Hydraulic Clutch Smarties Needed

[sik68]

Hi, I'm hoping you have ideas on why I'm having a problem with my hydraulic throwout bearing.

I installed the Mcleod 1400 series slip on throwout bearing, and for the first couple of clutch pedal pushes, I would just barely get the clutch to disengage near the end of pedal stroke. However, a few pumps later, it would not disengage. I guessed at a leak, and sure enough, there was a small puddle of clutch fluid in my bellhousing that I could feel through the clutch fork hole. Drat.

I thought it was a leaky fitting...so today we pulled the transmission off the bellhousing but kept the hose attached. Then we put 2 C clamps on the throwout bearing piston so that we could lightly push the pedal confirm that it was the fitting leaking. It was not the fitting, and we could not reproduce the leak! We could reproduce the leak when only 1 C clamp was on though, as the piston would slightly tilt, making a poor seal. Reinstalling 2 clamps, the leak would not occur, and the pedal did not budge as expected since the C clamps prevent any travel (I did not push the pedal any harder than it takes to disengage a clutch). I don't know why the TO bearing seemingly leaks while pushing against the clutch fingers, but not one bit when pushing on C clamps.

I have 2 ideas, but I don't want to bolt this thing back together until I'm sure I know what the problem was.



1) The seals of the bearing are very sensitive to any angle-ing of throwout bearing. Since the slip on bearing actually threads onto a sleeve, perhaps it is the tolerancing of the threads between the bearing and the sleeeve. The sloppiness in the threads is noticeable because you can wobble the throwout bearing by hand. Right now I only have 3 turns onto the threaded sleeve, and Mcleod includes a spacer sleeve that I could use, which would allow me to engage more threads.

2) If you are familiar with centerforce clutches, then you know they sometimes put a ring of weights (for additional torque capacity) onto the pressure plate fingers. I am wondering if these weights are interfering with the TO bearing. The more I studied it, the less I think this is likely, as the weights look like they stay out of the way.

I'm throwing those 2 ideas out there, but right now I am stumped and don't want this problem to come back to haunt me because of not making any corrections.

Thanks,
Steven

[sik68]

Bump! Moving up
EDIT: my issue was not solved.

[Larry Callahan]

What was it?

[Tom 72RS/SS]

Yeah, I'd like to know too.

[sik68]

Misunderstanding! I was bumping this thread up because the thread with the question about the nut was solved.

I'm still hitting refresh every 30mins hoping for some answers!

[Jim Nilsen]

Hi, I'm hoping you have ideas on why I'm having a problem with my hydraulic throwout bearing.

I installed the Mcleod 1400 series slip on throwout bearing, and for the first couple of clutch pedal pushes, I would just barely get the clutch to disengage near the end of pedal stroke. However, a few pumps later, it would not disengage. I guessed at a leak, and sure enough, there was a small puddle of clutch fluid in my bellhousing that I could feel through the clutch fork hole. Drat.

I thought it was a leaky fitting...so today we pulled the transmission off the bellhousing but kept the hose attached. Then we put 2 C clamps on the throwout bearing piston so that we could lightly push the pedal confirm that it was the fitting leaking. It was not the fitting, and we could not reproduce the leak! We could reproduce the leak when only 1 C clamp was on though, as the piston would slightly tilt, making a poor seal. Reinstalling 2 clamps, the leak would not occur, and the pedal did not budge as expected since the C clamps prevent any travel (I did not push the pedal any harder than it takes to disengage a clutch). I don't know why the TO bearing seemingly leaks while pushing against the clutch fingers, but not one bit when pushing on C clamps.

I have 2 ideas, but I don't want to bolt this thing back together until I'm sure I know what the problem was.

1) The seals of the bearing are very sensitive to any angle-ing of throwout bearing. Since the slip on bearing actually threads onto a sleeve, perhaps it is the tolerancing of the threads between the bearing and the sleeeve. The sloppiness in the threads is noticeable because you can wobble the throwout bearing by hand. Right now I only have 3 turns onto the threaded sleeve, and Mcleod includes a spacer sleeve that I could use, which would allow me to engage more threads.

