VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1937 clutch

Re: 1937 MD clutch. A few years ago while my transmisson was being rebuilt I decided to freshen up my clutch (resurface flywheel/pressure plate, new throwout bearing, pilot bearing, clutch disk). I couldn't find NOS clutch springs so used the old ones because the clutch was working when I pulled it apart. Well, it has not worked smoothly since--rough shudder when down shifting to 2nd gear and now 1st gear is a struggle. I found a NOS box of clutch springs and they are on the way--my question: what else should I be looking for as I begin pulling things apart again--it's my diagnosis that the clutch is slipping.

I would lean more to the problem being with the clutch disc.

Check for worn splines on both the disc and input shaft.

You can look for a 38 or 39 flywheel and clutch. They are like the more modern cars. They also have the ball bearing throw out bearing. Thats the only years that still has a four bolt flywheel.

I am interested in this discussion here. So if a 38 or 39 were used, would that require a clutch fork from those years? What about the linkage?

The linkage is the same. The fork is very different and the trans. front bearing retainer needs to be changed. Not sure if the old style 1937 starter woill work on the later flywheel.

Going back to the original question, the problem was not there with the original parts so my thoughts are one of the new parts is the culprit.

Thanks to all, looks like the answer will be more apparent when the parts are out and in my hands, it will be awhile but I'll let you know what I find. More to come. . . .

Gene, I should tell you that during my initial rebuild I had the clutch disk re-lined since replacements are unavailable. Your suspicion is probably right, I wonder myself what I will find. If it is the disk I wonder what my options will be.

When I converted my '37 from the original dog dish flywheel/clutch assembly to the '38 flat flywheel and pressure plate assembly, I didn't even remove the starter. Turned the key to the on position and engaged the startorator. The starter engaged perfectly.
I used the original adjuster, but everything else was from the '38 set-up that I pilfered from a spare engine/trans combo I had. I believe we had a forum on it.

This is an amendment to my last post.

I had the pressure plate and the flywheel resurfaced. The 1937 flywheel I call a dog dish design, similiar to the Chevy Vega. The reason for the up-date to a '38 clutch is the '37 wouldn't work after the machine work and I'm afraid that the amount of material removed was not equal. By that I mean the mount surface for the pressure plate on the flywheel of the '37 has to be the same amount as that removed from the face of the flywheel where the disk engages the flywheel to keep the mechanical distance the same as if it were new. If one surface is machined more than the other, than there will be a problem. Either slippage or no disengagement.

If anyone can tell me how to verify my theory, I would love to be able to reinstall my '37 clutch assembly.

Your theroy may be correct. For a flat flyweel the surface that the pressure plate boltsagainst has material removed also.

I had a problem with my 32 not disengaging after fw and plate were surfaced and a relined disc installed. i mounted thin shims under the pressure plate/bolts and it solved the problem. That solved the problem of not disengaging but I don't have an answer on slippage other than to recut the flywheel mounting surface.

Every time I have had a flywheel resurfaced both the disc face and the pressure plate mounting surface have been done, this keeps the pressure plate clamping to original specs.
Tony

I handn't thought about where the pressure plate attaches to the flywheel. I assume that an automotive machine shop can figure out the specs of the disk/pressure plate when bolted to the flywheel after they have been resurfaced. This could be my problem all along if it hadn't been done initially.

Question about hooking up the emergency brake linkage: I've got the repaired clutch in place, transmission replaced and began to hook up the pull rods to the rear brakes on the cross shaft bracket. When I first disconnected the pull rods a 6" spring fell to the floor and I didn't see where it came from. Checking the manual does not show a spring so I don't know if it belongs or if it does, where it attaches. The spring is really rusty and old so it's been under the car for a long time. Any thoughts?

The parking brake linkage pullback spring was 5 1/2 " with 40 coils and be attached to the bar up in front of the cables.The foot brake spring was 4 1/2 with 30 coils and the clutch 4 11/16 long

The parking brake spring mayhave stretched it bit.

I see a hole on the cross shaft bracket that looks like the location for one end of the spring but no idea for the other end, unless that's not correct.

Thanks Gene, I should try replace all three.

Well, I have been waiting all summer for this day! I fired-up the Chevy and took her for a shake-down drive after going through the clutch and replacing the drain plug on the oil pan. I had two tables setup in my garage for all the parts that needed to come out for the projects! I sure admire the mechanics who could make a living doing jobs like these on a daily basis. My clutch problem was a shudder when down-shifting from 3rd to 2nd which ultimately moved to 1st gear on take-off. Once everything was apart I was happy that there were no apparent issues--I was fortunate to find a box of NOS clutch springs on eBay and found that they were about 1/8 " taller than the old ones. So with everything back together after 3 months and a fresh oil change I was back on the road again. I would say that I have about a 90% improvement in smoothness and after some more miles I will play with the adjustment if needed. It's hard not to expect the same shifting that my modern manual transmission has with 80 year old technology and use! Thanks for all your help with these projects, it really helped!

There is a major difference between the 2 transmissions but with practice you will get that way not many will notice the difference.
Tony

So it's been a couple of months now and I took Tony's advice and "practiced" different clutch procedures and I found two that really worked: On initial take-off I use low rpm's, really just enough to get moving without stalling or over-slipping the clutch; when down shifting from 3rd to 2nd I double-clutch and release the clutch under light power and the action is very smooth. Looks like the main problem was the driver! Thanks for the good advice Tony, it worked.

No problems. It takes a bit of getting used to these old cars, I occassionally get to drive a truck with non synchro gearbox and still miss the change the 1st few attempts.
Tony