SWB wheel bearings- a few technical notes

[304065]

Installation and removal is a little different than the LWB.

Outer bearing is the big one, 80mm outside diameter on the outer race. To the face of the race (what you'd have to push on to remove or install the bearing) is about 73.5mm

Inner bearing (the little EXPENSIVE one) has an OD of about 55.5mm, 50.6mm to the center of the outer race.

The "cup" you need for pulling the inner bearing must be wider than the lip of the opening in the trailing arm for the stub axle-- this is around 55mm.

The front bearings are same as the LWB-- front outers have a diameter of 45.3mm, face of the outer hub is 50mm. Inner diameter is 59.2mm, face of the inner hub is about 64mm.

When I say "about" for the dimension to the center of the face it's not an exact measurment to the center, it's an approximation of the diameter washer it would take to span the opening if you were to fabricate a puller.

I made my own puller out of a piece of 1/2" all-thread (12 inches long), a couple of 1/2" nuts, some fender washers and a plumbing flange. I'll post the photos in this thread when I get around to installing the bearings-- I don't have the plating back so it's premature to begin.

Hope this helps somebody. . . someday. . . I sure found it helpful in measuring plumbing parts at the hardware store!

[67Porsche911S]

Thanks for your effort!
Please keep us updated.

[304065]

Thanks Michael.

I got the front bearings out of the hubs today after considerable effort. I couldn't have done it without my new Harbor Frieight six ton press. (The VW press is, unfortunately, not available )

Fortunately the Factory did leave a few bread crumbs as a trail. First, they say you press the bearings out with a press. That is actually pretty easy, the bearings fall out outboard, leaving the inner races behind. It's the races that are hard to remove from the hubs.

The outboard race is the smaller of the two-- this one is easy, you just have to find something to press on the lip of the race. I don't remember the precise dimension, it is probably very close to the 43.5mm OD of the bearing race, but a PERFECT tool to get it out is one of the thick washers from the stub axle. That lines up with the edge of the outboard race exactly-- I put a socket on the washer to space it up for the nose of the press, a few pumps and the job was done. Always, always wear safety glasses when doing this kind of operation and be careful-- the press generates enormous pressure (hmmm. . . ) and can easily damage persons or property.

You can see the factory uses a spacer that's 35mm high to space up the hub so the bolts don't hit the press plate, and also to square the hub against the nose of the press.

Ok so the easy one is done. Now the difficult one. Here's the rub.

Remember when I said above that the diameter of the inboard bearing race is 59.2mm? Ok, that's about the size of washer or other tool that you need to get it to move out of the hub.

Uhh, except that I said that the diameter of the OUTBOARD bearing, the one that came out so easily, is only 43.5mm. Which means you can't put a washer up against the inside of the inboard race to press it out, it won't fit inside the hub!

So what do you do? Well, I was able to get the nose of the press to engage the lip of the inboard bearing race, and by holding the hub at a slight angle, was able to engage it like that. This didn't do any damage to the hub where the race sits, I was careful of that.

Anyway, I can't imagine doing this operation without a press, this thing cost me like $80, and I can use it to install the bearings front and rear, it has already paid for itself! Putting them back in will be a breeze comparatively.

Now I just have to get 40 years of brake dust off-- they are currently soaking in mineral spirits, can't use corrosive cleaners on these.

That's all for now! Enjoy.

p.s a clue to what the "mystery" factory tool looks like to remove the outboard race is in this thread. . . .

http://forums.pelicanparts.com/porsc...l?pagenumber=2

[304065]

Another step in the process was to drive off the spindle spacer. SWB the spacer is 17mm. LWB it's 21mm. The way to get it off is to heat it with a MAPP torch, then use a drift to pound the edge of the spacer alternating sides until it releases. Of course, you can bugger the edge if you are not careful, so it may require some dressing with a file to be sure you haven't peened it up.

The factory o-ring is still available-- I put one on each before pressing the ring back with my press, fairly simple operation.

Now to press in the bearings!

[304065]

Finally pressed the bearings in. If I ever do this again, I'm going to lathe a piece of aluminum to the exact diameter of the bearing race and use that to drive the race into the hub. That said, I got them seated, and used a caliper to measure around the race at 90 degree intervals, to confirm that they are square with the hub.

[davep]

John
I have a few questions. Is the 17mm spacer the same for both vented & non-vented front rotor hubs on a 1966 strut? If you change to a vented rotor hub is there anything else to be aware of? If a 21 mm spacer is required, where can they be obtained from? What were the hardware store parts you bought to use in the press?

[304065]

Dave,

The 17mm spacer ring is for all SWB, vented or non-vented, according to the parts manual.

The only difference between vented and non-vented in the SWB cars is the vented rotor itself and the spacer between the caliper halves. Of course, I qualify that by saying that there were four different hubs over the life of the aircooled 911, so you have to assume that you're using post '67 hubs.

If you wanted a 21mm spacer, which I can't imagine you would want given that it's only suitable for the later strut housing, they are available new from Porsche, for about $50 each.

The hardware store parts: a 3" PVC coupler with an ID big enough to fit around the outer hub, and still fit inside the wheel studs. A 2.5" PVC coupler, this had a diameter of the right size to drive the inner race about half way in. These are helpful, but there's no substitute for machining a metal disc that is the exact size of the bearing race so you can press it in. If you don't have a lathe, I suppose a large diameter washer could be chucked up in a drill and turned down with a file to fit. Too small and it slips off, too big and it doesn't fit.

I have another set of hubs to do, I'm probably going to make the right tools next time around. VW 447F? Unobtainium!

[davep]

Thanks. I'm planning on making some of the discs to press in/out the bearings. It might be worth while to make up a few sets.

[edmayo]

Hi John, The factory tool for pressing out the bearing races is a spring loaded expandable tool, that's how it fits in the small end then expands to the larger race diameter. The tools for driving in the new bearing races (after the hub is heated and the race frozen) are generic bearing race driver sets. If you would like I can post some pictures of these.

[304065]

Ed, photos would be great! Anything that could help replicate the factory tools would be outstanding.