engine and drivetrain transmission diagnosis

[cliffwarren@yahoo.com]

Here is my scenario for a '75 four speed. When I push in the clutch pedal, sometimes the clutch doesn't release. At first, it's OK, it's tolerable, but as the car warms up for about five minutes, it becomes VERY difficult to shift. Lately, I've been needing to pull over, shut off the car, put it in gear and then use the starter to break the connection that the clutch has on the car.

If I'm stopped at a light, and take the car out of gear and let go of the clutch, there is a noise. Not a terrible noise, but it's there. Pushing the clutch in, the noise goes away (assuming that the clutch is actually moved).

I've reverse bled the system a couple of times. That seemed to go well, and I don't have any loss of fluid.

So, is this a throwout bearing?

If anyone does a full FAQ complete with pictures that shows the transmission removal and overhaul process, that would be much appreciated. I've never taken out a transmission before.

[JFT]

If I recall correctly, a throwout bearing would continue to howl when you depress the clutch pedal but would have no effect on shifting difficulties. I think that perhaps you have a clutch adjustment problem - among, perhaps, other things. I have to wonder how much slack the pedal movement has, when you depress it, before it begins to encounter resistance. Should be at least an inch and not a lot more than that, I should think.

[cliffwarren@yahoo.com]

Not too much slack in the pedal, I don't think. I'm going to be replacing the carpet eventually, so I cut it open down there at the pedal box. The box really seems to be in good shape. I think the car has only 108K miles total.

It seems to shift a little better if I take it really slow, pushing the pedal down. But then, it will do it's thing whenever it wants to, and not release that clutch.

I was thinking that the clutch master or slave could be bad, but I don't lose any fluid. I suppose I could replace/rebuild those parts first before digging deeper into the transmission, but I hate replacing parts when it isn't the problem.

What's the best overall shop manual for this car?

[Arshloch]

It is not the throwout bearing, hence there is no noise when you push the pedal in. Your tranny is a toast if you can hear it humming or making howling noises without touching the clutch. Layshaft and input shafts bearing failure are very common with these. A little bit of noise is OK.

The throwout bearing is rotating only when you actually working the clutch pedal, the rest of the time there is no load on it and it doesnt rotate.

The reason why you cant shift is either incomplete clutch disengagement-read master/slave cylinder or air in the system. In this case, you usually grind the reverse gear real hard, or shift with difficulty without losing completely drivability of the car.

The less likely thing is that your tranny has completely disintegrated, which you would have noticed by now.

I think you should go and look for a small break fluid leak somewhere (look inside the boot), which allows the air to enter. It might not even appear to leak, because that little amount of fluid collects inside the boot and seats there.

Bleed the system properly. It's quite easy-do the gravity bleeding first and get somebody to pump pedal just as if you were doing breaks. I pump myself and use a big breaker bar to wedge in between the seat and pedal to keep the pedal depresses while I crack the nipple open.

P.S. if your clutch master/slave appear too be old and the car has sat for awhile, get the new parts and do it, because it will leak eventually or take them apart and see if they have corrosion inside of them.

Rebuilding these things is futile because of all the rust pitting on these babies. The bore must be literally "flawless" in order to overhaul these components.

[cliffwarren@yahoo.com]

OK, yeah, the noise is really not noise. You hardly notice it. I should maybe start looking at the two cylinders and the hose between them.

Where is a good source for the hose that goes between the two? If I can replace all three parts for $150, it might be worth it to get it done.

[Arshloch]

ireland engineering for $30 (used to be $15). The one for the 5 spd swap, it's a braided peice which you bend in order to avoid rubbing (It's a bit too long, but I run it anyway with no problems, plus it fits the 5spd)

http://store.nexternal.com/shared/StoreFront/default.asp?CS=ireland&StoreType=BtoC&Count1=708919703&Count2=626060128

Or a local hydraulic supply shop- ask them to make it for you.

Find the problem first, then replace.

Does it grind when you try to shift in reverse?

[cliffwarren@yahoo.com]

>> Does it grind when you try to shift in reverse?

Most definitely, if the clutch isn't disengaged. Sometimes it's fine... then other times I basically loose all clutch disengagement. When that happens, all bets are off. Like I say, the first five minutes of operation are pretty good. Then it all goes downhill.

When this happens and it's severe, sometimes the only way to get it back in gear is to force it into reverse. It sounds TERRIBLE when I have to do that. If I have time to shut the car off, I prefer to do that of course.

[Arshloch]

Oh, I ve been there many a time.

Try my one man bleeding method first, takes 5 minutes to do. It should do the trick for a short time before the pedal goes limp again.

[c.d.iesel]

no ~ it's two areas only and not the T-O bearing.

your clutch hydraulics - need new master and slave cylinder-

seals are rotten and cylinder bores rusted

and your transmission input shaft splines -

full of dirt, clutch dust, oil, baked in grease,

remove the trans and give it some overdue

attention

and wouldn't hurt to change the transmission oil -

refill it with ATF for now on the outside chance that you have

little to no oil in there now, and the junk that's in

there is causing some of the difficulty - easiest

thing to try next.