clutch adjustment dilemma

richard rink

richard rink

Member
Here's my problem: I have just installed an 8CM with the 50 Merc pressure plate in my '40 coupe. The final step involves adjusting for the proper travel of the clutch pedal. I found that there was not enough length on the adjusting rod. That is, the rod clevis came to the end of the adjusting rod before the pedal "free play" was anything short of several inches. Looking through the transmission inspection port shows that the clutch plate release levers are too far "forward" for the release bearing to reach with the usual adjustment.

Short of pulling the engine and looking for another type of pressure plate, is there anything else I can do? What about adjusting the position of the clutch plate release levers? I can see a nut for each? Is this a possibility?

Thanks in advance.

Richard
 
if the clutch plate is new or rebuilt i would leave it alone, this should be set.....i have heard of guys making the adjustment rod longer, i would do this before messing with the clutch plate. make sure you have the right pressure plate. i ran into a problem with my 49 F1 when replacing the pressure plate.....i got a deal at mac's.....a kit thing.....not a good thing, the plate fingers were hitting the transmisson throw out bearing shaft..make sure the fingers dont hit anything, if they do it will make a long distance for the throw out bearing to travel.
 
Thanks Kendall, I'm working on extending the length of the rod by finding a way to mate a similarly threaded stud to the rod. I'll leave the pressure plate alone. No problem with the plate fingers being too close to the bearing shaft.
 
Check the pressure plate on that motor. A '50 Merc would have had the 10" Borg & Beck style clutch. If your clutch is the 9-1/2" pressure plate, you will have to remove it and replace it with a 9" or 10". Either would require changing out the flywheel (or redrilling the current flywheel to accept the bolt pattern for the clutch you go with. Without going into details....do not use the 9-1/2" clutch.....it has the wrong release fingers for your early style Ford transmission.
 
There are numbers on the inner circular opening on those Borg & Beck units (if it is in fact a B&B). The model numbers for a 49 through early 51 are 0988 and 1310 for later replacements. These covers are adjusted at overhaul and can only be readjusted by a rebuilder that has the new lock nuts & proper tools. To my knowledge, these are the only ones originally manufactured to work with the early type throw out bearing & hub assembly. There are other B&Bs with longer fingers, bent fingers, and shorter fingers that will not work correctly. A clutch rebuilder can get the correct parts to make one of these up if he has the parts, references, and the experience. A later mid 70s Chevrolet diaphragm type clutch pressure plate can also be modified to work with the B&B bolt patern flywheel too but it is a little bigger than 10 inch. Centerforce makes plates that will work for this type of set up and the big 1 3/8' 10-spline trans input.

The B&B should work without adjusting the pedal all that much. The front end of the 49/E51 Merc transmission is identical to the 1940 Ford remote shift types and the Mercury even shares a lot of the original equalizer design. Be sure your throw out hub & bearing are in there correctly. If the throw out fork isn't making contact with the hub flats correctly, this could be the problem.

Kerby
 
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Thanks for the advice.....I'm trying to adjust the clevis on an extra length of threaded rod. Right now, I've got too much length. I'll post when I get it right.

Richard
 
You say 40 do you have a floor shift trans.If so do you have 40 clutch leakage that is mount to other frame.If 39 pedal you don,t have much travel,and maybe wrong lever.What to do, if 40 remove linkage and put adjuable wrench and see if you can release clutch.
 
You've probably got the 50 Merc flywheel in there behind the 8ba, check out the starter vs the flywheel- that is, how the starter engages- and that it does not stay in contact... Karl
 
I had the same problem and ended up cutting an old clevis in half an using a short section of pipe in the middle to ad an inch.The pipe was just big enough to slide the two pieces in then I cross drilled thru the pipe/clevis rod on both halves and used a cotter pin to secure the pipe to the clevis rod.
 
The mercury pressure plate you need is like this one for use with 39 style trans large spaced fingers. 10 inch clutch.If you are just swapping engines should just be a linkage problem.

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George, that's the pressure plate that I'm using. I've used this combination in the '40 one other time, and it works fine. For whatever reason the clutch adjustment is problematic this time.

Fibber McGee, I am using a variation of your technique and have attached a threaded stud to the end of the original rod. Now I find that he clevis needs to be shortened; with the added inch, as I am backing the clevis down the length, it encounters the "joint" before the correct adjustment is reached. A half inch off the clevis should be about right.
 
I think you'll find the clutch disc is to think and making the finger pull in further. If you can lengthen the ajustment rod it will probably do mit. Walt
 
I tried to figure out a reason it was doing that and never did but mines worked for several thousand miles.Your way should work the same,I guess sometimes you have to improvise.
 
i heated the arm and bent it back a little got all the ajustment i needed the arm that goes on the cross shaft where the threaded ajustment fits
 
Walt, your comment about clutch thickness may have identified the "root cause." I had the plate rebuilt at a local shop; never thought about thickness.

52Merc, I keep your suggestion in mind should the shortened clevis fail to allow for the adjustment. This afternoon I'll install the shortened clevis and see what happens.
 
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