If it seems like I write about hydraulics a lot, it is because I do! Hydraulic bearings, internal slave cylinders, and master cylinders seem to be the most taken tech calls and emails we receive. So here are a few more things you need to add to your knowledgebase.
SHIMMING THE BEARING WILL INCREASE TRAVEL OF MY BEARING
False! Whether it’s a factory slave cylinder or a RAM aftermarket hydraulic bearing, adding shims to your install because you are not getting adequate release will NOT solve your problem. We cannot stress this enough!
With factory slaves, the bearing works on the principle of preload as often described previously. If you have the proper preload for your application, and the hydraulic system is functioning properly, you will get adequate bearing travel. If you don’t have enough preload, you won’t get enough potential travel, so this is the only case where shimming could benefit. Otherwise, there is another problem in the system. Our factory slave cylinder installation videowill walk you though the procedure to check bearing preload.
With the RAM hydraulic release bearing, and most other aftermarket models, the bearing is set up
at a predetermined ‘gap’, leaving room for clutch wear over time. Now listen close – if you have the gap set correctly, shimming the bearing closer to the fingers will not increase the bearing travel. As soon as you cycle the clutch pedal, the bearing is only going to retract as far as the clutch fingers push it back. So, on the next stroke of the pedal, the bearing is pushing right from the finger starting position. Shimming will NOT change this, only leave less gap for wear over time in the clutch system. Our RAM hydraulic bearing installation video will help you get the setup gap correct to start.
IF THE SPECIFIED MASTER CYLINDER SIZE IS GOOD, THEN BIGGER MUST BE BETTER, RIGHT?
False! For RAM hydraulic bearing is the recommended master cylinder size is ¾” bore with a stroke length of 1.1” to 1.4”. This sizing provides travel in the bearing
ranging from .475” to .550”. We are often asked if a bigger master will provide more travel – the answer is yes, BUT, increasing the bore size of the master cylinder has another effect. As you go up in size, the pedal effort required to disengage the clutch becomes higher. Our specified size offers the best balance between travel length and pedal effort.
IF I CHANGE MY CLUTCH, I DON’T NEED TO RESET THE BEARING GAP/HEIGHT SINCE I ALREADY SET IT ONCE
False! Most clutch packages will have a variance in the setup height of the clutch, and this always needs to be rechecked and the shimming appropriately adjusted to the recommended .150-.200” gap. You might have your own hydraulics myths you have encountered. We would love to hear from you explaining your experience and how you dealt with it!
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