Rule of thumb on proper adjustment of clutch

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Model T Ford Forum: Forum 2010: Rule of thumb on proper adjustment of clutch
Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick - (2) '26's - Bartow, FL on Wednesday, December 15, 2010 - 10:15 am:

I'm still having trouble with the outside adjustment of the clutch pedal on my '26. I believe when it would not go into high before, it was because the teeth on the forward portion of the emergency brake quadrant were stripped flat and the pawl worked its way back, preventing the clutch from going into high gear, because when I let the pedal off, it wouldn't go into high until I pushed the lever forward all the way, therefore, when I loosened the clutch adjustment, I believe I loosened it too much because I have to step on clutch really hard for it to go into low.

I have wooden bands that were slid on at the time of the rebuild so they are not distorted. What is a good rule of thumb when adjusting the clutch so that there is a good balance between low and high? Is there a basic length the outside adjustment lug should be between the hogshead and the end of the threaded adjustment lug? or is there a basic space that one should shoot for between the front of the clutch pedal (when pressed down so that it is engaged) and the back of the floorboard hole?

I will be getting a new emergency brake quadrant so the pawl, which is in good condition, will stay put and won't work its' way back so as to be in the way of the high gear engagement.

Thank you.

Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank Harris Big Bear Lake, California on Wednesday, December 15, 2010 - 11:14 am:

In many instances, you can re-shape the teeth with a file. The old metalon the originals is harder than the new ones. You can replace the latching pawl and rivet though sometimes you can reshape an original hard one. Those are soft too. The best way to use the handle is to pull the release and then move the handle. I replaced my ratchet and pawl with new ones and an inspector at a Speedster Contest pulled it back without releasing the lever and he rounded all of the teeth off with one pull so that it would not latch. They didn't want me to run for safety reasons and I made an emergency hook out of wire to hold the brake lever to the seat belt until I could re-file the teeth.

You can see that the teeth are not all even in the picture down below, but they catch the latch.




ratchet


Top of pagePrevious messageNext messageBottom of page Link to this message  By George...Cherry Hill, NJ on Wednesday, December 15, 2010 - 11:18 am:

Jim,

The dimension you are asking depends on the condition and location of the cam slides on the pedal shaft. You only really use the front side of the slides to 'engage' and sometimes these are worn and wallowed. A wallow has a hit on a floorboad no matter what else you adjust as the pedal just can't get there before running into interference. Some find this wear and try to replace what can be replaced, others simply realize it is the forward side that does the work and then push it all forward and bend the pedal back to get clearance to the floorboard/plate.

Setting up all else from there requires a little thinking. Sure, there are recommendations etc. as to dimensions, but I'm personally not so sure setting to dimensions is good enough. Have to think through what is being required.

Stick at about 12 o'clock should have engaged the shaft lever, but still kept the drum brakes from coming on. Slightly forward of 12 o'clock come off the lever and now it is total foot control.

From 12 back, you want to be on that clutch lever and at the same time bring the drum brakes in 'full' At the point your brakes are fully engaged and you are still in 'neutral' as far as the tranny is concerned, the stick does not need to be full bsck tight, just have good teeth on the quadrant at the point you sense 'full'!

Now...the nasty is that little L shaped threaded rod and its clearance in the clevice on the side of the tranny...with luck it will be all right...if you have my luck it will want to 'knuckle' at the sweet spot you just went and found, and thats bad, you can not allow it to knuckle under any conditions!

So if you are unlucky, then it is a sort it from there...I then usually try to set that rod/clevis for the 'as stated' dimension for clearance and keeping it from knuckling, and then play with all the other again keeping in mind desired function, until it all works in concert again.

Others may have a better or easier way...but thats one guys opinion and the way that I have 'thought' through any brake drum cam changes, or clutch changes, after the fact.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick - (2) '26's - Bartow, FL on Wednesday, December 15, 2010 - 11:36 am:

Thank you, George. What do you mean by knucking?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick - (2) '26's - Bartow, FL on Wednesday, December 15, 2010 - 11:37 am:

Sorry. Forgot the L. Knuckling.


