FJ40 3speed to 4speed Clutch Problems... HELP! (1 Viewer)

Rainman

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Okay. I just measured the travel of all the MCs. Two are the big ones, two are the skinny ones. One of the skinnies is on the truck. The other one has a travel EMPTY of only 1.25". If the pedal only travels 1", then it sounds to me like getting most of the distance is better than just over half.

The fat ones have a travel of 1.75". You can see the sharpie marks on the posts.

More volume will help but since I can't get any more than 1 inch out of the pedal, what choices are right? You realize, I've tried all the combinations already. I've repeated myself time and time again. One of us has the answer stuck in our brain somewhere.
2 MCs.jpg


This appears to be exactly like the other skinny one other than the side port. This is a 10mm fitting, the other is a banjo fitting.
current MC.jpg
 
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You provided some good info. But, it is critical to know the bore size of the "fat" and the "skinny" masters. You can't determine your slave travel without knowing this.

When you say you "can't get more than 1" out of the pedal"....... exactly what are you measuring? The critical measurement is where the master attaches to the clutch. Is that where you measured? If that is the case, your problem lies somewhere in the mounting of the clutch arm or an incorrect clutch arm (as someone else mentioned). Stated simply..... you have to move the master rod about 1 5/8" if you are sticking with the '76 master and slave combo.

So...... you have to use the correct master and slave: master with 3/4" bore and a travel of 1 5/8" . A Slave with 13/16" bore should move right at 1 3/8". And...... your clutch arm absolutely needs to be able to push the master rod the required 1 5/8". If you're going to try other combinations....... all bets are off on what you will end up with.

But here is a thought for you: Perhaps your clutch arm set up is for a pre 1966. I just did some calcs and if you use a pre 1966 master with a 1" bore, and move the master rod 1" (like you said you can do), you will move a 13/16" bore slave cylinder (which you say you have) about 1 1/2". End of problem. But once again......master bore size is absolutely critical!! And further, you need to confirm that the slave can travel 1 1/2" without popping the piston out the end.
 
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Rainman

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atazman,

You are the man. By far the most knowledge about this to date. I would be VERY surprised if the clutch arm is out of another truck. That would mean it and the brake arm is. This truck was too clean to need to do that. Or, it was too clean for any need or evidence to make that kind of adjustment. So...

We will attack the combination approach. 1" is all I have to go on. Believe me. And that IS marked on the post where it sits in the boot at idle, then marked again at full pedal. With the tub and pedal I have. It's WAY too late to change that. So, find a 1" bore master and 13/16" bore slave. (I read your post twice to make sure that was right.)
 
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Rainman

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My buddy is on the way to tag team this and with the new knowledge we hope to have this baby driving by lunch.
this is painful to say the least....
You are not just whistlin' Dixie! Thanks for the moral support.
 

Rainman

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@atazman

I have a sc that measures a hair under 3/4". Will that work? Having it a tad smaller would help the master "overcome" the slave a little wouldn't it?
 
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As far as I know, the 3/4" bore is the smallest slave made for FJ-40s. I don't know what you have that would measure smaller.

But.... please be reminded that you must consider the bore of the master. The pre 66 master (1"bore") and pre-66 slave (7/8" bore) would move your slave rod about 1 1/4". Toyota knew what they were doing with these systems, and they matched the master to the slave and designed the clutch arm system to deliver the intended throw on the clutch fork.

I mentioned using the 13/16" slave bore only because I thought that you already have that slave.

If you need to buy either another new master or slave, be sure you get the bore size you want, as opposed to buying for a particular year truck. In other words, just make sure you are getting the 1" bore size for a pre-66 master before you make a purchase.

Good luck with your decision.
 

Rainman

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IT RUNS!!!
62490999705__A452B611-6CA0-4805-99D6-6B603416936A.jpeg


I used a 1" bore Master.
A 13/16" bore Slave.
Pulled the gravel pan and found a clip in the bottom of the pan and the other missing. I was either asleep that day or screwing with the fork on install day as much as everyone did messed it up. That had to be one of the problems. I really don't care who's fault it is. I'm just glad this is mostly over.

I say mostly because the clutch disengages near the bottom of the pedal. I like it at the top. I think I may be able to help it a tad by tightening up the gap on the slave push rod. I believe I have a little room.

So here she sits in the front yard under her own power. First time in over a year. The steering needs alignment. The timing needs adjusting. But by God, the last hard thing is over!
 
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Good for you, Rainman! Where did you end up buying the 1" bore Master. Did you measure (on the bench) how much stroke it has? Am interested in getting one myself.

Thnaks
 

pbgbottle

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Congrats finallly solved.
it would be nice since you have been playing with all the masters and slaves I’d you could post up the bore and stoke info of all your parts you have measured and tested. I could use a 1/4 in more stroke.
 

Rainman

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Guys. Maybe my beers for the pizza dinner after a long day may be messing this up but sorry, I didn't bench test these. I just knew that we'd either figure it out (which we did) or simply putting the recommended parts in would do the job. And the combo did. I'm guessing the clip situation made more difference than the cylinders did. I'm still disappointed in the clutch pedal though. The sweet spot is still at the bottom. I'm not sure if I can move it or not. I'm doubting it.
 

BreckenridgeCruiser

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@Rainman did you spin out the fork on the master to get the 'slack' out of the pedal? As long as you can be sure the throw out is not touching the fingers of the pressure plate at rest then you could apply a little preload to the system by lengthening the master piston fork... Again just checking in case you didn't do this already
 

Rainman

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I did. Like I've said, this isn't the first roundup for me. I realize doing something many times, you can't start thinking it's simple and forget stuff. But doing this over and over with different parts, I repeated all the steps until I was blue in the face. I know how to get there for adjusting the clutch and raising the soft spot. It Just Won't. Got to be a result of the mixed equipment. I don't really believe that but it's the only explanation. It's not mixed from the pedal to the fork. When I get the front end aligned next week, I'm going to get fresh eyes on it and see what he says.
 
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Give us some help, Rainman. Did you measure the stroke (on the bench) of your 1" bore master? And where did you get it? Do you have a part # for it?

Thanks!
 

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