Clutch problem..

[pat julian]

Back AGAIN this week with yet another issue on my '93 2.5 manual Ranger..having a problem the clutch..I have diagnosed it I think with one of two issues..Clutch all the way depressed..let off the brake..and the truck starts to creep forward...and is hard to shift. I believe either I have air in the hydraulic system..or the pilot bearing is sticking...At times I have to stop the engine to put it in first gear..then restart..I can shift well enough to drive it by double clutching a lot...trans never grinds going into gear..other than reverse at bit ,and the clutch does not slip at all....It shifts better sometimes than at others..pedal release is just a fraction off the floorboard and feels soft first thing in the morning..but does get firmer as the day goes on....274,000 on the clock..any thought ??? thanks...pj

 

[enjr44]

Well, I assume you have checked for leaks and there is fluid in the clutch master. Without leaks I do not understand how air got in the system. Air in (unless you have been working on the system) means a leak someplace. Either the slave, the line or the master. Guess you could bleed the system; but, I believe it would only be a short term fix.

 

[Mark_88]

The clutch fluid is actually brake fluid, of course, and can get moisture saturated over time. If you've never replaced the fluids or bled the clutch system then it might help. The wear of the clutch would typically result in a higher release closer to the full pedal travel outward rather than inward.

When the clutch releases closer to the floor than usual it may be a sign of the floor flexing or the bracket holding the master is broken...you may need to take a good look at the structural components before doing any physical work on the clutch...

So I would suggest inspecting the flooring and master bracket...then try bleeding the clutch.

My 1988 firewall was so badly rusted that the master popped right out and I noticed it was engaging closer to the floor...managed to patch that with a wrench head (open end) bolted to the floor so the master could push against that instead of pushing through...but I ended up replacing the cab a year later...and the master was still holding strong...

 

[pat julian]

Thanks for the replies..there is no apparent leak I can see..still full I check all fluids several times per week as I drive 300 miles per day..I don't see any indication of rust in the floors either..but will look under the dashboard for a possible pedal problem..I've added some fluid several months ago to the resovoir..but just a spoonful...Never bled the system since I've had it..two years this month..the truck sat for seven years before I bought it..could the fluid just be old and have moisture in it ?? It's never shifted as smoothly as a Japanese truck...kind clunky...but never hard to get into gear as is the case now...Thanks again for the help

 

[pat julian]

There doesn't seem to be any problem with pedals or brackets under the dash..as I mentioned..at times it shift as it should usually after I've driven for a few miles..but at times stays hard to shift all day...that makes me think it may be the pilot bearing sticking..only way to know is pull the tranny...and at that point might as well do a clutch job..which I have planned for April...but hoping to bleed and see if that helps for the time being.....

 

[tomw]

You have not indicated the locale where you are having the problem. As noted, brake fluid will absorb water. You might have a system that has so much water that it is starting to freeze, and thus is difficult to pump through the tube, move the slave piston, etc.
Draining or bleeding and effectively draining and replacing the fluid might not be a bad idea.
If the clutch bearing was sticking, the master could not be pushed down, and the slave would not extend and press on the bearing surface, and thus press on the pressure plate fingers. It could stick in the 'extended' position, but you'd get slippage, likely. If it were to stick in the retracted position, you would not get the pedal to go down as the fluid is incompressible, for all intents and purposes.
If you had air, for whatever reason, in the system, the air would compress until the pressure in the system matched the pressure required to move the throwout bearing, at which time it would start to move.
tom

 

[enjr44]

Water is not causing the problem. It does not compress any more than brake fluid. You could use straight water in the system except for freezing and rust. A dragging clutch is from loss of slave moving the clutch plate fingers in far enough to disengage the friction disk. Or the fingers not moving the plate.

Internally leaking master, internally/externally leaking slave, no/low fluid and air in system are the common causes.

Less likely is, like stated above, the pedal quit pushing the rod far enough into the master for some reason or the clutch plate is failing to disengage due to mechanical failure .

 

[msubully82]

I had a clutch job done a couple of years ago. Symptom was the clutch would not release fully - hard to shift. I think air got into the system due to a leaking slave cylinder. I also had the replacement cylinder leak and it was replaced under warranty. You cannot see the leak because the slave is inside the bell housing. The transmission shop dogged Ford because the system is so hard to bleed (I think) due to the master cylinder being tilted. The guy went on an on about that.

 

[zekew64]

For what it's worth:

Brake fluid can and will absorb water. This can be confirmed through simple observation, and then checked with a DVOM.

Think about it: If vaporization can happen in brakes, where it appears you have plenty of fluid but the brake pedal is low, then because the same fluid is also used in clutches, water can be absorbed by condensation in the metal components heating up and cooling down. When this happens, the fluid starts becoming acidic and eating the various rubber components, such as seals and o-rings.

Don't believe me? Look at your fluid and see how dark it is. The darker the fluid (blacker it is), the more likely some rubber has been eaten away. Also, take a DVOM, set it tenths of a volt DC (0.1 v). Take one probe, submerge it in the fluid, place the other probe against the cylinder body. You get a reading of 0.3 volts or higher, time to do an inspection and especially do a fluid change. Why does the DVOM confirm a fluid change? Water itself conducts electricity, and when added to brake fluid, converts the fluid to a low electrolyte due to the acidity of the fluid (pH).

Understand it now?

Literally, I have seen chunks of rubber in a reservoir after the fluid has been sucked out. This was after doing a brake job where the fluid in the lines had to be changed because the brakes would not hold pressure and the fluid was blacker than a raven during a new moon.

 

[zekew64]

Also, the reason you have a low pedal in the morning and as time goes on, it stiffens, is because there is air in the system. The firmer pedal is the result of air in the system compressing because the brake fluid in the system expanding due to heat.