How to fix ovalised hole?

[tut]

have you thought about zipties?

[KDog]

Can the later splined shaft model be retrofitted? That would be best.

Spring pins will be a fail.

[Babalouie]

Can the later splined shaft model be retrofitted? That would be best.

Yes, but I'd have to find a complete 993 pedal cluster.

[Momus]

Can the later splined shaft model be retrofitted? That would be best.

Spring pins will be a fail.

^Eddie, go and have a look at what holds a trailer ball hitch to the overide brake slider shaft....

Spring pin was the OE solution and will be fine.

Unbrako's recomendation for hole size using a 1/4" pin is:

Min .250" Max .256"
1/4" roll pin min double shear strength is 7700 lb.
5/32" roll pin min double shear strength is 3000 lb.

This is giving over 10000 lb telescoped shear strength minimum on a relatively lightly loaded application.
I would gang drill using a $6.00 6.3 diameter twist dril, rather than pay for a $50 ream, or someones services.

If you want to ream, and get the most strength, a diemakers 1/4" dowell pin from Unbrako has a min double shear strength of 14700 lbs.

[Babalouie]

I don't think there's any risk of the rollpin shearing. What happens is that eventually the rollpin develops a crack on the side (presumably from flexing slightly every time it's loaded) and you get this freeplay at the pedal. But I guess if it only happens every ten years it's not the end of the world.

I don't mind buying a 1/4 ream just to have a go at using one for the first time, but do they need a "clean" hole, or can you start them on an ovalised hole and go from there? If the reamers are fussy about the surface, I think I could get away with just drilling, since we're jamming a spring pin in there, and not an interference fit dowel or anything like that.

[Babalouie]

By the way....if my car was a 1992 model, I'd just go and buy a new clutch pedal, because they're $40. But because my car is a 1993 model, they are $478

[Momus]

What sort of ream are you going to use? If it is a machine ream rather than an adjustable hand item, measure the hole for ovality and if ok use plenty of oil and drive the ream at a slow speed with your cordless drill.

My early, a 2.4S, has a cable operated clutch with the pedal and actuator in one piece welded and straddling 2 demountable bearings.
I am fitting it with a 3.6/3.8 with a 3 plate 5.5" metallic push, rather than oe pull clutch and retaining the 915 box. I reckon I can convert to a hydro clutch and a concentric release bearing by putting the master directly in front of the pedal, beside the brake MC and running a conventional pushrod.

[Babalouie]

I don't have any reams at the moment, I was gonna buy one when I went to the fastener shop next week My mind's open as to whether a drill ream or hand ream is better for the application. But given that I'm just opening up the hold slightly, I was going to go for a hand ream if it gave me more control.

964 and 993 pedals have the master cylinder mounted in a cradle that's part of the whole pedal cluster, with a softline to the reservoir in the boot. Photobucket seems to be borked at the moment, but I'll post up some pics a bit later if it's working again

[Gammaboy]

Quick tip for you 911 guys - the early cars with the unboosted tandem master - the section of hardline that plugs into the feed line can be replicated with some 1/4 line and the first stage of a double flare (so basically a 1/4" bubble flare) to fit the gromets. I'm using one of those masters and there was no way I was paying pelican $200 odd for the feed lines.

[Faux Forg]

I don't think there's any risk of the rollpin shearing. What happens is that eventually the rollpin develops a crack on the side (presumably from flexing slightly every time it's loaded) and you get this freeplay at the pedal. But I guess if it only happens every ten years it's not the end of the world.

I don't mind buying a 1/4 ream just to have a go at using one for the first time, but do they need a "clean" hole, or can you start them on an ovalised hole and go from there? If the reamers are fussy about the surface, I think I could get away with just drilling, since we're jamming a spring pin in there, and not an interference fit dowel or anything like that.

It won't matter if the holes are all oval to the same extent. But if the hole in the shaft is oval and the holes in the bellcrank are still round then it will fail. If you decide to open out the hole, use a hand reamer with a tapered lead in on it and plenty of lube. Ream the whole lot in its assembled configuration so that everything lines up too. Then double spring pin FTW. IMHO a dowel pin will end up being loose in either the shaft or the crank and then you'll be back in the same position but with less metal to re-size.