1995 gmc sierra clutch pressure problem

It takes a lot of bleeding, keep bleeding it off, make sure your hose clamps or nuts are tight, sometimes there's an o-ring where the hose is, check to see if yours has one, but you have to bleed the system thoroughly

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These and Blazers were notoriously hard to bleed the air out of the system. I actually had to make up a clutch reservoir cap with a nipple on the top so I could hook it up to a vacuum pump. With the system full, try to attach a vacuum pump (hand operated one works fine) over top of the reservoir, or if need be to the feed line to the master cylinder. Apply vacuum until you can see fluid, soon you should see bubbles in the line. Maintain constant vacuum until all air is gone the system should be fully functional after that.

You cannot bleed these clutch hydraulics. They are meant to be a pre-bled sealed unit that you buy. You should never replace just the slave or the master. Buy them both and replace them as one unit which is already bled from the factory. Otherwise you will experience what you are describing.

Make sure you install the slave cylinder (into the transmission hole) first and then the master cylinder (pedal side) next and do not hook up the pedal until everything is installed.

If you take the slave out with the pedal attached it will extend the rod and ruin the hydraulics rendering them useless.

If hydralic, it sound like you have air in the hydralic line. You need to bleed it off at the slave cylinder (gearbox end of the line)

If cable type, then you may need to reset the ratchet on the clutch pedal.

It is called a slave cylinder. Replace it and bleed the system.

From your comments, your clutch master is no longer
working. Check your clutch master, and replace all the
worn out parts. You can buy all of these in one pack,
specify Clutch Master Repair Kit for 1989 GMC Sierra.

It needs a clutch pressure plate force is to great do lining & reface flywheel then good to go for a longggggg time

With the hydraulic systems, there is no adjustment. So what pedal travel you have is likely normal for that vehicle.

either the clutch master cylinder went bad or the clutch slave went bad. look for dripping fluid

replace the intermediate unit , it controlls backflow and pressure, this should fix your prob