Oh what a day...

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Riddler

Riddler

Project EH-Body
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So I’m working on getting my 7/8” Wilwood clutch master setup. I’m only getting 9/16” if throw and can’t figure out why. I finally have my friend push the pedal down while I watch and low and behold. The firewall is flexing 1/2”-3/4”. I thought I measured the throw right.

Now the only fix I can think of is a 1/8” plate on the inside of the firewall about 3” in every direction to help push the pressure over a larger area.

Once this is done, I’ll be able to get the clutch safety switch and pedal stop figures out.

Riddler

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If i was building it, had the switch,why not. It is a cya situation.some beginner hops in and hits the key,door open and in reverse for example. Honestly i have been there, my son hit the key in a chevy,and it fired in reverse,door caught the hoist and wrapped it right around. He was damn lucky. Scared the **** outta me. And him i guess. Things you never thought would happen.
 
My friend had a Mccloud hydraulic clutch in a 65 Barracuda. Same thing, firewall flexing. So we looked and came up with a slant six transmission support bracket from the shock tower to the firewall. Worked and later found out that others did the same thing.
 
Clutch switches can work both ways. In the early 70's I nearly "had a cow" on a goat. I was somewhat dirty and did not want to get into the car. Reached in and twisted the switch, then realized it has a clutch switch. ALSO it had the reverse / column lock interlock.

I balanced on my left foot, reached in, put my foot on the clutch with my right. Pulled the shifter "out of gear." What I DID NOT REALIZE is that the shifter was a bit out of adjustment and it DID NOT ACTUALLY come out of reverse.

Twisted the key, let out the clutch and the CAR STARTED TO THE REAR!!!!

Now let's "replay" that with no clutch switch..........the car is in some gear, you reach in and twist the key. The car lurches, and you IMMEDIATELY are startled and release the key. VERY doubtful it will fire and run in that "instant."
 
pishta said:
My friend had a Mccloud hydraulic clutch in a 65 Barracuda. Same thing, firewall flexing. So we looked and came up with a slant six transmission support bracket from the shock tower to the firewall. Worked and later found out that others did the same thing.
Click to expand...
Have a picture of what you talking about? I’d love to brace it better as well.

As for the switch, I have to have one to pass safety. No switch, no plate.

Riddler
 
Yes, I ran a brace from the shock tower area of the inner fender well to a stud on the brake cylinder. A kind of round pipe with tabs on the end bent to fit flat against the firewall and flat against that inner fender area.

brace.jpg
 
How about a plate on the inside of the car to hold the load?
 
Riddler said:
As for the switch, I have to have one to pass safety. No switch, no plate.

Riddler
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That sucks, my '93 Jeep Cherokee is a 5-speed manual and never had a clutch safety switch. I always start it in neutral with my foot off the clutch, helps save the thrust bearing (it has 240k miles). Also nice to have for off-roading or some other emergency if something happens to the engine you can push the car by cranking the starter in gear lol.
 
Put a booster on it; when the booster hits the hood, the flexing will stop. You might have to shim it a bit to get the timing right.
Of course I'm kidding.
Ok, it was funnier in my head,lol.
 
I’m going to be trying a plate inside the car. If that doesn’t stop all the flex I’ll try making braces from the master to the inner fender.

Riddler
 
pishta said:
My friend had a Mccloud hydraulic clutch in a 65 Barracuda. Same thing, firewall flexing. So we looked and came up with a slant six transmission support bracket from the shock tower to the firewall. Worked and later found out that others did the same thing.
Click to expand...
Yes put a strut (threaded rod ) to clutch firewall area with large washers on each side to capture firewall
flex and bend other of the rod to a 90 deg angle and
attach to the inner fender. Adjust the nuts on the
firewall side for no firewall flex. That little flex movement makes a big difference in clutch performance. I don't know if there was less flex when the cars where new? or if its a wear issue.
 
Here’s what I did in my Duster. Had I cut it out with a jig saw of band saw, I think I could’ve done a better job but I had a local shop cut it out with a plasma cutter. Shoulda have it CNC’d I guess. It’s 1/8 or 3/16” aluminum. Held in place by the studs on the MC and the steering column bolts.

This is the side that goes against the firewall.

DE153A64-9D68-4A6A-84C6-7864E0C0C00D.jpeg
 
75slant6 said:
Here’s what I did in my Duster. Had I cut it out with a jig saw of band saw, I think I could’ve done a better job but I had a local shop cut it out with a plasma cutter. Shoulda have it CNC’d I guess. It’s 1/8 or 3/16” aluminum. Held in place by the studs on the MC and the steering column bolts.

This is the side that goes against the firewall.

View attachment 1715128095
Click to expand...

I made up a steel plate to reinforce my firewall. I added a clutch switch but only wired it to my cruise control
Jim

IMG_1397_1280x719.JPG


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IMG_1424_1280x719.JPG
 
I did the plate on the inside of the car thing. Saw it on another thread here, I think on the T56 install thread. Welded a tab to the pedal box to extend it to the left for the clutch master for some better support. So far so good.
 
I guess I should specify that I used a master and slave cylinder from a early 90s S10. The base of the master is angled which allowed me to use the original hole for the factory shift linkage. That’s why I was able to make a plate that captured the MC and steering column.
 
From an engineering perspective, I'd recommend a steel plate instead of Al since the steel will not deflect as much under load. I think my plate was 1/8" thick.
Jim
 
RealWing said:
From an engineering perspective, I'd recommend a steel plate instead of Al since the steel will not deflect as much under load. I think my plate was 1/8" thick.
Jim
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You're using it as a sandwich plate, the more important thing is that you grab enough surface area on the firewall. The aluminum plate isn't going to be the part that deforms, the weak link is the firewall.
 
72bluNblu said:
You're using it as a sandwich plate, the more important thing is that you grab enough surface area on the firewall. The aluminum plate isn't going to be the part that deforms, the weak link is the firewall.
Click to expand...

I agree - you want to bear on as much of the firewall as possible to distribute the load. Space is really limited on the inside. I can see a little bit of firewall deflection on my Cuda but it is pretty small.
 
I’ve got pretty much enough room to go 3” all around.

Just trying to find a place that can cut one for me. My laser cutter is swamped with work.

Joe
 
72bluNblu said:
Not mine, but one way to do it. May be the one map63vette saw. It's super easy. There are also places that make generic plates for hydraulic master conversions, Wilwood makes brackets for its master cylinders Wilwood Master Cylinder Adapter Brackets 250-3677

View attachment 1715128580 View attachment 1715128581 View attachment 1715128582
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Yep, that looks like the one. I had originally thought about doing one of the American Powertrain setups or whatever it is that mounts the master where the factory clutch linkage used to come through, but didn't think their little bracket was worth the $300+ or whatever they wanted for it. A simple steel plate and some welds was much more up my financial alley.
 
Map63Vette said:
Yep, that looks like the one. I had originally thought about doing one of the American Powertrain setups or whatever it is that mounts the master where the factory clutch linkage used to come through, but didn't think their little bracket was worth the $300+ or whatever they wanted for it. A simple steel plate and some welds was much more up my financial alley.
Click to expand...

Yeah I can't believe what American Powertrain charges for that hydraulic set up. Ridiculous.
 
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