Clutch Pedal Fitment/Throw Question

[BrewCityCobra]

For a bit of background on this question, I have a MKIV complete kit with the Wilwood pedal box, Forte hydraulic clutch kit, Russ Thompson gas pedal, and Forte gas pedal linkage. I'm not sure what size my clutch master cylinder is but can check if need be.

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As for the situation at hand, after finalizing the fitment of my seats I've come to realize that while my gas and brake pedal fit my seat location nicely, I'm having trouble getting the clutch pedal to feel comfortable. Basically, the throw on the clutch pedal feels like it is just waaayyy too long. For context, I've aligned my clutch pedal just ahead of my brake pedal - and the brake pedal is already set about as far forward as it can be (close to that cross-bar shown in the photo above), but even with the clutch brought forward that far I am still depressing the clutch effectively all the way back to the rear wall which requires me to basically either sit so close to the pedals that I feel scrunched, or sit comfortably but then I'm pushing the clutch with my tippytoes at full stroke. I am not the tallest person in the world so I'm sure that contributes to the situation, but it seems a bit egregious. I was hoping to see if maybe I could shorten the stroke a bit to make it more comfortable.

In light of all this, my questions to the group are:

1) Is there a way to test when the clutch actually releases? Basically to see if I'm traversing the clutch pedal more than I need to? The easiest solution would just be to set my stop further forward and call the situation solved.

2) If such a long stroke seems normal, has anybody tried to increase the size of their master cylinder to try to shorten it? If so, does it make the clutch difficult to operate and/or really stiff? And also, what size did you increase to?

Any help much appreciated.

[F500guy]

I have a Hydraulic TOB, but determining the stroke, with the car running, I pushed in the clutch in small increments until I could get it in gear with with out hearing any gear noise, then added a 1/4 -3/8 inch extra stroke.

[Mike.Bray]

As far as testing, with the engine off put it in gear and try rotating the driveshaft by hand while slowly depressing the clutch pedal. When you can rotate it the clutch is released.

The stock clutch MC Factory Five supply is a Wilwood 3/4" bore. Two issues here, 1)it's a Wilwood MC and they are poor quality/prone to failure and 2)3/4" bore is too small for most hydraulic clutch applications. I ended up going to a 13/16" (0.812") bore and it's perfect.

[JohnK]

I needed to find the clutch release point to fabricate a stop for my hydraulic TOB. I used a Dewalt clamp/spreader and a long piece of wood against the cockpit back wall to be able to precisely move the clutch pedal to find the actuation point. With the rear wheels on stands, I was able to move the clutch pedal a small amount at a time until I could rotate the rear wheels by hand.

[dbo_texas]

I'm pretty sure the Forte hydraulic clutch should use a 13/16" (.81") MC. I had a 3/4" installed in mine when I got my kit from another builder (they re-used one of the Wilwood brake MCs since they also had a hydroboost installed with different MCs). While troubleshooting some other issues I asked Forte what size MC to use with his hydroboost and at the time he insisted it needs to be the 13/16 size, so I swapped mine out.

[BrewCityCobra]

As far as testing, with the engine off put it in gear and try rotating the driveshaft by hand while slowly depressing the clutch pedal. When you can rotate it the clutch is released.

The stock clutch MC Factory Five supply is a Wilwood 3/4" bore. Two issues here, 1)it's a Wilwood MC and they are poor quality/prone to failure and 2)3/4" bore is too small for most hydraulic clutch applications. I ended up going to a 13/16" (0.812") bore and it's perfect.

So I checked my system and I already have a 0.812 in place. I guess I'll have to consider a 7/8". But first I will try running a test to see if I am just over-traveling the clutch and not realizing it.

Appreciate all of your input.

[BrewCityCobra]

I needed to find the clutch release point to fabricate a stop for my hydraulic TOB. I used a Dewalt clamp/spreader and a long piece of wood against the cockpit back wall to be able to precisely move the clutch pedal to find the actuation point. With the rear wheels on stands, I was able to move the clutch pedal a small amount at a time until I could rotate the rear wheels by hand.

