McLeod RXT dual disc clutch, Hydramax hydraulic T.O. bearing installed since Oct and I have PROBLEM

[biomedtechguy]

I'm hoping that the few people on the forum that have a:
Hydramax hydraulic throwout bearing
AND/OR
McLeod RSX or RTX (what I have) dual disc clutch and pressure plate may offer advice, but I'll take advice from anyone who may be able to help.
I didn't install the setup, and while I shouldn't have to fix something that I paid good money to have done, the shop owner did so much work to my car, and unfortunately there seems to be few options available to me to have this kind of work done, I'd rather solve this myself.
Long story short, the clutch is acting as though it is not fully disengaged.
When the car is stopped, I have to kill the engine to go into reverse. The shifts are easier when RPM matched. ALL of that is telling me the clutch isn't fully disengaged.
The problem is that spacers seem to be the only solution, although the conglomeration of parts that make up the clutch rod (from the pedal to the hydraulic cylinder) do offer some length adjustment.
Advice?
I'd rather not have to remove the transmission and hope to find a spacer solution because my understanding is that due to the "step" on the input shaft bearing retainer, the aluminum anti spin spacer American Powertrain provides was machined by a shop and made to optimize the required distance to fully disengage the clutch, and "just adding a spacer" or reducing the space would be very difficult.
Thanks for any help.

 

[Jeremiah]

Did you check the clutch disc air gap with a feeler gauge to ensure there is sufficient clearance? If the bellhousing runout is out of spec you will have similar symptoms.

 

[69Bee]

I was going to look at the clutch air gap too (OEM spec is about 0.020"), but the throwout bearing should not be turning when the clutch pedal is released. I have never installed one of these, has to be a way to locate the hydraulic bearing sleeve, unless it just floats in there?

 

[biomedtechguy]

Did you check the clutch disc air gap with a feeler gauge to ensure there is sufficient clearance? If the bellhousing runout is out of spec you will have similar symptoms.

My bellhousing runout should be 100% spot on. Not only did I provide the shop owner (who did the work himself) with brand new, straight bellhousing dowels (0% offset) but all 2 or 3 offset dowels by Robb Mac. More importantly, I invested in the bellhousing runout alignment tool kit that makes it impossible to screw up the procedure as the kit has an aluminum piece that almost completely fills the hole in the bellhousing where the transmission goes through.
I haven't checked any gap.
If you look at the videos of the diaphragm springs and the hydraulic throwout bearing, you will see that the bearing outer shell turns even when the clutch is disengaged.

 

[Mick56]

I've seen where a person get the tranny half way in, and lets it hang, which can warp the clutch disk. If that happened, the disk will always be dragging, and will not disengage.

 

[5.7 hemi]

The throw out bearing should be a minimum of .125 from the pressure plate fingers. No exception. If it’s to close, you will encounter problems, just like you have mentioned. Seems to me a few shims need to be taken away from behind the throw out bearing.

 

[Daves69]

IMO, If you are not releasing the disc completely it would indicate a travel distance issue with the hydraulic bearing, or more unlikely, the input shaft binding on the crank bushing / register bearing.
Never the less, that bearing spinning while the clutch is engaged is bad news (at least it is for a B&B set up). Possible air in the system and it's not retracting? Piston bottoming out on a hard stop? Travel limits incorrect? I'm not real familiar with these. Just throwing in some ideas.
From the first video, this appears to me like the fingers are in constant contact with the bearing....

FWIW, MP indicates "approximately .060" gap for the B&B clutch set. Can be checked with a feeler gauge. Better to adjust up toward the .060". You may only need .040"-.050". You don't want to bottom the fingers into the disc rollers with too much pedal and bend or distort something.

