I normally just cruise the pages here to read, learn and have a little fun. I have an issue I think you guys can settle for me. So, I have a WILWOOD clutch pedal and hydraulic reservoir hooked to a stock chevy hydraulic slave cylinder. It runs via a 3/8 inch that is about 2 feet long. Just long enough with play. From there to a 10 inch clutch and T5. The clutch pedal has to go almost 6 inches to get the clutch fork to move about 1.5 inches, This does not seem enough to engage the clutch fully, I have tons of adjustment in the pedal but it is already really high. This is in a 54 chevy pu so you have and angled floor that come in from the fire wall about 2 inches top to floor. see pics Thanks for any suggestions.
A master with a bigger bore would do it, but the effort would probably be higher. Or a slave with a smaller cylinder.
Typical overall clutch pedal ratios are around 11:1, which will result in just over 1/2 " total throw-out bearing movement with 6" of pedal travel. With the linkage adjusted for about .100" T/O bearing clearance to the pressure plate you'll have about 1" pedal free play, and about 3/8" T/O travel with another 4" of pedal travel, enough to disengage most clutches, with 1" pedal travel reserve. Your present ratio of about 4:1 is way too high and results in way too much T/O movement.
Are you saying that you have a problem with disengaging the clutch at full pedal and master cylinder travel? What type of pressure plate are you using? I learned because of a 1 ton Chevy application, that with a hydraulic release setup, you have to stay with a diaphragm type clutch---typically. This was a wrecker that was being repaired. I also learned with info from tech service folks at the clutch supplier our company used, that on a diaphragm type pressure plate setup and hydraulic release, that the release bearing should always be in some contact with the fingers of the pressure plate. And on some vehicles, if you resurface the flywheel, because of the limited slave/release bearing travel available, sometimes the flywheel installer needs to know how far the flywheel has been ground to know how many thousandths shim thickness to put between the flywheel and crankshaft. Is the throwout bearing able to provide travel to release the disc? Back to pedal ratio or master cylinder bore.
Let me see if I can give you guys more info. It does disengage the clutch but, it has too move that whole distance of 5 3/4 inches to do it. From it's resting position up and back to the floor. It has to go into first to catch reverse. It will not go directly. There is 4 inches of movement before the clutch begins to disengage. The slave, clutch fork, clutch, pressure plate, bellhousing and tranny are all 1984.5 Camaro V8 components. No adjustment ?. All brand new except for bellhousing. V8 Bob, how do I get your ratio with current equipment? Thanks for your answers and suggestions all.
OK. You're getting drag on the clutch disc because of not enough slave travel, induced by pedal ratio or hydraulic ratio. You will possibly need a larger bore clutch master cylinder, for volume of fluid moved, to make the current pedal ratio work.
Or, you may need to shim the flywheel back due to some unknown circumstance, to allow the current throwout bearing travel to do its job.
It has to be in the pedal. All the rest is new or rebuilt. No machining on the trans. Seems like moving more fluid, ie; bigger bore master. Thanks again.
I just went through a bunch of this with my Ford. I have a 1" Wilwood master (compact and remote reservoir) that I would sell you for $50. It's new except I had to clearance one side of it. From what I learned, the master bore should be slightly larger than the slave to get some decent throw. More fluid (larger master) pushes the slave farther. It's just a harder pedal. At a 4:1 ratio though it's going to be like pushing your whole car with your foot. I went with 12:1...
Multiplying the pedal ratio with the clutch release arm ratio (and any bell crank or equalizer ratio) will be a good start. That overall ratio will determine the master and slave bores to arrive at something around a 10.5-11:1 ratio. Similar bores would not change the ratio, as an example.
I m watching this thread with interest. I have pretty much exactly the same parts as RCM59 on my new build. I am getting ~1/2" of slave cylinder travel for 4-5" of pedal travel, which doesn't seem like much. V8 Bob above mentions 3/8" of T/O travel. Maybe I have enough?? I will get my driveshaft back from balancing on Tuesday so I can see if the clutch is actually disengaging. Like RCM59 says, this is pretty much a belly button parts combo and shouldn't be so troublesome.
That is a lot of movement at the pedal. I'm running a 3/4" Wilwood master and a Speedway 7/8" slave bolted to my bellhousing and it works nicely. How big is the stock Chevy slave? Later slaves are a lot smaller. I originally moved my pedal link lower on the pedal arm, it was convenient, but it took 2 people to move the clutch pedal. So I went up to the stock location and had to machine up a new plate that located the clutch and brake masters. Success.
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