Hydraulic Throw Out Bearing

[Back in Black]

Or so it seems. WHO installed your T/O bearing? If it was Vern you can bet he did the same as he did to mine and just tossed it in there without proper adjustment. Mine was blown out on delivery due to the T/O bearing having to overtravel to dis-engage the clutch! It was "repaired" but my clutch guys assumed that the manufacturer had the T/O bearing properly set and so they just replaced the lines and bled the system. 2,500 miles later it blew again, that time due to a slow leak..

During the reconstruction of my car this winter and spring, we were going to create a pedal stop, using an Energy Systems brand hard rubber bumper mounted thru the floor/firewall to a small plate with a welded-to-the-plate nut in the center. But we discovered that disengagement occured fully at about 3/4 of an inch from the floor anyway, this with the Tilton T/O bearing and the new style Tilton lines. The new Tilton banjo fittings are supposed to be "blow proof" and I do have 400 miles now on the revival of my car.. the clutch works great/smooth/light and it's a 12 inch McLeod. I bet your T/O bearing is OK and you just need the new style Tilton lines (hopefully that's not what you have!) and to have the T/O bearing set by a pro to the proper travel.

[XXQQQME]

B in B,
Thanks for your reply. Vern did not do the installation. I have done virtually all the assembly of my car. My checkbook is quite slender compaired to most Cobra owners, and hence, I perform all the work myself. I quit smoking 9 months ago and I've been buying little gifts for myself as a reward. The new Tilton TOB is just one of these gifts. As I mentioned earlier in this thread, I've had the tranny out of the car twice before for clutch/pressure line/pressure plate problems before and I'm just not real excited about jacking this bugger a foot off the floor and crawling around beneath it. I've called a local hot rod shop: Slim's Collision and Rod Shop. I spoke to one of their mechanics and he was familiar with Cobra Replicas and hydraulic TOBs etc. I have to go to the same place for a front end alignment so I figured they might as well do the clutch work anyway. I told the mechanic I would hang around to answer any of his questions and assist if necessary. . . we'll see how it goes.

It seems every time I read more replies, I have more questions. . . so here goes,
Would it be prudent to have another clutch disc ready to install? I'm not exactly sure what failed i.e.: pressure lines, fittings or seals, so if the clutch disc has been showered with brake fluid, it should be replaced. Now for the question, the disc (from memory) is a Hays 11 inch 1.375 x 10 spline. Is anyone using something different? If so , what would be some suggestions? Please provide supplier/brand name and web/link.

Thanks,
Kimba

[Back in Black]

My buddies at the transmission shop told me that my original 10.5 inch Centerforce dual friction clutch was reuseable.. but it was not soaked as most of the fluid had leaked out/down as the car sat for 2 weeks (I saw the failure coming and took her off the street) I would go ahead and get a spare and maybe you could even then have the original cleaned somehow and then have a spare for later?

I am using the McLeod 12 inch and it grips wonderfully. http://www.mcleodind.com/ Rated for 750 HP. It was not that expensive either. The Tilton stuff was ! Lakewood bellhousing.

Steven

[Roscoe]

Kim,
I'm using the Centerforce Dual Friction 11".

http://www.centerforce.com/frontpage.tpl

Originally purchased from:

http://www.re-racing.com/

Roscoe

[XXQQQME]

Thanks again fellers,

I think I'll order a spare just in case. Depending on how the one that's in there looks, I could always return the spare.

Anyhow,
I appreciate all the suggestions. Experience is a great teacher, don't you think!!

Adios for now,
Kimba

[XXQQQME]

Well fellas,
I bit the bullet and decided to do the work myself. I figured if I ran into any problems that required ordering parts I wouldn't be stuck at some shop, just in my own garage. That being said, once I removed the tranny, bellhousing, pressure plate, clutch disc and flywheel, I found "O" rings had been blown out of the t/o bearing. Probable lack of pedal stop caused this. . . my own fault.

The car now has a 1/2" stop bolt with rubber bumper. Anyway, the "buttons" on the ends of the clutch levers seemed to be worn inconsistently. One was gouged and the other two looked as though they weren't even making contact. I held the face of the t/o bearing up to the levers and sure enough the contact ring was too small in diameter. I held the new Tilton in the same manner and it has plenty of surface to cover the lever buttons at any position. . . also probably my fault for not checking. To continue, it also appears that the clutch disc is worn excessively has been soaked with brake fluid and the flywheel has what looks to be scorch marks on it.
I plan to replace all of the above with new parts seek help when I'm ready to reassemble. As mentioned earlier in this thread, a local Hot Rod shop is willing to perform the work and is familiar with the installation of all the above. I've been in contact with David Kee Toploaders via email as to what I've selected for replacement and am awaiting his reply. I'll be out of town for the weekend, so won't be able to work on it until last weekend in July. Hope to have it on the road for my birthday (Aug 4th). Note: cash gifts accepted, pls contact for mailing addr.
Anyway, this being the third time I've had drive line problems, I hope the new parts and experienced help will once and for all resolve this reoccuring problem. Hopefully I'll get the right parts the first time ordering. Wish me success, I must have it done for the Dream Cruise on Woodward August 21st!!!

