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Screw in ball joint for post '78 ali rear arm ARB drop link?
Posted: Sun Oct 14, 2018 4:33 pm
by amallagh
Does anywhere make a screw in ball jount for post '78 ali rear arms to backdate them to '74-'77 Carrera arms with the ball joint fitting for the earlier rear anti roll bar drop link ?
Having bent my left year arm on my RS, I have committed to buy another ali rear arm. It has the same casting number so assumed it was identical but it is a later version with the bolt hole attachment for the later dog bone drop link. I hope I haven't wasted my money on getting these other arms and that someone sells a ball joint conversion part.
Please let me know of you can help.
Regards
Andrew
Re: Screw in ball joint for post '78 ali rear arm ARB drop l
Posted: Sun Oct 14, 2018 10:20 pm
by 911hillclimber
Maybe a call to Chris at Fenn Lane Andrew?
Good luck with your quest.
Graham.
Re: Screw in ball joint for post '78 ali rear arm ARB drop l
Posted: Mon Oct 15, 2018 2:16 am
by amallagh
Thanks Graham.
I might have found a donor part. Ball on end of gear lever is same diamtere and section above it is 12mm. Could be perfect. Juts trying to sort out a donor gear lever and I think I might have one somewhere to butcher.
Would still prefer an off the shelf bolt in ball joint parts if anyone knows where to get one.
I am assuming that the pre '78 and post '78 arms are otherwise identical and all parts like hubs, bearings etc. are otherwise the same (?)
Re: Screw in ball joint for post '78 ali rear arm ARB drop l
Posted: Mon Oct 15, 2018 6:15 am
by Magnum
Hi Andrew
I have just been through this - wilth help (via DDK) from Chris at Fenn Lane and Mike Bainbridge who happily responded. In short I've taken the standard Porsche pre-73 ball pin (i.e. that is welded to the steel arms) and machined a thread, as well as a shoulder at the base of the ball.
I've not yet fitted my arms but have every confidence this will be fine.
Good luck!
Re: Screw in ball joint for post '78 ali rear arm ARB drop l
Posted: Mon Oct 15, 2018 12:20 pm
by amallagh
Magnum wrote:Hi Andrew
I have just been through this - will help (via DDK) from Chris at Fenn Lane and Mike Bainbridge who happily responded. In short I've taken the standard Porsche pre-73 ball pin (i.e. that is welded to the steel arms) and machined a thread, as well as a shoulder at the base of the ball.
I've not yet fitted my arms but have every confidence this will be fine.
Good luck!
Thanks Magnus. I was thinking a similar thing. Plenty of meat on those pre'73 pins to machine a thread. Was just wondering if anyone had an off the shelf fitment option to keep the costs/time down.
I even have an old gearstick with the same ball on the end that I could butcher and use as I already have that.
Hard to believe we are the only 2 people wanting to do this so surprised there is not a commercially available solution as early Carrera arms are not so common these days and asking prices are therefore higher relative to later SC/3.2 arms and there is no other difference as far as I am aware.
Re: Screw in ball joint for post '78 ali rear arm ARB drop l
Posted: Mon Oct 15, 2018 1:32 pm
by Magnum
Completely agree Andrew, there must have been a lot of upgrades in the past, and present day too, so surprised there isn't an "accessible/off the shelf" solution. Interestingly I think the choice most make is to update their roll bar to get round the problem, rather than what should be a simpler fix (ie our is preferred route).
I decided to go with the Porsche pin as the repeated forces are apparently quite high - the grade of steel etc. is important.
Regards
Re: Screw in ball joint for post '78 ali rear arm ARB drop l
Posted: Mon Oct 15, 2018 5:36 pm
by 911hillclimber
My alum arms are 1976 iirc and have the ball but look to me to be over-cast so not removable.
I fitted my steel arm components (73T) to these arms so to use the large dia 4 bolt/ 2 dowel pin CVs from the 73T.
Somewhere along the line the smaller CVs came in.
I agree that the roll bar components get a lot of reverse loading, so need to be a robust mounting.
Screw them in with good loctite!