Help identifying clutch system

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Take a look at the pictures in post #12 in this thread. You will notice that there is a retainer clip on the back of the shift fork. When you installed yours, are you sure that the clip locked over the head of the pivot pin? Also, when installing the fork did you do it without the slave/rod installed? If they were installed the adjustment might have been to tight and limited the amount you would have had to move the clutch fork and throw out bearing. Was the clutch system bled? If there is air in the system it won't disengage the clutch.
 

avicenna110

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Take a look at the pictures in post #12 in this thread. You will notice that there is a retainer clip on the back of the shift fork. When you installed yours, are you sure that the clip locked over the head of the pivot pin? Also, when installing the fork did you do it without the slave/rod installed? If they were installed the adjustment might have been to tight and limited the amount you would have had to move the clutch fork and throw out bearing. Was the clutch system bled? If there is air in the system it won't disengage the clutch.
Yes the clip was installed and the fork was pivoting. I installed the bearing and fork with the slave/rod installed, and it was hard to get them on. So now I know that’s not the right way.

I backed off the bolt on the rod about 3/4 inch and now it disengages, at a similar place it did before about 75% from floor to top. I drove the car around and it felt nice (no whinny TC anymore, yay). I was planning on flushing the master/slave fluid after. But I think I’m lacking the proper knowledge on how to adjust the clutch. Any tips or resources? Thank you.
 

pb4ugo

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20220711_211038.jpg
 

pb4ugo

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Follow the instructions, beginning to end. I run a sbc, nv4500 & a sbc,sm420. Adjust pedal height. Pedal free play is when the slave initially moves, not resistance. Then adjust clutch fork. The slave piston needs to be fully seated in the cyldr and run a return spring. Put pressure on the slave rod and crack the bleeder to ensure it's seated. The t/o bearing should not be in contact with the pp.
 

avicenna110

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Follow the instructions, beginning to end. I run a sbc, nv4500 & a sbc,sm420. Adjust pedal height. Pedal free play is when the slave initially moves, not resistance. Then adjust clutch fork. The slave piston needs to be fully seated in the cyldr and run a return spring. Put pressure on the slave rod and crack the bleeder to ensure it's seated. The t/o bearing should not be in contact with the pp.
Understood, thank you for the tips.
 
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I’d recommend a ‘73 clutch slave to ensure the maximum travel. I’ve got one and a ‘73 master, a braided SS line, and a LUK clutch. In 26 years I’ve always had plenty of travel… I’m now on the 2nd 350, and it still has lots of life left in it.

The only time I’ve had any issues with it is when the slave and master were failing at roughly 12 years of age. It is recommended to replace them every 10 years before they start to fail. In the 30 years I’ve had it I’ve replaced both the slave & master 3 times… at 11-12 years of age each time.
 
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Downey

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Here are some things I noticed in this photo:

View attachment 3114653

The mounting plate for the slave cylinder is a block that spaces it out, probably to keep the rod straighter into the outside pivot spot. That throw out bearing arm actually has a second pivot point as shown in the red circle. Take a look at this adapter as it will allow you to use the inner pivot location which will translate to more throw. Download the documentation for it and it will have pictures of what I'm talking about.
1,000% agree, your Toyota hydraulics barely has enough travel to disengage a Chevy or LUK clutch, so you can't waist any of the travel by mounting the slave cylinder push rod into the outside slot/hole on the shift fork, soooooo getting the Advance Adapters slave cylinder mounting bracket and mounting into the inside slot/hole is a must.
 

avicenna110

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Follow the instructions, beginning to end. I run a sbc, nv4500 & a sbc,sm420. Adjust pedal height. Pedal free play is when the slave initially moves, not resistance. Then adjust clutch fork. The slave piston needs to be fully seated in the cyldr and run a return spring. Put pressure on the slave rod and crack the bleeder to ensure it's seated. The t/o bearing should not be in contact with the pp.
1,000% agree, your Toyota hydraulics barely has enough travel to disengage a Chevy or LUK clutch, so you can't waist any of the travel by mounting the slave cylinder push rod into the outside slot/hole on the shift fork, soooooo getting the Advance Adapters slave cylinder mounting bracket and mounting into the inside slot/hole is a must.
Thanks. I’m learning a lot here. I didn’t know the throw out bearing shouldn’t touch the pressure plate. It makes sense, you don’t want it to rotate when it doesn’t have to.

I bought the adapter from AA and had a hard time installing it on the bellhousing. The holes didn’t quite line up and it seems that I was missing one spacer (the face of the bellhousing isn’t flat). Another issue was that my rod on the slave was cut and an extension was added, so there wasn’t enough thread to make it as short as the new adapter required it be. At this point I have worked on the car way more than I’ve driven it so I really just wanna drive it even though I admit that isn’t the best thing to do always. I will still make sure the bearing isn’t touching the pp and the clutch works as it should be, but I don’t wanna swap new parts unless I have to. Let’s see how it goes. Thanks for your advice again.
 
