Robert Kenney
Super Moderator
Your pin is 3.5"long? I May have one I can measure for reference of measure the stick out on my 65'. I you think that would help.
Clutch slave hose
- Thread starter Mastiff
- Start date
Mastiff
Member
Yeah, let me know. Thanks.
Robert Kenney
Super Moderator
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
All the pushrods I have are bootyfab junk from all directions, I need an oem pushrod myself to use for mockup. I bet Isa has one!
The one I have that May be closest to oem measures rounded tip-to-center of the eye, 2-3/4". One of the worst of the bootyfab units measures about the same.
So I'm suggesting that your pushrod was fabbed and is not oem, that is common when folks try and lengthen the throwout stroke that ends up with the clutch eating away the throwout fork from hard contact. Maybe use an old drill bit cut down to make a test pushrod and then rig it to test stroke with. Now that everything is back to original as far as throw, see if the nominal 2-3/4" length appears to be ballpark. Then you can cut down your existing pushroda a small amount at a time until the throw is perfect. But make sure the pedal free-play at the pedal/master interface is right, so the master is not partially depressed. I have several master cylinder pushrods that are booty-fabbed also to try and make the clutch work, some of these donors had both pushrods scruud over which only makes the entire actuation geometery worse!
The one I have that May be closest to oem measures rounded tip-to-center of the eye, 2-3/4". One of the worst of the bootyfab units measures about the same.
So I'm suggesting that your pushrod was fabbed and is not oem, that is common when folks try and lengthen the throwout stroke that ends up with the clutch eating away the throwout fork from hard contact. Maybe use an old drill bit cut down to make a test pushrod and then rig it to test stroke with. Now that everything is back to original as far as throw, see if the nominal 2-3/4" length appears to be ballpark. Then you can cut down your existing pushroda a small amount at a time until the throw is perfect. But make sure the pedal free-play at the pedal/master interface is right, so the master is not partially depressed. I have several master cylinder pushrods that are booty-fabbed also to try and make the clutch work, some of these donors had both pushrods scruud over which only makes the entire actuation geometery worse!
Mastiff
Member
Mine's a little tighter than yours. I'm a little over 1.5" when the throwout is touching, maybe 1 9/16". So, if I use your 3/16" number for slop, I'm at 1 3/8" to your 1 3/4" between slave collar and fork eye. 3/8" difference. I suppose that's within tolerance for these old rigs...?
I haven't tried loosening the mount yet. I can't tell if it's original or not. Is your slave tight in its mount? I have two of those mounting bands, and my slave is a little jiggly in both of them. It would work fine, but I put a strip of gasket material in there to make it tight.
Maybe when mm checks in he'll know the length of a factory actuator pin.
Thanks for the help.
Edit: this was response to Robert. I previewed it and walked away thinking it was posted.
I haven't tried loosening the mount yet. I can't tell if it's original or not. Is your slave tight in its mount? I have two of those mounting bands, and my slave is a little jiggly in both of them. It would work fine, but I put a strip of gasket material in there to make it tight.
Maybe when mm checks in he'll know the length of a factory actuator pin.
Thanks for the help.
Edit: this was response to Robert. I previewed it and walked away thinking it was posted.
Last edited:
Mastiff
Member
2 3/4" would certainly work, though it could be longer and still work too. I'm a little unclear on what happens when it's too long. I think from other threads of yours I've read, you are saying that there really is nothing to stop the fork from going right up into the clutch pp body and getting shredded if the throw is too long? If so, that's just awful design! Ideally then, what stops the travel? Does the pedal stop up against the firewall, or the slave or master reach full travel? The slave only has a little piece of wire holding its piston in if I'm looking at it right...
With the fatter fork it looks like the fork hitting the bellhousing could be a hard limit, so ideally that would bottom out before the fork hit the clutch housing?
I want to make sure I go about the tuning process properly.
With the fatter fork it looks like the fork hitting the bellhousing could be a hard limit, so ideally that would bottom out before the fork hit the clutch housing?
I want to make sure I go about the tuning process properly.
Robert Kenney
Super Moderator
The components within the IH bell housing are basically the same as has been used since clutches were introduced.
There is no stroke limit for the tob. Only the design of the master and slave. All limits/specifications assume things are assembled correctly.
Yes the pedal does hit the firewall well actually the Scout has a small round bumper that the pedal bottoms on.
