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Hello. I was thinking about installing a Speed Direct rod linkage kit in my 69. Thought t might be a good replacement for some of the stock and slightly worn linkage in the car at present. In reading some reviews the main problem appears to be the Bracket that attaches the fork to the lower rod. some have mentioned that it move sideways slightly, as it is only tightened down by a bolt that for some reason doesn't stop the sideway movement of the bracket? The result being that linkage doesn't move correctly and clutch doesn't operate properly. Some have said they somehow altered the bracket but show no pictures to show exactly how that works. So my questions are, if the the SD kit is an improvement over new stock linkage rods and does any one have a picture or idea of a way that the Bracket can be held in place at the fork in addition to the supplied bolt. Hope this makes sense. Thanks and take care.
I opened up the end of my clutch fork so the rod end fit in the end of the fork, eliminating the bracket you are talking about. Just took a little time with the dremel. I did need to order a longer lower rod though, and I believe a different rod end for the fork end pin. I think it is 3/8 where the bracket uses a 5/16th bolt. If you are interested I can probably find the part numbers. It was all available at Summit.
This is the linkage as I installed it in 2014. Absolutely no play in the setup. The ball joints take out any binding that might otherwise be caused by the constraints of the throws.
Addendum: Found another photo that I had to blow up significantly. That's why it's fuzzy. Point being there is a tubing spacer inside of the clutch fork. I suppose there are plenty of ways to attach things, this being what I did. As a general note you can buy various sized bolts like this with pre-drilled holes. Had a lot of luck finding what I needed at Pegasus Racing.
So, saw this thread this morning and was going to jump on and say how much I loved my Speed Direct Linkage. Think I installed it at least 13 or 14 years ago. May be more.
Then, on the way home today, clutch pedal went to the floor. No linkage. Got home by starting car at stop lights in first gear and careful rpm matching shifting gears. Only ground gears a couple of times.
So, what happened? Bracket between rod and clutch fork broke. Spoke to Tim at Speed Direct and he is gong to figure out what I need since their system doesn't list individual parts.
That's not right. Hey, isn't that supposed to be one piece? Oops.
My guess is that happened because you've been unintentionally bending that piece of metal and it eventually work hardened and broke. You probably reached the travel limit on your bearing and didn't know it.. You would have had to check it both unladed and fully loaded. Maybe I'm being Captain Obvious, but look at my second picture, the left hand side of my pushrod follows the arc of the z-bar and the angle changes where it meets the clutch fork. That's probably where you ran out of travel.
Your story amuses me because I once got home the same way when my original rod slipped off the clutch pedal. I wore out the cotter pin connection then. Stop lights were especially a bitch. Some highly questionable u-turns were made on side streets.
Ok sorry for the delay to the OP. So the thread below in post 15 shows what I did to my fork. Post 20 shows the part numbers. The March rod number is still good at Summit racing. The rod ends part numbers I got at Summit also. You need a left hand thread and a right hand thread 3/8-24, one with a 3/8 inch hole for the clutch fork, and another 3/8-24 with a 5/16th inch hole for the Z bar end. I also used shoulder bolts from the local Ace hardware for their smooth surface for the rod ends to pivot on, but I am just **** like that. A picture of those is also below. Just got them with the shank length corresponding to the thickness of the rod end, and secured them with nylock nuts. My system works great and I would do it again by modifying the fork to capture the rod end. The only part I used from the Speed Direct kit was the long rod attached to the pedal, and their ends for this rod.
My guess is that happened because you've been unintentionally bending that piece of metal and it eventually work hardened and broke. You probably reached the travel limit on your bearing and didn't know it.. You would have had to check it both unladed and fully loaded. Maybe I'm being Captain Obvious, but look at my second picture, the left hand side of my pushrod follows the arc of the z-bar and the angle changes where it meets the clutch fork. That's probably where you ran out of travel.
Your story amuses me because I once got home the same way when my original rod slipped off the clutch pedal. I wore out the cotter pin connection then. Stop lights were especially a bitch. Some highly questionable u-turns were made on side streets.
