Hydraulic Throwout Bearing Issues (maybe) - help!

[James OLC]

I am going to be the first to admit that clutches (et al) are not my strong suit to begin with and the T56 and hydraulic TOB in the '67 is the first one that I have ever done (besides servicing in my old WS6).

That said, as a lot of you know I was having issues downshifting the car car at the Optima challenge - the car would upsift fine but when I tried to do higher speed/rpm downshifts the transmission wouldn't slip into gear. Heck, it wouldn't be forced into gear either... some times it would go with a little more aggressive blip but not always.

Opinions at the time ranged from transmission (doubtful - new by Rockland), to fluid (it was full), to clutch/TOB engaugement (possible), and hardware issues (but after inspection nothing is loose, backed out or missing).

So, out comes the transmission. At first look everything appears to be ok - nothing is loose or appears unusual. So, following some instructions I found on the RAM site I take some measurements to see if maybe the TOB needs a shim (which was one of the more common suggestions up front).

I measured the distance from the clutch fingers to the bellhousing mounting surface - 2.25".

I measured the distance from the compressed TOB bearing surface to the plane of the transmission mounting surface - 2.4"

It would seem to be (and as admitted, I am a far cry from an expert here) that the TOB isn't compressing enough and that based on these measurements there is pressure on the clutch fingers all the time.

so...

Does anyone have any suggestions, ideas, or recommendations on what these measurement mean and what remedy there may be?

My first thought was maybe bad TOB?

Any help would be appreciated.

Thanks,
James

[camcojb]

what clutch master are you using?

Jody

[James OLC]

McLeod SFI LS bellhousing
McLeod RST dual disc clutch
McLeod aluminim LS flywheel
Stock GM hydraulic throwout bearing (new but maybe refurbished)
Rockland Standard T-56 - Son of Tranzilla

0.75" Tilton 77-series Master Cylinder with CV remote reservoir

[camcojb]

McLeod SFI LS bellhousing
McLeod RST dual disc clutch
McLeod aluminim LS flywheel
Stock GM hydraulic throwout bearing (new but maybe refurbished)
Rockland Standard T-56 - Son of Tranzilla

0.75" Tilton 77-series Master Cylinder with CV remote reservoir

does the stock GM throwout bearing have enough travel to disengage the dual disc clutch? I didn't think it did, but not positive. I thought the McLeod dual discs had their own bearing to use, mine did.

Jody

[Vegas69]

I don't know if this has anything to do with it, but when I looked at the car on Tylers lift I was a little concerned with how close your hydraulic line was to your header pipe. Does it get worse with heat?

[James OLC]

does the stock GM throwout bearing have enough travel to disengage the dual disc clutch? I didn't think it did, but not positive. I thought the McLeod dual discs had their own bearing to use, mine did.

Jody

Jody,

I spoke to McLeod earlier today... it hurts even thinking about the conversation...

It's the same thing every time I call them... "a clutch either works or it does not work, if you can upshift you can downshift... you have a transmission problem." After convincing them that I was looking the the throwout bearing as a possible issue and specifically bringing up your point, they said that "the stock GM TOB with a stock GM 3/4 master just barely releases properly and they have two solutions to ensure full release - their 13/16 master or their TOB." But again, if it upshifts it downshifts so that can't be it anyways. Man, are they defensive (to be polite).

I did also ask them about the apparent preload on the clutch fingers. Their response was that it is "perfectly normal and acceptable and all clutches have that preload. As long as the bearing does not bottom out it's not a problem." Now, that seems contrary to what most other clutch manufactures say (and when I mentioned that and the word shim he didn't seem to know that there were other clutch manufacturers) so I don't know.

Definately losing my mind here...

[James OLC]

I don't know if this has anything to do with it, but when I looked at the car on Tylers lift I was a little concerned with how close your hydraulic line was to your header pipe. Does it get worse with heat?


I guess that it's possible. I can't say for certain that I notice a worsening with heat - but that is because I tend to make sure that everything is warm before proceeding to hammer on it. I have considered a fluid issue (with respect to volume not temperature) but since one of my off season projects is heat shielding everything that even looks like it will bite me, I'll definately be covering that when it goes back together.

On the fluid volume side of things, the Tilton MC's come out of the master with a -3AN line and the factory disconnect is a -4an line. I am wondering if the couple feet of -3 vs -4 is an issue and I'm not getting proper fluid flow down to the slave. I'm going to look into that as well...