Kim
Makeshift Mechanic/a$$hole

P.S.: Thanks again for all you help and suggestions, the pedal stop turned out better than esspected!!

[poorboy]

With the McLeod thow out bearing the instructions state with a 3/4" master cylinder you are not to exceed 1" of piston travel. The clearence between thow out bearing and pressure plate should be between .100-.125. Also make sure the fluid line is on the bottom when installed.

Poorboy

[Pete Munroe]

Poorboy, et al,

The instructions with the McLeod t/o indeed state 0.10 to 0.125.

However, after my third trip to the McLeod factory, speaking to Red McLeod and to George, the shop lead, the clearance can/should be larger, up to 0.20...the unit can absorb that, BUT YOU MUST HAVE A PEDAL STOP TO RESTRICT PEDAL THROW beyond what it takes to release the clutch and operate safely.

The new clutch/flywheel/pressure plate surface will will eat up some of the clearance in the initial bedding in.

The pedal stop is not a joke...but you can increase the clearance if you have a good stop...that will accomadate the initial "wear in" that removes the "fuzz" off the pressure plate and eats up some of the clearance.

If you have questions, CALL McLEOD...they are very busy, you may be on hold, but Red McLeod or George in the shop will answer polite well thought out questions, they are good people and want the product to work for you.

I went through this the hard way, letting some one else set up the old unit, and getting the NEW McLeod housing and doing the job myself.

Pete

[poorboy]

Sounds like someone at McLeod needs to off their butts and redo the instructions. The set I quoted was with one I just got from McLeod 2 weeks ago.

Poorboy

[XXQQQME]

After tearing this driveline apart, I'm convinced that the pedal stop was the culprit (live and learn). I still can't explain the "chewed" up ring gear on the flywheel or the "buggered" up "buttons" on the pressure plate levers (3). I'm also thinking that some of the driveline components weren't necessarily correct for my application. . .

Ford 460, ('71), 1-3/8 x 10 input Toploader(RUG-E2, C70R-7A040A), McLeod Mini-starter

[cobrashoch]

Interesting thread you guys got here. I've switched over to a automatic (old age I guess) but I used a Tilton with no problems what so ever before the switch. I did use a pedal stop and had a couple of custom hoses made instead of using the cheap "fittings and hose kit" that came with the bearing. My pedal stop was just a block of wood that would stop the arm. (old Sox and Martin trick)
A word to the wise; all hydro. throw out bearings have a rating that will limit the pressure plate weight rating you can use. If your clutch pressure plate is too heavy it will cause premature o-ring failure/leakage. The Tilton I used would be maxed out at about 3000 lbs I was told by Tilton. Matter of fact they also told me that their bearing was really designed to be use with a duel friction Centerforce clutch. Most of them are rated at about 2500 static they said.
I can't help but think some of you guys that have had o-ring failures and leaks also have heavy clutches I'd bet. Understand, hyd. T.O. bearings will work with a heavy clutch, for a while,,,,,,,,,, A alternitive to a heavy clutch is to use a so called "Pro" clutch pressure plate, but that is a subject for another thread.

Cul8er - Your pressure plate was too heavy. That's the reason the buttons wore on the fingers. The throwout bearing was operating past its pressure hold limit, causing the T.O. bearing itself to flutter. Your really lucky you know, you found a problem before all of that stuff came unglued in a power shift. Food for thought.
cobrashock

[XXQQQME]

Originally posted by cobrashoch


Interesting thread you guys got here. I've switched over to a automatic (old age I guess) but I used a Tilton with no problems what so ever before the switch. I did use a pedal stop and had a couple of custom hoses made instead of using the cheap "fittings and hose kit" that came with the bearing. My pedal stop was just a block of wood that would stop the arm. (old Sox and Martin trick)
A word to the wise; all hydro. throw out bearings have a rating that will limit the pressure plate weight rating you can use. If your clutch pressure plate is too heavy it will cause premature o-ring failure/leakage. The Tilton I used would be maxed out at about 3000 lbs I was told by Tilton. Matter of fact they also told me that their bearing was really designed to be use with a duel friction Centerforce clutch. Most of them are rated at about 2500 static they said.
I can't help but think some of you guys that have had o-ring failures and leaks also have heavy clutches I'd bet. Understand, hyd. T.O. bearings will work with a heavy clutch, for a while,,,,,,,,,, A alternitive to a heavy clutch is to use a so called "Pro" clutch pressure plate, but that is a subject for another thread.

