Heavy Clutch Pedal

[Railroad]

I have the Wilwood pedal box with Forte's hyd clutch, with slave cyl.
I am considering making changes to lighten the clutch pedal effort.
It seems I have a 1 1/8" master cyl and 7/8" slave. The body is on the car in gel coat, so the master cylinder is not accessible. I am searching for a 1" slave cyl. I have found 1 for a 1960's Chev truck and another for a MG.
Prices are about $30 and $15. The bolt spacing and piston travel seem to be the only specs, I have not confirmed.
I called Forte, without success, but was rewarded by enjoying conversation with him.
If anyone has any suggestions on this, I am listening.
thanks,

[Jacob McCrea]

I have the same size master cylinder and slave cylinder on my coupe, albeit with mounting brackets at the transmission and clutch fork of my own design. It seems to me that you could try spacing both the slave cylinder and the bracket at the clutch fork as far away from the engine as possible, to give the slave more mechanical leverage over the clutch fork. But, due to the geometry changes, there will be some outer limit to how far you can space the assembly away from the transmission, and at some point the slave cylinder will run out of travel and blow out of the bore. I think there was a recent thread here about just that problem. In the picture below, I have the slave and bracket on the clutch fork tucked in about as close to the engine as possible, for the quickest pedal that those parts will allow. Pedal effort is not light. Hope this helps.

129031

[GoDadGo]

Though not a Ford set up, I'm using a .75" Master Cylinder with 1.0625" ( 1 1/16" ) Slave.

My setup for the clutch is buttery smooth and has a good feel.

Just remember that you need to do the math to get the length of the piston volumes right.

[CraigS]

Jacob has a good idea and I believe Forte has a clutch lever extender kit normally used w/ a cable which could help you.

[Railroad]

Jacob has a good idea and I believe Forte has a clutch lever extender kit normally used w/ a cable which could help you.

Wonder how much improvement I would get from, say an inch longer lever?
Might be a lot of work for no feel of improvement. Anyone have experience in the longer lever effect?
If it works it would worth the effort.
thanks,

[mcwho]

My setup uses the same size cylindes and GoDadGo

I'm using a .75" Master Cylinder with 1.0625" ( 1 1/16" ) Slave.

[Higgybulin]

My setup uses the same size cylindes and GoDadGo

I'm using a .75" Master Cylinder with 1.0625" ( 1 1/16" ) Slave.


Though not a Ford set up, I'm using a .75" Master Cylinder with 1.0625" ( 1 1/16" ) Slave.

My setup for the clutch is buttery smooth and has a good feel.

Just remember that you need to do the math to get the length of the piston volumes right.

Which slave are you guys using?
Higgy

[Jacob McCrea]

"Wonder how much improvement I would get from, say an inch longer lever?
Might be a lot of work for no feel of improvement. Anyone have experience in the longer lever effect?"

No personal experience, and I'm not an engineer. But I would assume that with, say, 10" between the ball pivot and where the slave's pushrod attaches, another 1" would give you about a 10% reduction in effort. Whether that would make a meaningful difference at your foot, I have no idea. Maybe a bona fide engineer can comment.

[Railroad]

My setup uses the same size cylindes and GoDadGo

I'm using a .75" Master Cylinder with 1.0625" ( 1 1/16" ) Slave.

Do you know the brand on the slave?
I am sure that would make a big diff in the effort.
I looked at Tilton and Wilwood. Maybe check with Baer.

Looking forward to your reply.
thanks,

[RBachman]

Give Mike Forte' a call. He set up my clutch master/slave system and it works great. My only issue was getting the clutch pedal adjusted so I got a good full disengagement and proper pedal height compared to the brake and throttle. A little bit of tweaking and all is great. Mike sent me the Willwood master, and I think it may be the same bore as the brake masters. Never bothered to find out because it works so well. Not sure about the clutch slave either, but they work great.

[karlos]

No personal experience, and I'm not an engineer. But I would assume that with, say, 10" between the ball pivot and where the slave's pushrod attaches, another 1" would give you about a 10% reduction in effort. Whether that would make a meaningful difference at your foot, I have no idea. Maybe a bona fide engineer can comment.