I am also going to double check runout after I pull the clutch tonight. I haven't encountered anyone who has even found an issue there with the LS engine and the McLeod stuff but it's easy enough to check again.

Jason at Katech mentioned that he has seen disengagement issues related to a bend clutch disk so that will get some attention as well.


Anything else anyone can think of looking at? Without seeing a definative problem I am at a bit of a loss for what to do next...

[Vegas69]

Reading through your comments I don't like the barely sufficient explanation for the stock throw out bearing. Sure doesn't seem like it gives you much room for error in regards to master cylinder stroke. Any variation in your bellhousing depth or pressure plate springs could easily make barely not work. If it was me I would take barely out of the equation and call Rockland. I assume it's in every gear?

[James OLC]

I have an email in to Rockland now and am waiting to hear back. I agree that it seems that 'barely' is not the word that you want to come to mind in this case but I am taking everything that I heard in that conversation with a grain of salt...

[Vegas69]

I hear ya...I know how that goes. You call in twice and get two different answers. If you can verify enough disengagment it has to be internal tranny. Can you put the bellhousing back on and simulate the tranny with a bracket and measure the clutch disengament? Did it every creep in gear with the clutch in?

[James OLC]

I hear ya...I know how that goes. You call in twice and get two different answers. If you can verify enough disengagment it has to be internal tranny. Can you put the bellhousing back on and simulate the tranny with a bracket and measure the clutch disengament? Did it every creep in gear with the clutch in?

Right now the order of the day appears to be patience (at least for the weekend) and talk to Rockland on Monday to get there thoughts.

I was just on the phone with a very well versed friend/racer and his comments came around to fluid as well. He had asked if there I noticed anything with the fluid - which in fact I had - the fluid in the reservoir was slightly cloudier than the fluid in the brake reservoirs. He came to two possible reasons (naturally) - heat and water.

Going to go crazy sooner rather than later...

[68protouring454]

not that it pertains, but i have a spec stage 5 clutch in my 69, and it needed a .110 shim to give correct throw etc. that said i have the mcloed master, stock gm internal tb, and mine line is very close tot he header as well but i have it double wrapped in heat sleeve.
does it upshift fine in all conditions?
i would agree if it up shifts good(and has same tb throw everytime), it should down shift, unless there is an internal tranny issue(syncro etc)

[tjbruning]

Not sure if this will help, but Centerforce recommended that we use a tilton 400 series release bearing. The stroke was changed using a different Tilton face bearing to get the stroke correct for our application.

Good tech in the Tilton instruction manual

http://www.tiltonracing.com/content.php?page=list2&id=209&m=d#

[The WidowMaker]

when i talked to mcleod, they were big on getting the proper engagement though the use of shims. since they sell three different thickness' of flywheels, it just complicates things even more.

+1 on the shifting. i dont see how the tob cares whether youre upshifting or downshifting. all it does is release the clutch???????????

[James OLC]

I wish that I had actually received some help from McLeod but no such luck... the guy didn't want to listen to anything after "I have a problem"... darn

I know what you are saying about upshifting vs downshifting - at least in principal - but I need to explore all of the options...

[JamesJ]

Some good info here...

http://www.pro-touring.com/forum/showthread.php?t=40904&page=3

[Vegas69]

Great info James!:thumbsup:

[JamesJ]

The trans has ATF fluid in it? If you put 30W it will have problems shifting. I have to disagree about upshifting and downshifting, upshifting is easer to do with out the RPM "matched" Drive around and shift with out the clutch and see ow it acts. Maybe you will learn somthigng else that can lead you to the answer.

[JamesJ]

when the car is sitting can you tell any difference in upshifting or downshifting? And then when the car is running is it the same? When you engage the clutch all the way can you hear any audible differences?

[fabricatordave]

http://www.thedrivenman.com/

call this guy he will talk to you he will answer call back 7 days a week usually

[James OLC]

The trans has ATF fluid in it? If you put 30W it will have problems shifting. I have to disagree about upshifting and downshifting, upshifting is easer to do with out the RPM "matched" Drive around and shift with out the clutch and see ow it acts. Maybe you will learn somthigng else that can lead you to the answer.

