47-55.1 Adjusting pedal height for Hydraulic clutch

[Second Series]

I put a Hydraulic Clutch in my ’47 Chevy truck. I used a pedal bracket from Kugel Komponents. The Clutch Master is from the donor ’88 GMC truck, I cut off the eye and threaded for a clevis yoke. The only adjustment can be made by turning the yoke, but that changes pedal height. I set it so the pedal was level with the brake pedal, but it didn’t feel right shifting into gear. Looking in the inspection hole on the bell housing, the fork was being moved to about the middle of the hole. Compared to my ’90 Chevy truck the fork moves well past the hole. To get the actuator to move there, I had to raise the pedal something like an inch. Not a lot, but noticeable. I thought about my options. I could modify the pedal bracket by moving the pivot up to give a wider swing. I played around with LEGOS to get a working model of a clutch doubler. That would allow for a lower pedal with the same throw. It adds an intermediate arm between the pedal and the pushrod. My question is Has anybody done something like this? Now, recently I ran across a post about adding a hydraulic clutch to a ‘60’s truck where they used a kit from Captain Fab. This is for going from a manual to hydraulic set up. This has an intermediate arm I’m guessing to reduce the force? This makes me think it is doable. Is there an off the shelf solution? Has anyone gone through this? Is there a better suited clutch bracket for firewall mounted in the AD trucks?

[Tempest67]

I am not familiar with your parts, but instead of adjusting the pedal throw, can you increase the length of the push rod to the clutch fork?

just a suggestion

[leegreen]

So the bellhousing, master and slave are from the same donor, so they will work together?
Are you getting full travel on the master with full pedal travel?

The wilwood master you show uses the extra linkage for mechanical advantage - more pedal travel for less master travel but more pressure.

I have a home brew setup, bellhousing from c10 with mechanical clutch linkage, homemade plate bolted to bellhousing bolts holding slave which pushes on clutch arm, modified 60s C10 pedal box. I drew the pedal box geometry on paper and worked out how long a lever arm I needed to get full master travel with pedal height to match brake. it works well

I think you should just change the length here:

to get full travel. You can either shim the master or move mounting point up or down so the pushrod is lined up with master at midpoint of pedal travel

[mr48chev]

Miss matched parts that weren't designed to work together seldom work as hoped for.

I'll probably get a smackdown from Ricky but hope his time he understands the why of my following comments

Kugel designed the system to work with a specific clutch master cylinder and offers a few different bores. when you get away from that and cobble things together you end up with a mess. To make that master cylinder work with that bracket and pedal you have to cut the pushrod off at the right length to thread it into the supplied clevis and hopefully have the master cylinder in perfect alignment with the spot the clevis mounts on the arm. That is how you make it adjustable and how you make it work. Even then you might not get the correct pedal travel or height because the master stroke may be way off for what the pedal assembly is designed for.

I'm not finding a stand alone brake pedal bracket making me wonder if that isn't a second brake pedal bracket.

[Rickysnickers]

mr48, why would you get a "smackdown?" What you just typed was clear, nice and helpful. There was no sarcasm or anything mean or nasty. Thank you for helping him . Carry on

[Second Series]

Originally Posted by Tempest67

I am not familiar with your parts, but instead of adjusting the pedal throw, can you increase the length of the push rod to the clutch fork?

just a suggestion

That could work, but I’d like to keep the system stock for ease of future serviceability. GM engineered this to work, their clutch pedal had fixed dimensions. I modified the control end, so I need to adjust there.

Originally Posted by leegreen

So the bellhousing, master and slave are from the same donor, so they will work together?
Are you getting full travel on the master with full pedal travel?

The wilwood master you show uses the extra linkage for mechanical advantage - more pedal travel for less master travel but more pressure.

I have a home brew setup, bellhousing from c10 with mechanical clutch linkage, homemade plate bolted to bellhousing bolts holding slave which pushes on clutch arm, modified 60s C10 pedal box. I drew the pedal box geometry on paper and worked out how long a lever arm I needed to get full master travel with pedal height to match brake. it works well

I think you should just change the length here:
to get full travel. You can either shim the master or move mounting point up or down so the pushrod is lined up with master at midpoint of pedal travel

That is one option I am considering, or a pedal arm more like an S shape. There just isn’t the clearance between firewall and pedal location in the A.D. trucks like in newer models. The pedal was bottoming out on the Toe Board before I adjusted it up. That is why I was thinking about an extra linkage, although it would be less pedal travel for more master travel in my setup. And yes, I am using the bellhousing, master and slave from the same donor.

