Title was initially: 5-speed clutch pedal sticks on floor in morning (three days in a row)
New title: How to diagnose, fix, & redesign your squeaky or sticking clutch pedal return torsion springs & Q-P-Q bushings.

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For three days in a row, I'm told the clutch pedal sticks to the floorboard when starting in the morning.
The clutch pedal seems to stick and not lift up all the way.

Once it is literally unstuck, it seems to work correctly.
At one point, the user couldn't shift into first gear in the morning.

The pedal is not catching on the carpet (or anything else).

Any idea where I should look for what the remedy is?
When the pedal is stuck to the floor, it can't get out of first gear.

AFTER-THE-FACT-EDIT (to save you time):
It turned out to be the pedal-return torsion-spring & Q-P-Q bushings (see detail below sufficient to identify and solve the problem if you get here by searching).

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Worn pressure plate....

crawl under and look at your pedal assembly. Could be worn pressure plate but could also be a worn pedal assembly. there are little white bushings that wear out and then the springs begin to eat into the pedal and cause this exact problem.

How do I diagnose that it's definitely the pressure plate?
What test can I run?
Can I remove a cover plate to look and measure if it's a worn pressure plate?

Up until this morning, it was only intermittent (things changed this morning - see below).

It's not actually my 4runner, it's someone else's, and they took it to work (foolishly, I think) this morning after I bled the clutch assembly last night.

The DOT3 hydraulic fluid was full but very dark brown, but there were no visible leaks (slave cylinder is a pretty clean pink, for example).

When I first bled the slave cylinder from under the 4-runner, the young teen who was helping me by pressing on the clutch thought the black float in the master cylinder was actually the fluid level, so we ran the master cylinder dry.

That was an interesting accidental diagnostic because, right after that, the pedal just "flopped" in both directions, until we bled the pocket of air out.

So after re-bleeding, the pedal got its pressure back, but, the sticking problem is re-occurring (only worse now).

I was originally thinking it could be the slave cylinder not holding pressure, but I'm not sure why they even have a slave cylinder.

Why do they need TWO cylinders (master, and slave)?
Anyway, I'm really looking for diagnostics more than anything else.

Since neither of you mentioned the slave or master cylinder, are you saying that the symptoms are NOT those of hydraulics?

I'll google for photos of this white bushing as I can't tell from your description where it is (is this white bushing inside the cockpit, or inside the transmission clutch assembly, or in the undercar linkages in between?). I'll also google for how to test a pressure plate and what its symptoms are, but any additional experience and diagnostics would be appreciated.

I'm searching for a picture of this "white bushings".

In my search, I noticed that the 6-cyl clutch pedal is apparently different than the 4-cyl clutch pedal.
Swap V6 clutch pedal assy for 4cyl?

LATER EDIT: The 4-cyl & 6-cyl on the 4Runner are not different! That was bad information above. However, the diagram to the left shows what the retrofit will look like, since all attachment points exist in the 4Runner!

Can you point out this white bushing in the 4-cylinder assembly?

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Still searching for how to diagnose when the clutch pedal sticks to the floor.

This is a clutch replacement DIY for a 97 SR5 (which is a different model):
Clutch Replacement Writeup

In that thread, I found this suggestion for clutch replacement DIYs from TheDurk, so, that at least gives me some pictures of the 5-speed transmission and how to remove it (although the 2WD is likely different).

There is a picture and diagram of the "pressure plate" in that thread.
But it makes no sense to remove the transmission until I figure out what's wrong with diagnostics that prove it (or at least make sense).

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I googled for why there are *two* hydraulic cylinders, where the answer seems to be that the master cylinder's job (of course) is to convert mechanical pressure to hydraulic pressure. Seems to me that should be enough, because all you'd need is a brake-caliper-piston-like "cup" at the other end, but what they use instead of a cup is another cylinder, the slave cylinder, to convert the hydraulic pressure back to mechanical (to force the pressure-plate springs to yield).

Since the hydraulic fluid was definitely murky, maybe a rubber seal has disintegrated in the hydraulics?
Or maybe debris has scratched a piston?

I don't see any leaks, and the fluid level was high, so, I don't think things are leaking "out" but fluid could be leaking past the pistons, especially overnight.

In looking up how best to test that both the slave cylinder & master cylinder are actually working properly, I found this thread which suggests Aisin as the OEM brand for both.

Can I get away with using non-OEM clutch master and slave cylinders?

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I feel your pain. I have not faced this issue myself--my two Toyota 4Runners are the only hydraulic clutches I have dealt with and they have 38 trouble-free years between them.

I'd first look to see if there is any issue at the pedal you can find--bushings, springs, etc. It sounds like you have done that. I think then I would get underneath and unbolt the slave from the bell housing. It's one of the early steps in a clutch renew and is pretty easy to do. There is enough slack in the lines to move it some. There is, if I recall, one line bracket you may want to unbolt as well. If the clutch is on the floor, and there is tension between the fork lever and the slave piston, the issue is between the slave and the pedal. If the fork lever is only lightly under tension, or not at all, then the issue is inside the bell, and it's time to yank the trans. Even if the clutch is up, you can see how hard it is to move the fork lever by hand. It should be pretty much impossible without major leverage and a tool. If it moves at all, time to pull the trans....

I would vote on master or slave cyl, I had mine both go out fairly close together between 150k and 180k.

My bushings never wore and I replaced the clutch at 150k because it was slipping.

Since diagnostics are what I'm asking for, I love this response since it gives me an idea HOW to test to see where the problem lies.

Basically, the diagnostics you suggest make sense in that I BREAK the system in half at the slave cylinder, and then I test which half has lack of tension.

