VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Clutch problem 1931

Hi Guys,

What advise on the clutch setting can you offer. When I try to put in gear it battles to go in gear and the scratching sound doesn't help either. At lower revs (if adjust the carb to a low engine revolution) it manage to engage.
Any suggestions?

Hello Oukar,
With the engine running, does your transmission shift in and out of gear (ok) when you are not moving? If yes, do a search on the topic of double clutching to learn how to allow the gears in the transmission to rotate at equal speed for smooth/quiet gear selection when accelerating and decelerating. If the gears grind when you are not moving, try allowing a little more time after you push in the clutch (to the floor) before you select a gear. If it still grinds, suspect that the clutch is not fully disengaging the flywheel. Other members who have more knowledge about the technique and function of shifting should offer comment so we may all learn.

Hi Oukar
Your clutch problem could be improper adjustment which causes the clutch plate not to completely release, worn parts or interference inside the clutch set up its self.

Here is a link http://chevy.oldcarmanualproject.com/chevyowner/30om24.htm to a picture of the clutch set up from the 1930 Chevrolet owners manual which is the same as the 31. To see more online information for the old Chevrolets, click on this link
http://chevy.oldcarmanualproject.com/ .

This is what happens when you operate the clutch pedal:

Once the clutch pedal is pushed down to the floor, the clutch fork is pulled back which makes the throw out bearing end of the clutch fork move forward causing the carbon throw out bearing to contact the clutch sleeve which in turn pushes on the 4 clutch fingers causing the clutch pressure plate to retract thus releasing the clutch disc from between the flywheel and the clutch pressure plate.

If there is any wear on the linkage or inside the pressure plate assemble causing the clutch disc to not completely release and drag, the input shaft will not quit turning causing hard shifting and/or grinding at a dead stop when trying to get the transmission in gear. Other causes can be bent clutch disc, worn clutch disc hub and input shaft splines or dragging pilot bearing among other things.

If the clutch disc and pressure plate assemble were not enclosed in the flywheel, you could pull the flywheel housing dust cover and watch how everything is operating and see if the clutch disc is being completely released.

If you come to the point were you may need parts, please contact us at bob@marxpart.com or see our website www.marxparts.com . Hope this helps.
Regards Bob@marxparts

Thanks guys, very informative! Will put your advice to practice and update soon

Be sure to check to see if the carbon in the throw out bearing is still in place. Occasionally it fractures and falls apart. I have never had it happen but I know of a couple others that have.

Thanks Chip, will have a look

I've loosen the clutch adjustment screw with lock nut a and the clutch is now loose, the last picture shows how loose it is. When it is looser, it seems to get into gear easier.

Does the parts still look ok or am I missing something? Aren't I'm missing a clutch throw out carbon insert in the assembly?

Part "B" is turning slowly while the motor is running. Shouldn't this part stand still?

Am I missing this part? CLUTCH THROW OUT CARBON INSERT #835776 (Filling station)

Looks like you are missing the carbon insert. I suggest that you get a new one from the Filling Station.

I believe that part "B" in your picture is in fact the carbon insert, badly worn. It definitely should NOT turn with the engine running, it should be tightly clamped into the throwout bearing housing as shown in the photo that Bill posted. I'd say you need to replace the throwout bearing (and its carbon insert) with a new assembly. They are available from several vendors as mentioned above and also show up on ebay fairly often. Hope that helps.

All the Best, Chip

Thanks guys for the help.

If you are going to replace the throwout bearing, you should also inspect the clutch disk, flywheel surface, and pressure plate at that time.

An original 1931 throw out bearing has a split holder for the carbon insert. There is a bolt on one edge to tighten the carbon in the throwout assembly. It may just need to be tightened , or the carbon replaced in the original holder.

In the states by 1931 the throwout bearing had the carbon pressed in. Earlier versions, like on my '28s, had the bolt to secure the carbon in the holder.

Chipper ,
Both my 1931 parts book , and the 1931 engineering features book says that the carbon is clamped into the throw out trunion.
My 1929-1932 parts book show the superceded and new bearing.The new bearing assembly is also described in the 1932 engineering features book.

Never found a '31 with the clamped carbon. All were pressed in. Have taken apart several of them. Maybe I need to look into that further.

Checked parts books. Release of New Parts No. 137 for Independence Model Nov 15, 1930 and Master Parts Price List Feb 1, 1931 show the 835776 bearing which is the separate carbon to be installed in the clamp type housing. The May '31 Canadian Parts Book also shows that number. The Master Parts Price List Aug. 1, 1931 shows 836489 which is the pressed in carbon. Apparently between May 1931 (or the printing date for the parts book) and August the change was made in the parts system. Likely the production change was earlier than the parts system as it took time for part changes to filter through the system and enough of the old stock depleted so new stock necessary.

Chipper my 1931 parts book is November 1930 ,and is dedicated 1931 Independence models only. It is a General Motors (Australia)PTY LTD printed copy.(as you worked out earlier). But i have never found a part number which does not co-incide with the USA part number.
The throw out bearing collar (trunion) part number is 835775, and is the part number cast into one of the collars i have.
The carbon is 835776 as you have stated.

The carbon diameter is a larger diameter outside than the replacement bearing assembly which i have. , 2.575" compared to 2.375".

Hi Guys,

Got the new assembly, now ready to install.


Question:
1. See the red arrow on picture, what is this for. Is this an oiling port? If so it answers my second question.
2. Installation, must this cup (red arrow) be on top or at the bottom facing the road when installed. My gut feel says it must face up (to the the sky). Reason I ask is that my previous one faced the road.
3. If an oiling port, what oil should be used "if any"

Thanks again for your input

Awe

A light mineral oil can be used. 10W-30, ATF, MMO all will work. The oil can improve the lubricity of the carbon insert but is not 100% necessary. If the oil port is pointed up then it can be re-lubricated later if desired. A port on the '31 and later clutch housing made this possible.