View Full Version : Clutch Pedal & Frame interference
JeepFlyer
08-13-2012, 11:34 PM
Please tell me this is an easy fix. My worry is with a hydraulic clutch setup, I won't get enough actuation with just 4 inches of throw to push enough fluid. I don't remember reading anything about this particular problem, unless I'm just starting out with my pedals too far back to begin with.
Resting position relative to the front footbox aluminum
11299
Stopping point due to the upper part of the arm hitting the angled 3/4" tubing
11300
View from the driver's seat
11301
View from the side
11302
View from the bottom looking up
11303
Thoughts? Thanks in advance
oldguy668
08-14-2012, 06:26 AM
That's a common problem and there are two ways to fix it. The first is to get a master cylinder of a diameter that will work with the 4" of pedal throw that you have. The other (and I'll get flamed for this for sure) is to notch the pedal arm right where it hits the frame. I just cut off the reinforcing ribs where they hit and the notch serves as a pretty good pedal stop. Yes, I have weakened the arm, and no, I wouldn't do it to the brake arm.
CHOTIS BILL
08-14-2012, 09:02 AM
I slotted the mounting holes in the master cylinder mounting bracket and slid the peddles over to the right and got more peddle travel.
Bill Lomenick
its an easy fix. Mark where the pedal hits the 3/4 tube and just cut with an air grinding wheel in the direction of travel for the pedal. You dont go all the way through the tubing. Your just notching it. After this, the pedal will bottom out onto the front of the footbox as it should. Many have done it this way.
JeepFlyer
08-14-2012, 03:06 PM
Wouldn't cutting the frame, in a place that provides protection to the driver be less favorable than just cutting a 1" section of the webbing off one side of the pedal? When I looked at it this morning, it looked like I could cut between two of the diagonal web sections so it wouldn't lose much structural integrity. If I did cut the frame I would want to reinforce it, boxing it in at the very least. Just a thought.
the 3/4 square tube does not offer any protection. Thats what the 2" round tube is there for. The 3/4 is there for a mounting point.
additionally, your chances of breaking a pedal would be much greater and believe me, you dont want to be replacing that when the car is all together.
cobrajj
08-14-2012, 06:22 PM
Check out this mod on the other forum. http://www.ffcars.com/forums/17-factory-five-roadsters/294610-wilwood-clutch-pedal-hits-3-4-frame.html
JeepFlyer
08-15-2012, 02:34 AM
Cobrajj,
That looks more like what I'm thinking. Thanks for the advice everyone. Looks like welding won't be in my near future, thank goodness! Although, this will definitely go in my "Next time I'm going to..." folder for future reference. Is it bad that I'm already planning my next build and I'm only 100 pages into the build manual? haha
JeepFlyer
08-17-2012, 01:22 AM
I did some soul searching and decided to break out the dremel and have a go at the pedal before I went after the frame. Here are some pictures of what I came up with. My biggest regret was not having matte finish black paint, but it's going to be deep in the footbox so if anyone notices when the car is finished and together, I'll give them a dollar.
113221132311324
I did some soul searching and decided to break out the dremel and have a go at the pedal before I went after the frame. Here are some pictures of what I came up with. My biggest regret was not having matte finish black paint, but it's going to be deep in the footbox so if anyone notices when the car is finished and together, I'll give them a dollar.
113221132311324
My first pass on this issue was to use the old style pedals. The problem with this is, without any carpet my foot is about 1/4 inch from the brake pedal when positioned at the gas. Once I add a little insulation and carpet there won't be any space and my next option would be pedal cutting/trimming. The new Wilwoods with the adjustable pedal solve this but of course the clutch hits the frame. After a few conversations with Factory Five its apparent they aren't thrilled with the prospect of cutting the frame even though its not a critical section.
What's the bottom line...
...I did the same thing as you and trimmed the webbing on the pedal arm so it doesn't contact the frame at all. Lets hope it doesn't weaken the pedal arm to the point of breaking.
Thank you to the "oldguy668" for the idea.
-Fred
JeepFlyer
08-17-2012, 01:10 PM
After a few conversations with Factory Five its apparent they aren't thrilled with the prospect of cutting the frame even though its not a critical section.
...Lets hope it doesn't weaken the pedal arm to the point of breaking.
That pedal is pretty staunch. I don't see how one section of webbing could weaken it to the point of failure. If I had the time and didn't live in BFE, I would order the bare frame and make a couple mods before having it powder coated (not to mention cleaning up their welds). The fuel tank filler running into the frame would be the second fix. Both of those seem easy enough... cut or angle the 3/4" tubing 1/2 inch one way or the other and problem is solved. It's not like it would require a redesign from the ground up.
ATOLightning
08-17-2012, 01:28 PM
...I did the same thing as you and trimmed the webbing on the pedal arm so it doesn't contact the frame at all. Lets hope it doesn't weaken the pedal arm to the point of breaking.
-Fred
I agree. From an engineering POV, the webbing should help more from a twisting perspective. That part of the pedal will have a bending moment that reacts more with the "meat" of the pedal and not as much with the webbing, I believe. Granted, the webbing does make the pedal stonger as a whole.
Like I said, though, removing some webbing will weaken the structure of the pedal overall. It's not the brake pedal, though.
ATOLightning
08-17-2012, 01:29 PM
I did some soul searching and decided to break out the dremel and have a go at the pedal before I went after the frame. Here are some pictures of what I came up with. My biggest regret was not having matte finish black paint, but it's going to be deep in the footbox so if anyone notices when the car is finished and together, I'll give them a dollar.
113221132311324
I haven't determined what I will do about the interference, yet, but did that cut give you plenty of clearance?
Jacob McCrea
08-17-2012, 02:02 PM
That's a common problem and there are two ways to fix it. The first is to get a master cylinder of a diameter that will work with the 4" of pedal throw that you have. The other (and I'll get flamed for this for sure) is to notch the pedal arm right where it hits the frame. I just cut off the reinforcing ribs where they hit and the notch serves as a pretty good pedal stop. Yes, I have weakened the arm, and no, I wouldn't do it to the brake arm.
I agree with these comments. I have worked through this issue with my coupe, although the interference was far greater due to some frame mods I did. One of the things I did, and have not seen mentioned above, was to move the pedal box back toward the driver by about half an inch. I am not sure how much the FFR pedal box mounting bracket allows this as my mounts are custom. You may need to make some spacers at the front of the footbox. Anyway, I just wanted to throw this out there in case it can help someone.
JeepFlyer
08-18-2012, 12:21 AM
I haven't determined what I will do about the interference, yet, but did that cut give you plenty of clearance?
I think so. Granted it was a PITA, I'll probably go-kart the car before I put the panels in that area on permanently. I can always take a little more off, but right now it's less than an inch from bottoming out on the front wall of the footbox like the brakes do. I adjusted the linkage to bring the pedal forward about 1/2" to get a little more throw. I'll remeasure tomorrow and see what the difference is.