 

[Mike67]

Sounds like the distance from the face of the bearing to the fingers maybe the issue.
I've never done a Mopar but have done this on the last two I did do using McLeod hydraulic TO.
https://www.americanmuscle.com/mcleod-adj-tob-slave-cylinder-0516-manu-install.html
https://www.hotrod.com/articles/american-powertrains-hydraulic-throwout-bearing-conversion-kit/

 

[biomedtechguy]

Thanks everyone!
I seem to recall telling Gary at American Powertrain that the silver color bearing was always spinning, but I recall him saying that's how hydraulic throwout bearings work. I am at .127" clearance, according to the shop owner/installer. That end of the range should provide the greatest push distance to disengage the clutch by pushing on the diaphragm spring.
I have to leave to go by that same friend's house. He's wrapping up a Turbo 400 transmission torque converter installation in his Conquest TSi...powered by a single turbo 2JZ 6 cylinder. BWA HAA HAAA.
I think that I should have clearance between the silver bearing and whatever is making it spin, but I'm not sure. Moving that away from the clutch would reduce the disengagement travel distance, so I have to look at this again.

 

[5.7 hemi]

The two sets of measurements provide the variables needed for the final calculation using the following formula. This equation will tell you how many shims are needed to achieve the proper air gap between the bearing and the diaphragm. The recommended air gap is .150-.200”, you can have as little as .100” (absolute minimum), but try to stay inside the recommended range. It is possible on some GM applications to not have enough room to get to even the .100”. If this is the case, you make have to shim the actual transmission from the bell housing using washers. This is due to the shallow nature of the GM bell housing design. There are 3 shim thicknesses for the big 3. Mopar uses .063, GM uses .090 and Ford uses .057

 

[Mike67]

One thing I forgot to mention , it may have been mentioned here, but is air in the TO. I used a vacuum pump, to bleed it.
Bio you may have access to an old one but I used a suction machine, we had an old one in storage that was never used, even had the glass collector, I took it to the shop and now use it to bleed brakes, and it worked great in the hydraulic clutch! Works great!

 

[biomedtechguy]

Seems to me a few shims need to be taken away from behind the throw out bearing.

That's one "unique" problem with my particular installation, and I believe that it may be common on this particular Hydramax hydraulic throwout bearing conversion kit and MOPAR 833/Passon 855 transmissions, or the input shaft bearing retainer more specifically. There's a guy w/a YouTube channel that I've spoken with. He's a real character. He too had to come up with a method of spacing the TO bearing that was not part of the kit.
In my case, the shop owner (who has done extensive work on my wife's GTO, and a little work on my Roadrunner until this latest round last year, and that was a LOT of work) he had the anti-spin collar (which also acts as a spacer) machined down to fit "just right" and provide .127" clearance.
I haven't really "checked" much of anything. That's all about to change.
I think it would be of great benefit for me to pull the transmission because that's likely going to be required to address or at least assess the problem, AND I'll have a better idea of how it's all put together.
Ideally, when you pay $9k in labor to have multiple systems and parts installed, all planned out in advance and of course the things that seem to always "come up" when doing this much work with these many systems and parts in different areas (all related one way or another to the 2 or 3 goals that were set) even those surprise add ons were discussed, ideally when I get the call "the car is ready" and pay the man, everything should be correct and ready to drive, with maybe a little tweak here or there.
BUT
In THIS case, I find out the shift linkage is flip-flopped for 1/2 and 3/4 gears on my 855 5 speed...well that makes me think I should be grateful for what was done and finish it up myself.

 

[biomedtechguy]

I've seen where a person get the tranny half way in, and lets it hang, which can warp the clutch disk. If that happened, the disk will always be dragging, and will not disengage.

