The clutch master cylinder reservoir on my son's truck ran dry somehow. He's been driving it that way for a while not knowing that it was empty, and of course it's been very hard to shift.

We refilled the reservoir and tried to bleed the system for more than an hour. After opening the bleeder valve each time, the clutch pedal will not return--have to pull it up by hand. With the engine running, it refuses to go into any gear. Basically, there is no clutch whatsoever right now.

Since it ran dry, we thought that perhaps we had a problem with the master cylinder or slave cylinder. We replaced both and tried to bleed the system again. Same result as before.

At this point, I have no idea what to check next. Can anyone lend a hand?

To bleed the clutch m/c, use the hard line fitting on the m/c itself, since there is no separate bleeder there. To do so, crack that line open to let out trapped air and close like you would do with a real bleeder valve. Since that is the highest point in the system, you may have air trapped there that the bleeder down on the slave won't let out.

Thanks 4Crawler. No air is coming out the bleeder valve on the slave, so it makes sense that air could be trapped up top. We'll try this tonight.

If that doesnt work, bench bleed it by bending a spare line hooked up to the master into a loop back into the reservouir. Push the cylinder in slowly until all bubbles go away.

Fixed. Thanks for all the help. As it turns out, bleeding was not the issue at all. Unbeknowns to us, the backing plate for the brake and clutch pedal had broken due to flexing and stress cracks and had been repaired shoddily by the previous owner. Could not get a proper adjustment, hence no clutch.

The root cause of all of this was a mounting point for the backing plate above the clutch pedal. Age and metal fatigue had caused this mounting point to break, which in turn allowed the backing plate to flex excessively. This caused it to crack and break. Apparently it had been like this for a long time and the previous owner had tried to tack weld the broken backing plate.

I had to fabricate a bracket to replace the broken mounting point and get a replacement clutch/brake pedal assembly from a junkyard. Shifts better than it ever has now. Full clutch pedal and no gear grinding.

Fairly commom problem, especally on 3rd Gen pickups.

I use my vacuum pump (hand held) to bleed lines. Saves a lot of time and cussing. I just hook it up to the bleeded valve and start drawing a vacuum. I've even used it to bleed my fuel line.

Best $30 investment I ever made.

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I have never had to bleed my 89. My slave cyl leaked and it ran dry more than once, I just add fluid and it works fine.

I remember pulling that clutch bracket and welding it up when mine cracked. I wondered for a week why it was squeaking before it broke.