Clutch Fail

[Farang]

86 Toyota Pickup
22R Engine

Problem is I can't shift gears.

Ok I've got it down to one question which will help me decide what to do next: When starting in first gear with the clutch pedal down, could the car move forward if the hydraulics were functioning properly? This symptom is what is making me not replace the clutch right away because from what I can tell, even if the disc is worn it should still be disengaged and therefore not move forward when I have the pedal down. At the same time the amount of travel on the slave cylinder push rod/clutch release fork looks sufficient but I am having trouble finding specifications.

 

[boomerang]

I have a hard time following your post, but here's what I've learned from it.

Your truck is 23 years old.

Your brother doesn't understand hydraulics.

You should have replaced everything that needed replacing last time a clutch was put in it. If it needed a new pressure plate, it should have been replaced.

I don't know if it makes a difference but the clutch will engage if the engine is off, I can put it into gears. If I try to start with the clutch engaged in first and the clutch pedal depressed, the car won't start

A clutch is engaged when your foot is off the pedal. Conversely, it's disengaged when your foot has the pedal depressed. You may want to redo the post keeping this in mind, because for now, I'm not sure when you're mixing up these two terms.

 

[Zenmervolt]

Originally posted by: Farang
Could air bubbles cause a sudden clutch failure with no symptoms from the pedal?

No.

Originally posted by: Farang
Right now my only theory is from my brother who says that me having refilled the clutch fluid when I tightened the slave cylinder a both ago may have increased pressure on the system and burst some springs in the clutch, springs which he saw were busted when he last replaced it 60,000 miles ago (at 100k). It seems to much of a coincidence to me that the clutch fails just a month after I messed with the hydraulics, but this theory reconciles that.

Your brother is an idiot. Never let him touch your car to make any repairs again.

The springs in the clutch center are not part of the hydraulics in any way whatsoever. On top of that, it is IMPOSSIBLE to increase hydraulic pressure by over-filling the reservoir. In addition to both of those, if something burst in the hydraulics from overpressure, the clutch pedal would either fall to the floor and not return or it would have almost no resistance when you pushed the pedal down.

The springs in the clutch center break when the driver is too abrupt with the clutch (e.g. he lets off on the clutch pedal too fast), causing the vehicle to jerk with each shift. This puts a load on those springs and can snap them if this type of abusive shifting is continued for a long period.

Originally posted by: Farang
Does it seem like the problem is in the clutch itself and would it be worth it to replace it, or is there anything I'm leaving undone to the hydraulic lines? I'd rather exhaust all of my options there before taking out the transmission.

edit: I don't know if it makes a difference but the clutch will engage if the engine is off, I can put it into gears. If I try to start with the clutch engaged in first and the clutch pedal depressed, the car won't start.

Often, you can shift gears without pushing the clutch in at all when the car is off. The only way to see if the clutch is actually disengaging is to check through the inspection hole (if your bellhousing has one) and verify that the slave cylinder's piston has an appropriate amount of travel when the pedal is depressed.

The most likely issue here is that the slave cylinder is loose again and is not pushing against the release fork properly. Have a trained mechanic take care of the repair.

ZV

 

[thedarkwolf]

Could have killed the master cylinder after replacing the slave. I had the happen in my miata. Replaced the slave and the master died. Replaced the master and the rubber section of hose burst, I got really good at shifting with no clutch.

Should start in first with the clutch depressed whether the clutch is working or not. Your car will just start moving while it starts. Its how you take off with a dead hydraulic clutch system.

 

[Farang]

Slave cylinder is not loose. The amount of travel is something I have questioned and will look into, although from dealing with the slave cylinder both when it was loose and not I don't think this is the problem (when it was loose the amount of travel was tiny and the clutch still worked, until it got to a miniscule distance and then the clutch finally stopped working).

Also please refrain from namecalling if you're nice enough to give me advice, that is uncalled for.

 

[Farang]

So from what I can tell if it was the clutch that was broken, I should be able to start the car in first gear. That is not possible. I am going to replace the slave cylinder next I think unless I can come up with something else that might be causing the problem. Is the car not being able to start in first gear a symptom that the clutch is not the (or at least "not only the") problem?

 

[thedarkwolf]

If you have the parking brake or the brake pedal pushed while trying to start it it isn't going to start in first. It needs to be able to move so don't drive into your house. What does it do with it in gear when you try to start it? There is a safety switch on the clutch pedal that tells the car not to start unless the clutch pedal is depressed. It doesn't have any idea the hydraulic system is dead and the car is going to take off.

 

[Farang]

I have a specific symptom now that you guys maybe can use to diagnose this issue.

The car starts in first gear (darkwolf's advice helped me do it right), but even with the clutch pedal depressed the car moves forward and wants to drive. From what I can tell clutches fail due to worn discs so this seems to indicate that the pedal being down must prove that the problem is with the hydraulics, but I am having trouble finding concrete info on this. My reasoning is a worn pedal should still be able to disengage with the pedal down so why would the car lurch forward?

Without knowing fore certain what the problem is, my plan at this point is to replace the slave cylinder because it is $12 as opposed to a new clutch at $110, and given the history with the slave it seems worth covering my bases there.

 

[StageLeft]

It does sound like hydraulic, like it's not allowing full pulling back of the clutch to disengage, when you press the pedal in. I assume it feels a bit floppier than it used to or spongy.

Damn those are cheap parts. I did my slave this year and from autozone it was $60 or something like that. In my car there is slave, TWO lines to the master, and the master. There are two bleed screws, one lower (do first), then the upper (do second).

If there is a leak, you'll see the fluid level go down over time from the master cylinder. If it's not going down over time, there is no leak and I'd question the importance of replacing another part and go back to improper bleeding procedure (something I have experience with, hee hee).

 

[Zenmervolt]

Originally posted by: Farang
Also please refrain from namecalling if you're nice enough to give me advice, that is uncalled for.

There is no other possible way to describe your brother's theory. It may be impolitic to say so, but it's the absolute truth.

Originally posted by: Farang
Without knowing fore certain what the problem is, my plan at this point is to replace the slave cylinder because it is $12 as opposed to a new clutch at $110, and given the history with the slave it seems worth covering my bases there.

Well, if you're just going to throw parts at it, replace the master cylinder too. Technically the master and slave cylinders should always be replaced as a pair anyway since it's quite common for one to fail soon after the other does.

ZV

 

[Farang]

Originally posted by: Skoorb
It does sound like hydraulic, like it's not allowing full pulling back of the clutch to disengage, when you press the pedal in. I assume it feels a bit floppier than it used to or spongy.

Damn those are cheap parts. I did my slave this year and from autozone it was $60 or something like that. In my car there is slave, TWO lines to the master, and the master. There are two bleed screws, one lower (do first), then the upper (do second).

If there is a leak, you'll see the fluid level go down over time from the master cylinder. If it's not going down over time, there is no leak and I'd question the importance of replacing another part and go back to improper bleeding procedure (something I have experience with, hee hee).

I do think I might not have bled it properly but my impression is that the symptom of air in the line is the pedal feeling weak, it doesn't at all and pops back up with a gusto when I lift my foot off. I'm going to read up on symptoms of air in the lines

edit: don't know if all systems are like mine but I get that impression because when we accidently pumped air into the system before bleeding it, the pedal lost all resistance. Now that it is has strong resistance I'm concluding there is no air.

 

[Farang]

updated OP removing unnecessary info