Ranger Clutch Fluid Change procedure?

Fountainhead

Hi All,
Open the Clutch Master Cylinder reservoir lid and have someone press the clutch in and out and you will see the fluid of the MC reservoir moving as you cycle the clutch. Think about it, where will the volume of fluid pushed into the CSC return to after actuation? The CSC rides against the Clutch fingers and CSC is normally depressed about 50% position. When the clutch pedal is pressed the CSC fully extends and presses the clutch fingers in about ~0.5 to 0.75 in. When the clutch pedal is pressed in and released, the CSC returns to 50% position. The volume of liquid used to increase the CSC position has nowhere else to go but back into the master cylinder. CSC fluid is constantly changing location from the CSC back to the Clutch master cylinder reservoir.

Brakes only travel a fraction of an inch to press the calipers and the volume of liquid moving is far far less, traveling 5x the distance of the Clutch fluid so there is really no noticeable change/fluid volume change in the brake reservoir.

So in short, the Clutch fluid does move around and is not trapped entirely in the CSC.
Brake fluid is trapped at the Caliper cylinder and cannot move back to the Brake master cylinder.

yes I still regularly change my clutch fluid and for 5 years have used DOT 3/4 Valvoline and so far no problems. It's clean as a whistle. I never let it get even slightly dirty.
I usually empty the master, fill it up, pump the pedal about 12 times then empty the master and fill it back up again. I suppose one day I'll bleed the CSC from the bottom but I will only do so to find out if it has foreign bodies *clutch dust* in the bottom. If the video guy had pumped the clutch about 12 times after the initial fluid removal/addition you would have seen the dirty fluid returning to the master reservoir after a few pumps. Honestly mine has never been dirty enough but to barely see the fluid is contaminated, so I doubt mine is dirty down at the CSC.
If it had been black and chunky I would have bled from the bottom. I may still bleed from bottom, and report back here but I expect to see clear fluid.

SINISTER

Thanks for commenting!

So your saying that the ranger protocol would essentially work if you were to do as instructed. Which is removing the old fluid from clutch master, adding new, pumping approximately 30 times the pedal, and repeating the pattern multiple times....??

I looked at the Hydraulic Layout of our cars (service manual) and sure enough it is Master cylinder, clutch hose, clutch tube, then CSC...no return line only a line coming off the CSC for the bleed valve. Unsure without a return line how new fluid could commingle with fluid way at the bottom and work its way back up....seems like adding new fluid in the clutch master and pumping the clutch would simply be putting pressure at the top downward and the top portion of fluid would be clean but near the bottom would stay dirty....

Fountainhead

You're welcome!

Well the fluid has no where to go after pedal release but back into the reservoir. Since fluid does not compress there is no "squeezing" the fluid, it's a solid under pressure. After releasing the pedal the fluid from the bellows/CSC cylinder must go somewhere and there is no room anywhere in the hydraulics *(hose, CSC) but in the reservoir. Just experiment and see for yourself.
It wouldn't hurt to bleed the system just for your peace of mind. Be careful to not release the clutch pedal until the valve/bleed screw is closed. And be gentle when pressing the pedal as there won't be any fluid/cylinder resistance to limit the pedal travel and you could damage the O-rings in the master cylinder. My fluid has always been crystal clear so I've never had to pump "30 times" usually only about 12. Just for my peace of mind, lol. Peace of mind is worth a LOT. Plus I'm a short shifter, non dragster, non launcher so my CSC will probably never get even slightly dirty.

Good Luck Sinister, and welcome to the forum!

nis350

1. when you release the clutch pedal, the csc would retract to its original position and pushing the fluid back to the same spot in the clutch line. The operation is quite simple, when you press on the clutch pedal, the cmc pushes the fluid downward to the csc, and you release the clutch pedal, the fluid goes back to the same spot on the clutch line. So the fluid just goes back and forth in the clutch line pretty much on the same spot as there is no way for it to circulate anywhere else.

2. during the bleeding process, you press the clutch pedal down first, then open the bleed valve. so there is pressure/resistance as normal. also, the cmc always does full stroke when you press down the clutch pedal, so there is no groove to damage the seals like an old brake master cylinder.

Fountainhead

How to account for the volume of fluid added inside the clutch SC required to push the SC bearing about .5 inches into the clutch fingers? The fluid amount required for that bearing SC travel isn't occupying the lines when the clutch is released. The clutch fingers press the bearing down .5 inches into the SC bellows when the clutch pedal is released. That additional fluid is introduced from the MC reservoir during pedal press. The hydraulic action of moving the SC bearing into the Clutch Fingers requires additional fluid on top of what was already in the lines. So there is a "cycling" of fluid from the MC into the lines, otherwise the pedal couldn't move outward into the clutch fingers unless the volume of liquid changed.
I get your point about the lines never changing volume but even if the fluid in the lines remains static, then MC ram uses fluid from the MC reservoir to move the bearing into the fingers.