Air Assist parts for clutch

Brian Diehl · March 23, 2007, 06:20:03 AM

Well, I had wanted to use a hydraulic system to actuate my clutch. However, I can't find any used truck parts and really haven't looked at what new parts would cost. Do any of you have your air assist parts left over from converting your manual over to automatic? I'm thinking I could us an air assist to make using my existing transmission shifter cable as a clutch cable workable. I.E. I'm thinking of using my existing automatic tranny shifter cable as the clutch actuator cable. Then, I would hookup an air assist on the transmission to reduce the actual load placed on the cable and make the leg work easier. Is this a workable idea?

Stan · March 23, 2007, 08:10:23 AM

Brian: It might be easier to operate the clutch release arm with a small air pot (16 to 24) and a foot control at the front.

TomC · March 23, 2007, 08:42:43 AM

Freightliner has gone to an excellent hydraulically operated clutch on their M2 line of medium duty trucks. I don't see why it wouldn't work for your application, so long as all air bubbles are blead out. Good Luck, TomC

NJT 5573 · March 23, 2007, 09:54:17 PM

I like Stan's idea, you could operate the clutch with a trailer flip switch by hand from the drivers seat. Air on air off.

NJT 5573 · March 23, 2007, 09:59:22 PM

I changed my mind. Can't see how to work the clutch brake. What are the odds it won't be destroyed anyway?

Brian Diehl · March 25, 2007, 07:48:33 AM

I think this would work in conjunction with my mechanical linkage as long as I setup the air pressure BELOW what is required to actually disengage the clutch. This way I retain control over how far and how quickly the clutch is released/engaged. I like this idea. .. will ruminate on it some. I already have the brake air control valve from the truck and I could get an air pot from Caylor supply ... like one off the tag axle of an MCI.

TomC · March 25, 2007, 09:42:44 AM

In the 80's UPS used 6 speed transmissions on their big rigs with air operated clutches. The clutch pedal looked exactly like the brake pedal. The advantage to this setup is that the pedal pressure is much lighter, but doesn't have the feel that a direct pedal linkage would have. Also, with the distance to the rear, would be a lag time, much the same that an air throttle has. So your timing would have to be anticipated. Good Luck, TomC

Stan · March 25, 2007, 12:26:01 PM

I put an air operated clutch on a MC-5, for reasons too long to go into here, and it was easier to shift than previously with a malfunctioning mechanical linkage. I didn't have room to mount the control in the clutch pedal position so I left the original clutch pedal in place and and used the arm coming off the pedal to push on the rod sitcking out the top of the brake control. I had about two inches of clutch pedal travel which I could operate with my heel on the floor and modulate it very smoothly. You can set the clutch arm travel by having the airpot at full travel when the clutch arm is at the fully disengaged position. Any overtravel in the other direction is just like the clutch pedal return spring pulling on the clutch release lever.