Originally Posted by mr48chev

Miss matched parts that weren't designed to work together seldom work as hoped for.

I'll probably get a smackdown from Ricky but hope his time he understands the why of my following comments

Kugel designed the system to work with a specific clutch master cylinder and offers a few different bores. when you get away from that and cobble things together you end up with a mess. To make that master cylinder work with that bracket and pedal you have to cut the pushrod off at the right length to thread it into the supplied clevis and hopefully have the master cylinder in perfect alignment with the spot the clevis mounts on the arm. That is how you make it adjustable and how you make it work. Even then you might not get the correct pedal travel or height because the master stroke may be way off for what the pedal assembly is designed for.

I'm not finding a stand alone brake pedal bracket making me wonder if that isn't a second brake pedal bracket.

That is where I am at now, fine tuning the “cobbled together mess”. I chose to use the Kugel brackets because they just looked beefier than everything else available from the parts vendors. I saw Old57 used them, but that was on a TF truck. They created a new part number for me for just the clutch bracket, fabbed it, and I got it like 3 days later. So far this mess is doing fine for the 20 mile commute in rush hour traffic.

[leegreen]

If it's working fine for commuting what are you trying to fix? As the clutch wears the limited travel of slave will matter less.

The C10 pedals are S shaped. Here is a shot of my C10 pedal box fitted up after modifying for hydraulic clutch and to fit the AD cab. (red dot where upper pivot is) This setup, bolted to the dash and firewall is more rigid than my modern vehicles where I can flex the firewall with brake pedal

If I did this again I'd make the pedal stops adjustable, I could have the clutch pedal an inch closer to the floor. Not sure I am willing to limit brake master travel, but I'm converting to front disk this spring and will be thinking about it.

FWIW my clutch slave is a 88-91 GMC c1500 and the master is Dorman CM39386 for mid 80s Dodge. They work fine together with the travel required for a mechanical clutch style bell and clutch arm

[mr48chev]

Leegreen I am thinking that he just needs a bit of direction about how to do it so it does what he wants it to do. You think out of the box, I don't have a box and some people have a lid on the box and no windows to look out of.

The heim end with internal threads is on his pedal arm in the photo. what he has to do is first figure out if the push rod is the correct diameter to be able to thread so it screws into the Heim end.

Second step is space the pedal off the floor at the height that he is comfortable with that still allows full piston travel in the master cylinder (just make sure he pedal doesn't hit the floor before the piston stops moving)

Then mark the push rod where you will have enough threads on the end to screw into the Heim end and be safely attached. More than the thickness of the nut that is going to be the Jam nut but not so long it bottoms out and leaves a bit of space for adjustment either way.

Then cut the rod, thread it and screw the jam nut and rod end on it and put it all together.

[Second Series]

leegreen, Do you have a build thread? I’d like to see more, that is an interesting solution you have.
I’m just trying to make this perfect for me. That clutch push rod diameter was perfect for threading. I set it up 2 years ago. That picture was just for reference. Now that this is a daily driver I’m working out the bugs. It shifted o.k. before, but sometimes I had to push it into gear more than I liked. It was not grinding, it just didn’t feel right. This is the 5LM60 transmission maybe like an NV3500. Definitely a different shift feel than the SM420. I found my notes from a couple months ago when I raised the pedal. The stock setup in my ’90 Chevy truck has the clutch pushrod moving 1 ½”. That pedal bottoms out when it depresses the clutch start switch. My ’47 with the clutch pedal even with the brake pedal has the clutch pushrod moving 1”. That bottoms out when the pedal hits the floor. I raised the pedal 1” to get the pushrod movement at 1 ½”. The pedal still hits the floor but the clutch action is mid throw instead of at the end. I took some pictures last night. The first one is the pedal. The second picture is the pushrod at rest. Next is the pushrod floored, there is still about an inch of pushrod there, but the floor is the limiting factor. Last picture is the yokes. When I first set it up I used the supplied yokes, both pedals were high. I got some short yokes that lowered the pedals without affecting the throw. Recently I went back with the longer yoke on the clutch pushrod.

[leegreen]

No build thread, sorry. Maybe someday.

Changing yokes is going to make master and slave start at a different point in their travel but not increase the amount of travel. ?

Do you know how much additional travel there is in each with current setup?

You don't want the pistons in the cylinders to act as travel stops by running into the ends of the bores, for seal longevity there needs to be a bit of space left for crud to accumulate, not crush the seal into the crud every shift.