This is a good setup. I will give it a try. Appreciate the tip.

[BrewCityCobra]

I'm pretty sure the Forte hydraulic clutch should use a 13/16" (.81") MC. I had a 3/4" installed in mine when I got my kit from another builder (they re-used one of the Wilwood brake MCs since they also had a hydroboost installed with different MCs). While troubleshooting some other issues I asked Forte what size MC to use with his hydroboost and at the time he insisted it needs to be the 13/16 size, so I swapped mine out.

After reading Mike's comment I went and checked my setup and sure-enough, I have a 0.81" in mine already. Makes me think I must be over-traveling the clutch pedal (or I'm just being too picky). Sounds like nobody has upped to a 7/8" master cylinder.

[Mike.Bray]

After reading Mike's comment I went and checked my setup and sure-enough, I have a 0.81" in mine already. Makes me think I must be over-traveling the clutch pedal (or I'm just being too picky). Sounds like nobody has upped to a 7/8" master cylinder.

Some additional thoughts:

Is the system fully bled? Sounds simple but... Did you pressure bleed? Maybe try gravity bleeding?

Are the mechanics of the system all good? Any flexing going on?

Is the Wilwood MC leaking internally? A somewhat common problem with the Wilwoods.

[BrewCityCobra]

Some additional thoughts:

Is the system fully bled? Sounds simple but... Did you pressure bleed? Maybe try gravity bleeding?

Are the mechanics of the system all good? Any flexing going on?

Is the Wilwood MC leaking internally? A somewhat common problem with the Wilwoods.

I bled the system when I first installed it (probably 6 months ago now), but probably worth double checking just to make sure (along with the rest of the system).

I have to admit all this talk about Wilwood MCs leaking really has me on the ropes. I even cut a hole in my driver footbox to make sure I would always have access to that third MC. I'm still pre-paint so things can be fixed but I would be lying if I didn't say the moment I can't get at those things anymore I'll be scared ****less one is going to let loose on me. I mean it's just the brakes right?!? Not that important.

Is there a good way to check them? Just pull back the boot I suspect.

[Mike.Bray]

I bled the system when I first installed it (probably 6 months ago now), but probably worth double checking just to make sure (along with the rest of the system).

I have to admit all this talk about Wilwood MCs leaking really has me on the ropes. I even cut a hole in my driver footbox to make sure I would always have access to that third MC. I'm still pre-paint so things can be fixed but I would be lying if I didn't say the moment I can't get at those things anymore I'll be scared ****less one is going to let loose on me. I mean it's just the brakes right?!? Not that important.

Is there a good way to check them? Just pull back the boot I suspect.

I tossed three brand new in the box Wilwoods in the trash, that's how much confidence I have in them.

Splurge $100 and buy a 13/16" Tilton and see how you go. I'm betting you'll be in business.

[dbo_texas]

I tossed three brand new in the box Wilwoods in the trash, that's how much confidence I have in them.

Splurge $100 and buy a 13/16" Tilton and see how you go. I'm betting you'll be in business.

Are the Tilton MC's drop-in (i.e. same mounting holes, roughly same size as the Wilwood)?

[OB6]

Are the Tilton MC's drop-in (i.e. same mounting holes, roughly same size as the Wilwood)?

Direct bolt-in. I just replaced all three last week. Only the clutch MC was leaking, but I decided to do all three while I was at it.

[BrewCityCobra]

Direct bolt-in. I just replaced all three last week. Only the clutch MC was leaking, but I decided to do all three while I was at it.

All this talk of failed Wilwood MCs really has me wondering if I should replace all three now while I have some semblance of a chance. I closed my driver-side footbox like two weeks ago (because of course this would come to a head right after I sealed it up) but do not yet have the body on for good and do have an extra access panel that should allow me to get to the clutch cylinder without much issue. Once that body goes on I suspect getting to the clutch MC is basically impossible.

Has anybody actually swapped out the two brake MCs using only the access panel provided or is this a "I need to pull apart the panels" type situation?

