride height 24.5"
- New front rotors and new pads at all 4 corners
- bone yard LF hub to correct my out-of-round hub
- All new barrier hoses
- New Evaporator and pro-cooler - still R12
- new shaft seal on compressor
- new Evap. fan motor

Car is stiffer than before but not too bad ( wife and daughter have yet to take a ride). I didn't drive it very far, but the car handles better than it has in the 7 years I've owned it. No more squirrelly feeling (I know it's not a technical description but it's the best description of how it felt). Oh, and I had 37F air on med/high fan speed.

My driveway isn't level so the attached photo isn't a true representation of how the car looks on level ground - but you get the idea.

Money, time, and a little frustration well spent.

[wcc]

Great Job Kurt!! Lookin' SWEEEEEEET!!

[Oh Haha]

Oh yeah!!!! Excellent job, Curt.

I was hoping you could have made the brunch run this past Sunday.

Now get out there and drive that baby.

[Asjac]

Please post the wife/daughter comments when you get them. I am thinking of going 23/31 and would like to know the stiffness increase.

[Kurt peterson]

I've only driven the car for one day, but I can't imagine it being any stiffer than this for purely street driving. As I drive it more I'm sure I'll get used to it. Having said that, part of the problem is the pothole roads we have here in SE Michigan.


Wife and daughter will go for a ride tomorrow or Thurs.

[azasadny]

Kurt,
Beautiful car!!

[rick-l]

Originally posted by Huh
yes please I too would like to know how to measure run out.

Get a dial indicator (I can't see anything wrong with my $12 harbor freight one).

Take the rods off the Harbor Freight magnetic base use a vice grips, angle iron and C-clamps to rigidly fasten it to a suspension part and adjust it perpendicular to the rotor.

Turn the rotor and record max and min readings.

[Kurt peterson]

I removed the disk, mounted my magnetic base to the strut, hooked up the dial indicator, and measured each of the individual bosses by the lug nuts. You have to be careful as you can't just spin the hub, you need to slowly turn the hub and hold the spindle of the dial indicator as you move over the non-machined surfaces of the hub. Once you have it set up it takes less than a minute to take the actual measurements.

[Kurt peterson]

The more I drive my car, the less I think that it's too stiff. Maybe I've been spending too much time in my wifes Volvo.

Took the wife and daughter for as ride today and they said it was OK, although my daughter (5 years old) did comment that the road was bumpier than before - but that could be the new pot holes since last year.

I actually had to turn down the A/C during in-town driving at 2:30 PM with full sun and about 87F. The wife said she was cold!!