Hydraulic Clutch Pedal

[mlewis]

Hi all,

I'm in the final assembly of my Pedal box with willwood brakes and hydraulic clutch ( set-up from Forte).

My question is, what stops the clutch pedal at full stroke ( bottoming out on the floor or at the MC) since there is no stop like the one on the cable clutch set-up ?

Also, what's the opinion on trimming the threaded shaft length on the clutch MC. I see some have done this, I don't see the need in my set-up but want the make sure I'm not missing something.

Likewise, I see some do/don't trim the threaded shaft length on the brake MC's. Any input here is appreciated.

Munch thanks in advance,

Mark

[Fugi]

That is a great question, I'm using a hydraulic clutch from Forte for a Wilwood brakes, but opted for the stock pedal box due to the hydroboost that I wanted. The stock pedal box has a stop on the shaft.

[edwardb]

Last easy question first. Trim the Wilwood MC threaded shafts if you need to. But not unless necessary. I wouldn't trim anything until trial fitting your specific build. Don't take a dimension out of the manual or another build. It's going to depend on where your specific pedal placement is. If you have the pedals pretty high (closer to the driver) they may not need trimming. Lower and maybe they will. You don't want the threaded shaft to hit the front of the pedal when it's pushed down. But you also want threads all the way through the clevis. So cut only as much as needed, if at all.

For a pedal stop, kind of depends on your final setup. You may find with the clutch pedal hard on the floor the maximum travel of the MC and slave cylinders are not exceeded, and if so may not be required. But more likely you will find the pedal needs to be stopped before the floor, so you'll need to fab something. This is a somewhat unrelated video (installing a hydraulic release bearing) but it's a FF Roadster they're working on and explains and shows a clutch pedal stop that's typical of what many do. This link goes to the part of the video where it's discussed. https://youtu.be/0X2JAoHhy0A?t=174

[Paul2STL]

mlewis,

I trimmed the threaded shaft length to get the peddle to sit even with the brake pedal. I think that is why most people have done this mod. For a cable setup the stop is to protect the cable from being stretched.

[Murd]

I Figured out the max travel I needed to release the clutch and built a stop for the pedal. Sitting in the seat with the transmission in gear, I pushed the clutch in and turned the driveshaft at the same time so I could feel where the clutch bites and where it releases, also watching to make sure the slave wasn’t overextended.
Wanted to post a pic but don’t see how?

[Paul2STL]

Last easy question first. Trim the Wilwood MC threaded shafts if you need to. But not unless necessary. I wouldn't trim anything until trial fitting your specific build. Don't take a dimension out of the manual or another build. It's going to depend on where your specific pedal placement is. If you have the pedals pretty high (closer to the driver) they may not need trimming. Lower and maybe they will. You don't want the threaded shaft to hit the front of the pedal when it's pushed down. But you also want threads all the way through the clevis. So cut only as much as needed, if at all.

For a pedal stop, kind of depends on your final setup. You may find with the clutch pedal hard on the floor the maximum travel of the MC and slave cylinders are not exceeded, and if so may not be required. But more likely you will find the pedal needs to be stopped before the floor, so you'll need to fab something. This is a somewhat unrelated video (installing a hydraulic release bearing) but it's a FF Roadster they're working on and explains and shows a clutch pedal stop that's typical of what many do. This link goes to the part of the video where it's discussed. https://youtu.be/0X2JAoHhy0A?t=174

Paul,

Did you do this mod in the video or did you do something else for a pedal stop? I have mocked up my pedal assembly, but have not hooked everything up yet.

[boat737]

I have a clutch pedal safety switch (in parallel with the trans neutral safety switch, which allows starting in gear if the clutch pedal is depressed fully). I didn't want that little switch bracket to be taking the brunt of the force at full clutch pedal travel. I made a stop that is integrated with my throttle pedal stop. It's very strong and has absolutely no give or bending. It was a bit of engineering and fabrication since it seems nothing is straight or parallel in there, but I'm sure glad I did it. Very solid, and eliminates over-travel for both the safety switch bracket as well as the slave cylinder.

I didn't have to trim any of the master rods, brakes or clutch, but I did use one size smaller clutch master than came with the Forte kit. I think it is a 1" like EdwardB used.

[edwardb]

Paul,

Did you do this mod in the video or did you do something else for a pedal stop? I have mocked up my pedal assembly, but have not hooked everything up yet.

No, I didn't find I needed a pedal stop for either of the hydraulic setups I've done. In both cases, I matched the master to the slave such that with the clutch pedal hard against the floor, neither were beyond their rated travel. For the most recent build, the 20th Anniversary Roadster, a 1-inch master cylinder worked perfectly with the 7/8 inch slave provided by Forte.

[mlewis]

Thanks All for the feedback. I'm glad I did not follow the instructions and trim any of my shafts. I will do a fit once installed and then go from there.

I like the options for the clutch pedal stop. I will assess the travel of the clutch once I install the pedal box assembly and assess operation to see if a stop is needed feed. I am uneasy about relying on the MC to stop the motion.
DSCN6366.JPG

[Murd]

I like that clutch safety switch. Did you get that from Forte too, or FFR? I got my whole pedal box set up from him, not FFR but didn’t get that.
I made one similar to the way the brake light switch works.

I’m sure every set up is different but my master/slave combo could easily over extend.

[mlewis]

I received most of the metal with the pedal box from FFR. Had to make several alterations to the brackets and make a new actuator as the brackets are originally designed for the clutch cable set-up.