2) If you are familiar with centerforce clutches, then you know they sometimes put a ring of weights (for additional torque capacity) onto the pressure plate fingers. I am wondering if these weights are interfering with the TO bearing. The more I studied it, the less I think this is likely, as the weights look like they stay out of the way.

I'm throwing those 2 ideas out there, but right now I am stumped and don't want this problem to come back to haunt me because of not making any corrections.

Thanks,
Steven

When I talked to Mccleod about their bearing I asked them if I was able to use it with a Centerforce clutch and I was told the weights would have to be removed because their bearing doesn't like the weights for clearance reasons.

I would call them and ask, they seemed very knowledgable and saved me a lot of money being honest about it all.

I kept my Howe and just put a new seal kit in it that they sent me for free, they had size the o-ring wrong by just a couple of thousands in the first batch that I had mine from. All is good now.

McCleod told me I could remove the weights off of the clutch but they are there for a reason and I wanted to leave them on.

Goodluck

[sik68]

Thank you very much Jim! I may take off those weights since as of right now, I am further invested then you were. The more I think about those weights, maybe that is the correct solution. I'll make a quick video of that in a minute here.

Here is a video of my first idea, with the sloppiness in the threads:

[Tom 72RS/SS]

Wow, that is a lot of slop and I know that the tolerances for hyd. clutch are very tight. As much as I've talked about switching to hydraulic, I don't want to deal with these kinds of issues.

[sik68]

Here's a video of the second idea, that seems to indicate what Jim Nilsen talked about with Mcleod.

[Jim Nilsen]

The rocking of the bearing actually helps it self align but the weights do look like they can get caught on the sides making the bearing shift and leak.

Once you get it all working it won't seem so bad but getting there sometimes is no fun. I wouldn't go back to a clutch fork if hydraulics were double. The Howe,Quartermaster,and the factory style seem to all work with the Centerforce clutch but the McCleod is larger in diameter I from what I see.

You're very close.

[sik68]

Well, there goes my centerforce warranty...I'd rather have a running car.


I took the weights off in 2 steps:
Disclaimer: I am not condoning nor responsible for your actions
1) Using multiple flathead screwdrivers, use them to pry the outer thick ring from out behind the weights.
2) Using a Dremel to cut the thin ring.

After removing, we spent the rest of the afternoon reinstalling all the stuff we took apart. Tomorrow we will test to see if it works.

[latamud]

Here's a video of the second idea, that seems to indicate what Jim Nilsen talked about with Mcleod.

The weights are under centrifugal force, as long as they are spinning they will want to spread outward away from the throwout bearing. Even when disengaging the clutch and the fingers flatten out.

My vote is on idea number one, the loose threads allowing the bearing to misalign and causing the o-ring to open up a little. Imaging holding a bare o-ring between your thumb and forefinger, now squeeze. At two points the ring expands. Now picture the same ring wrapped around a rod, squeeze it again between fingers. It will be tight at the point where your fingers contact, and the pressure you're putting on the rubber spreads out expanding the outer sides ovalizing the ring until you release it I would bet the threaded base you are using has compromised tolerances.

[sik68]

The weights are under centrifugal force, as long as they are spinning they will want to spread outward away from the throwout bearing. Even when disengaging the clutch and the fingers flatten out.

Very true...but it is not clear how the weights react when the starter is cranking or when at idle. I'm banking on the hope that it is the fault of the weights.

[latamud]

Very true...but it is not clear how the weights react when the starter is cranking or when at idle. I'm banking on the hope that it is the fault of the weights.

I was editing my post while you were responding to me. I suppose t idle the weights could fall and sit on top of the bearing and the weight could cause the TOB to misalign momentarily. If you read my theory of what the o-ring is doing in my edited post the weights could contribute to the problem. I still think the fact that you have slack in the TOB could cause the leak.
I have the same slip on TOB on a Ford T5 that leaks when it sits for a long time. I think it is due to temperature related expansion and contraction while the car sits in storage. Mine is 5 years old and only now starting to leak. It does not have any slop, it is still very tight.