Your intuition was right on. Numbers work out at almost exactly a 10% reduction in pedal effort for every inch of outboard movement of the slave cylinder. The shaded row in the table shows that with the slave relocated 1" further outboard the pedal force would reduce by 10.4%. The curve shows that the effect is fairly linear, so you get pretty close to an additional 10% for every additional inch. Guessing that the perceived effort wouldn't be much different until you hit something like a 25% reduction, which unfortunately would require that the slave cylinder be relocated 3" further outboard :(




https://thefactoryfiveforum.com/attachment.php?attachmentid=129156&d=1590635923

[Railroad]

Karlos, thanks for the chart and numbers. If I have a 30 or even 40 lb pedal, as you stated 10% is only 3 or 4 lbs.
Not really worth the effort. I can see getting a 1" change, but more than that would require too much apparatus.

Not having much luck on finding a direct replacement push slave with 1 or 1 1/16"bore.
I may go by the parts store and see what the 60 Chev truck slave looks like.

Maybe I can find a small wiry person to swap out my master cyl.

[CraigS]

I sure hope that truck slave will work for you. I just read back through this thread and see that the other posters who included their sizes are just opposite of yours. Yours is larger master than slave and their's smaller master than slave. If that slave won't work I am afraid it is going to be new MC. Ughhhh. One more try I think would be worth while. Call both Wilwood and Tilton. They have been well known in this business for many decades (I bought parts from Tilton in the 70s) so they may just have an idea for you.

[BradCraig]

"Wonder how much improvement I would get from, say an inch longer lever?
Might be a lot of work for no feel of improvement. Anyone have experience in the longer lever effect?"

No personal experience, and I'm not an engineer. But I would assume that with, say, 10" between the ball pivot and where the slave's pushrod attaches, another 1" would give you about a 10% reduction in effort. Whether that would make a meaningful difference at your foot, I have no idea. Maybe a bona fide engineer can comment.

Guess you could say "Every inch counts"? :-) I have the Forte extension and cable, haven't driven it yet but pedal doesn't seem too stiff.

[Railroad]

I sure hope that truck slave will work for you. I just read back through this thread and see that the other posters who included their sizes are just opposite of yours. Yours is larger master than slave and their's smaller master than slave. If that slave won't work I am afraid it is going to be new MC. Ughhhh. One more try I think would be worth while. Call both Wilwood and Tilton. They have been well known in this business for many decades (I bought parts from Tilton in the 70s) so they may just have an idea for you.

I actually did not know my hyd clutch cyl sizes. Mike Forte, ask me the color of my slave, he knew what ratio sizes he sold. I think edwardb, realized the effort was high and swapped his prior to everything getting covered up.
I am in line for J Klien to paint me at the end of the year, I hope. Maybe, I will be able to crawl over it and get the master swapped out.
My clutch is on the grabby side and the high effort, short engagement makes it tough at times.
Wilwood and Tilton do not list anything larger than 7/8", but a phone call might get some results.
Mike had a 1" slave, but the bleed is on the bottom and on a cast boss. No place to drill and tap a new location.
I could bleed it, then install it, but thought, I might be asking for problems with that set up.
Keep me in mind if you hear of something, thanks for the reply and advise.

[Jacob McCrea]

"Your intuition was right on." Not bad; even the guess on the clutch fork length was pretty close. I'm reminded of the saying that even a broken clock is right twice a day.

"My clutch is on the grabby side and the high effort, short engagement makes it tough at times." I actually have the opposite problem, with a 1.125" master, a 7/8 slave and a Luk clutch assembly requiring far more pedal travel than I want. What kind of clutch assembly do you have; it sounds like that's what I need.

I wouldn't look forward to doing it, but I'd probably break down and install a smaller master cylinder, and maybe an access panel (or 2) atop the footbox, if you don't have one already.

[JohnK]

This conversation is very interesting to me. My TKO600 and Coyote are put together but are not installed in the car yet. I have the Forte's hydraulic clutch setup on it at the moment but am now reconsidering going with the Tilton HRB. Now would be the time to make the switch, as it would be just a few bolts to pull the tranny off the engine and make the swap. Even having to swap a MC would be easy as I haven't finished the pedal box yet. I know there are many happy folks using Mike's hydraulic clutch setup, and I'd probably think it was just fine too. I have a similar (Modern Driveline) hydraulic clutch setup in my '67 Mustang and was thrilled with how much better it feels vs. the old cable clutch. However, Edwardb's comparison of the Fortes unit to the Tilton HRB has me now second-guessing my choice and I'd hate to keep second-guessing my choice after the engine is in.

[Railroad]

"Your intuition was right on." Not bad; even the guess on the clutch fork length was pretty close. I'm reminded of the saying that even a broken clock is right twice a day.

"My clutch is on the grabby side and the high effort, short engagement makes it tough at times." I actually have the opposite problem, with a 1.125" master, a 7/8 slave and a Luk clutch assembly requiring far more pedal travel than I want. What kind of clutch assembly do you have; it sounds like that's what I need.

