!991 Jeep Wrangler clutch pedal loses pressure. I have to pump it to get enough pressure to shift. I keep it full of brake fluid. I can see no leaks. Thanks for any help.

Look to make sure your Hydraulic fluid level is full for the clutch. It is located near the brake master cylinder(see owners manual) . If it is low , fill it and pump the clutch pedal a few times and see if that takes care of it. If it doesn't then I would be looking at replacing the slave cylinder and master slave cylinder for the clutch. If it is completely empty and you fill it and pump it a few times, and its back to empty. Yes, you guessed it, look for a leak.

First place you need to look is at the clutch master cylinder on the firewall next to the brake MC. Ifg it's empty then re-fill it and s5tart to look for a leak. It is a sealed system exactly like your brake,therefore any fluid loss indicates a leak. Check on the firewall under the master, where the clutch pedal rod goes into the cylinder under the dashboard (inside the car). Check the line to the slave unit and the slave. It helps to have someone pump the clutch pedal to make any leak more obvious. If you find the leak, replace the part that is leaking. If it appears not to be leaking, replace the master as it can internally bypass and not build pressure.
Bleed valve is located on the slave. Bleed as you would a brake.
Some slave units are part of the throwout bearing...if so, to replace it, the transmission needs to be removed. but bleed valve should be on a line right near the pressure line going into the bellhousing.

The clutch on this vehicle is hydraulicly operated and usually what happens is either the system develops a small leak and loses fluid or the seals inside the master or slave cylinder fail and won't allow enough pressure to build up to release the clutch. Start by checking the clutch master cylinder reservoir fluid level [located under the hood on the drivers side of the firewall] to make sure it is full. It holds only a few ounces of fluid so even a tiny leak will quickly deplete it. You could also have a clutch disc or pressure plate that has failed or fallen apart which would also give you the same symptoms.

It is likely leaking at the slave cylinder

Sounds like you are having a clutch problem. The sudden looseness in the clutch pedal indicates a problem with either the hydralic system, (slave or master or line) leaking or clutch pressure plate going out. Check your clutch fluid resevoir first, if low look for a leak under the vehicle, have a friend push the clutch and get underneath to find leak.

Sound like your clutch master cylinder has developed a internal leak or maybe even leaking out the back past the seals. Have you checked the brake fluid level in the clutch master cylinder resorvoir it may be low and you have air in the system. Either way you have a leak somwhere in the system and you need to determine where it is. Fill your resorvoir with approved fluid and while some one is pumping your clutch pedal see if you can see where the fluid is leaking from the jeep. Reair or replace as necessary.
good Luck

Your clutch system works the same as brakes do. The necessity to bleed tells you that there is a malfunction permitting air into the system. Check where the pedal rod goes into the firewall under the dash, the line itself, and the slave unit (some are inside the bellhousing...look for fluid dripping from bottom to verify if leaking) Not unlike brake master, they can also internally bypass. If you find no leaks, change master. Bleed system and you should be fine

It's possible the master cylinder could be it, if it were the slave cylinder you'd be losing clutch fluid.. Are you losing the fluid too?

A special pump is used to back bleed the system. If you don't own one then you have to be patient and just keep pumping the clutch pedal until it comes back. It can take a half hour to get it back. Just depents on how much air is inside.

Likely, you have a hydraulic clutch system. Check clutch master cylijnder for fluid and leakage, check hydraulic line and slave cylinder for leaks. If fluid low or empty, bleed as you would a brake wheel cylinder. If full,have someone work the clutch while you watch slave cylinder to make sure it is moving clutch fork. If system full and little or no movement, the master may be "bypassing" internally (replace) Also, check pedal mechanical linkage. Not often but sometimes these parts can break! Could also be athat clutch itself is worn, but this does not happen overnight and you would have noted slip long before this!