[sik68]

Update for everyone:

Today, after removing the weights from the clutch and reinstalling all the components, the clutch worked well and I drove the car for the first time in 2.5 years when the whole project got started. Ran through all the gears and reverse several times. The hydraulic clutch feels very smooth, and even with the dual friction clutches being notoriously stiff, I think the hydraulic TO bearing is very effective at minimizing the effort...it doesn't feel too stiff at all and I'm 150lbs.

I ran into a problem though, as after 50+ good shifts, all of a sudden the car wouldn't go into any gear. I think I have air in the line still and the air reached the piston. Is this a symptom of air in the lines? The amount of fluid in ther reservoir remained the same so I'm pretty sure it's not a leak

[Jim Nilsen]

Update for everyone:

Today, after removing the weights from the clutch and reinstalling all the components, the clutch worked well and I drove the car for the first time in 2.5 years when the whole project got started. Ran through all the gears and reverse several times. The hydraulic clutch feels very smooth, and even with the dual friction clutches being notoriously stiff, I think the hydraulic TO bearing is very effective at minimizing the effort...it doesn't feel too stiff at all and I'm 150lbs.

I ran into a problem though, as after 50+ good shifts, all of a sudden the car wouldn't go into any gear. I think I have air in the line still and the air reached the piston. Is this a symptom of air in the lines? The amount of fluid in ther reservoir remained the same so I'm pretty sure it's not a leak

Check the linkage and make sure they are all coming back to center. if more than one doesn't come back to center it can sort of lock up the shifter because of the misalignment. It probably isn't the clutch at this point. One or 2 turns on the linkage can make the world of difference.

Glad you got it to this point, not much further to go.

[sik68]

Check the linkage and make sure they are all coming back to center. if more than one doesn't come back to center it can sort of lock up the shifter because of the misalignment. It probably isn't the clutch at this point. One or 2 turns on the linkage can make the world of difference.

Glad you got it to this point, not much further to go.

Hmm, I'm not sure what you mean about linkage. I'm running a TKO500 and a Pro 5.0 shifter. Do I need to take the shifter off?

Thanks for hanging with me!
Steven

[David Pozzi]

TKO's are known to have shifter dis engagement issues. The heavy gear can keep moving by it's inertia and go into another gear instead of stopping in neutral, while the stick is engaged with another rail.

Hard to describe but do a search on it. Here is one: http://www.chevelles.com/forums/showthread.php?t=219156

[sik68]

TKO's are known to have shifter dis engagement issues. The heavy gear can keep moving by it's inertia and go into another gear instead of stopping in neutral, while the stick is engaged with another rail.

Hard to describe but do a search on it. Here is one: http://www.chevelles.com/forums/showthread.php?t=219156

Hi Mr. Pozzi! I sure hope that's not my issue. Before the problems engaging gears, I felt like I was bottoming out the clutch master cylinder (pedal comes to a hard stop well before it reaches the floor and I was getting over 1" of cylinder rod travel) and was only barely disengaging. The way I have my clutch set up I should have disengagement very soon after I push the pedal, which I wasn't getting until about 3+ inches of pedal stroke.

The way the gear engagement problem started with my car is that I was in reverse, which was hard to engage and I had to pull a bit more forcefully than other times I reversed. Then, I pushed the clutch in and then shifted into neutral and went to put it in 1st and it would not go...almost like there was no gate for 1st all of a sudden. Then I tried 2nd and not there either...figeting among 1st through 3 trying to find a gear, it would ONLY go into 4th. Since I had to get home I did a 4th gear start with an aluminum flywheel. Haha. Actually it wasn't THAT bad.

EDIT: It's going to be great meeting you and the Mrs. at upcoming Bay Area events. Any events on your calendar in Jan. or Feb.?

[Ollie8974]

You may have too much clutch travel and are over centering the fingers.
Have you read this post? the op broke the clutch linkage and was installing a stop.
https://www.pro-touring.com/forum/sh...ad.php?t=62008