Yeah, I certainly don't think that is the situation. He used a transmission jack and does work like this a lot, knows how important this is, how much the parts and systems cost, and we have had a good relationship. I am likely going to pull the trans out by necessity, but it will give me the best opportunity to understand how everything works. IF I don't have to pull it out, honestly I'd rather not, BUT if I do I'm going to make the most of it.
The RTX dual clutch and PP setup alone cost about $900 (It's the 1,000 HP version, not for the 1k HP factor but because the friction material is ceramic metallic and that's what McLeod recommended to handle the wear of the HitMaster launch control system).
Once I get THIS PROBLEM resolved, so much of the rest of the parts and systems can FINALLY come into use:
Launch control
Calvert split mono leaf springs and sliders
Viking triple adjustable rear shocks
Smith Racecraft Assassin traction bars
AND
Although the following parts are more for my BMP aluminum block based, 541 cu inch, somewhere around 6XX HP and 700 ft lbs Torque engine that I'm already invested in, they will get a "good break in" with my current engine:
Strange chromoly driveshaft, slider trans yoke, rear pinion yoke, caps. All chromoly plus solid 1350 U-Joints. USCT subframe connectors, front and rear frame boxes and rear leaf spring hanger braces.
Yep, and that's far from everything I had installed, but that's all the stuff that's dependent upon my clutch working properly, and until it does, I can't really use any of the rest.
Sincerely,
Frustrated but grateful for all of you!

 

[biomedtechguy]

the input shaft binding on the crank bushing / register bearing.

It's a bushing, and I did consider that.
I replaced it a couple of years ago and I've always been careful to note its condition and not beat it up.

 

[biomedtechguy]

From the first video, this appears to me like the fingers are

Yes, they are, and I'm pretty sure American Powertrain said that's how these work. I realize that's NOT how a mechanical clutch works, and I'm kind of starting over regarding questions for tech support just because it's been months since I started trying to figure out the problem.

 

[biomedtechguy]

Sounds like the distance from the face of the bearing to the fingers maybe the issue.
I've never done a Mopar but have done this on the last two I did do using McLeod hydraulic TO.
https://www.americanmuscle.com/mcleod-adj-tob-slave-cylinder-0516-manu-install.html
https://www.hotrod.com/articles/american-powertrains-hydraulic-throwout-bearing-conversion-kit/

THIS may wind up answering a lot of questions.
Thanks a lot.

 

[Mike67]

THIS may wind up answering a lot of questions.
Thanks a lot.

As far as the TO bearing spinning, and I'm no proffesional mechanic, I see some have said it's not supposed to spin. I cannot quote any sources but isnt why the face is a bearing ? so it can spin? .100 to .200 clearance is easily taken up with your foot on the clutch pedal (riding) with a hydraulic compared to a mechanical I would think.
When I was measuring travel on the the 6 spd in the Nova it didnt take much to start the cylinder moving.
Not arguing that it's a bad thing for it to spin, just curious if it is designed to allow that.?

 

[padam]

You have to have the proper amount of plate departure (separation of the clutch disk from the flywheel) to be able to shift.

The proper distance depends on use (racing more departure) and clutch type.
I think you need more with a marcel spring than without. I'm sure duel disks have a different number.

You have to set that distance first.

Then the pedal free play needs set so the clutch and throw out brg will live.

Linkage needs to be assembled to allow those two things to be correct.

 

[5.7 hemi]

How exactly does one set plate departure when there isn’t a way to do it. He has a dual disc set up. His TB is too close to the fingers, that’s why it dies at a stop. Move TB back, that will get the face of the bearing off the clutch fingers. As long as the brake fluid is bled, no air, then I stand by my diagnostics over the net.

Bio, when the TB was bled, did he have the bleeder inside of brake fluid?

 

[padam]

How exactly does one set plate departure when there isn’t a way to do it. He has a dual disc set up. His TB is too close to the fingers, that’s why it dies at a stop. Move TB back, that will get the face of the bearing off the clutch fingers. As long as the brake fluid is bled, no air, then I stand by my diagnostics over the net.

Bio, when the TB was bled, did he have the bleeder inside of brake fluid?

If he doesn't have enough plate departure AND the tb is riding on the fingers his linkage is seriously short of travel.