I wouldn't look forward to doing it, but I'd probably break down and install a smaller master cylinder, and maybe an access panel (or 2) atop the footbox, if you don't have one already.

Here is a link to it. I got a better price than listed. I bought it from Mike Forte with my engine/trans package.
On a side note, it does have some chatter, especially if you try to take off from idle. A little above idle, 895 idle rpm, and it smooths it out.

https://performanceparts.ford.com/part/M-7560-T46

[rich grsc]

"Your intuition was right on." Not bad; even the guess on the clutch fork length was pretty close. I'm reminded of the saying that even a broken clock is right twice a day.

"My clutch is on the grabby side and the high effort, short engagement makes it tough at times." I actually have the opposite problem, with a 1.125" master, a 7/8 slave and a Luk clutch assembly requiring far more pedal travel than I want. What kind of clutch assembly do you have; it sounds like that's what I need.

I wouldn't look forward to doing it, but I'd probably break down and install a smaller master cylinder, and maybe an access panel (or 2) atop the footbox, if you don't have one already.

Are you sure you don't have your numbers reversed? The larger the MC the more pressure required and the less travel to move the slave cylinder a given amount. Your description of easy pedal with longe pedal travel would be more likely with a small MC and a large slave.

[GoDadGo]

Railroad,

The slave cylinder from a 1984 thru 1988 Corvette has a 1" bore.

WAGNER SC103781 / 1.0" Bore

Could this be a viable option because Rock Auto has it available along with others?

Steve

NOTE:..The manual Corvettes from the 1st generation of the C-4's platform used a Doug Nash (T-10 Center) that had an overdrive mounted on the back of it which they called the 4+3 Transmission.

[Railroad]

Railroad,

The slave cylinder from a 1984 thru 1988 Corvette has a 1" bore.

WAGNER SC103781 / 1.0" Bore

Could this be a viable option because Rock Auto has it available along with others?

Steve

NOTE:..The manual Corvettes from the 1st generation of the C-4's platform used a Doug Nash (T-10 Center) that had an overdrive mounted on the back of it which they called the 4+3 Transmission.

That looks good. A lot better than the 1960 model cast iron model.
Thanks for the info. Looks like you might get a Chev part on my car!

[GoDadGo]

I've got Ford Explore Rear Brakes in addition to my Mustang Fuel Tank & Front Brakes!

Hope It Works!

[Railroad]

I've got Ford Explore Rear Brakes in addition to my Mustang Fuel Tank & Front Brakes!

Hope It Works!

Oops, just realized the bleeder will be on the bottom with that model.

[GoDadGo]

Oops, just realized the bleeder will be on the bottom with that model.

Could you use aluminum barrel spacers to mount it in an offset position so that the bleed would be on the up-side?

Just Spit Balling Ideas From The Dark Dyslexic Side!

[GoDadGo]

Check out this little deal from Speedway:

https://www.speedwaymotors.com/Speedway-Push-Type-Clutch-Release-Slave-Cylinder,1944.html?sku=91025605&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=CjwKCAjw5cL2BRASEiwAENqAPsl1eD9SHmwancJJz5q8 qLqB11Zafj5r8wpKcbTH27_IyBso8dvRtBoCPh8QAvD_BwE

It is a Push-Type design with the bleed and feed being swap-able.

[Railroad]

Check out this little deal from Speedway:

https://www.speedwaymotors.com/Speedway-Push-Type-Clutch-Release-Slave-Cylinder,1944.html?sku=91025605&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=CjwKCAjw5cL2BRASEiwAENqAPsl1eD9SHmwancJJz5q8 qLqB11Zafj5r8wpKcbTH27_IyBso8dvRtBoCPh8QAvD_BwE

It is a Push-Type design with the bleed in a better loaction.

7/8" bore. Same size I have now. But keep digging, I might have missed one.
I called Tilton and Wilwood, no luck. Will call McCloud today.

[Railroad]

This is one, I am considering.

http://www.classicpartsusa.com/product/CSC61_1960/1960_Truck_Parts_Brake_Master_Cylinders

[Jacob McCrea]

Are you sure you don't have your numbers reversed? The larger the MC the more pressure required and the less travel to move the slave cylinder a given amount. Your description of easy pedal with longe pedal travel would be more likely with a small MC and a large slave.

