Ford cmp clutch question
 

Hello
A question about my ford Fat clutch, I install my just restored engine and my gearbox in my truck, clutch works great, pedal is smooth, but the lever on the gearbox twist a bit when i press the pedal.
Is that common or are my clutch springs too hard?
I would be bad if that lever would brake... :mad:

Thank you
Cheers
Sylvain

Clutch release shaft wear
 

Hello Harle,

Your problem could be wear in the clutch release shaft and their bushings.

The shaft can wear appreciably as shown in the attached photos along with their bushings allowing the shaft to twist in the transmission housing. Note the very noticeable ridges at the the bushing areas.
Years of civilian owner neglect is the probable cause if not lubricated regularly.

I replaced mine with NOS items but they should be available from Ford Flathead V8 suppliers.

Hope this helps.

Cheers

hello Jacques

Thank you for your interess, It's not easy to explain in english, That's not the schaft that twist, but the end of the arm.

I removed the shaft when I rebuilt the gearbox it looks great and was greased.

Cheers
Sylvain

Clutch release shaft arm twist
 

Hello Harle,

Sorry I misunderstood. Wish I had learnt another language, French, when I was in school but you do very well with English. My French first name is just my Father's admiration of Jacques Cousteau when I was born but I know no French.

Your clutch lever on gearbox twisting seems unusual. Is it actually twisting the lever, or is it just moving on the end of the shaft?
I have looked at mine and noticed there is some sloppiness with the lever on the shaft end. It can wobble (twist) slightly.
If the actual metal of the lever is twisting that indicates a very high stress on the arm and seems like something is very wrong. Eventually it will break from metal fatigue. Sorry I cannot give you a definite answer.

Hope this is of some help.

Cheers,

Video?
 

Hi Hair

Any chance of a video? Would sure help understand the problem.

Cheers Phil

hello
Jacques and phil
Here is a video , tell me what you think about?


https://youtu.be/L-vZvRLSK5Y


Jacques, Comandant Cousteau was a great man and a pioneer in see exploration,I watch al his videos when I was a child.
Do you also wear a red wool cap? :D :D

Cheers
Sylvain

Looks more like the pull rod is flexing, should it have a bend in it? They work better if they are straight.

Something is out of line
 

Hi Harlé

The video sure helps explaining the problem, it does look like something is out of line. Not having Ford it will take look at the manual which I did when I looked at the manual found that clutch assembly is not unlike the whole setup in my 49 Lincoln which basically has a Ford Truck engine.

It does in deed look like something is bent, worn or out of line.

Attachment 98808

Check my logic guys

7508 Bushing on both sides, as the load is all forward on drivers side and mostly backwards on the passenger side would tend to wear on one side.

7510 Shaft with even the slightest bend would make the lever arm 7511 look like it was bending as rotation. This shaft could be bent if the linkage 7531 up to the clutch peddle was allowed to over travel. Is it just a trick of the photo that your linkage looks like it has been welded?

You guys with the Fords will have to step in on clutch adjustment how you set it up so that it disengages near the top of the stroke yet the peddle hits the floor/stop before you are trying to over rotate the fork shaft causing it to bend.

If all of those parts are OK then check the pins 352581-S are they worn or have the worn the shaft holes to allow play.

Keep us posted on your progress.

Cheers Phil

Clutch release shaft arm twist
 

Hello Harle,

I looked at the video, good suggestion Phil and as Richard pointed out the pull rod seems to have an excessive bend in the middle which is causing it to flex when under load.

I looked and the one on my truck and the spare one in the attached photo and they are mostly straight except at the clevis ends where they are slightly bent.
I assume this is to allow for the two levers not operating in direct line with each other.

Also Harle, yes, the red wool hat was his trademark, but I haven't started wearing one just yet. Maybe as my hair gets thinner I too will don a red woolen hat. I then might get more done in my cold garage in winter too.

Cheers,

My poor eyes....
 

...maybe it's my eyes but do I see a flat metal strip added to the rod..... in the end nearest the pedal........ as if there was a bending problems before and some one tried to reinforce the rod by welding a strapping.....which is now doing the S wiggle.

I suspect that once the rod is bent it would be difficult to ever get it perfectly straight again as the weak area would always remain.

The amazing part of all this is a video is being used to diagnose a mechanical problem thousands of miles from the source.

Bonne chance Harle

Hello Bob,

I certainly agree. This is one of the good things about the internet despite the recent Facebook controversy. People from three different nations using it to help out a person from a fourth nation.

For me, this video sure beats watching a cat playing the piano on You Tube!

Cheers,

Hello
Problem solved!!! :thup2: :thup2: :thup2:

thank you all for this Help :D I was afraid to change my Clutch ,It is a bren new french one but I was not sure that it was exact the same .

The rod was completly damaged , it looks original angled , but was not...



Your picture was very usefull Jacques!


Youre right Internet has his good thinks,
I could never restaure this truck without world wilde help pictures and plans.
I find that is what is also interesting with CMP trucks, some trucks where left worldwilde!

Merci encore
Thank you again
Sylvain

Now that's interesting....that Clutch control rod looks almost identical to the hand brake rods used on the Chevrolet C8. Jacques, Sylvain, can I ask what lenght the rod is? And the diameter of the rod itself?......around 8mm?

regards,
Alex

Ford CMP clutch control rod
 

Hi Alex,

The rod is 490mm long from the center of the clevis pin at the clutch end to the end of rod at the threaded end. Yes, it is 8mm diameter too.

Hope this helps. Perhaps another off the shelf part used by both manufacturers?

Cheers,

Jacques, Thanks. I think that might be slightly shorter overall when compared to the C8 brake rods, but overall they look identical.

Yes, could well be. I wonder if it's used as a civvy part as well, but I haven't found it at Macs yet.

Alex

Try your local tractor dealer
 

Hi

I've found these threaded clevis ends at the local tractor dealer, the older the better. Don't remember the thread count 1/4 X 24 sticks in my head. Easy to make up what ever length you need two clevis ends, two lock nuts, and length of shaft.

Cheers Phil

Standard should be......
 

1/4. ...... 20 tpi........Or. 1/4 ....28 tpi for the fine thread

I also believe that a tube would be stronger than a solid rod.

Cheers

Based on the 8mm given by others above, I believe the rod and yokes are threaded 5/16-24 (fine thread).

Clutch release rod threads
 

Hi Grant,

Just checked my rod. That is correct. Threads are 5/16-24 UNF

Cheers,

Hi Phil. I intend to do so. I have got the rods and the clevis ends which are available at Macs and also the Chev parts suppliers. So, I have the parts to make something that works........however, the original is a rod with clevis as one part....and a seperate nut and clevis at the other end. The clevis that is part of the rod is shorter than the seperate clevis at the other end. So, i was interested to see if the rod-clevis part was an off-the shelve item available at one of the parts suppliers......just to get that bit more originality that the Pebble beach judges love....

Alex