Clutch booster?
 

Checking and replacing all the fluids in my 84 with the 4+3, I have come acrossed a item I am not sure what it is and I cannot find anything in my manual that shows it. Next to the Master cylinder is another smaller component that looks similar to the master cylinder. It has one fill top that unscrews to add? something. I followed the line from it and it goes to the side of the transmission to whatI think is the clutch fork, cylinder of some kind. The fluid in it is almost non existent, just a small amount on the bottom of the reservoir. I assume that thatit is not good. Any ideas as to what it does, type of fluid, andany proceedureI need to take to fill it, bleed, etc.?

RE: Clutch booster?
 

You have a hydraulic operated clutch, works on the same principal as the brakes. The single small resevoir is for the master cylinder for the clutch, not having serviced C4's I dont know the recommended fluid, check the owners guide.

RE: Clutch booster?
 

That's your clutch master cylinder.There's a bleed screw on the slave cylinder,open it and have someone keep filling the resevoir-it should bleed itself.Correct fluid is GM12345347

RE: Clutch booster?
 

The clutch slave cylinder uses DOT 3 brake fluid. It bleeds just like brakes, open bleeder, one stroke of pedal down, close bleeder, pull pedal up. Repeat process until you have pedal. [8D]

RE: Clutch booster?
 

Thanks all. Got her handled now.