So the clutch won't fully disengage on my '62 Chevy truck, when the slave's rod is adjusted to factory specs (shop manual says there should be 5/32 between the rod's contact point with the clutch fork). Things drag a little bit when putting it in gear. I suspect this is what led to the synchros dying in the original Granny 4spd. If I adjust the hydraulic slave's rod out enough to put constant pressure on the clutch fork, it has enough travel to fully disengage the clutch. I've driven it like this for a lot of miles, and when I had the throw-out bearing in my hand today, it doesn't look like the bearin'gs contact area on the clutch diaphram is worn to hell. BUT, the original throw-out bearing was worn in half. Then again, it was original. 45 years of use will do that. The pivot ball was also worn to a sharp cone...but I can't just dismiss the condition of the original one, because this adjustment isn't to spec. So, my question is: as the clutch has worn (it's an old clutch...I should replace it, but that's not in the cards right now), will I have to adjust the linkage out farther and farther? Are very bad things going to happen with the clutch fork adjusted to the point that there is no free play in it at all? In fact, I would almost say there's a little bit of pre-load. The adjustmet at the pedal's rod going into the master cylinder is fine; there's about 1/8-inch travel of the pedal before it starts moving the piston. The return and over-center springs are all in place as well. I'll sacrifice a clutch and bearing at this point to preserve the freshly rebuilt 4spd OD manual trans. I just need to know if what I'm experiencing is normal, or am forcing the retirement of something? Have other people adjusted all the free play out of their clutch linkage? And if so, were there negative results? -Brad
Are you sure you have the correct master cylinder bore? Sounds like you may be running out of MC volume before you get to full stroke. Just a guess.....slide
it will just spin the brearing all the time but don't get it to tight...as soon as you start pushin the plate in the disk lets go
Sounds like the input shaft may be dragging in the spigot bearing .If the clutch plate is grabbing on the input shaft spline it wont release properly either . What are the fingers on the cover ***embly like? worn,loose? again if theres wear there the clutch wont release .
Adjust the pedal free play on the master down to where it can barely be felt - like 1/16" or less. Then adjust the slave. We can ***ume the hydraulics are 100%, right ?
I ran into a similar problem in my 327 powered 63 Chevy half ton. In my case, the clutch wouldn't engage all the way and slipped at full throttle. This, after two new clutch pressure plate and disc installs. The problem was, the throwout bearing was too tall. Parts guy - who solved the problem - told me there are three different heights of throwout bearings for the SBCs of the era. Looks like your hydraulic mechanism is probably set up right, you may want to look at the next shorter throwout bearing.
Thanks guys: I thought there were only two t/o bearings, didn't know there was a third. I'll check that. The clutch master is a brand new Wilwood, 1-inch bore, on the CCP power brake kit for these trucks. The slave is new as well...and I just rebuilt it, since it's a 1-inch bore and the old master cylinder was a 1 1/8-inch bore, I blew the seals. There is some wear in the clutch diaphragm's fingers...I felt around in there through the bellhousing, and the fingers had a little play in them. Not much, but it wasn't anything like hitting a solid piece either. Sounds like I'll be setting it up as-is for a little while, checking on that third bearing height, and then replace the clutch. At that point, everything in the driveline will be brand new and rebuilt, except the differential (and as of now, that's fine, the posi still works, and it just needs a pinion seal and new dif gasket). Thanks for the help. If anyone else has any input, please contribute! -Brad
Did I understand you correct in that the original mc was 1 1/8 and the new one is 1 inch bore? If so that is the problem. You dont have enough fluid volume to move the slave its full travel. Need to get the right size mc to get full travel. Mark
The stock-type cylinder was 1 1/8-inch bore, with a 1-inch bore on the new slave cylinder I installed shortly after getting the truck. I blew the seals out of the slave, because I was pushing too much fluid with it. I am now matched: master cylinder and slave cylinder both have a 1-inch bore. -Brad
Most of the time the clutch pedal to the clutchmaster cyl. pin wears out YOu adjust the bottom and because the top pin is worn you can't get a good release .... check that pin it eggshapes ..
Therein lies the problem Brad. The 1 1/8 shoved more fluid to the slave at a LOWER pressure rate. The slave died from age, not pressure. Now, you're sending more pressure with less volume. And you run out of fluid volume before the slave gets done travelling. You need to go back to a 1 1/8 bore master, it will not ruin the slave. Cheers, John
50 burb nailed it. the smaller master has higher pressure but less volume. Will an 1 1/8" Wilwood fit where the 1" is? I know "Darn, more money," but you want it right, right?
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