I need to know if anyone else has had these problems. I am using a manual trans in the 37. Thought, why bother with manual linkage when I can use a hydraulic throwout bearing? For one thing I cannot get enough travel on the diaphragm to release the clutch. The first throwout only had about 3/8 of an inch of travel. This did not do the trick, so, I bought another unit with close to 3/4 inch travel. Now I think the diaphragm is catching on the bearings sleeve. I pulled the trans out cut some off the ends of the diaphragm (3/16) thinking surely this will work. (by the way this was only one of 6 times to remove the trans to try and solve this). Well it did not it still will not disengage. Clutch and pressure plate brand new fitting a 55 chevy. Running 283 with 3 speed manual o/d. Now I am going to try and install manual linkage with a pulling slave. I plotted out all the linkage and I think I can get 3/4 inch of travel with out too much effort on the clutch pedal. Maybe someone else has ran into this before. I know some of you have or know of someone who has. Any help would be appreciated.
'57 to '60 Ford trucks used hydraulic clutches. Maybe the hydraulics from those systems are closer to what you need, vs. Hydraulic throwout bearings from later models.
I just did a non-hyd mechanical linkage on a 37 Ply with stock pedal. On that pedal, there is an eyelet for the linkage, but I knew it was not enough throw for the clutch. I made up a Z bar to change/reverse the throw and it works great, even with a Centerforce race pressure plate. I do have a 36 chev in the shop right now, so I can look at the stock pedal if it might be the same. I also did 2 other hotrods recently, with a 60-62 chevy pickup master and slave, those work nice, but both used the 60-62 pedal setups When you do mock ups, if you have a belly pan under the clutch, you can stick a ice pick on the edge of the disc, to try spinning it as the clutch pedal is going down. Then you will know if the throw is correct. Also on hyd slave mock ups; you can hook a shop airline to it. That won't be enough pressure to depress it all the way, but it will "hold" the TOB fork wherever you help pry it to, with a bar. This is helpful, as you can slowly pull on the fork while trying to spin the disc. Stop prying when the disc barely starts to be free. The air will hold it, even when you let go of the prybar. Now you can see if you have any extra stroke left in the slave.
Work backwards from the release bearing. You'll probably have to shim it to get it close to the diaphragm fingers so you don't use up all your stroke taking up free play. Did your release bearing come with a shim kit? What does the manufacturer recommend for a master cylinder? The masters I've messed with usually have about 1 3/8" of travel, and come in different bores. Hydraulic throwout bearings require a fair bit of fluid volume, so you'll probably want a 3/4" bore master cylinder. Also, you'll need to bleed the system thoroughly, otherwise you'll use up pedal travel and cylinder stroke just compressing air. Hate to tell you now, but I don't think I'd be cutting pressure plate diaphragm fingers. Risky business.
I have read on other threads where guys have solved this issue by going to the larger,1" bore master cyl and it fixed everything right up. If you have access to a 1",give it a shot. Scott Posted using the Full Custom H.A.M.B. App!
I really like that setup Russ! Thinking about fabbing a similar setup for my coupe. It's so simple,clean,and effective. Scott Posted using the Full Custom H.A.M.B. App!
My Dodge has a normal throwout bearing and fork that is activated by the hydraulic cylinder plumbed to a slave cylinder on the firewall that replaces the bell crank and linkage. Gene
I've recently learned that there is no free play when setting up a hydraulic throw out bearing. I know I know i know ... I said the same thing. Look it up.
That type of cable is referred to as a Morse cable. Used for hyd valve bodies on industrial and commercial apps. Morse cables are sold by lengths. The issue with that tight bend, and the pulling load on the inner cable, is that the inner cable will try to wear through the outer spriral reinforced jacket under the black outer skin. The sawing action is magnified greatly by two things; The load on the cable and more importantly, the very severe bend. Morse cables are difficult to lube with oil, as they have rubber sealing boots on both ends to keep water out. You can slide these back and hold the cable upright in a vise, to get oil to travel through the inner cable. On long term use, with that cable angle and load, it will need to be lubed.