Rich,

Those are the numbers; I stopped at my shop on the way to work and confirmed. But my first comment mentions that pedal effort is not light, as we would expect with those sizes. It's heavier than my Xterra, although not by much. I think my problem I have is a clutch disk and pressure plate (near-new and reused from the donor car) that simply takes a lot of travel to disengage. I think that when I assembled the system with a 7/8" master, the clutch pedal ran out of travel and hit the frame before the clutch would fully disengage (I did move the pedal box location toward the engine, limiting pedal travel). The clutch pedal still sits higher than the other 2 pedals, which I don't like. Maybe the pressure plate fingers are more flexible than a high-performance clutch assembly; maybe it's in the geometry of the pressure plate; I don't know. I imagine if I installed the clutch assembly that Railroad has, or got around to installing the 3/4" slave I have on the shelf, I'd be good to go.

And that 1 1/8" Chevy slave cylinder looks like a winner.

[Railroad]

I think this will work.

129604

1" bore. If the bolt holes are off minutely, I can slot one of them.

[CraigS]

Cool, I hope it works out. Re; chatter and another poster's comment about needing a long travel to disengage. Many times a little bit of usage will fix both. Back in the day one of the British sportscars had a clutch that wouldn't disengage completely right after a new one was installed. We finally realized that the wear material had a slightly fuzzy surface and if we ran the car a little and did a couple of starts in 2nd gear we could accelerate the parts 'wearing in' phase and it would be fine after that. More recently when I put a new Spec clutch in my FFR when I did the 408W, it chattered much like yours. It was especially bad backing out of the garage. I put up w/ it for a month or so and finally figured that, if I couldn't get rid of the chatter, it would have to be replaced. 5 or 6 2nd gear starts fixed that too. The key is to abuse it a little but not so much that you build heat. I would go on a local drive and do the 2nd gear starts at each intersection so I'd have maybe 2-5 miles between each start to let it cool. Over the last few years about once per year the chatter would start to come back so I'd just do 2 more 2nd gear starts and all would be well.

[Railroad]

It cost more to be stubborn. I put the car on the lift and started pulling down the Forte slave set up.
I noticed how much more clutch fork I had not being used. Just a quick measurement, showed I could move the slave and pushrod, out a max of 1.5 inches. I made a spacer block 1.25" thick, used longer bolts and everything bolted up pretty good. The push rod needed no adjustment, used longer bolts to mount the slave through the spacer block.
The 1/8" pipe to 3 AN fitting needs to swapped out to a 45*. The present fitting puts the line below the frame.
The clutch effort is perfect. The engagement point moved from the top of pedal travel to the middle.
If anyone needs a 1" bore slave cylinder, I can fix you up, new in the box.

129659129660129661

[Jacob McCrea]

Looks good; glad you got it to your satisfaction. I would probably swap those grade 5 bolts for some grade 8s or (if available) NAS bolts or ARP studs, and have someone operate the clutch while you check that block for deflection. My guess is it's fine with 5s but I'd be more comfortable with grade 8s.

[Railroad]

I left it on the rack, waiting on the hyd line fitting. I will get someone to watch the block, while the clutch is pressed.
I pulled it down pretty tight, but worth checking.

[rich grsc]

Absolutely no need for grade 8 bolts, there is very little load, the bolts on there are strong enough to bend the clutch arm before they'd break.

[CraigS]

Pic #2 looks like the pushrod angles down a little to meet the T/O lever. Probably not enough to cause much problem but it may make the slave wear a little faster since it will put a little side load into it. Could the mount bolts be loosened so the slave could be aimed down a little due to clearance in the bolt holes?

[Railroad]

Pic #2 looks like the pushrod angles down a little to meet the T/O lever. Probably not enough to cause much problem but it may make the slave wear a little faster since it will put a little side load into it. Could the mount bolts be loosened so the slave could be aimed down a little due to clearance in the bolt holes?

For some reason, I think the pic makes it look like it has a lot of angle. The spacer and bolts have no play for adjustment. I will check the slave for any play, after I confirm the angle. The push rod has a ball end and the rod is not binding.
Thanks for checking it out.

Oh, the clutch is so much better!

[Railroad]

Pic #2 looks like the pushrod angles down a little to meet the T/O lever. Probably not enough to cause much problem but it may make the slave wear a little faster since it will put a little side load into it. Could the mount bolts be loosened so the slave could be aimed down a little due to clearance in the bolt holes?

For some reason, I think the pic makes it look like it has a lot of angle. The spacer and bolts have no play for adjustment. I will check the slave for any play, after I confirm the angle. The push rod has a ball end and the rod is not binding.
Thanks for checking it out.

Oh, the clutch is so much better!