Top of pagePrevious messageNext messageBottom of page Link to this message  By scott conger on Wednesday, December 15, 2010 - 01:02 pm:

I'm betting he means going over center and then locking up in low.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Wednesday, December 15, 2010 - 01:21 pm:

I have found that if the rear brake rods are adjusted too long, it will force the handle back while you are in neutral or low. Then it will not go in high until you push the handle forward. You will notice the ratchet is built in such a way that it will move backward easy, but will not move forward unless you release the grip. Try shortening the rods to the point that the clevis pins just go in without any forcing when the lever is all the way forward.

The low band should bottom out when the pedal is between 1" and 1 1/2" above the floorboard. It should not be higher than that, but tight enough that it won't slip at all when you are in low.

For adjustment of the link, see diagram attached.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank Harris Big Bear Lake, California on Wednesday, December 15, 2010 - 01:30 pm:

Rule of thumb. Remember that the rule of thumb in olden days was that it was alright to beat your wife with a stick, but that the stick could be no thicker than your thumb. Many men exercised their thumbs to increase their thumb size. Beatings usually continued until moral improved.

This note was posted for historical purposes and not for thumb measurements


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erich Bruckner, Vancouver, WA on Wednesday, December 15, 2010 - 01:33 pm:

Norm, I have always been a bit perplesed by this illustration. It looks like the yoke is shown in relation to the arm without the pin in place. Is that true? If so, I have been doing it wrong.......sd I never understood exactly where that 1/16 inch play was supposed to be.


Top of pagePrevious messageNext messageBottom of page Link to this message  By George...Cherry Hill, NJ on Wednesday, December 15, 2010 - 01:45 pm:

Jim,

sorry, knuckling is going over center and when that happens it doesn't come back of its own...can be scary!


Top of pagePrevious messageNext messageBottom of page Link to this message  By George...Cherry Hill, NJ on Wednesday, December 15, 2010 - 01:50 pm:

Norm,

Said it much better than I can or tried to say.

I do drop the brake clevises off when doing what Jim is trying to do, and then when all else 'works', I then bring back in the brake rods to match whatever position I moved the rest of the mechanisms to, treating the brake adjustment at the clevis on its own.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John A Kuehn on Wednesday, December 15, 2010 - 03:41 pm:

Norm, Thanks again fo the "close up view" of the illustration on the clutch adjustment.
It helps to illustratate this adjustment much better than the Ford service manual does.
The pic of this in the manual is so small you cant see the 1/16 yoke play. I have 2 of these manuals and you cant clearly see the pic detail in either one.
I have 2 model T's and I have the clutchs in both adjusted going by this illustration. My cars are just a little different from each other but are adjusted so to have a good neutral and good clutch action.
I have a feeling not all 'Ts' will adjust out exactly the same due to differences in wear and parts tolerances. My opinion of course but the standard diagram is a must to start with.
It really helps since it is a good close up shot of what its supposed to be.
Thanks a bunch


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis - Lyons, GA on Wednesday, December 15, 2010 - 04:21 pm:

Erich,

What it is basically saying is that with the pedal pulled all the way to the rear, the clevis should lack about 1/16" lining up with the clutch bell crank. In other words, you will have to push the pedal down some before the pin will go in.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Wednesday, December 15, 2010 - 04:33 pm:

What Hal said is correct. The spring inside the clutch should completely seat. That play will assure that it is seated. However, if the hole in the pedal is worn, or the rod is worn where it goes into the pedal, you need to compensate for that by lengthening the rod enough so that 1/16" play occurs when the rod is all the way pushed toward the pedal. Sometimes if the wear is excessive, you will need to fill and re-drill the hole, and either fill and grind the rod or replace the rod.
Norm


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