James - that is my opinion with respect to shifting as well. I can upshift much better (in general - not specifically with the '67) with only partial clutch or no clutch at all. My rev matching skills on downshifting can definately use improvement (and assistance via the clutch). Since the whole package (engine, transmission and clutch) were fresh I was trying to "take it easy" on everything at the time - relatively speaking.

Transmission fluid is Rockland spec Tranzilla fluid.

[James OLC]

So... couple of things already this morning. First is that I am at a loss as to how to properly gauge the throw of the TOB in it's "dissassembled" state - at least by myself. I'll get some help this afternoon because it would seem that (with the stock GM TOB) you need one person to "compress" the TOB to it's in situ depth while the other person presses the clutch pedal. Without the TOB compressed, pumping the clutch pedal has no effect other than to (eventually - with multiple pumps) pressurize the complete slave to it's full extended (dissassembled at rest) depth.

Second, I pulled the clutch out (leaving the bellhousing in place for simplicity at this point. I didn't see or find anything that stood out to me but I took some pictures of the individual components for your input:

The Flywheel and base ring:
http://www.onelapcamaro.com/OLC_pics/clutch/Base%20Ring%20and%20Flywheel.JPG

The Pilot Bearing:
http://www.onelapcamaro.com/OLC_pics/clutch/Pilot%20Bearing.JPG

[James OLC]

Flywheel Disk (back or Flywheel side):
http://www.onelapcamaro.com/OLC_pics/clutch/Flywheel%20Disc%20Back.JPG

Flywheel Disk (front or pressure plate side):
http://www.onelapcamaro.com/OLC_pics/clutch/Flywheel%20Disk%20Front.JPG

Pressure Place (back or flywheel side):
http://www.onelapcamaro.com/OLC_pics/clutch/Pressure%20Plate%20Back.JPG


Pressure Plate (front or clutch side):
http://www.onelapcamaro.com/OLC_pics/clutch/Pressure%20Plate%20Front.JPG

[James OLC]

Clutch Disk (back or pressure plate side):
http://www.onelapcamaro.com/OLC_pics/clutch/Top%20Disk%20Back.JPG

Clutch Disk (front or clutch side):
http://www.onelapcamaro.com/OLC_pics/clutch/Top%20Disk%20Front.JPG

Clutch Back (disk side):
http://www.onelapcamaro.com/OLC_pics/clutch/Clutch%20Back.JPG

Clutch Front (transmission side):
http://www.onelapcamaro.com/OLC_pics/clutch/Clutch%20Front.JPG

[James OLC]

If anyone sees anything or wants more detail on anything let me know. Like I said, nothing obvious to my (inexperienced) eye.

There is probably 100 miles total on the clutch - some polite street miles, some sort-of inpolite track miles...

And for the record - checked the transmission fuild level - it was completely full and clean with no indication of contamination.

[KEISLER]

Does anyone have any suggestions, ideas, or recommendations on what these measurement mean and what remedy there may be?

My first thought was maybe bad TOB?

Any help would be appreciated.

Thanks,
James

** DELETED BY KEISLER DUE TO IRRELEVANT CONTENT **

[James OLC]

Yeah... thanks :rolleyes:

And now back to something that's actually relevant/applicable...
(sorry pet peeve)

I'm still waiting for the replacment TOB (should be here tomorrow) but, following Andrew's advice, I picked up a proper Quartermaster machined alignment tool. More annoying than self serving tripe is the useless alignment tool that McLeod ships with thir clutch... you would think that when you charge nearly a thousand bucks for a clutch, you would include an alignent tool that fits the application (then again, I would also think that when you sell a scattershield for an LSx you would include metric hardware - but what do I know).

So the clutch is back in and as soon as the TOB show's up I'll change the hydraulic lines and reinstall everything.

[XcYZ]

Shafi, I don't see what pushing your kit has to do with the downshifting issue that James is seeing.

James, out of curiousity, did you check the bellhousing centerline alignment?

[James OLC]

I didn't see the relevance there myself...

The McLeod bellhousing makes it really difficult to check or double check any of the conventional alignment or runout specs - the big irregular hole might make it easier for some things but a consistent reference it is not. There is no indication on the pilot bearing or the input shaft of it being out of alignment but it is something that I am trying to rule out.

