FJ40 3speed to 4speed Clutch Problems... HELP! (2 Viewers)

[Rainman]

I started with e 3 speed slave. Then replaced it with a '74 and they seem to be exactly the same. Same problem.
I then bought a '74 master. No improvement. I agree, maybe a later cylinder will have a larger bore.

I really thought the idea mentioned above to check if a longer post could be installed. Hoping the piston wasn't all the way back, I tried. No go. It was already all the way back. Same problem.

It's not making much sense to me, and it's not making much sense to anyone I've talked to. I have lots of experience with brake and clutch systems and have never seen this problem before. I'm baffled. I'm also tired of tossing money at it. But I guess I'll have to try a later system. What's $150 between friends?

"Calgon, take me away!!!..."

 

[SteveH]

I have always gravity bled the clutch system - just open the slave bleeder and let it drip for 10 minutes, keeping an eye on the master to keep it full. No pressure or vacuum or pedal pumping. Have you tried that?

Is the pedal immediately firm, or is the first part of the travel squishy?

Are all the masters you've tried Chinese ones? I haven't had a problem with non-OEM, I just wondered.

 

[Rainman]

I've bled the system every possible way, including the slow gravity bleed. Nothing has made a difference.

The pedal throughout this process has beed completely soft all the way down but just a tad firm at the last inch. Every time.

Combination of Toyota and aftermarket. Again, I've never had any of these problems before. It's all new issues to me.

I believe right after I order new cylinders, I'm going to just ignore it for a couple of days. I'll work on other Cruiser stuff.

For statistic purposes:
I'm ordering a slave for, 8/74 - 7/80
I have a Master cylinder for, 7/70 - 7/80

They both look like what I have but the bore just might be different. Hey, it's supposed to work, right? And besides, I may have just added to my perfectly good spare parts pile. The jury is still out on that I guess.

Thanks again for all the tries, sorry I shot down most of your thoughts but I'd just thought of them already. But, that at least confirmed my knowledge.

 

[FJ40Jim]

The MC & SC is not the same for 70-78. There is a significant change in bore sizes in late 74 when the clutch changes from coil spring to diaphragm.
It appears you have the E-74 master & slave, but a 76 clutch assembly.

Edit: Useful info below. somebody else can verify & fill in missing data.

IIRC, the E-74 MC bore is 1".
75-later MC bore 3/4"

E-74 SC bore ?
75-later SC bore 13/16"

 

[Rainman]

Thanks Jim,

So. What are you telling me? Which combination should I use? Earlier combo isn't working no matter what I do. I figured that now that there's a '76 drive line in it, I should use the same year cylinders. That would be the two I just ordered... Right?

I did find it odd that it called for the master to cover 70 to 80. The truck is actually a 3/70 truck which would follow suit that it could change in 7/70 but why the change then?

Reading your post again, it seems odd that the bore went down in later years. I need to go up in the master for more travel don't I?

 

[FJ40Jim]

To speed up/increase motion/increase pedal effort: increase MC bore or decrease SC bore.

 

[Rainman]

I get that. Completely. So you're saying an early MC and later (possibly) SC. IS that right?

(We still don't know the difference between the SC bores do we?

 

[pbgbottle]

There is a thread on slave cylinder bore not sure what it was called we where discussing it in the past it may be a tread on a V8 setup but same issue. “Travel” we discussed bore size and part numbers.

 

[Rainman]

See if this thought is wrong:

The engine and transmission are '76. That means the clutch assembly is '76. I purchased a '76 (covered) MC and SC.

THAT should be the right units and have no issues. Am I wrong? The year of the body, frame and the mount it's attached to should have no bearing on this.

Now, I don't have much confidence in it. Why should I? I've gone through every other option in the book. Again, I refuse to believe I failed at bleeding the system more than once in nearly a dozen tries. Gravity, pump, reverse, vacuum, and pressure bled. Most of them multiple times. This makes the first time I've not had success with a clutch system. I'm beyond frustrated. I'm numb.

 

[Jdc1]

See if this thought is wrong:

The engine and transmission are '76. That means the clutch assembly is '76. I purchased a '76 (covered) MC and SC.

THAT should be the right units and have no issues. Am I wrong? The year of the body, frame and the mount it's attached to should have no bearing on this.

Now, I don't have much confidence in it. Why should I? I've gone through every other option in the book. Again, I refuse to believe I failed at bleeding the system more than once in nearly a dozen tries. Gravity, pump, reverse, vacuum, and pressure bled. Most of them multiple times. This makes the first time I've not had success with a clutch system. I'm beyond frustrated. I'm numb.

