Clutch Troubleshooting

[AeroF16]

Many of you probably know that I’m working through a clutch issue. Wasn’t sure if it was the trans or the clutch but today I had the opportunity to drive a 2018 Hellcat 6 speed with a Barton shifter and the CDV delete done, which is the same setup my 2016 has. The 2018 drove great, so something is definitely up with mine. Both stock clutches.

The first thing I noticed was how stiff the 2018 clutch pedal was. Makes mine feel like a clutch from a Honda Civic haha. So I’m inclined to think that my clutch isn’t fully disengaging.

I had the trans out and replaced the slave cylinder, so it’s not that. I’ve bled the clutch as much as possible, so more of that isn’t going to help. I’m down to changing the master cylinder and, if that doesn’t work, assuming the pressure plate has somehow failed and isn’t releasing the clutch all the way.

Any thoughts? Symptoms are random difficulties when shifting up from one gear to the next and apparently a soft clutch pedal. The clutch pedal does have a decent amount of resistance and does come all the way back up to the top when released.

 

[BULL]

It's a stab in the dark (almost), but are you comfortable with the pilot bearing alignment?

(Subscribed)

 

[AeroF16]

It's a stab in the dark (almost), but are you comfortable with the pilot bearing alignment?

(Subscribed)

I didn’t take a look at it specifically, not sure how I’d know without pulling the clutch and if I do that, I’m replacing it all anyways haha.

Care to elaborate?

 

[BULL]

My limited understanding of the issue is that the pilot bearing (it's sometimes a bushing) can be either just plain bad, or installed incorrectly (cocked/skewed).

Or alternatively the transmission input shaft can be out of alignment with it, causing binding. What I've never understood is what can be done about it?

Maybe @hellno or somebody else can provide better expertise.

 

[AeroF16]

My limited understanding of the issue is that the pilot bearing (it's sometimes a bushing) can be either just plain bad, or installed incorrectly (cocked/skewed).

Or alternatively the transmission input shaft can be out of alignment with it, causing binding. What I've never understood is what can be done about it?

Maybe @hellno or somebody else can provide better expertise.

When I re-stabbed the trans it went in nice and smooth, so I assume it wasn’t getting wedged against the pilot bearing.

 

[AeroF16]

Well at this point I guess I’ll order a new master cylinder/clutch pedal assembly and give that a shot.

I think they’re around $200 and it’s worth the gamble before pulling the trans again haha. Still open to any ideas anyone else might have.

 

[BULL]

 

[AeroF16]

Funny enough, the prior owner swears the trans shifted perfectly smooth when he sold it to me. I spent a lot of time chatting with him prior to the sale and actually still chat with him once in a while, and I don’t take him as the type to lie about stuff like this (though it’s possible) based on many other conversations we’ve had. I knew I was taking a bit of a risk not driving it but I was (and still am) ok with that. Tried to get Dodge to inspect it but they couldn’t get it in for two months.

It has had this issue since day 1 of me getting it off the trailer though, maybe it’s possible the master cylinder failed due to the extreme cold over the Winter? Just a guess, and a hope haha.

 

[Hickster]

Damn man,,, not good. It is a bearing and I have a 2018 and I am perfectly happy with the stock set up. One of my vets had that same issue and finally the clutch went out all together. It was the throw out bearing. This, damn could be a few things. Start with the cheapest fix 1st.

 

[AeroF16]

Damn man,,, not good. It is a bearing and I have a 2018 and I am perfectly happy with the stock set up. One of my vets had that same issue and finally the clutch went out all together. It was the throw out bearing. This, damn could be a few things. Start with the cheapest fix 1st.

I already pulled the trans to clean and re-lube the input shaft, replaced the throw out bearing while I was in there with a new one.

Flushed the system and put new fluid in. Next cheap thing is the master cylinder, which is attached to the clutch pedal assembly. If not that, then I’ll replace the clutch.

The inconsistencies and difference in performance based on temperature makes me think it’s a fluid thing, maybe some seal has failed in the master cylinder.

Either way, I’ll find it and fix it. I love working on my car and don’t mind spending a few bucks to get her back to perfect but I’m impatient and guessing at the problem is what’s driving me crazy haha.

 

[Hickster]

If you had a bad seal then air would be in the system and your foot would go to the floor. Sounds like you have a lot of time in this project. Right fluid? Bad master cylinder,,,, you would think it eat your ass up with problems. Process of eliminations.