I do have new news in that I drove the 4-runner today, from a cold start, for a 10 mile test around town, and it shifted fine EXCEPT that the clutch pedal this time, instead of staying down, wouldn't come all the way back up.

I kept having to LIFT it with my foot, the last two or one inch. In the beginning of the test it was about 2 or 3 inches and in the end of the test it was only 1 inch (decreasing as I drove).

I'm not sure what diagnostic value that has, but at this point, I'm only asking for diagnostic advice, so your idea to break the system in half is apropos.

I'm leaning toward the slave cylinder at the moment, mainly because that seems to be a weak part in the chain, and because TheDurk gave me a great diagnostic tool, which is, after all, 99.5% of fixing problems successfully.

The first half of diagnostics is figuring out how the system works, where the second half is testing each component individually, as TheDurk kindly outlined above.

To that end, I found this document about symptoms of a Bad or Failing Clutch Slave Cylinder
https://www.yourmechanic.com/article...slave-cylinder

And this one on "How a clutch slave cylinder works":
How the clutch system works
Clutch slave cylinder

This says if you have a bad clutch slave cylinder, you know it right away, so, maybe the symptoms are classic?
https://youtu.be/WoM9_30XdyQ?t=83way:

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Durks suggestion on testing the slave cylinder is a good suggestion and should be very easy to do. The slave is very accessible, and it's just a few bolts to get it off.

I'm sure you've looked at it already, but I've heard of folks pedal not returning all the way back up being attributed to a worn pedal spring (31301 in your diagram). Should also be something easy and quick to check/replace.

I'm leaning toward the slave or master cylinder also, or maybe that white bushing that I can't seem to figure out where it is.

I say that mainly because the clutch is "working", in that I drove it today for about 10 miles and it engaged and disengaged. I started on a hill in second gear and it didn't unduly slip, and I used the transmission to engine brake at about 30 or 40mph, and it braked the car.

It's actually only the pedal which is "not working" right.

In the morning, the pedal just sank to the floor and stayed there, but this afternoon, when I tested it, the pedal just wouldn't come back up all the way. I had to lift it up with my foot.

So, for "symptoms", that's all I have. The pedal goes to the floor in the morning (will test tomorrow as I traded cars with the owner), and the pedal never comes back all the way.

Since I have the 4runner in my garage, I can look closer tonight for leaks under the boots of the slave and master cylinder and I can look for that mysterious 2WD white bushing (but I don't know where to look yet).

This guy seems to have had the missing-last-inch problem also:
Clutch pedal issue - '97 SR5 with 226K

But he had clutch slippage, and, while I wouldn't know slippage if it were slight, I would know if the slippage were a lot, I think, in that the RPM would jump while the speed would stay the same. Slippage does not appear to be happening.

It's just that the clutch is acting definitely funny.
a. It won't come up the last inch
b. Sometimes it sinks to the floor and stays there

I had the identical symptoms, I had never dropped the tranny for any reason before this. I did not have a problem with master or slave and the clutch itself was worn but still good after I dropped the tranny but my pressure plate was toast. I drove it for two weeks lifting the pedal all the way up until I bought the Marlin Crawler clutch kit and did the re & re. If you are able to eliminate the slave and master, then you know how you to proceed.

I don't think the pressure plate could do that intermittently. It would be a very weird fail. If the issue is in the bell-housing, I'd think throw-out bearing (as in not sliding smoothly along the output shaft as it needs to do) or the fork mounting has broken and the fork is getting hung up in its travel. You are correct, the return force, other than the wimpy pedal spring, is ALL in the powerful springs in the fingers of the pressure plate, acting in opposition on the throw-out bearing, to the fork lever, to the slave cyl. piston, and through the master and back to the pedal. The issues can be mechanical at the pedal end, mechanical at the clutch end, or hydraulic in the middle. The first thing to do, IMHO, is figure out which of the three you have and go from there. As far as the pedal end, in addition to bushing and spring issues, I remember a few posters saying they had rust issues on the firewall where the pedal was mounted and the pedal bracket was shifting and causing the hangup. So just getting someone to work the pedal while you eyeball the motion underneath at the pedal bracket, on the firewall, and at the slave, may lead to an epiphany. Good luck.

My clutch slippage detection technique is pretty good, and I learned it as a function of the fact I live on the top of a hill. The road up is straight and a mild incline for about a half mile. On my rig, in third gear, the speedo and tach needles rotate at EXACTLY the same angles as revs increase. So I put it in 3rd at about 1800 RPM and FLOOR IT as I start from the bottom of the hill. Watch the needles (and the road) as they climb. If the tach needle jumps ahead of the speedo as they rise, THAT is slippage. It will do that first before anything else you will notice.

Actually, I only had a few minutes with the 4runner until now, but since I traded cars with the owner this afternoon, I have more time to explore all the great suggestions.

To that end, I looked under the dash for a good look for the first time tonight.

My first comment is that the "mechanical" part of that pedal assembly isn't as straightforward as a simple lever. There is a "double-coil" horseshoe spring, and a bushing on each end, and a bunch of other extensions and switches, but I can't tell exactly how it works yet (partly due to the fact that I'm apparently far bigger upside down than the space Toyota alotted to me down there).

Particularly, I can't see why a broken spring bushing alone would have any effect on the pedal not lifting up the last inch.

However, I did find this broken round white spring-end "bushing", about 1/4 inch ID and about 3/8" od (roughly eyeballing it), which was on the end of the thick double-coil horseshoe shaped pedal return spring.

Do you think this little tiny plastic bushing can have this much effect?

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