It is obvious if and when the Morse cable needs to be lubed; When it does have enough lube, the pedal will be super smooth feel, as you push it down or release it very slowly. If it starts to feel jumpy, and you are unable to stop the jumpy feeling with your foot, it needs oil. if you want to know if it is sawing through the outer spiral steel jacket, it will show up as gradually increasing free play at the pedal. Forgot to say that Morse cables also are available in various load capacities. the weaker ones have a very small threaded rod to attach the clevis to. The HD ones have much larger thread sizes. I thought they were color coded, but I could be wrong. these were also used on old style PTO's attached to truck transmissions.
My set-up works well. Mine uses a slave cyl mounted on the bell housing on the p*** side. I was told it's off an early '60's Chev truck.Not sure what master cyl they used....maybe you can see it on the left of the brake master
Before I made any decisions on mechanical vs. hydraulic clutch systems, I'd figure out if everything else is set up correctly. I'm a little concerned that you are t******* the fingers on the pressure plate diaphragm, as that's already heading down the wrong path. There shouldn't be any reason to trim the diaphragm if it was all purchased to match.
Same here on my '61 GMC. I think it would be easier to plumb lines than to get a full mechanical clutch linkage to work right.
I'm one of those guys you are talking about..........just set up a LS T-56 behind a 389 Pontiac and had the problem of the hydraulic throwout not traveling enough to depress the diaphragm completely (and release the clutch)........I found that the 3/4" bore master cylinder just didn't have the correct volume to move the hydraulic throwout enough to disengage the clutch........I changed to 1" bore master cylinder and it now works perfectly........If you can get the specs on the slave cylinder/hyd throwout you can probably find what bore MC is required.........CAUTION though......you don't want to go too big with the bore, else you will have PSO (pressure squirting out from over-extending the slave)...........hope this helps..........
I have been using mcleod hydraulic throwout bearings for years the first one I had gave me some problems as I bought it used and didn't understand it, I put it in and right away it was leaking turned out that the problem was the piston wasn't correct called mcleod tech learned how to measure for the correct piston and never had another problem or leak
Yep......I agree.........clearance measurement is critical to longevity, unless you like doing a clutch change out..........and on ******* set up such as mine, you need to do your homework to match the MC to the throwout requirements.......not hard to do, just needs to be done......
People, I really appreciate all the feedback. I really, really do. Never expected it, but, I think I have figured out my problem. I am using an eleven inch clutch which is what the 55's came with and to the best of my memory (and here we are diving off into a black hole) that is what I ordered it for. The fingers on an 11" are longer than those on say 8.5" or even a 10" the eleven will require more movement on the diaphragm than say the 8.5" to release the disc. I am very close as it is, but I have ordered a "pull" slave cylinder, a fork, pivot ball and conventional release bearing. Once I have this in place I can play with the linkage position on the fork to achieve what I need. I have way more movement on the new slave than I will need (at least that is what I have plotted out anyway) and then I will know for sure I have adequate clearance on the release bearing, of which I have none at present. I will re-post the results when I get it installed, hopefully by next weekend. Thanks again for all the feedback. I have never been on a site like this before. Most of the time you post something and it hangs out it never-never land.
Dude, with a hydraulic throw out bearing there is no free play or clearance at the bearing face to fingers. None zero zip zilch and as a matter or fact it's a preloaded tension. I tried telling you to look it up last week. Read your instructions or google it. When I first heard this I thought it was BS, but its not. Don't chase your tail, cut the diaphragm levers or throw money at it.
Just one more note on the hydraulics............if you don't have a good bleed on the system, you will likely have problems with pedal feel and disengagement........Try to always bench bleed the MC before you even start the process..........
I did bleed it and have bled it sever times (since I have a remote bleed line) during the process. I did have clearance using the first bearing. None with the second since it is about twice as thick as the first. I called Speedway where I bought it and was asking for dimensions on a release fork. I was informed by the tech I needed at least .100 clearance. I told him BS that would never happen with the setup as it was. It may not have to have clearance and it may live a long time turning all the time. Call me old school but I never found a release bearing that would live for long turning with the clutch all the time, they just did not have enough lubrication and being subject to moisture like they are. I do appreciate the feed back and to your point the dirt track boys here never worry about clearance but they do not put miles on the bearing as I plan to do.
FYI..My OT 92 F150 has a hyd throw out bearing [stock 11'" PP] and the bearing does stay in contact with the pressure plate fingers, NO clearance..Lasted 105k miles and it was the slave part that started leaking/releasing..All depends on the design of the bearing..
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