1929 Cadillac clutch sticking

[m-mman]

The car: 1929 Cadillac 341B  town sedan. 

I spent the last 4 years rebuilding everything I could on it. I am now spending even more time  working to sort things out. 

I had the clutch rebuilt/relined at a shop that does trucks and industrial components. (multiple disc, sealed unit) They did not flinch at the job, they are used to working with non standard assemblies. (they relined my brake shoes without any problems) 

 

Anyway, now SOMETIMES (but not always) the clutch simply does not release. Arrrrg!!!!

Push it down and it acts as if you had not. (gears clash etc)  Occasionally I have had to shut off the engine, put the trans into gear, push the pedal and restart the engine so that it can be moved/driven. (When this happens the clutch does not smoke or smell or try to drive the car like it is completely stuck). This could go on for a few more pedal pushes OR the next time you step on the clutch it is fine and releases normally.  (so the adjustment must be OK) It could work fine for a while then stick suddenly shifting between 2 & 3 and then it may or may not work at the next stop sign. 

 

I thought that maybe there was some glue or varnish from the rebuild that was acting sticky, so I have slipped it a few times (going up hill) to try to clean it off. . . . no change.

With a torque tube and the motor mounts on the enclosed bell housing, I do not want to remove it without a good reason or having something specific to look for when I do. 

 

Any thoughts or experience with one of these?

Thanks

[old car fan]

My thoughts,did the disk slide on the spine easily

[C Carl]

Jim, I have been thinking about this since you posted. I really can't offer much, particularly in that your predicament is intermittent. (!) Some aspects of your symptoms are similar to what we more primitive guys have to live with regarding our multiple, 15 or 17 plate clutch packs. In that case, going to a heavier gear lube would be your first stop. But you have only 2 driven plates, and synchrmesh on 2nd and 3rd gears. I fear you will ultimately have to open it up again. Unless someone else from the majority of the guys here who are much more experienced than I am feel it would be futile, (I echo old car fan's suspicions), I would suggest more diagnostics. Firstly, since first gear is non-synchro, the next time it is reluctant to go into first from idling stationary neutral on level ground, see if you can engage 2nd or 3rd easily, and then quickly try to drop into first - not a bad practice in general, used to be SOP for some transmissions without synchro on first. If that does the trick, try changing up to a higher viscosity gear lube. What are you using now? If you are using a GL 4 SAE 90 gear oil, (see the adjacent 160 weight topic), change it out to a heavier GL 1.  

 

Another resource available to you is your CLC international directory. As you know, by being listed therin, members consent to accepting cold calls at considerate times. Speaking of which, we have not talked in far too long. Please give me a call some convenient time for you. At present, I am using the 206-790-6912 number. It sure is handy having two numbers to cover the eventuality of equipment failure of one or the other ! I am in a situation which will eat up all of the rest of the year for me, selling the Seattle place and moving permanently to the ranch. Much harder on my bone-on-bone left shoulder than I had anticipated. I need enough range of motion  out of that tormented articulation to still be able to drive my oldies.

 

I suspect you will find that some flock-up has been inflicted upon your poor clutch. Surprisingly, in that this should have been elementary for your rebuilder. Sometimes clutches settle down with use, sometimes the opposite. But a new clutch should not have any nasty habits as far as I know. I wish I could have been of some real help to you.  -  Carl 

[m-mman]

Yup, I got it filled with the heavy 160(?) lube. I dont remember the exact brand or numbers but pumping it in was a PIA! 

Yup I have other non-syncro first cars, so using 2-3 to make an easier shift into first is a regular habit. But when it sticks it is as if the clutch is not depressed at all. 

When assembling it, I slid the trans onto/into the bellhousing on the floor and then installed hoisted the motor & trans as a unit. It went together easily. 

 

I guess I am looking at having to take things apart A-G-A-I-N . . . .

Oh, for the love of old cars.  

 

The 'clutch' is a unit that combines the plates and springs. There is no service information about disassembling it. (shop manual says it is serviced as a unit by the factory) When out, I guess I will have to learn how to pull it apart myself to find the problem. 

[tom_in_nh]

Not sure if your bellhousing is integral to the engine or not, but in the event that your bellhousing is a separate unit: Did you use a dial inicator while assembling the bellhousing to the engine? 

Misalignment of components could cause erratic shifting issues.

Edited July 4, 2018 by tom_in_nh
Adding additional information. (see edit history)

[m-mman]

Follow up for future diagnostics.

 

Clutch adjustment is important. The distance between the throwout bearing and the fingers or release mechanism is important.

Too close and the bearing is operating all the time and wears out prematurely

Too close and it is as if you have your foot half way down on the clutch and it slips under load.

Too far and you cant push the pedal down far enough to release the mechanism and the gears grind and clash.

 

Some people adjust their clutch to a personal preference based on how far from the floor it engages. This is not how a clutch should be adjusted, so it is nothing I typically evaluate.

Service literature describes feeling for “freeplay” in the pedal. How far can you push the pedal before the throwout bearing begins to touch the fingers on the pressure plate? (or other release mechanism)

 

On every 50s & 60s car I ever had this distance is easy to feel. The pedal swings freely and easily until you feel the bearing ‘hit’ the pressure plate. The books show a ruler placed against the floor/firewall and measuring a freeplay of about 1.5 to two inches.

I am learning that 20s cars are different. The pedal pivots have enough springs and slack adjustors that the tolerances are tight enough that the actual freeplay is not easy to discern.

 

In experimenting with my 1929 I looked down and noted that the clutch was engaging maybe ¼ inch off the floor. This meant that it was ‘too loose’ and barely releasing when slammed to the floor. Thus it was the likely source of all the symptoms. 

 

Today I pulled up the floor boards and tightened the adjustment. It now engages 2.5 to 2 inches from the floor.  I am not sure that the bearing is fully releasing with the pedal up, I can hope that it is. I wont be able to test it for a week or more (because I also need to fix the brake light switch) but hopefully this will fix my clutch sticking problem, without pulling the transmission.

Edited July 8, 2018 by m-mman (see edit history)