1959 Clutch Linkage
Hello, I am helping a friend restore a 1959 that he would like to have judged in the near future. Attempting to restore the clutch linkage to stock configuration, I replaced the missing over center (Gorilla) spring, hairpin clip, and bracket and link. I have attempted to adjust the bracket and clutch several times and cannot get the pedal to not stick in the down position. I have viewed all the posts on this site and have not seen a cure other than replacing the clutch pressure plate with a higher-pressure unit or modifying the current spring mount. The clutch operates properly without the assist spring assembly. With the over spring assembly installed, the pedal pressure is greatly reduced, however the pedal sticks to the floor. Does anyone have a solution for this issue that does not require clutch replacement or linkage modification? What would be the deducted points if we have to leave it in the current configuration without the spring? Thank you in advance for any and all suggestions. By the way, my friends name is Edward Sellers and he recently became an member of our "Great" club. Thanks again, John
-
-
Re: 1959 Clutch Linkage
Does the car have a diaphragm pressure plate installed? That is typically the reason for this to happen, changing from a 3 finger pressure plate to a diaphragm pressure plate.
Check the ST-12 service manual very carefully. There is a few sentences in the clutch section that covers an over center adjustment. This adjustment will correct the problem.
This adjustment is very sensitive, a slight adjustment can make a difference, so keep trying until you get the correct position to solve the issue. -
Re: 1959 Clutch Linkage
Agree with Dennis. The Pivot adjustment is very sensitive. Typically if the spring is at top center, with NO tension, the pedal won't return. Very typical when using the diaphragm bent finger type clutch, when the bent fingers over-travel beyond flat.
Additionally, variations in geometries of the cross shaft, levers, and fork and frame brackets can sometimes add to the problem.
I've had to do this on a few cars over the years. Sometimes the slotted hole in the Pivot needs to be opened up to allow more travel, to get the spring tension increased or decreased slightly to return the pedal. It's thick steel so a air grinder with a carbide bit works best, or use a coarse round file. Sometimes it doesn't need much to make the pedal return.
Here are a few images with notes explaining the process.... Rich
ClutchPivotMod2.jpg
ClutchPivotMod.jpgComment
-
Re: 1959 Clutch Linkage
Hello Dennis and Richard, thank you so much for your input. I have already attempted to adjust the arm in several positions. As illustrated above, I am going to modify the arm and attempt to adjust. The clutch is a diaphragm style, however, is fairly new. Again thanks, JohnComment
-
Re: 1959 Clutch Linkage
John, also check if throw out bearing is installed correctly on clutch fork..EdComment
-
Re: 1959 Clutch Linkage
I agree with everything Rich said, and he posted great pictures to help guide you.
Be patient, go very slow and remove a little material at a time, then try it on the car. I have seen where 3 strokes of a file made the difference and all was well.
Make sure you have the correct amount of free play on the clutch pedal. The adjusts for the clutch in the ST-12 may seem like unnecessary steps, but when followed result in a perfect adjustment - follow the procedure in the ST-12 for clutch adjustment.Comment
-
Re: 1959 Clutch Linkage
Hello E.J. and Dennis, Thank you both very much for your input. All suggestions are greatly appreciated. I will be working on the car the week after next and will post findings and hopefully the solution. Thanks again, JohnComment
Comment