[OB6]

Has anybody actually swapped out the two brake MCs using only the access panel provided or is this a "I need to pull apart the panels" type situation?

Plenty of people have R&R'd these in a finished car using access from above and below.

[CraigS]

I am not sure I understand your problem. Trans in neutral, engine idling, if you push the clutch down to a comfortable distance can you put the trans in gear? Or do you need to do the tip toe thing to get it in gear? Once it is in gear how far up/toward you, do you move the clutch pedal to get the car to move? If you have to tip toe it into gear, screw a 1" thick piece of wood on top of the pedal to make it easier to reach. Drive it like this for several longer drives to get used to the new position. How do you like it now? The advantage, if this works out, is that you keep the same effort level. Going to a larger MC, or smaller slave, will shorten the needed stroke but also increase the effort. BTW I have a 1" spacer on my 19 Stingray clutch pedal.

[Mike.Bray]

I am not sure I understand your problem. Trans in neutral, engine idling, if you push the clutch down to a comfortable distance can you put the trans in gear? Or do you need to do the tip toe thing to get it in gear? Once it is in gear how far up/toward you, do you move the clutch pedal to get the car to move? If you have to tip toe it into gear, screw a 1" thick piece of wood on top of the pedal to make it easier to reach. Drive it like this for several longer drives to get used to the new position. How do you like it now? The advantage, if this works out, is that you keep the same effort level. Going to a larger MC, or smaller slave, will shorten the needed stroke but also increase the effort. BTW I have a 1" spacer on my 19 Stingray clutch pedal.

I don't think I would ever worry about increasing the pedal effort on a hydraulic clutch setup by going to a larger MC, that's the advantage of hydraulics. A lot of power in a small package. Going up 1/16" or even 1/8" in bore diameter will increase the pedal effort but the amount of increased effort will be very small. Especially with street clutches.

[BrewCityCobra]

I tossed three brand new in the box Wilwoods in the trash, that's how much confidence I have in them.

Splurge $100 and buy a 13/16" Tilton and see how you go. I'm betting you'll be in business.

Do you recall what Tilton MC is the proper design? It looks like Series 74 is the way to go but figured it was worth confirming.

[BrewCityCobra]

I am not sure I understand your problem. Trans in neutral, engine idling, if you push the clutch down to a comfortable distance can you put the trans in gear? Or do you need to do the tip toe thing to get it in gear? Once it is in gear how far up/toward you, do you move the clutch pedal to get the car to move? If you have to tip toe it into gear, screw a 1" thick piece of wood on top of the pedal to make it easier to reach. Drive it like this for several longer drives to get used to the new position. How do you like it now? The advantage, if this works out, is that you keep the same effort level. Going to a larger MC, or smaller slave, will shorten the needed stroke but also increase the effort. BTW I have a 1" spacer on my 19 Stingray clutch pedal.

So I haven't tried shifting at a comfortable "end point" so to speak. Out of habit I push the pedal until it hits the stop and then shift. With that said, I plan on doing some checks to see if that amount of travel is really needed (and then adjust the stop accordingly).

I didn't think of adjusting the pedal itself. I was trying ot keep the clutch more or less even with the brake pedal but I suppose that isn't really needed. I will give that a try as well.

[OB6]

Do you recall what Tilton MC is the proper design? It looks like Series 74 is the way to go but figured it was worth confirming.

You'll want a series 75 or 76. They share the same internals, but the 76 has more outlet options. I used the 75.

[Blitzboy54]

I had very similar issues on my car. I also had the same setup as you. External slave cylinder and WW master. You don't think about it when your building the car but your actually sitting at an angle pointing toward the outside of the car. This makes the clutch the furthest point from your body in pedal box. I had also initially over tightened mine so the clutch would slip under load. I fixed this by backing off to the point where my TOB just made initial contact with the fingers (this is the proper way to start). I then extended the pushrod out and brought the pedal closer to me until I liked the position. I engaged the clutch under this arrangement pretty early in the stroke. If I needed to bring the pedal even closer I would have needed to either put a longer pushrod in or remove the pedal and set spacers between the arm and the pedal itself to bring it closer. I actually did this with the brake. I have an unusual body type, very long torso and short legs (kind of the worst of all worlds in a MK4) but ultimately made it work.