Hydraulically the system can not hyper extend, 5/8 slave with a given stroke, 5/8 master of a limited similar stroke under normal conditions never over strokes. In your situation things were not correct and you ended up over stroking the tob and pp till the levers bottom on the disk hub (deduced not witnessed). Not ever possible when set up per proper technique. Not saying you did a poor job but using it to explain why no hard stops are built in to a master slave system.
Proper pedal free play, proper tob to pp clearance and a properly assembled and adjusted pp you will never have a bottoming issue.
As the friction disk wears down the slave piston will be positioned further and further into the slave bore. Make sure you have enough remaining so the piston doesn't bottom. Back the fork stop off and by hand pull the fork back into the slave till it bottoms. That is your wear limit. You will need to monitor the tob free play as you drive your Scout over the years. The free play will go away as the clutch wears.
Robert Kenney
Super Moderator
I was referring to the release position like when your foot is off of the pedal. As the clutch disk wears(looses thickness) the pp fingers reach further toward the through out bearing. Thus the slave will need to be able to retract further.
Mastiff
Member
Oh okay. That makes sense.
I trimmed my pin down a little bit and everything seems to be functioning well now. There was a little bit of shimmy and noise (not much, but some) when the to just touched the clutch, like with the weight of my foot on the pedal. It seems to have gone away after the test drive though. Should I worry?
Also, the little spring I have on there doesn't always seem to draw back the fork to the stop. I can easily bring it back by hand, so I think maybe I just need a little stronger spring. It makes me wonder though, should there be any grease at all on the tranny snout for the to to ride on? I think I asked this when I was assembling everything and the answer was no, but it seems odd to have no lube on a friction surface like that. I think I put a film of rem oil on there but nothing else.
Anyway, it seems I dodged a bullet not having to pull the clutch or anything. It's seems to be working perfectly now.
now back to dialing in the engine.
Robert Kenney
Super Moderator
If it went away I would not worry about it.
Some tob hubbs have zirk fittings on them,
grease is the stuff to use but if you can not brush a bit on it now, don't worry about it.
Anyway, it seems I dodged a bullet not having to pull the clutch or anything. It's seems to be working perfectly now.
Glad it worked out for you.
Mastiff
Member
Well, that noise I was trying to explain above is actually not going away. Maybe I imagined that it did, I don't know. I have a noise and slight vibration when I'm at partial clutch. Full clutch and it goes away. It sounds sort of like the sound when they are making you a duplicate key, but not so high pitched. A periodic scraping sound. My only guess is that the clutch fingers are not all contacting at the same time? Or maybe its normal... I have no top plus numerous gaping holes into the engine compartment. I hear everything. What do you guys think?
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
There are two types of clutch throwout bearing collars used in these vehicles.
One of the collars has a roll pin inserted in it's periphery to prevent collar/inner bearing race rotation when the crankshaft is in motion.
The other type has no roll pin or any other method used to stop the entire bearing assembly from rotating continuously.
The "stopped" collar unit is quiet in operation, but it also wears tremendously at the two points where the fork contact points engage it in the slot. Over time, the wear of the fork tips and the two wear points in the collar groove, add up to the incorrect clutch throwout travel which is the root cause of all these issues!
The collar with no positive stop is noisey, but it also does not exhibit the two distinct wear points thus it's "better" over the long term, resulting in only the two points on the throwout fork wearing down over time like yours did (and everyone else's!!).
I "repair" the throwout collars with the stop pin by moving it to a new position. Eliminating the pin will not work on those due to the extreme wear points impressed into the groove, we can only "relocate" the wear points to an area where they are inconsequential when used with a remanufactured throwout fork. The only other choice is having new collars machined which we May have to do in the future, but those items would be very pricey.
The slight pedal pulsation you feel when "riding" the clutch is perfectly normal with any manual clutch. No doubt the pressure plate could stand to be rebuilt/adjusted, but it's sure not worth it to do so until it fails in my book. Don't obsess over stuff like that, these vehicles are one step removed from an IH manure spreader, they are not "finely crafted" examples of motor vehicle engineering!!
Robert Kenney
Super Moderator
Sure tell him that while I expect my Scout to keep up with kalifornicat spaztic drivers.
but seriously mastiff this is exactly the right mind set to have on these trucks as they are off-spring of a tractor.
