Hi everyone!

I have another question for you. I am trying to take out a number of interior bolts that have a strange drive type. The picture below shows one of them along the top of the backside of the instrument cluster. There are others like this attaching the mount for the control cables under the dash to the fresh air vents in the door posts.

What type are these - they look kind of like square (Robertson) or hex (Allen) but are more oval in the slot than square or hex.

What do you all use to remove/install them?

That is called a Clutch Head screw.

> > > Clutch Head Drivers < < <

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WA. state, 1 mile south of the Canadian border, I am not at the end of the world, but you can see it from here.




Edited 1 time(s). Last edit at 04/02/2021 07:50PM by American Mel.

Clutch Head, found in Powerglides, FC truck interiors, horn contacts, backside of instrument cluster (shown in your picture).

Available in those 1/4" bit sets many places. Found as socket bits on ebay or Amazon. Also available as screwdrivers. 4 common (if any are common anymore) sizes, maybe 8 in total.

Frank DuVal

Fredericksburg, VA

Thanks everyone!

I'm embarrassed to say it in all the years I've been turning wrenches, but this is the first time I've come across this type. Was this a common fastener for GM vehicles before the 1970s?

According to online sources , . . . . . . . .
They were used in the automobile industry from the '40s through the '60s, and adopted by the RV industry in the '70s.
I am sure some of the "Old-Timers" around here can give you better info than that, though.

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WA. state, 1 mile south of the Canadian border, I am not at the end of the world, but you can see it from here.

OldWrenchTurner Wrote:
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> Thanks everyone!
>
> I'm embarrassed to say it in all the years I've been turning wrenches, but this is the first time I've come across this type. Was this a common fastener for GM vehicles before the 1970s?

My 55 Chevy had a number of them in the dash area so GM was using them at least around that time. Think they were always looking for fasteners that made assembly and torquing easier, especially in that era.

I have a set of those drivers from working on my 55, haven’t needed to remove one from my 66 Corvair yet.

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Gary
1966 Corsa Convertible
Northern New Jersey

GM and Chevy trucks used them a lot in the 50's. I had a 1957 Chevy 1/2 ton Cameo that used them in a number of places.

The Corvair FC was a Chevy "truck" and therefore it had "clutch head" bolts in some places.

I've still got my clutch head driver bits.

Holley carbs also used them.

RJ tools
Salem,Oregon