Not really a problem yet, but I want to deal with it before it becomes one. The Ol' Furd has a stock style diaphragm clutch, and it's on hydraulic actuation. A Wilwood master and a Tilton hydraulic throwout bearing. A Napa pressure plate (Made by LuK). I put ball bearings on the pedal pivot and the link rods have spherical rod ends. There's about 1400 mile on the whole enchilada. Here's what is confusing... Very high pedal effort on the first push. After that, near normal operation, although pedal effort seems to be higher overall lately. I flushed the system with new fluid last week. Now I've been running hydraulic actuation on clutch systems I've built for a lot of years, and this is a problem I've never encountered before. Anyone encounter something similar?
Interesting. I have seen often on the brand of cars I work on for a living that the pedal effort will get greater as the disk wears, and the portion of the diaphragm where the throwout bearing rides gets higher, or "pointier." With so few miles on your setup, I wouldn't suspect this to be the case but a thought to throw out there. Devin
Thanks Devin. The pressure plate on this thing is a lot more "pointy" than I have seen with other stuff. The truck originally came with a long style spring clutch. I kinda went outta my way to find a diaphragm style. Looks like this... Kinda thinkin' maybe I should switch to the long style spring pressure plate.
Do some research. You may find the Long style has more spring pressure than the diaphragm. I use hydraulic set ups but haven't used internal throw out bearings so I don't have any ideas at the moment.
Question: Normal procedure would seem to be that you would step on the clutch the first time when the engine isn't running. Then subsequent pushes would be after you have either cranked the engine over or actually started it. I'm wondering if you shift into neutral before starting.......and then once the engine is running, push the clutch for the first time and see if its still hard to push. Might tell you something about whats causing the problem.
Running or not, the first press is hard. I typically press the clutch and shift into neutral before cranking. With a well worn trans, shifting into neutral might not need the clutch depressed. This trans is brand new, and is still "notchy". I'll try your suggestion today. Thanks for that
What is the bore of the Wilwood MC for the clutch and the pedal ratio? I also found a McCleod pressure plate that looked like a Borg&Beck but the roller actuation of a Long. The pedal became very easy. Good luck.
Rubber brake hoses can expand inside and inhibit or actually stop the flow of fluid. I imagine the same thing could happen with the rubber hose on a hydraulic clutch. Maybe when you press on the clutch pedal first time, you force open the hose and then it will work but still with greater effort. And it's getting worse as time goes by. Maybe?
MC bore is 7/8". I didn't write down the actual ratio. I used the factory pedal and pull rod, and worked out my bell crank (also on ball bearings) to get full stroke on the master without bottoming it out. Pretty much done in CAD (cardboard aided design) then transferred to metal and then run through the travel to get full MC stroke. I also had to figure in the max stroke of the hydraulic TO bearing. So, that's where it ended up. I looked at McLeod's site to see what they had. What they listed for this motor were a diaphragm and a long style. I'd imagine there'd be a borg and beck style that could work. I can pretty much put the throwout bearing anywhere for and aft to accommodate.....if that's what it took. Rickybop, there are all PFTE stainless braided lines and AN fittings.
Ok. did that on the first start-up today. Clutch operated normal. No stiff pedal. I'll be dipped! That get's to the o'l head scratching routine. Could it be the static interaction between the diaphragm fingers and the face of the TOB? Should I reach in there with something like a long skinny brush and put a little thick moly grease between those? I reckon the thing to do would be to make that the routine and see what happens.
OK, I'm still just guessing. Like you, my thought is the interaction of the clutch fingers and the throw out bearing. Wondering if when at rest there is a "catch" on a high point or maybe a groove shape in the bearing face????? and when the engine is started the diaphragm fingers move slightly due to centrifugal forces and the clutch works normally. Again, just guessing, but the only thing that changed during the test was the addition of rotational movement.........so that seems to tell me its not a hydraulic problem or a pedal problem. You know what Mike spelled backwards is........
I'm on the same page there Mike spelled backwards. I also have an e-mail correspondence going with the techies at Tilton, just looking for insight. I'll report back when there's something to report! I appreciate the input from all of ya!
Tilton tech support is awesome! They got back to me quickly even though I wasn't looking to spend money, but just looking for advice. Their tech guy, after a few Q&A sessions about what I'm actually using, said this a common thing, and is exactly what we were thinking, Mike spelled backwards. Because of the high cone of this style diaphragm, there seems to be added friction between the finger and the TOB face when the motor is not running. When the motor is running, the fingers will slip a bit before being squeezed, and thus operates normally. I might try going in through the release fork window and smearing just a dab of thick moly grease on the face of the TOB. Just a dab. Don't want that stuff slingin' off making a big ol' mess!
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