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I don't know if this was mentioned earlier as I skimmed through but, what direction is the clutch disc oriented? The flat side goes towards flywheel. Easily overlooked and frustrating to correct.
 

Downey

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The fact that your throw out bearing was riding on the fingers was so you could get full disengagement out of a Chevy clutch, but that will destroy the bearing prematurely, BUT unfortunately when you back the bearing off the fingers, you then don't have enough travel to disengage a Chevy clutch. I've beat this dead horse.. (and the actual measurements) on Mud until guys don't want to hear it anymore.
 
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My chevy clutch works, TO does not run on fingers, all toyota hydraulics, 1970, I wouldnt be suprised if it is the OEM MC on the clutch and brakes.
Jim, curious, because I have run the same MC/slave on the gen 1 sbc & the ls all with a sm420, you are correct in that the clutch has a very, very small window of adjustment like the TO is 1mm off the fingers, it has plenty of throw. In the above statement which clutch master & slave have not enough throw for the chevy ? I know its all been said before, I can't remember which MC & slave come up short, no pun intended....
 

Downey

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Cripes, my information goes way back maybe 40-50 years ago when we first started manufacturing Chevota Specific clutches. Our first clutches were manufactured by McLeod Industries, Red (owner of McLeod at that time) did all the math for us regarding stock Toyota hydraulics travel at the throw out bearing, amount of travel a stock Chevy clutch required to disengage, and amount of travel our Chevota Specific clutches required to disengage. Since so many Mud guys have been claiming their stock Chevy clutch (or a LUK) works just fine on their Chevota, I believe either (a) Toyota hydraulics have been improved, or (b) Chevy clutches have been improved. Either way, I'm through telling guys they need a Downey or AA Chevota Specific clutch.
 

avicenna110

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I worked on it a bit more tonight. For the release bearing to not touch the pp I had to adjust the nut on the slave rod all the way in. In fact I had to remove one nut, so there is just one there, but it’s not going anywhere. The bearing has a few mil gap with the pp. I didn’t start the car yet because I didn’t wanna wake the neighbors, also didn’t wanna think about it all night in case the hydraulics don’t have enough travel.

I’m pretty sure the PO had the bearing riding on the pp. I didn’t check before disassembling but there is no way it wasn’t based on the rod adjustment. Either way I’m glad I went that deep, at least I learned how it’s supposed to be. Will update tomorrow.
 

avicenna110

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Just started the car and it starts rolling with the clutch pedal at about 10% from the floor. I can still adjust the bearing a couple of mil closer to the pp, but I’ll leave it for now. I’ll flush the fluid and drive it a bit. But I’m happy it didn’t run out of room for adjustment. I can see that there is very little room though as you guys say. Thanks all.
 

avicenna110

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I bled the clutch, and it’s better now. The clutch is adjusted just as I’d like it to, with no more room left for adjustment. The fluid was pretty dirty, in the pic below half of it is clean brake fluid so it must have been worse

63A85088-4E7A-4BFB-812B-5A9AD2B22498.jpeg


When it comes to change the hydraulics what should I be looking for? Any recommendations? I see replacement kits for earlier cruisers but I’m not sure what the brands are and of they’re any good. Ideally I’d like to keep it stock but I couldn’t find a rebuilt kit, or a new master/slave replacement for my year. Thanks
 
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Here's what my research shows regarding clutch master and slave bore sizes:

Clutch Master and Slave Cylinder bore sizes for various FJ-40 years:
Clutch Master Cyl.:
inches
58-66
1​
66-1/75
3/4​
1/75-4/85
3/4​
Clutch Slave Cyl.:
inches
58-66
7/8​
66-74
3/4​
74-85
13/16​
Brake Master Cyl.:
inches
58-70
1​
70-74
1​
75-80
1​

I bled the clutch, and it’s better now. The clutch is adjusted just as I’d like it to, with no more room left for adjustment. The fluid was pretty dirty, in the pic below half of it is clean brake fluid so it must have been worse

View attachment 3147906

When it comes to change the hydraulics what should I be looking for? Any recommendations? I see replacement kits for earlier cruisers but I’m not sure what the brands are and of they’re any good. Ideally I’d like to keep it stock but I couldn’t find a rebuilt kit, or a new master/slave replacement for my year. Thanks

I’d start by measuring the bores of the slave and master you have. If it’s a 1” clutch master and a 7/8” slave cylinder then you should have enough travel do long as the flex hose doesn’t flex too much. I’d start with a stainless steel braided flex line. If you still need more travel a ‘76 would have more at 13/16… or even more with a ‘73 clutch slave.
 

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