Clutch trouble, 20R truck

[Mr Tode]

Hi all,

I have a '78 20R truck with a five-speed. I've been struggling with this clutch issue for months, so I thought I'd run it by you guys. A few months back, I was sitting in traffic, in first gear, with the clutch in, and felt the truck start to creep. If I revved up the motor, I could feel the clutch grabbing even though I had the pedal down. No problem—I thought—the clutch hydraulics were ancient, and the symptoms pointed toward a loss of hydraulic pressure. So I replaced the master and slave, and guess what—I'm still experiencing the problem. I figured that I hadn't bled all the air out, so I bled it another 3 or 4 times to no avail. There just ain't no bubbles coming out of there. I'm not losing fluid, either. Since I've been dealing with this problem for a while, I have a couple of general observations, also:

1. As long as I'm moving, and don't get stuck in heavy traffic, the clutch is fine. Once I get into a stop-and-go situation, it starts to act up. Specifically, it's difficult to get the truck back into gear from neutral. Occasionally, if I'm already in gear with the clutch in, I can feel the truck tugging forward.

2. The problem seems to crop up most often when I try to go from reverse to first, like when I'm parallel parking. It'll go into reverse just fine (most of the time), but when I try to shift back into first (or any of the other forward gears), it doesn't want to go in, as if the clutch isn't letting go. Going back to reverse at this point results in grinding.

A bit of other general crap:

1. The clutch itself is pretty new, less than a year old. But could this be an internal hardware problem with the clutch itself?

2. The only piece of the hydraulic puzzle I haven't replaced is the line from the master to the slave, which does include a short length of flex hose. The flex hose looks OK, and I've hesitated to replace it since it's a special-order part and I'm not even sure that it's a potential culprit. But could it be the source of the trouble?

3. I'm pretty sure I've got the clutch adjusted right—again, the clutch works fine unless I get stuck in traffic or that parking situation. If anything, the clutch "grab" point is toward the top of the pedal travel. But maybe my adjustment is way off.

I've been to hell and back with this truck, and I hate to be bogged down in what seems like a simple problem. But it's got me stumped.

Anything you've got will be of help....

[87_SR5]

I think it may be a internal problem...something with the pressure plate. It seems like you got the hydraulics figured out to determine its not the problem. This started to happen to me (and it didn't seem like the clutch was going bad....like slipping)...If I would some to a complete stop with it in neutral (clutch in)...I could not get it back into first, or any other gear. I would have to grind it in reverse and then go quick into first. So I learned to get it into gear before I stopped rolling or else I would have troubles.

Also, if you are sitting in the truck with it in neutral (clutch out), you should be able to put the clutch in and then be able to get it into reverse without any grinding (within several seconds). When I was having this problem, I would do this and reverse would never stop grinding.

I don't know... someone else will have a better explanation for you....

[azdave35]

hydraulic clutches are very difficult to bleed....next time it acts up on you....try pumping the clutch pedal a few times before you put it in gear....if this makes your problem go away..then you know it is a hydraulic problem

[qsd-dan]

If all else fails, try replacing the rubber and nylon shifter seat bushings. These little buggers will cause sloppyness, stiff and hard shifting, and even grinding into certain gears. If they have never been replaced, I can guarrentee you that the rubber bushing is toast. The nylon may be fine though. Worth a try and the parts are pretty cheap from the dealer. Here is the write-up on it.

http://www.off-road.com/toyota/tech/shifter/