Hard To Push Manual Clutch Pedal NV4500

[doober]

Hey Guys, On my 92 6.5 pickup my clutch pedel has become harder to push. It is the NV4500 manual transmission. It is pushing hard enough that I broke out the bottom of the plastic master cylinder housing. I have since put a new master cylinder on. I have searched around and would like all the experts advice. I even stopped at a transmission shop and they told me to start by changing the Slave cylinder because that could be corroided up and causing the pedel to push hard. I don't know if I am buying that though. I have the exterior slave cylinder and it would be easy to replace if you guys think I should start there.

It feels like to me as though the throwout bearing isn't sliding smoothly on the aluminum snout. The strange thing about it is when I leave in the morning the clutch pedel pushes pretty easy. Once down the road a few miles it starts to push harder. You can start to feel the clutch pedel sorta pulse all the way down. Almost like the throwout bearing has turned at an angle on the shaft and it acts like it is catching all the way down the shaft. Why it doesn't do this for the first five minutes of the day is beyond me.

I took the truck to the cities last week and I was worried I would blow out another master cylinder because it started pushing pretty hard. I could live with it but it just isn't safe because you never know when the master cylinder will decide to fail.

You guys have taught me to research all I could and not throw parts at it. So instead of just putting on a slave cylinder I am asking you guys for advice first before putting on the slave cylinder. Thanks for all your help guys.

 

[bison]

sounds like you said,throwout bearing assembly locking up on the guide,a worn out clutchfork ball and socket might make it worse.

 

[chevyCowboy]

iv got my tranny out right now and evidently the pilot bearing had been bad for saome time beacouse now my input shaft is toast. the snout is all worn funny. i never experinced any of the sytmptoms you are talking about tho.

 

[midniteplowboyy]

Sounds like the clutch pivot ball and fork is worn.

 

[bison]

iv got my tranny out right now and evidently the pilot bearing had been bad for saome time beacouse now my input shaft is toast. the snout is all worn funny. i never experinced any of the sytmptoms you are talking about tho.

you can weld the tip of that input shaft up and have it turned back to size,prob a lot cheaper than buying new.

 

[doober]

I just wonder why though if it is the ball and fork that is bad why the pedal pushes easy for a while. It seems like once things warm up it starts to push hard.

 

[doober]

Just alittle more information that I want to share. A few months ago I had a fuel leak. The hose that went from the filter housing to the injector pump was leaking. I think there is a drain hole towards the back of the block. I am not sure but doesn't that hole lead down somewhere down by the bell housing?

 

[SmithvilleD]

Even with the high pedal effort, is the clutch releasing fully?

It's common for the roller bearing pilot bearings to fail after some miles. Reports make it sound like dirt gets in & when they go bad, they soon take the input shaft end out. The snout the throw out bearing rides on can get buggered up, which makes that front bearing holder/snout a commonly sold replacement part.

Lots of guys recommend going back to the old "oilite" type bushing, or possibly the Kevlar replacement pilot bushing instead of the OEM bearing. Seems like Southbend Clutch used to have an article disussing the merits of roller pilot bearing - vs - bushing, but I wasn't able to find it in a quick search.

If memory serves, the article I read didn't sound like any of these options was full-proof.

The Dodge NV4500 trans have a bit bigger, sealed roller bearing/diameter input shaft pilot tip as OEM. They can also get an aftermarket bigger bearing that can be fitted with a machine work opening up the hole the bearing sets in.

I had an issue with occasional poorly releasing clutch that got worse over time until it just wouldn't release at all. It ended up being part of the metal hydraulic line had worn throw & was leaking.

If the truck has high miles & you don't have any details about recent clutch/flywheel/pressure plate/throwout bearing/pilot bearing, I suspect the best plan is to pull it apart so you can see what's what & replace what's necessary.

 

[SmithvilleD]

If you end up having a buggered input shaft welded & turned back to size, you might want to do some research on what pilot bearing/bushing is recommended for that situation.

Seems like I've heard the relative hardness of welded/turned input shafts should be compatible with the pilot bearing/bushing used if the weld material is of notably different hardness.