[KEISLER]

Yeah... thanks :rolleyes:

And now back to something that's actually relevant/applicable...
(sorry pet peeve)

I'm still waiting for the replacment TOB (should be here tomorrow) but, following Andrew's advice, I picked up a proper Quartermaster machined alignment tool. More annoying than self serving tripe is the useless alignment tool that McLeod ships with thir clutch...

James, that is a lame reply to someone trying to help you. On the Pro-Touring.com website, I responded to your same call for help on the same issue here (http://www.pro-touring.com/forum/showthread.php?t=51898&page=2). Since my post above was unclear, I'll post some more information that should be a little more relevant:

First, here is the response I posted on P-T:
"James, I have not read all of these post replies, but I can tell you that if your numbers are correct then you are constantly engaging the clutch fingers and it would be a wonder the clutch is not burned up.

If the 2.25inch number is correct, you need to reshim the bearing to 2.10 - 2.0inch compressed and not any more. You can see my comments about why on the other thread mentioned with the Pontiac guy with the Weir bellhousing.

If you hit a wall on this, PM me and we'll help you further."

It's clear to me - with the experience of selling more than several hundred of the same McLeod bearing you are using, and more than a couple hundred McLeod Street Twin just like you are prematurely toasting - that either the wrong bearing piston size was sent (bolt-on design) or you installed it wrong (slip on design). Either way the instructions that came with the product *should* have provided you with adequate information to prevent this problem.

Next, you can set up the bearing however you'd like, but I will tell you what you *should* do if you don't want to continue ruining the clutch:
1. maintain .150 +.05 / -.03 clearance from the fingers of your clutch to the face of the bearing in the compressed state
2.A) if you are using the McLeod slip on type, LOCKTITE BLUE the thread in sleeve so it doesnt' back in or out, because it will likely change position if you don't
2.B) if you are using the McLeod bolt on type, the pistons are numbered 1-8, and they increment in .200 inch. So you will will need to determine which piston change by the amount of interference or air gap. You can't do this with the unit apart as you are trying to do.
3. pre-bleed the entire system, then install it to the car and final bleed it
4. if you did everything above correctly, AND you have the correct master cylinder bore and stroke AND you have connected it to the pedal at the correct location to achieve the correct throw WITHOUT bottoming out the master cylinder before landing the pedal on the floor THEN the clutch should release at 1/3 to 1/2 of pedal travel. IF it releases at the top of the pedal, then you need to go back to square one and recheck you numbers.


A couple other tips for the McLeod hydr bearing - both slip on and bolt on:
1. if it comes with banjo joints, throw them away and make hard lines. You can get the inverted flare seat fitting with the correct male side to screw in from most any good hydraulic store
2. get a couple spare sets of o-ring kits from them 'cause you will need it and you don't want to be stuck without one. They used to send a spare oring set with the unit just for this purpose.
3. run DOT4 fluid


Good luck

[KEISLER]

Shafi, I don't see what pushing your kit has to do with the downshifting issue that James is seeing.

James, out of curiousity, did you check the bellhousing centerline alignment?

XcTZ,

The downshifting issue is very likely related to the clutch release issue. The clutch is not releasing cleanly. Once James get's the hydraulic bearing issue corrected, then he will next need to determine if the twin disk floater is moving cleanly and releasing the clutch.

Here's the "pushing sales" pitch, so brace yourself. Our hydraulic kits are a far more advanced and better design and we don't have these sorts of problems. Years ago before we discontinued the product in 2003, we sold many hundreds of the McLeod hydraulic product and the Street Twin clutch. We worked through these problems first hand, issued recall notices, issue repair/upgrade parts, issued replacement notices for the entire bearing.

In all fairness, my original post from yesterday fell short of conveying the proper level of information.

[James OLC]

I guess my frustration with your post(s) is that appears, at least to me, that (as you mentioned on the PT reply) that you haven't read through the thread and are not addressing my issue. I appreciate your input and that you have a bunch of experience but your first reply here yesterday was a promotion for a product that you offer that does not fit my car - not a solution. Your post today, while informative, is also not applicable to my circumstance. I don't have a McLeod TOB...

[James OLC]

I do agree that the clutch release and hydraulic 'system' is very probably the issue - especially given the appearance of the clutch (ie. not burnt up or abnormally worn) but again, your product does not appear to be applicable to my application (ie. Tilton 77 series MC with 900-series pedal assembly).

