Rear Axle Bolt Problem

Chas911 · 05-03-2003, 10:06 AM

Hi Team!
Intro: I have been lurking here for awhile and am astounded by the knowledge on this board. I used to build performance engines for a living (althought not Porsche engines,) so I think I can discern between what is knowledge and what is just verbiage. I have 2 911SC's, a '78 and a '79 that are constant projects. BTW the 79 is for sale!

Now for the question.
I just put a brand new Lobro axle on the '78. When I put the bolts back in, they go through the flange so far that they rub on the control arm and keep the wheel and axle from turning. As far as I can tell they are the original 8mm bolts without washers. I had to put them in with 2 lock washers on each bolt to keep them from rubbing. It now works but not my preferred method of making it work. Anyone else ever run into this. The new axle was part # 923 332 033 02 which is the right one for the '78 unless it was miss boxed.

Thanks
Chuck

Jim Sims · 05-03-2003, 02:43 PM

See the 78-83 911 Porsche parts diagrams listed elsewhere on this site. Look at the rear axle diagram. Do you have the arc shaped bearing washers (item #22) in the grip of the 8 mm screws? Also, some of these axles required a gasket (item #19) on both sides of the CV joint for a total of four gaskets per side or eight gaskets total for the car. In addition, there is the Schnorr type lockwasher (a toothed Belleville washer) between the head of the screw and the arc shaped bearing washer. Look at your old axle to see if there were four gaskets per side. I suspect if you add any of these possibly missing parts back into the grip of the screws they will not protrude out the back side of the wheel flange. Cheers, Jim

Chas911 · 05-03-2003, 03:33 PM

Thanks Jim for the reply.
1. I do not have the arc shaped bearing washers. However, I did look to put those on but could not definately find any for the flanges with 8mm bolts with six bolts per side. I also cannot remember seeing any of them on six bolt axles. Have you? I talked to both Pelican and the dealer and both show a quantity of 4 which would be 2 per flange which would lead me to believe they are only for the 4 bolt axles. I would prefer to use them over extra lock washers though if I could find them.
2. The extra gasket is possible I haven't seen ever seen that. I did however put a gasket on each side of the axle. I don't think the extra gasket would make up for the difference, since I had to use 2 washers per bolt to space them back far enough.
3. I am pretty sure this car had the original bolts with no washers. I always put washers back on as a matter of course, so was really suprised when I needed an extra washer.
4. What really confuses me is that the parts list shows different length bolts for the 10mm bolts but not for the 8mm bolts. Therefor it seems it must be flange thickness, but again I had never run into that so just wanted to make sure I wasn't missing something.

Thanks again
Chuck

mussberger · 05-03-2003, 04:48 PM

If you have the updated lobro axle you can not use the old bolt on both ends. The updated axle is not as thick as the original It has sheet metal covers that require the two bolt plates that displace the pressure from the bolt heads against the sheet metal. you can use the 50mm bolts on the trans end of the axles but you have to use 45mm bolts on the wheel end to prevent the bolts from protruding too far through the flange. Make sure the threads are clean and dry before you torque everything down to 31 ft pds and it would not hurt to use locktite.

I used 50mm bolts from PP on the trans ends"they sent me the wrong two bolt plates" and 45mm bolts from Vertex on the wheel ends who sent me the right two bolt plates.

You do not need schnoor washers and there is no extra gaskets.

Drive it and re check your torques.

Just did it to my 81sc two days ago.

Jim Sims · 05-03-2003, 05:56 PM

Mussberger is right; Technical Bulletin 5 in the Parts and Technical Reference catalog 1974-1989 covers this. You need washer plates PN 911.332.191.00 Cheers, Jim

Chas911 · 05-03-2003, 06:40 PM

Thanks guys, exactly the information I was looking for. And I thought I knew everything!
Jim are you sure that part # works for 8mm six bolt flange. It looks to me like it works for 10mm 4 bolt flange. I can't imagine they would interchange, but I have been wrong before.
mussberger, what bolt plates did Vertex send you?
Thanks

Jim Sims · 05-03-2003, 07:03 PM

The years of application listed are 74-89 but like you point out that can't possibly be correct because the screw sizes varied between 8 and 10 mm over those years. Perhaps Mussberger can shed some light on the part numbers. Jim

mussberger · 05-03-2003, 07:19 PM

I got bolt plates from pelican that were ordered under the proper part number but came wrong. I had bought the complete updated axles from vertex but did not receive the bolt plates which were not listed on their site but after that I found out that the bolt plates and the 45mm bolts normally come with the updated axles. Vertex corrected their error and I returned the wrong parts to pelican.I might add that the the reason for the purchase of the axles from Vertex was price.

Chas911 · 05-03-2003, 07:26 PM

Thanks mussberger.
I don't see a 45mm long 8mm bolt listed anywhere so I asumed there weren't any. I have already talked to Pelican a couple of times and they didn't know the answer, so do you think Vertex would know if I called them?

mussberger · 05-03-2003, 07:27 PM

I relied on the Porsche parts publications for my part numbers.

Chas911 · 05-03-2003, 07:38 PM

Thanks mussberger but I don't see it. I have PET, I have sheets from the dealer, I have sheets from Pelican, and I still don't see the 45mm long bolts or the bolt plates that are definately for the 8mm bolts. Any light you can shed would be appreciated.

Early_S_Man · 05-03-2003, 07:41 PM

45 mm is a 'standard' size, so any bolt store that carries DIN 12.9 bolts should have them ...

mussberger · 05-03-2003, 07:47 PM

They are very up on this subject. You are going through the exact same thing I did last week. Call them and say I have the same problem as their customer Dabney. I do not want to take anything away from PP as they provide a terrific "value added service" and I have spent many dollars with them but they came up a little short this time.

Chas911 · 05-03-2003, 07:49 PM

Thanks Warren. It just bothers me when I can't find the info in the Porsche listings. It makes me think I am missing something. Thanks again

Chas911 · 05-03-2003, 07:51 PM

Thanks for all your help mussberger. I will call them