Hydraulic Clutch conversion

[billd5string]

I'm in the middle of updating my 65 C20 with the crossmember/brakes/steering/454 from a 75 C20. I will be keeping the SM420 from the 65, and need to switch from the manual clutch to hydraulic. I've searched around on here and can't find anything about how anyone else has mounted the master cylinder for the clutch in a 65.

I've got a wilwood master cylinder, and the truck already has the power brake booster. I am thinking about mounting it right on the firewall between the booster and the inner fender, but there is very little room and probably only one place where it can be positioned correctly. My problem is I'm concerned that the leverage from the pedal will be incorrect for the master cylinder.

Has anyone else done this type of conversion? I don't really want to go down the the factory path for a 60-62 style.

[Rufton]

FWIW (about 0 cents): I converted OEM mechanical linkage to heim joints and really like it.

[billd5string]

That's exactly what I was thinking as well - where did you end up mounting the actual master cylinder? It looks like your heim joint is pretty high so it probably doesn't over extend the cylinder... very nice!

[1963c-10]

PM captainfab....he makes a conversion plate for this specific application. I have purchased all the parts to do the conversion myself using his mounting plate and hardware and a Novak kit -similiar to what is used on jeeps. I would suggest checking out the Novak site for GM's also. I beleive the engine bay pic shows one of captainfabs mounts, the master for the clutch is seen to the right of the brake master

[Brad54]

Wow, most guys usually go the other way! '60-62 came with a factory hydraulic clutch.

There's someone on here who sells a bracket to convert to power steering, and that bracket kit comes has the mount and linkage for a hycraulic clutch.

If you wanted to go a bit more bucks-up, you could get the power brake conversion from CCP, and a brake pedal assembly from a '60-'62.

-Brad

[markeb01]

When I originally built the truck I switched from the granny 4 speed to a 350/350 automatic. Later I switched back to a passenger car 4 speed manual. I fabricated a larger firewall plate for support and mounted a Wilwood 3/4" master cylinder directly in front of the original clutch operating arm, which is to the right of the brake pedal on the far end of the pivot shaft. The arm is connected to the master cylinder with a heim joint, steel spacers and a grade 8 bolt. I attached the bolt with double nuts to allow tension adjustment and lock in place. By retaining operation of the stock actuating lever, the pedal leverage ratio remains unchanged.

I've included a couple of photos to clarify the installation and shape of the firewall plate.





The Wilwood master cylinder can be seen here:

http://www.summitracing.com/parts/WIL-260-1304/

Hydraulic clutch systems are normally designed with a 1 to 1 ratio between the master and slave cylinders (both are the same size). Quite by accident I used a ¾” master cylinder connected to a 7/8” slave cylinder. This decreases pedal pressure at the expense of travel, in effect providing a “power” clutch. This arrangement releases completely, so I’ve never bothered to correct it. If I were to change the slave cylinder to ¾”, I could lower the pedal closer to the floor for convenience, but this would also increase pedal pressure. Since it works perfectly I’m leaving it as is as I prefer the easier clutch operation.

For the slave cylinder I purchased a Novak kit designed to install a Chevy V8 in a Jeep. I believe they have changed the kit somewhat, but here’s what mine looks like:



And here’s a link to their site:

http://www.novak-adapt.com/catalog/kit_hcrc.htm

CaptainFab also makes a nice setup similar to the Master Power Brakes arrangement that mounts the master cylinder on the outboard side of the brake booster. The CaptFab design corrects the pedal ratio issue inside the truck.

[billd5string]

Thanks for the help guys. I'll be working it this weekend.

[1963c-10]

I've got everything pulled together for mine, but still have to get my Dad to mill the 9:00 boss down to the same height at the 10:00 boss

[billd5string]

Well - the original plan is out the window now. The new crossmember is in, and motor mounts for the 454 are in place, but it's obvious that the 454 won't be able to bolt up to the factory bellhousing in the original location. The spacing from the motor mount to the bellhousing is 2 inches longer in the truck, than the spacing on the motor.

So the stock bellhousing crossmember will need to come out, and the SM420 doesn't have any place to mount up to a crossmember, so I guess I'm going to need a different transmission and driveline now.

[billd5string]

The crossmember is from a 75 C20 with a 454, which is the motor I'm sticking in my 65.

[1963c-10]

i caught that late, when i scrolled back up
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[1963c-10]

captainfab seems to have alot of knowledge in this area...id try him
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[billd5string]

Originally Posted by 1963c-10

captainfab seems to have alot of knowledge in this area...id try him
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I was just thinking the same thing. I sent him a message asking about his hydraulic clutch brackets, I think he's probably going to have the right answer for my motor mount issues.

[1963c-10]

Heres my mock up so far. Chevy bellhousing # 3815891. Was originally in a 64 c-10 v8 truck and there are two ways to go with the mount. You can machine the 9 o'clock boss down or use spacer/shorten the push rod. I opted for the machine work. I need to file the clutch fork access some as the factory left them rough, and the novak clutch fork is thicker than the oem clutch fork. Napa will supply the new clutch fork gasket, and i used AN fittings and stainless steel hose to plumb. More pics as progress unfolds. Getting closer now that engine is here at the house. The big block came out great.

[1963c-10]

Heres a pic of what I'm going to bolt it too

[Rufton]

Looking Good!

[1963c-10]

thanks, my clutch pedal will also be helm joint
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[Rufton]

Looking real good then

[TR65]

Here is how I mounted the clutch master cylinder in my 65.
After 12,000 miles still works with no troubles.

http://67-72chevytrucks.com/vboard/s...d.php?t=300087

TR

[1963c-10]

I have been working on the access cover for the clutch fork. How much of a tolerance should I be looking for. Right now the clutch fork operates forward and rear just fine, but with 1/64 tolerance from the clutch fork to the top & bottom of the casting. I would need 1/4" total to allow for the gasket due to the thicker clutch fork that came with the kit. My other option would be to take the arm to my local fab shop and have them dimple the fork or take more off the bellhousing. Any suggestions on which avenue is best? The OEM fork is 1" & the Novak fork is 1 11/16"

I would like to mock it up on the trans w/complete clutch/flywheel assembly to see if it rubs any. I would like to be able to use the clutch fork gasket to keep rocks & crap out of the bellhousing is the ultimate goal here.

[Captainfab]

I would open up the bellhousing. If you try and squeeze the fork together, that could potentially be a failure point.

[1963c-10]

allright, so its back to the file work then. how much clearance should i be looking for?
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[61_FL_Apache]

Looking great so far!!