Diagnosing a Worn Clutch Master or Slave

[Blind Driver2]

My clutch is engaging too fast. I have to push it all the way to the floor to disengage the clutch. I read a bunch of threads, but they always come up how to bleed or replace components, or how to replace the rod.

Did I miss a thread?

 

[lotzagoodstuff]

You most likely have one of two issues:

1) air in the master and/or slave cylinder

2) worn out clutch pedal bushing

Do a search, lots of info on both, but i would have somebody look at your clutch pedal/linkage 2 while you push the pedal. Very popular to retrofit with a rod end. Again very well documented.

A little inspection and some quick research and you should be able to find your issue.

Good luck

 

[jwalterus]

check play in the clutch pushrod, and check if the eye that snaps onto the pedal is worn

 

[IDIoit]

as stated, you either have worn linkage,
or air in the system.
the only 2 other options that could be causing your problem is a busted clutch fork, or a worn clutch.

 

[IDIoit]

you can also work the pedal,
sometimes when my truck is cold, I have to press the clutch pedal in a few times to get it to go into reverse.
its an easy test.

 

[riotwarrior]

Take a flash light....open drivers door...look directly above throttle pedal...should see an arm w a pin passing into a rod end...worck clutch by hand see if slop is there or worn eye...also watch if shaft going from pedal across to little arm wiggles weird...it could be worn cross shaft bushings...likely..or worn rod and pin...likely...both is common...

Good luck.

 

[Blind Driver2]

The pedal has about 1" of free travel before any action happens. I'll check it out closer tomorrow.

 

[austin92]

The pedal has about 1" of free travel before any action happens. I'll check it out closer tomorrow.

That should just be the return spring doing its job to keep pressure off the throw out bearing. Could also be the rod going into the master cyl out of adjustment


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[Macrobb]

That should just be the return spring doing its job to keep pressure off the throw out bearing. Could also be the rod going into the master cyl out of adjustment

No, NO, no.

The ZF clutch throwout bearings are always engaged, with a fairly hefty spring inside the slave cylinder if nothing else.

On the master side, you should have a /little/ free play between the pedal in the 'up' position and where it starts engaging the master cylinder... I'd aim for maby 1/16" or so. Just enough to make sure that when the pedal is up all the way, it is /not/ prematurely engaging the master cylinder.

 

[austin92]

No, NO, no.

The ZF clutch throwout bearings are always engaged, with a fairly hefty spring inside the slave cylinder if nothing else.

On the master side, you should have a /little/ free play between the pedal in the 'up' position and where it starts engaging the master cylinder... I'd aim for maby 1/16" or so. Just enough to make sure that when the pedal is up all the way, it is /not/ prematurely engaging the master cylinder.

Yeah, it's always spinning but the first inch or so of the clutch pedal doesn't pressurize the hydraulic clutch system. Kinda why you're not supposed to drive with your foot resting on the clutch pedal, keeps pressure off the TOB.


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[Macrobb]

Yeah, it's always spinning but the first inch or so of the clutch pedal doesn't pressurize the hydraulic clutch system.

I don't see any reason why you should have such a large gap. If the master cylinder is all the way in the 'retracted' position, whether you have .001" or 100 inches of free-play in the linkage makes no difference to the resting position... however, it makes a big difference when you go to activate the pedal. The less free play, the more actual hydraulic travel you get.
And, especially on earlier model trucks, you want as much travel as you can get due to the firewall flexing and 'eating' up some of the travel.

In addition, you want as much disengagement as you can if you expect the transmission synchro's to last - when you end up only mostly disengaging the clutch, it's really ******* those synchros.

Kinda why you're not supposed to drive with your foot resting on the clutch pedal, keeps pressure off the TOB.

Actually... I'm still not convinced that it matters with this truck. In a different application, where the throwout bearing is /not/ always spinning, I could see it matter, but I'm not sure it makes much of any difference when it's spinning already.
Now, I'm just talking about 'resting your foot', and not putting any large force on it.

Pretty sure that most of the throwout bearings getting worn out on IDIs is due to the grease leaking out more than any other cause.

 

[austin92]

I don't see any reason why you should have such a large gap. If the master cylinder is all the way in the 'retracted' position, whether you have .001" or 100 inches of free-play in the linkage makes no difference to the resting position... however, it makes a big difference when you go to activate the pedal. The less free play, the more actual hydraulic travel you get.
And, especially on earlier model trucks, you want as much travel as you can get due to the firewall flexing and 'eating' up some of the travel.

In addition, you want as much disengagement as you can if you expect the transmission synchro's to last - when you end up only mostly disengaging the clutch, it's really ******* those synchros.


Actually... I'm still not convinced that it matters with this truck. In a different application, where the throwout bearing is /not/ always spinning, I could see it matter, but I'm not sure it makes much of any difference when it's spinning already.
Now, I'm just talking about 'resting your foot', and not putting any large force on it.

Pretty sure that most of the throwout bearings getting worn out on IDIs is due to the grease leaking out more than any other cause.

Ok....


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[Blind Driver2]

I just noticed that my steering column moves down and to the left when I depress the clutch pedal. I guess this would explain the 1x1 piece of steel tubing that is welded from the floor to the column.

Too much firewall flex I guess. At least I know why the clutch grabs too fast

Truck is currently on Craigslist. Hope it sells

I only bught this truck to put a clutch in it and resell anyway