The Most Important Bolt On A '69 911?

[lopena]

Thanks for the input from those of you with experience with sample sizes greater than 2. FYI the factory torque spec is 33 lb ft as stated on pg S48 of 1973 factory service manual. Frequency of checking is every 6000 miles as stated in owners manual maintenane schedule(pg 57 1969 912 owners manual)

Thanks, Phil.

The torque setting you mention is for the updated wedge type bolt.

Do you, or anyone else, have the factory-recommended torque setting for the early type of pinch bolts as used on 1969 models?

Thanks again guys!
Alan
N.J.

[gled49]

They call the bolt a nut, M10 x 30-10k 6.5 mkp. About 47 lbs.

[SIMI BOB]

Edit: Also added new drawing
Let me be clear here because there seems to be some confusion. The procedure below is to remedy the fact that the hole in the bottom of the strut, where the ball joint enters the strut, being egg shaped and allowing the ball joint to wobble in the bottom of the strut. At the end, I address the fact that the pinch bolt seems to get loose by adding a longer mounting bolt (M10 35, in pic below), torque to factory spec, then put another nut on the threads protruding from the far side to make sure that this bolt does not get loose. I am also spot facing the strut to make sure the new nut has an even surface to seat on.

Original post:
So, here is my plan, figuring that finding a matching strut are almost "0", (saw a really crappy looking one for $750). A machinist at Supertec mentioned this, so here I go. Chuck the whole shock in a lathe and enlarge the ball joint hole (standard size is 16 mm, or .630) to .6875 and tap for a 3/4-16 bolt. Install 3/4-16 grade 8 bolt. Cut off head flush with bottom of shock, weld a few spots around edge of bolt at parting line and bore hole in bolt to 16 mm again. Then cut the pinch slot equal to the slot in the shock body. Finally Spot Face the other side of the longer pinch bolt hole and put a nut there as seen in the pic below.




Please chime in if you see any problems with this course of action.
Thanks, Bob B

[Phil Planck]

Im not sure what spot face means but you will need to drill into the sleeve to get the bolt in. Large hole on entry and small hole on exit without hiting threads. Some red loctite on the large stailess bolt might help also.

My factory manual clearly shows the pinch type strut and torque spec of 33 lb ft. Very confusing.

[SIMI BOB]

Phil, Thanks for the reply. Spot face means to create a flat surface for the nut to sit on. The side that the head of the bolt sits on is spot faced from the factory, but the threaded side is not. I am proposing to insert a longer bolt into the hole, torque the bolt to 33 lb ft, then red loctite the nut on to the threaded part that sticks out, So I am just doing exactly what the factory did, but adding a pinch nut to the far end of the bolt.

Sorry, there was a typo in my post above, it said "Finally Spot Face the other side of the bolt hole and put a bolt there". It should have said "put a NUT there".

Bob B

[Phil Planck]

Bob
I was suggesting red loctite for the 3 4 bolt. I would use blue on the pinch bolt or you will need heat to break it loose for your 6000 mils torque check.

[lopena]

Well, I finally got around to removing one of the pinch bolts on my ‘69 911…sure enough the bolt was a total mess.

In addition, there were metal shavings in the bolt hole, so I think the threads in the strut housing itself are also toast.

I am now resigned to buying a set of updated front struts…I simply don’t want to worry about this anymore.

[Chris Pomares]

Would there be enough metal for a machinist to recut for some type of oversized wedge pin?

[RoadTrippin911s]

Wow. Did you have any observable play or knocking in the ball joint with this bolt? I had mine checked out and the ball joints seem rock solid so the knowledgeable expert advice was “don’t waste your money” but we didn’t go as far as removing the bolt.

Anyone else with experience in this regard - do these bolts fail without any warning or is one ok as long as we check them regularly and don’t track the car?

Well, I finally got around to removing one of the pinch bolts on my ‘69 911…sure enough the bolt was a total mess.

In addition, there were metal shavings in the bolt hole, so I think the threads in the strut housing itself are also toast.

I am now resigned to buying a set of updated front struts…I simply don’t want to worry about this anymore.

[Phil Planck]

Alan
Just curious - did the bolt come out easily? Possibly threads were damaged during removal. You could try threading a new bolt in from the opposite side to check strut threads. If true the pin needs to be realigned until bolt easily slides in until it hits threaded portion of strut. Im not trying to discourage you from upgrading the strut.
Phil