Cul8er - Your pressure plate was too heavy. That's the reason the buttons wore on the fingers. The throwout bearing was operating past its pressure hold limit, causing the T.O. bearing itself to flutter. Your really lucky you know, you found a problem before all of that stuff came unglued in a power shift. Food for thought.
cobrashock

cobrashoch,
no power shifts here (yet) I've only got around 600 miles on her as we speak! As I mentioned earlier, I'm thinking that my problem(s) are a culmination (sp) oversites and parts that weren't meant to work together.
The most important thing I have learned is to ASK QUESTIONS!!!!!
So, I'm doing that via this thread . . . and again I am very greatful for all of your wisdom, replies and suggestions, which prompts me to ask these questions, but first let describe the scenario:

Had a Hays High Performance Clutch (Lever/Long type). I have no idea the pressure rating for this clutch. Had a Wilwood 3/4 slave cylinder and a McLeod T/O bearing.

Assembled driveline myself. Measured Installed Height of T/O bearing and Bellhousing to levers to establish .125 to .150 clearance. Car drove fine (I babied the hell out of this set up, never lit 'em up, or power shifted as I didn't want to break anything). Forgot to install pedal stop and now I'm suffering the consequences.

Now come the question(s):
1. Ring gear all chewed up. Occasionally upon trying to start car, I heard grinding. . . maybe 1 in ten times . . . What caused this?

2. In the market for a clutch disc and pressure plate . . . is a "diaphram" type easier on the left leg? What are the benefits of one style over the other . . . (Diaphram vs Lever?)

3. What are the benefits (if any) of a Kevlar clutch disc over Organic?

I realize that I can get all these questions answered by making a call to say David Kee or McLeod, but I would like to get first hand "customer" experience and then perhaps call the suppliers.

FYI: my driving habits are somewhat "tame" to say the least. For fear of breaking stuff, I take it easy. I've never had a car with this sort of power and need more "seat time" before I attempt to hammer on it a little.

That being said, your experiences/suggestions/recommendations gladly accepted.

Thanks,
Kim
p.s.: car is up on jack stands, driveline disassembled, waiting for "correct" parts selection.

[Roscoe]

1) Starter may be out of alignment or hanging up after start.
2) Centerforce Dual Friction Clutch
3) Beats the sh1t out of me.

Roscoe

[XXQQQME]

Originally posted by Roscoe


1) Starter may be out of alignment or hanging up after start.
2) Centerforce Dual Friction Clutch
3) Beats the sh1t out of me.

Roscoe

Roscoe,
Would you care to elaborate on the "how's come" for item #1?
or how to fix it if it's out of alignment?

Tanx,
Kimba

[Roscoe]

If the starter is cocked and not square to the bellhousing it can cause excessive wear. If the starter is in too far, or not far enough, it can cause chewed up ring gear. If the gear 'hangs' after starting it can also cause the ring gear to show wear.

What starter/bell housing are you using?

Roscoe

[XXQQQME]

Lakewood bellhousing and McLeod starter

[Roscoe]

While you have it all apart I would install the starter and look at the headspace and alignment.

Roscoe

[XXQQQME]

Good Idea! I'll keep you posted.

Thanks

[cobrashoch]

CUL8ER/ Kimba- The questions you ask can fill a tech manual.
Some basics though:
A diaphram pressure plates clamping force is pretty well maxed out at about 2800 lbs by design. Centerforce adds weights to the construction of their pressure plates that add weight and clamping force by centrifical action. It's been my overall experience with diaphram pressure plates that none of them will hold on engines that have more that 500 lbs of torque or if you use big tires, and that includes a Centerforce. A diaphram pressure plate can/will also STICK TO THE FLOORBOARD if you go past its internally set spring center line. Not to worry though if you are using a hyd. T.O. bearing as they don't have that much travel and cannot get past the pressure plate centerline. If you once stick a diaphram clutch to the floorboard it will come back weaker, and each successive time you stick it it will get weaker still because you are streatching the springs. Rock solid square contact patch with the disk is a good characteristic of this design.

Borg and Beck, long style, 3 finger, etc all :
By design more room for larger springs results in higher pressure plate holding pressures possible, but not necessarly so. Heavier construction possible also results in a pressure plate that takes heat better(less fade). Heavier components also means a heavier in weight clutch. This means, contrary to popular belief, that you can't shift a 3 finger clutch as fast as can with a diaphram clutch.
Going past the spring centerline when shifting, using this design results in a bent finger. This will cause clutch chatter when going down the road. Contact patch with the disc is controled by points with this design, as apposed a diapram above. In addition the housing has to be larger and tends to flex more. Bottom line is sometimes a 3 finger clutch will wear out the disc faster. I believe that all of these problems are addressed using the so called "pro" clutch settup. But that's another thread due to it's complexity.
A informal rule in drag racing with a 3000 lbs car is, you will need about 300 lbs of clamping force on your clutch for every inch of rear tire width. Design your clutch with that in mind and the chances are you can't go wrong. More later if you wish.
cobrashock

[need4speed]

Now that's the best and most specific explanation that I have ever heard on this topic. Thanks Ron.