[KEISLER]

I guess my frustration with your post(s) is that appears, at least to me, that (as you mentioned on the PT reply) that you haven't read through the thread and are not addressing my issue. I appreciate your input and that you have a bunch of experience but your first reply here yesterday was a promotion for a product that you offer that does not fit my car - not a solution. Your post today, while informative, is also not applicable to my circumstance. I don't have a McLeod TOB...

James,
I read through ALL of this thread's post before replying today. The majority of what I posted regarding setup is relevant for the pancake style slip on CSC hydraulic bearings.

In fact, we do offer a solution for this unless I am missing something that you have declared in this thread.

Regarding your clutch, I am unsure how to read your comment about the pristine condition of the clutch. Indeed, the Street Twin clutch pictures presented are not of a pristine clutch, but one that is showing considerable signs of hotspotting and abnormal wear. I'll exit off this thread, and I wish you the best in getting it all worked out.

[JodysTransmissions]

Checking the pictures of your flywheel and clutch components, there are a lot of heat spots for only 100 miles. That tends to lean towards your clutch not fully releasing or you ride the clutch a lot to get moving. I would doubt with a 6 speed you need to ride the clutch?!

I doubt this is in the transmission issue since up shifting is fine. Hopefully this will ease your mind a bit.

Downshifting a transmission is harder than upshifting one, as you downshift, each mainshaft gear is spinning faster than the higher selected gear you shifted down from. That is why you can easily shift 1-2-3-6 but you need to slow your vehicle speed down if you want to shift 6-3-2-1.

What ever you do, you need to resolve this before you ruin your expensive clutch and your Rockzilla. Maybe an engineered hydrauilic kit might save you some money.

Those heat spots may now cause clutch chatter once your other issues are resovled.

[James OLC]

Thanks Jody, I appreciate you comments and agree. Those are the same conclusions that we've reached and we're addressing the hydraulic issues now. If need be we'll look at switching out the master cylinder to a 7/8" bore when we get the car to California.

[Avgasman]

I'll be watching this thread closely James. I did purchase an ATS modified TOB as well as the McLeod RST and am still quite a ways away from trying it out.

I do agree that those burn marks do appear to be a problem, especially with only a hundred or so "hard" miles on it.

Best of luck.

[JETSET700]

James , I hope things are getting resolved. I am yet to start my car & it has
the same or close setup from ATS. I'm not positive on which TOB I have, I think it's the McLeod bolt on. Very interested to see what your solution to problem is.

Peter

[Harri-76]

I am going to be the first to admit that clutches (et al) are not my strong suit to begin with and the T56 and hydraulic TOB in the '67 is the first one that I have ever done (besides servicing in my old WS6).

That said, as a lot of you know I was having issues downshifting the car car at the Optima challenge - the car would upsift fine but when I tried to do higher speed/rpm downshifts the transmission wouldn't slip into gear. Heck, it wouldn't be forced into gear either... some times it would go with a little more aggressive blip but not always.

Opinions at the time ranged from transmission (doubtful - new by Rockland), to fluid (it was full), to clutch/TOB engaugement (possible), and hardware issues (but after inspection nothing is loose, backed out or missing).

So, out comes the transmission. At first look everything appears to be ok - nothing is loose or appears unusual. So, following some instructions I found on the RAM site I take some measurements to see if maybe the TOB needs a shim (which was one of the more common suggestions up front).

I measured the distance from the clutch fingers to the bellhousing mounting surface - 2.25".

I measured the distance from the compressed TOB bearing surface to the plane of the transmission mounting surface - 2.4"

It would seem to be (and as admitted, I am a far cry from an expert here) that the TOB isn't compressing enough and that based on these measurements there is pressure on the clutch fingers all the time.

so...

Does anyone have any suggestions, ideas, or recommendations on what these measurement mean and what remedy there may be?

My first thought was maybe bad TOB?

Any help would be appreciated.

Thanks,
James

I had the same problems like you James. I´ve tko 600 and pretty much the same combo on my vette. I had difficulties tu shift up and down on high rev (above 2500). The problem was that I had a slight pre-compression on the clutch assembly and for that reason it didn´t reliese the clutch fully when driving hard. -> That way the sncrons won´t work the way they should and it is hard to do shifting. Let me know I´m just speeking BS, because I have learned thise things by doing something wrong in the first place.

That is my best quess right now.