Clutch Pedal Release Height ?

[IDave]

Searched here and did a bit of searching on the internet without a clear answer to my question.

This is my daughter's 84 4x4 Mini Pickup with (after low speed roll) 86 tub on it.

Essentially, the issue is that unless she floors the clutch pedal at a stop sign or light with the engine running she'll stall.

Now admittedly shes on the short side to start with. I have always pushed the clutch pedal to the wall to shift, myself. Just was taught that way. In her case, you have to get it pretty far down there to disengauge. Maybe less than an inch from the floorboard.

Maybe that's normal. I don't know. Our RAV4 is the same. But my FJ45 and 40 are not: they engage about 1/2 way through the pedal swing.

So, is that normal? How can I tell? How much movement must the slave pushrod push the release fork to get good disengagement?

I mean, it could be weak pressure plate springs, or it could be poor push rod movement. I think if I knew the proper swing of the end of the fork I could tell if it was less and make it an upstream problem rather than a downstream (weak springs) issue.

Assume no obvious leakage from either master or slave. I would think air in the line, or too little pedal height, not letting the cylinder to fully load before pressing down on the pedal. Right? But then I would have too little free play, right?

PS, the Slave push rod is nonadjustable in this setting.

How do I tell what I've got (I am not in Fort Collins until Memorial Day)?

Would the clutch pedal engagement height tell me anything? Is it too high or low? I think it's about an inch, but that's what the RAV4 has, much closer to the firewall than my FJ45 pedal???

 

[corax]

IIRC the later (90's?) Toyota's used a larger bore clutch master cylinder. Even made of aluminum for a bit of extra bling. Might want to do a bit of research over at NAPAonline where they usually have specs for such things.

A bigger clutch MC bore would make the pedal a bit stiffer, but would also cause the clutch to release higher

 

[WarDamnEagle]

It sounds to me like the clutch is starting to go (unless it's always been that way). I noticed in my 85 4Runner (the only time the clutch had to be replaced) that the clutch would only disengage at the very bottom of pedal travel for a while and then some weeks later it started slipping.

 

[IDave]

IIRC the later (90's?) Toyota's used a larger bore clutch master cylinder. Even made of aluminum for a bit of extra bling. Might want to do a bit of research over at NAPAonline where they usually have specs for such things.

A bigger clutch MC bore would make the pedal a bit stiffer, but would also cause the clutch to release higher

That's an interesting thought! Thanks!

Thing is, I'm not really sure how high above the floor the release point should be. I found specs for later pickups (and my RAV is this way) that said the release point is only about an inch above the floor. In which case, this may be normal. I can't find specs for an 84.

What release height do others with this truck have? Is an inch normal?

 

[IDave]

It sounds to me like the clutch is starting to go (unless it's always been that way). I noticed in my 85 4Runner (the only time the clutch had to be replaced) that the clutch would only disengage at the very bottom of pedal travel for a while and then some weeks later it started slipping.

I wonder this, too, but I can't (in my mind) picture why a worn and presumably thinner clutch disc would require more and not less pedal travel (and therefore pressure plate travel) to release. Maybe it's just me and someone can explain.

 

[IDave]

No one can help me with this? Just tell me how far off the floor your pedal releases?


Pretty please?

 

[freds40]

In my old '83 and in a friend's '80 I recently drove 15 hrs. , they both release probably 1/3 up from the floor. Not sure in inches but it it's roughly the upper 2/3 that has engagement.

 

[IDave]

Thanks! That's very helpful!

 

[2ndGenToyotaFan]

Crawl under the dash and adjust the release rod... loosen the lock nut and turn the rod so it moves to the front of the truck. But make sure the rod still has a little play...

 

[IDave]

I extended that about as far as it will go before she took it to college. Only a couple of threads showing. It was low then, but worse now, apparently, Jerod. She also told me yesterday has to point her toe and stretch to get the pedal to the floor, so some of this may be her being somewhat vertically challenged. It was marginal before, though.

I'm worried either the new master or the new slave has an internal leak. I don't recall exactly, but I think they are aftermarket, and I know they can come bad from the factory.

The only other thing I wonder is this: although they use the same clutch master, the different years 84-88 have varying pedal height settings (like either 5.6 or 6.04 inches). Could the fact that we have a later tub on this project vehicle and set it for 84 make a difference? It doesn't seem like much change, and if there's proper freeplay it seems like the master should be fully loaded. But???

Thanks

 

[corax]

The only other thing I wonder is this: although they use the same clutch master, the different years 84-88 have varying pedal height settings (like either 5.6 or 6.04 inches). Could the fact that we have a later tub on this project vehicle and set it for 84 make a difference? It doesn't seem like much change, and if there's proper freeplay it seems like the master should be fully loaded. But???

Thanks

The different tub might have a different pedal assembly and pedal pivot length on it - distance from pedal to pushrod to pedal pivot - if true, the different pivot length might give less linear distance to the master cylinder in exchange for more "leverage" through the pedal itself . . . if that doesn't make sense, let me know, I sometimes get muddle brained trying to explain things that make sense in my own head

 

[IDave]

Thanks. It's in colorado, so I can't look, but, now that I think of it, doesn't the clutch/brake assembly bolt to the firewall? I think we just transferred it over from the old truck, or maybe we used the "new" one. Crap, I can't remember.

 

[IDave]

It sounds to me like the clutch is starting to go (unless it's always been that way). I noticed in my 85 4Runner (the only time the clutch had to be replaced) that the clutch would only disengage at the very bottom of pedal travel for a while and then some weeks later it started slipping.

Well, I think you're right. I got a chance to look at it, quick visit, and even replaced the aftermarket clutch master with an Aisen to be sure. But the slave pushrod seems to move just fine. The clutch pedal seems to be pushing against little resistance. So I'm guessing that the clutch pressure disc finger springs are worn and old, and we will have to do a clutch job sooner than later.

 

[WarDamnEagle]

Sorry I couldn't help you any further earlier as a) I'm not a clutch expert and b) my 4Runner is about 6000 miles away. Otherwise I would have posted.

Just put a good clutch in and she should be good to go for a long time ...unless your clutch-challenged brother-in-law smokes your clutch pulling your Ski Nautique up a boat ramp while you sit in said boat choking on burnt clutch fumes! I guess it was better to trust him with the old 4Runner than the relatively new boat.

 

[IDave]

Sorry I couldn't help you any further earlier as a) I'm not a clutch expert and b) my 4Runner is about 6000 miles away. Otherwise I would have posted.

Just put a good clutch in and she should be good to go for a long time ...unless your clutch-challenged brother-in-law smokes your clutch pulling your Ski Nautique up a boat ramp while you sit in said boat choking on burnt clutch fumes! I guess it was better to trust him with the old 4Runner than the relatively new boat.

Hmm. Now is that the voice of experience?

Getting her to do it before she's stuck might be a challenge when I'm 1000 miles away. Ah, well.