You just had one of the heavyweights weigh in and advise. My next step would be to call one of the mud vendors(cruiser outfitters, valley hybrids, marks off-road....) and tell them what you need(mid to late 70s 4 speed slave and master). Or you can pull the existing and check the bores against Jim’s measurements. Good luck.

 

[pbgbottle]

sounds good to me i usually only gravity bleed it and its good to go not much to mess with,
with this setup . your right its pretty straight forward ...

See if this thought is wrong:

The engine and transmission are '76. That means the clutch assembly is '76. I purchased a '76 (covered) MC and SC.

THAT should be the right units and have no issues. Am I wrong? The year of the body, frame and the mount it's attached to should have no bearing on this.

Now, I don't have much confidence in it. Why should I? I've gone through every other option in the book. Again, I refuse to believe I failed at bleeding the system more than once in nearly a dozen tries. Gravity, pump, reverse, vacuum, and pressure bled. Most of them multiple times. This makes the first time I've not had success with a clutch system. I'm beyond frustrated. I'm numb.

 

[pbgbottle]

here are the part numbers for the master and slave on 40 or 55 series cruisers for early 69-80 ish for reference on years and crossover years


,,,,

 

[Rainman]

Unbelievable. Just simply unbelievable.

Installed new MC and SC for a '76. Gravity bled it first. It went really fast for some reason. Failed.
Pump bled it twice. Got air first time. No air second. Failed.
Power bled it... Twice. Air first time. None second. Failed.

I have absolutely no idea how to fix this now. And once again, I had to make a new hard line since the new master has a double flair fitting port on the side unlike the previous 3. So my total now is:
3 Slave cylinders.
4 master cylinders.
2 hoses.
3 hard lines.

Same issue every time. Yes, I am the only constant but I have lots of experience doing this and it obviously isn't paying off.

 

[Rainman]

So now my only option is to pull the damn drive train out to look at the clutch itself. Since the truck is a '70 and the tranny is a 4speed, I have no choice for inspection but to at least lift and tip the engine and all so I can pull the gear boxes off. A major pain in the ass for a finished truck. I'm just absolutely sick over it. This stinking truck is simply kicking my ass.

 

[matzell]

Take the bellhousing mounts off at the bellhousing, put a jack under the oil pan first and lower it that way, it will rock on the front mounts. Watch that the fan does not hit the shroud, may have to loose it up and let it float. Then re-install in same order.

 

[Rainman]

Thanks. I know that drill.

The jury of friends is still out on this because, no matter what I do, the slave still after all this, only travels about that same 1/2 inch. I'm dumbfounded. 15 times and the exact same results. I find it so hard to believe. But it's no different no matter what I try? It just doesn't make sense.

@Onur , can you shed any light on this? Sorry to bother you.

 

[atazman]

Here is some info on master/slave clutch cylinders:

	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

 

[atazman]

If you are not getting the required 1" + throw from your slave cylinder........ you definitely have a hydraulic or linkage adjustment problem. I would suggest resolving this issue before pulling your drive train to check the clutch.

I realize you have done all kinds of bleeding, but are you sure your slave cylinder is free of air? Maybe I missed somewhere in your 3 pages .....but I did not see where you specifically said you bled the slave cylinder. Just hoping it is that easy. After all, a soft pedal does mean air like you mentioned.

With a 3/4" master and a 13/16" slave, your master throw should be 1 5/8" and your slave throw should be 1 1/8" .

Not sure how you would measure the throw on your master, but it sure would be helpful to determine whether your problem is within the master or the slave. To separate the two (master and slave), can you measure how much travel the master piston has by measuring linkage movement under the dash? If this measurement is not possible, break the hose connection at the master and measure the travel of your master piston when you depress the clutch pedal. You really need that 1 5/8" travel.

Soooooo .......... I think I end up right where you are. It is either air or linkage adjustment; both of which you say you have checked multiple times. Sorry for rambling, but just trying to help you avoid pulling your drive train.

 

[DEADSALT]

just went through this,

make sure your new slave "piston" is pushed all the way back in the assembly.

and that the rods for both mc and sc are the same length as the ones you pulled...

might check the clutch fork as well, mine was near pierced from use after 40 years.

 

[pbgbottle]

Question. If he went with the early smaller bore slave would that also give him slightly more travel. ??