 

[BULL]

When you first got this back together, you stated it was good (paraphrasing) and smooth. Has that changed since you first drove it after the trans reinstall?

If the MY18 was stiff in comparison, perhaps it was suffering from the same issue as your trans input shaft was?

Or is it that while the clutch is "smooth", you're still having shifting issues?

 

[AeroF16]

When you first got this back together, you stated it was good (paraphrasing) and smooth. Has that changed since you first drove it after the trans reinstall?

If the MY18 was stiff in comparison, perhaps it was suffering from the same issue as your trans input shaft was?

Or is it that while the clutch is "smooth", you're still having shifting issues?

The best way to describe it is the clutch inconsistently isn’t fully disengaging. Some days I drive it and it shifts great, other days I drive it and it feels as if the clutch isn’t fully disengaging and is difficult to get into gear.

The stiffness I was quoting about the 2018 is in the clutch pedal. That pedal was incredibly firm compared to mine and his car shifted great.

The pedal feel is what is leading me to the master cylinder or possible pressure plate diaphragm failure. I guess air could be getting in the system but I wouldn’t know where, would have to be the master cylinder.

 

[AeroF16]

I would think, if it was the pressure plate diaphram that failed, the problem would be much more consistent but I don’t have a ton of experience in that area.

Im thinking maybe with the change in temperatures somehow fluid is getting passed the seals in the master cylinder when the pedal is depressed and not providing enough pressure to the pressure plate to fully release, but that is simply a theory (and a hope haha) right now.

For me, cold temps = hard shifts with a little grinding (very minimal). Warm temps = smooth shifts but I do occasionally push the clutch pedal down and think to myself “that didn’t seem as stiff as usual”.

 

[BULL]

I would think, if it was the pressure plate diaphram that failed, the problem would be much more consistent but I don’t have a ton of experience in that area.

Im thinking maybe with the change in temperatures somehow fluid is getting passed the seals in the master cylinder when the pedal is depressed and not providing enough pressure to the pressure plate to fully release, but that is simply a theory (and a hope haha) right now.

For me, cold temps = hard shifts with a little grinding (very minimal). Warm temps = smooth shifts but I do occasionally push the clutch pedal down and think to myself “that didn’t seem as stiff as usual”.

Not many people know this, but just as a point of reference, the manual states that to properly bleed the brakes on our cars, you're supposed to jack up the rear of the car (I forget by how much, 12"???)

I wonder if you've got a bubble trapped in the clutch line that is refusing to bleed out?

It would be subtle, but ambient air would affect a bubble like that too...

Just thinking out loud...

 

[AeroF16]

Not many people know this, but just as a point of reference, the manual states that to properly bleed the brakes on our cars, you're supposed to jack up the rear of the car (I forget by how much, 12"???)

I wonder if you've got a bubble trapped in the clutch line that is refusing to bleed out?

It would be subtle, but ambient air would affect a bubble like that too...

Just thinking out loud...

Yeah I saw that, not sure how you’re actually supposed to execute it though? Leave front wheels on the ground, then jack the rear up?

I didn’t do it though. The manual says you only need to do that in order to get all the air out “in a timely manner” or something like that. I just used my pressure bleeder and took my time, pretty confident there is no air in the system (when I bled it).

I also flushed and bled the clutch line to the slave cylinder directly too, independent of the brakes, just to ensure there was new fluid in there.

Maybe I’ll rebleed everything after changing the master cylinder.

 

[Hickster]

I can hear ya all the way over heaaa. Easy boy.

 

[BULL]

Yeah I saw that, not sure how you’re actually supposed to execute it though? Leave front wheels on the ground, then jack the rear up?

I didn’t do it though. The manual says you only need to do that in order to get all the air out “in a timely manner” or something like that. I just used my pressure bleeder and took my time, pretty confident there is no air in the system (when I bled it).

I also flushed and bled the clutch line to the slave cylinder directly too, independent of the brakes, just to ensure there was new fluid in there.

Maybe I’ll rebleed everything after changing the master cylinder.

For the "200 pumps" to bleed the clutch, do they specify a speed at which you do the pumps?

Slow, fast, with pauses?

 

[Hickster]

I can hear ya all the way over heaaa. Easy boy.

 

[AeroF16]

For the "200 pumps" to bleed the clutch, do they specify a speed at which you do the pumps?

Slow, fast, with pauses?

No. But I just do it the old school way, slow and smooth, ensuring the pedal reaches the top of its travel on the release.