1965 L78 clutch bracket mounting position.

[Jim S.]

The clutch bracket can be mounted in one of two positions. One position allows the bracket to use the 'tall' bump stop and allows the clutch pedal to align with the brake pedal height. The other bolt hole position allows the bracket to use the 'lower' bump stop which also sets the clutch pedal higher than the brake pedal.
What determines which bolt hole to use? Should it be the one on the right or the left? The AIM is not clear on this issue. Thanks.
img_71966288b2f44b149e948f4aa4a79639.jpg img_485a3042ab514f4b9e0a51a7c55ec19c.jpg img_98f0a4f986054aa59d8923ceba53c24a.jpg

[John H.]

Re: 1965 L78 clutch bracket mounting position.

The clutch bracket can be mounted in one of two positions. One position allows the bracket to use the 'tall' bump stop and allows the clutch pedal to align with the brake pedal height. The other bolt hole position allows the bracket to use the 'lower' bump stop which also sets the clutch pedal higher than the brake pedal.
What determines which bolt hole to use? Should it be the one on the right or the left? The AIM is not clear on this issue. Thanks.
[ATTACH=CONFIG]52904[/ATTACH] [ATTACH=CONFIG]52905[/ATTACH] [ATTACH=CONFIG]52906[/ATTACH]

Jim -

You won't find any reference in the A.I.M. to the alternate "quick-release" clutch pedal position - all Corvettes were built and shipped with the clutch pedal in the "normal" position; changing it to the "quick-release" position was done by dealers or owners. See two photos below that show the bracket-to-pedal relationship for both positions.


ClutchQuickRelease.jpgClutchPedalNormal.jpg

[Jim S.]

Re: 1965 L78 clutch bracket mounting position.

Jim -

You won't find any reference in the A.I.M. to the alternate "quick-release" clutch pedal position - all Corvettes were built and shipped with the clutch pedal in the "normal" position; changing it to the "quick-release" position was done by dealers or owners. See two photos below that show the bracket-to-pedal relationship for both positions.


[ATTACH=CONFIG]52907[/ATTACH][ATTACH=CONFIG]52908[/ATTACH]

Thanks John, now I'm confused why the 'quick release' position places the clutch pedal even with the brake pedal while the normal position puts the clutch pedal higher than the brake? Yes, the brake pedal is against its stop.

[Doug M.]

Re: 1965 L78 clutch bracket mounting position.

The clutch bracket can be mounted in one of two positions. One position allows the bracket to use the 'tall' bump stop and allows the clutch pedal to align with the brake pedal height. The other bolt hole position allows the bracket to use the 'lower' bump stop which also sets the clutch pedal higher than the brake pedal. What determines which bolt hole to use? Should it be the one on the right or the left? The AIM is not clear on this issue. Thanks.[ATTACH=CONFIG]52904[/ATTACH] [ATTACH=CONFIG]52905[/ATTACH] [ATTACH=CONFIG]52906[/ATTACH]

Jim,Going a little bit off topic , but interested in the picture of the clutch bracket itself. It looks like there is another hole below the pin for the clutch rod. Is that right?Thanks,Doug McClure

[Jim S.]

Re: 1965 L78 clutch bracket mounting position.

Jim,Going a little bit off topic , but interested in the picture of the clutch bracket itself. It looks like there is another hole below the pin for the clutch rod. Is that right?Thanks,Doug McClure

Correct, there is another hole below the clutch rod pin. No idea what it is for either.

[William C.]

Re: 1965 L78 clutch bracket mounting position.

Because it changes the lever arm to provide less travel with a higher effort resulting in the lower pedal. Longer travel is a result of changing the pivot point on the arm to reduce the effort required.

[Jim S.]

Re: 1965 L78 clutch bracket mounting position.

Because it changes the lever arm to provide less travel with a higher effort resulting in the lower pedal. Longer travel is a result of changing the pivot point on the arm to reduce the effort required.

Bill, I understand that part, my question is why the clutch pedal is on the same plane as the brake pedal when it's in the LOWER setting. When the clutch bracket is in the 'normal' position, the clutch pedal is higher than the brake pedal.

I would think that when the bracket is in the 'normal' position, the clutch & brake would be on the same plane.

You'll notice this in the pics in post #1

[Wayne M.]

Re: 1965 L78 clutch bracket mounting position.

..... my question is why the clutch pedal is on the same plane as the brake pedal when it's in the LOWER setting. When the clutch bracket is in the 'normal' position, the clutch pedal is higher than the brake pedal.
....

The answer is "quick release", as John H. says.

Here's 3 related pics of clutch push rods. To show the differences, I've lined up the holes at the pedal bracket -- there is a slight difference in bend angle. Then 2nd pic, I show the forward end of the 3 rods, with the pedal bracket holes still lined up, as in previous pic. 3rd shot is with start of threaded sections all lined up. Just to show the differences.

The "service" 3888213 was the unique rod for '66-7 427's, until it (also) replaced the small block rod. The unique 396 rod was still available as of my Jan '70 catalog.

[William C.]

Re: 1965 L78 clutch bracket mounting position.

Simply put, more travel is needed to reduce the pedal effort for "standard" drivers. The change in the pivot point for the "quick release" (also higher effort) position putting it level with the brake was likely at least as much by luck as design intent.

[Jim S.]

Re: 1965 L78 clutch bracket mounting position.

Simply put, more travel is needed to reduce the pedal effort for "standard" drivers. The change in the pivot point for the "quick release" (also higher effort) position putting it level with the brake was likely at least as much by luck as design intent.

Ok, so in the 'standard' position, the clutch pedal's position is higher than the brake pedal when both are against their bump stops? I must admit I have never noticed that in any C2. ;-)

[Wayne M.]

Re: 1965 L78 clutch bracket mounting position.

Ok, so in the 'standard' position, the clutch pedal's position is higher than the brake pedal when both are against their bump stops? I must admit I have never noticed that in any C2. ;-)

I would think at any NCRS judging event, the relative position of the clutch and brake pedals should be noted (similar to checking if 4-speed shifters are on the short or long throw).