A common tech question I receive focuses on adjusting the mechanical linkage on a clutch system. Many folks have a problem getting ‘enough’ adjustment or are having hard pedal and release issues. Fortunately, there are a few things you can try to get things working properly again.
If you are having trouble getting enough travel to disengage the clutch and your clutch rod is maxed out, disconnect the rod and manually pull the fork up until the release bearing is just touching the clutch fingers. At that point, your fork should have a forward angle in the bellhousing window (driver’s side pivoting forks) or a rearward angle (passenger side pivoting forks).
If your fork is sitting in the middle or opposite of the optimum angle listed above, you could easily have a leverage or travel issue.
So what exactly causes an adjustment problem?
It could be that your pivot ball or bellhousing has been changed at some point. Maybe your car had a different style diaphragm or previously used a lever style clutch and the finger height is different on the new one. Some GM applications in the mid to late ’60s, such as the Corvette, used a long release bearing from the factory in conjunction with a ‘flat’ fingered diaphragm. Now, the clutch you are replacing it with has a high cone and comes with a short-release bearing.
Your solution is to either change the pivot ball out for a longer one or use a longer release bearing which will correct the fork angle and kick it back into a higher leverage position. Usually, this also addresses the insufficient rod adjustment length. If you are using a scattershield, the best method is to use an adjustable pivot ball.
RAM offers release bearings in short, medium, and long lengths to help you correct these fork angles.
Another common question is, ‘how much freeplay should I adjust for’? The most important thing to know is that freeplay at the pedal is NOT the same as freeplay at the fork. When checking for bearing clearance you need to be checking it at the fork. We usually recommend a minimum of ¼” bearing clearance between the bearing and the fingers. Remember that as your clutch wears, the fingers get taller, or closer to the bearing. It is better to adjust for maximum free play (or, minimum release), so you are only traveling the fingers of the clutch as much as needed for full disengagement.
Getting your fork angled correctly and the bearing adjusted properly will allow you to experience much easier pedal effort and require less travel to achieve full disengagement of the clutch system, making your drive much more enjoyable!
Have more equations about proper adjustments? Send us a message through our e-tech form!