 

[doober]

Thanks for the help. But I don't think it is my end shaft that is bad. The clutch is releasing fully. Something just seems like it is binding. To me it just seems like it is that throwout bearing that slides on that snout. I am wondering if fuel got into that bell housing and got flung around? I am not sure but it seemed like this all might have started when I fixed the fuel leak. I suppose I could dump some more fuel in the valley and see if it gets better lol. This could be in my head but it seemed like if it was real cold out it worked better for a longer time before it got hard again. I just wonder if there was some frost on the snout? I also wonder if there was fuel getting in the clutch area that it collected alot of clutch dust and now that I fixed the leak it is gummed up? Would that be possible?

 

[SmithvilleD]

Most blocks I've seen have a little tube connecting that valley drain hole to an outlet above/around the oil cooler lines one the left/driver's side of the block.

So if that tube is intact, liquid entering that valley hole, should exit out the side of the block - not inside the bellhousing.

 

[doober]

Thanks, I thought someone might bring this up. I put this new to me engine in and I was in a hurry. If I remember right I did put some silicone around the tube in the valley. But for some reason I couldn't get it to line up real good at the hole on the block down by the cooler lines. If I remember right I had to wiggle it around quiet a bit to get it to fit. I probably don't have a good seal, either at the back of the valley or down by the oil cooler lines. This might be my problem?

 

[Slim Shady]

Have you greased the fork ball, there is a grease fitting on the lower portion of the case in the webbing, by the right side. You may need to clean out the crud to find it, Use a good grease gun and lube that up and see if your stiff pedal doesn't go away.

 

[doober]

Hi Slim Shady, Yea I did grease that fork ball. It didn't help. Does anyone think it might be the slave cylinder causing this problem? The transmission shop said I should try that first before pulling the tranny. It costs 40 dollars but if no one thinks that is the problem I would spend the 40 somewhere else. Thanks.

 

[bison]

Yea,a seized slave piston could be the prob as well,after reading the first post again i noticed you popped the master cyl,i thought it was the slave you popped apart.

 

[doober]

Bison, You made me feel alittle bit better. The slave cylinder would be a easy fix. I am going to get one Tomorrow morning and give that a try. The transmission specialist said to start with that. He said he sees that problem with the slave on fords alot. He also said he doesn't see it so much on Chevy's. It's worth a try before I pull the tranny.

 

[Slim Shady]

The slave cylinder pushes on the rod that pushes on the throw out fork which makes the throw out bearing move on a hollow tube which in turn makes the throw out bearing contact the clutch pressure plate spring plate compressing them .

If the pedal is that hard, there is something really wrong. My clutch fork was worn almost through where it pivots on the ball, this throws the whole geometry off. My pedal was stiff but not that stiff. There is an inspection cover on the side have you removed it and looked in the housing?

I have a handshaker and have removed it and replaced the dual mass flywheel with a LUX flywheel and clutch kit, been happy with it so far.

 

[bison]

Any thing is possible,
If the clutchfork socket would be worn to one side of the fork,it might cause the long slave pushrod to push under an angle,forcing both the slave piston and the release brg to one side of their respective guides. Over time one or both might wear enough to start to jam and cause problems.
The General did'nt deem it nessecairy to provide a decent inspection hole,so its hard to tell exactly whats up till one tears it apart.

 

[doober]

Yes, I just picked up the slave cylinder. If that doesn't work I will be pulling the tranny. That darn inspection hole is only really good for guiding the slave cylinder pin onto the fork it seems. Not only that the ss diesel cross over exhaust happened to be right up tight to the inspection hole cover. I would have to pull the cross over pipe off to look into the inspection hole. Do you think I should pull the cross over off? I don't know if I would really see anything anyway.

Ha, I was even thinking of using a hole saw to make a larger 2" hole in the housing so I could see what is going on. I was going to put a plastic plug from home depot in there LOL. 220,000 and original fork so it might be getting wore.

 

[Odlaw]

Sounds like the clutch pivot ball and fork is worn.

What he said....

After blowing out several master cylinders finally took my ole girl to a tranny shop. The pivot ball had never been lubricated and the ball wore a hole right through the fork. In case you didn't know there is a grease fitting bottom center for lubing the pivot ball. Only takes less than half a pump on a grease gun.