I definitely made sure the end of travel safety switch was not seeing any load. I too am concerned about over extension of the MC/slave. I am going to come up with some sort of separate hard stop on the pedal. Will need to assess after install (I suppose).

[Murd]

I made a steel L I bolted to the 3/4” frame just to the left of the clutch pedal as a hard stop for the clutch.

Do I have to have a certain number of posts to be able to post pictures?

[mlewis]

I would like to see your pic's.

For me the process of posting pic's has been a bit intermediate (actually surprised it work the last time).

I believe you do need to certain amount of posts to be allowed to post pic's. Check out the welcome and instruction forum and/or send a note to David Hodgkins.

[Murd]

Yep looks like 20 posts, will get there soon and share some pics

[mike forte]

Hi Mark,
Feel free to call me with any questions. I have several suggestions for a pedal stop that is very simple.

[mlewis]

Hi All,

Gong back to part 2 of my original question (MC treaded rod and pedal position).

Just completed the install on my Wilwood pedal box. I know this is obvious to the experience builders, in the process I found out the 3/4" cross member limits the up travel of the brake pedal.

Here is some pic's:

https://flic.kr/p/24ELdkZ

https://flic.kr/p/24ELdop

Unless I'm mistaken this itself dictate the trim of the MC thread rod in order to position the brake pedal off the cross member. Again this might be obvious to all, just want to make sure I'm heading in the right direction.

[mlewis]

re-post with the pic's drop in (still learning how to do this)


pedal box install 1 by Mark Lewis, on Flickr

pedal box install 1 by Mark Lewis, on Flickr

(I think)

[edwardb]

Hi All,

Gong back to part 2 of my original question (MC treaded rod and pedal position).

Just completed the install on my Wilwood pedal box. I know this is obvious to the experience builders, in the process I found out the 3/4" cross member limits the up travel of the brake pedal.

Unless I'm mistaken this itself dictate the trim of the MC thread rod in order to position the brake pedal off the cross member. Again this might be obvious to all, just want to make sure I'm heading in the right direction.

Yes, you need to trim a little off the length of the MC pushrods. I believe the manual says 3/8-inch (don't quote me on that...) but just take it a little at a time. You still want threads exposed when you're done. You don't want the arm hitting the cross bar. It has to stop short. Otherwise it messes up the plumbing in the MC and you'll have other issues.

[Murd]

Mine would hit the 3/4 crossbar but that was over extending the slave and more than needed to release the clutch. Will post pics when I get to 20.

[edwardb]

Mine would hit the 3/4 crossbar but that was over extending the slave and more than needed to release the clutch. Will post pics when I get to 20.

The question was about the brake arm hitting the 3/4-inch frame member on return, which it shouldn't do. For the clutch arm, there was an issue for several years with the arm hitting the frame when pushed down. About 3/4's or so down. Lots of debate of how to fix, etc. Factory Five has apparently made a change to where this interference no longer exists. If you have an older chassis though, may still have the interference and I would address it. If you're over extending the slave hitting at that point, or even at the floor all the way down, you have the wrong size MC IMO. You could limit the throw to not extend too far, but at the expense of higher pedal effort. I'd recommend stepping down in size on the MC.

[mlewis]

Thanks Paul.

Yeah I have a couple parallel items going on here (sorry for the confusion)

First the items that I was not refereeing to in my recent post. Yes, I did have had some interference on the clutch pedal. I addressed with a minor mod to the frame. As far as the clutch travel to MC/Slave travel. I need to evaluate and adjust this further once I figure out my pedal heights/positions.

Now for my recent post (RE the brake hitting the cross member on the up position). I was looking for some confirmation here that I should cut the MC threaded rod to correct. Thanks for your earlier post on this. I will sneak up on it as suggested (just looking for some feedback to go ahead and do so).

Once I get the brake pedal where I need it I will evaluate /adjust the clutch. I hope this makes sense.

Also installed the coyote accelerator pedal today, So I can check the position/location of it as the same time.

Thanks again, for your input.

Mark

[Murd]

The question was about the brake arm hitting the 3/4-inch frame member on return, which it shouldn't do. For the clutch arm, there was an issue for several years with the arm hitting the frame when pushed down. About 3/4's or so down. Lots of debate of how to fix, etc. Factory Five has apparently made a change to where this interference no longer exists. If you have an older chassis though, may still have the interference and I would address it. If you're over extending the slave hitting at that point, or even at the floor all the way down, you have the wrong size MC IMO. You could limit the throw to not extend too far, but at the expense of higher pedal effort. I'd recommend stepping down in size on the MC.

Oops, I miss read. I did my pedal box almost a year ago, I thought I recalled in the wilwood instructions that you needed a stop for the brake pedal on return so it didn’t slam shut on an internal valve or something? Might have only applied if you were using a return spring? I do understand if it hits before the master returns far enough it won’t open the resivoir valve.
What would be the other issue with the brake arm hitting the crossbar?

[edwardb]

Oops, I miss read. I did my pedal box almost a year ago, I thought I recalled in the wilwood instructions that you needed a stop for the brake pedal on return so it didn’t slam shut on an internal valve or something? Might have only applied if you were using a return spring? I do understand if it hits before the master returns far enough it won’t open the resivoir valve.
What would be the other issue with the brake arm hitting the crossbar?

Yes, the Wilwood instructions say to use an additional mechanical stop if a return spring is added. I haven't found either are necessary. Just keep it off the frame crossbar so it can seat against the internal snap ring with the internal spring. If it stops short the valving is messed up. Will have trouble bleeding and working properly. Both related so really is just the one issue.

[Murd]

That sounds like what I read.
Thanks!