[edwardb]

Ah... Wilwood MC's have replaced MSD ignition boxes as the latest "they all fail." I'm not going to defend Wilwood because there's no excuse for them failing out of the box. And I have high respect for Tilton parts. Everyone shares their own experiences and I respect that. Each builder has to decide for themselves what to put in their builds. But if the Wilwoods test OK, no reason IMO not to use them. In five builds and thousands of miles, all with various Wilwood parts including their MC's, I've had one immediate failure and that was a leaker due to a defective O-ring. Under magnification, it clearly had a defect. Probably a short shot when it was molded. $25 rebuild kit and all good since. As in many cases like this, failures get posted and the volume of forum members using parts without issues aren't reported. There's no way to know the actual failure rate. But I suspect it's very low. Everyone has their own opinion about Wilwood. But if their parts were really that bad, I think they would address it. Brake/safety parts are way too critical. Even though their lawyers had a field day with the disclaimers on their instructions. I have no way to know, but I'd be willing to bet their calipers are the same material, bore finishes, O-rings, etc. Haven't heard of anyone throwing those away. Not going to argue and don't flame me. Just trying to toss in a little balance.

[Grubester]

Just at the very beginning of my Mk IV build (rec'd it 7/21), but I've seen various comments in various threads about MC leaks (and at fittings).
If some of these MCs are leaking: why? I'm suspecting that contamination of the bore could be a real problem (prevent cup lip from sealing) considering what I've seen in my past.
If the bores aren't fully cleaned before factory assembly, that's serious. Further, for leaks (tracking root cause) is anyone finding cups with flaws that would prevent sealing?
***I did notice my F5 supplied brake lines are in poor condition: packaged uncapped, paint debris near tube opening, sealing surface that don't look very impressive. Ugh.
If the tubing is carry debris, it has a good chance of fouling cup seals in MC or caliper... seems to me.

[Mike.Bray]

Ah... Wilwood MC's have replaced MSD ignition boxes as the latest "they all fail." I'm not going to defend Wilwood because there's no excuse for them failing out of the box. And I have high respect for Tilton parts. Everyone shares their own experiences and I respect that. Each builder has to decide for themselves what to put in their builds. But if the Wilwoods test OK, no reason IMO not to use them. In five builds and thousands of miles, all with various Wilwood parts including their MC's, I've had one immediate failure and that was a leaker due to a defective O-ring. Under magnification, it clearly had a defect. Probably a short shot when it was molded. $25 rebuild kit and all good since. As in many cases like this, failures get posted and the volume of forum members using parts without issues aren't reported. There's no way to know the actual failure rate. But I suspect it's very low. Everyone has their own opinion about Wilwood. But if their parts were really that bad, I think they would address it. Brake/safety parts are way too critical. Even though their lawyers had a field day with the disclaimers on their instructions. I have no way to know, but I'd be willing to bet their calipers are the same material, bore finishes, O-rings, etc. Haven't heard of anyone throwing those away. Not going to argue and don't flame me. Just trying to toss in a little balance.

Like Terry reported I also inspected my FFR supplied Wilwood master cylinders and they did not feel "smooth" when I actuated them on the bench. The Tilton's were smooth as silk. This felt to me like a surface finish issue in the bore. For sure the number of Wilwood MCs that are working just fine far outnumber the ones that have failed. But as referenced above, one failure out of the box in his experience. Out of how many? 15? Not good odds in my book.

Reasons I changed my FFR-supplied Wilwood master cylinders to Tilton:

1) Lack of confidence in the Willwoods being 99.99% trouble-free.

2) Not all that easy to change in a finished MKIV.

3) In the scheme of things not terribly expensive.

4) If a master cylinder fails in the Wilwood pedal box you lose all brakes, not just the front or rear.

5) I could use banjo fittings to better interface with my AN fittings.

6) I ended up with three different sizes whereas Factory Five supply all three in 3/4" bore.