I don't think I ran out of travel. If I remember correctly, I have almost 2" of free play in my clutch. With the stock 1.25" to 1.5" of freeplay, my McLeod RST was starting to grab pretty high up in the clutch pedal travel.
I also have clearance issues with the Quicktime bell housing. The end of the clutch fork is right at the edge of the bell housing. Very tight.
The other thing that I noticed is that your Z-bar is angled slightly forward on the bottom leg at rest. Mine is angled slightly rearward. Thinking about it, I suspect that the top Speed Direct bar is too long. I found my stock linkage, I just don't feel like trying to get under the dash to fight that connection at the clutch pedal.
By travel, I mean angular travel. If you can wiggle either pushrod with no resistance, either unloaded or fully loaded, you should be OK. I don't think you need to either get under the dash or under the car, just have somebody who is able to push the clutch all the way in.
By travel, I mean angular travel. If you can wiggle either pushrod with no resistance, either unloaded or fully loaded, you should be OK. I don't think you need to either get under the dash or under the car, just have somebody who is able to push the clutch all the way in.
Copy. I am going to see what Speed Direct says tomorrow. May go for the longer rod setup and make the slot bigger on the fork.
I have the speed direct linkage on my 1968's 427 and it has been wonderful and smooth from that point on. It is easy to use and adjust if and when needed. It was easy to install and has held up for decades of usage. I don't remember anything being modified to use the new linkage. I installed the Clutch rod linkage while installing my Hurst shifter and was under the C3.
I hope you get it sorted out without too much trouble! It is a great part for the manual transmission Corvettes.
This is exactly what I intend to do on my RST clutch & BB. I see no need for the hydraulic cylinder clutch bearing setup.
SteveG75 I am very curious - is there any way you could measure the pedal pressure on your Speed Direct / RST setup? (I literally used a small 80 lb elec package scale on my street car..) Every C3 I have ever driven had a pretty stiff clutch, but my Z28 was much better. Trying to duck that stiff pedal.
With my RST and clutch linkage I can literally push the clutch in by hand. I have never measured it but it is lighter than stock for sure. The RST only uses a 1200lb pressure plate. I don't think the clutch linkage contributes to less pedal pressure, but you can feel noticeably less slop, and I am comparing it to a new stock system I had before. With this clutch, there really is no need for a hydraulic system at all. IMHO of course.
The other great thing about the RST is it releases in only .440 inches of travel, so it is very easy to get it adjusted to engage to your preference.
With my RST and clutch linkage I can literally push the clutch in by hand. I have never measured it but it is lighter than stock for sure. The RST only uses a 1200lb pressure plate. I don't think the clutch linkage contributes to less pedal pressure, but you can feel noticeably less slop, and I am comparing it to a new stock system I had before. With this clutch, there really is no need for a hydraulic system at all. IMHO of course.
The other great thing about the RST is it releases in only .440 inches of travel, so it is very easy to get it adjusted to engage to your preference.
Bill
Thanks Bill!
That is exactly what I am looking for.
No problem. After fighting a clutch release problem for years, not knowing how little travel we have in our clutch system, I can honestly say this is the best feeling clutch I have ever driven. You will love it!
I can try a measurement once I get a new linkage installed.
Speed Direct never called me back today. By the time I called them, it was too late since they close at 1PM CST on Fridays.
I did order some parts from Summit to see what I can fabricate.
One issue with my setup is the Quick Time T56 bell housing. They set the pivot ball so that the clutch fork end is actually lower than stock. This puts some weird angles on the linkage. Ideally, the Z-bar arm needs to be about an inch longer but then other ratios would be off.
The part numbers for this mod that 69ttop502 mentioned are now available from Summit:
March Performance Adjustment Rod Bodies R-6.000 $25.99
QA1 X Series Rod Ends XMR5-6 $13.89
QA1 X Series Rod Ends XML6 $15.99
Speed Direct Linkage
Got home by starting car at stop lights in first gear and careful rpm matching shifting gears. Only ground gears a couple of times. 
