McLEOD HYDRAULIC CLUTCH CONVERSION

They have their advantages and their disadvantages.

http://pantera.infopop.cc/eve/...=646103275#646103275

I bought mine from Dennis Quella. He modifies McLeod's kit so it's more of a bolt-in. You can also buy a kit that doesn't have a master cylinder but be prepared to do some fabrication/modification to make it work.

I haven’t used that eBay kit but unless I overlooked it, there is a critical part missing from the pictures in that eBay auction and it’s the spacer that slides on the ZF input shaft collar between the McLeod TOB and the ZF. It is necessary to position the initial installed height of the clutch. I have a healthy skepticism of throw together kits comprised of parts from different manufacturers, especially on eBay. That Wilwood master cylinder and McLeod TOB need to have been selected to provide the correct stroke for both the Pantera pedal ratio and the TOB. This is a good reason to buy from a Pantera vendor that has matched the parts correctly.

For example, I bought McLeod’s so-called “Pantera Kit” throw out bearing kit for use with one of their Street Twin clutches figuring I’d save myself some time. The McLeod throw out bearing (TOB) and actuator is a nice piece as you can see in Larry’s post at the link in the post above. However, I was not at all impressed with McLeods “Pantera Kit”. Just to be sure, I even made a preemptive call and spoke with their tech department who assured me they were familiar with the differences for a ZF installation versus a typical manual tranny……..I can assure you they were not. Of all the possible interface dimensions, they got one correct and the rest wrong. The one that was correct was the ID of the TOB which did fit the ZF input shaft collar. One would think a company like McLeod could do better. Also, there’s absolutely no way I would have followed what McLeod recommended for installation.

I have a detailed 20 page pdf “how to” describing what I did to install the McLeod TOB. It’s only 2.3MB but I don’t have a place to host it at the moment. If someone wants to do so and post a link, I will send them the file if they will post the link here.

Best,
K

The referenced previous thread will show I have previously posted to this issue.

In a nutshell I would advise you to avoid using an internal hydraulic throw out bearing.

The first time I had to address the failed o-rings in my unit, I learned that there had been an upgrade to the bearing that required a new bearing carrier piece. I obtained those pieces and a rebuild kit and was back on the road.

A couple years ago I once again had the clutch out of my car and did a preemptive rebuild of the hydraulic slave. I ordered the same rebuild kit as I previously had used and received a collection of O-rings that was nowhere close to the O-rings required.

After a amazingly ridiculous amount of research and phone calls I learned that McLeod had retained the same rebuild kit part number for all three versions of its internal hydraulic bearing. While the unit was upgraded over the years with design changes and subsequent different o-rings, the company for reasons they can only explain retained the same rebuild kit part number through all three versions even though the rebuild kit is not a universal one providing all o-rings needed for the three designs. I learned that McLeod no longer supported rebuild kits for either of the two earlier versions.

So, I returned my old used unit for a little bit of credit and received their new supposedly Pantera specific version. I discovered the newly supplied kit included a snout spacer that was not correct for the ZF snout, fittings on the hydraulic unit that did not allow safe routing of the hydraulic line within the bell housing, and a bleeding hose that protrudes an ugly 4 inches outside the bell housing.

The routing of the pressure line into the unit utilized a straight AN fitting, which required a highly tensioned and twisted routing to allow the hose to exit the original pivot shaft hole. Unseen within the bell housing, when the braided stainless hose was connected to the main chassis-mounted line connection, the fitting connecting torque displaced the hose's routing and shortly thereafter it suffered failure when its contact with the rotating clutch assembly ground a hole through the stainless line.

If this story of woe is not enough to discourage your purchase of this unit, I will point out that the unit you presented is described as being a custom fit unit. I can only imagine the problems you would experience in such an exercise would be far greater than what I experienced with a kit actually designated as being Pantera specific.

As I said. This is really not something you want to do.

Larry

I can see Larry has been the route as well. My file will addresses precisely what Larry is describing....Being the obstinate soul that I am, I didn't give in, but it took some effort. I just spec my own components now and don't bother with kits because I usually spend as much time and effort fixing the kit as do starting from scratch.

Best,
K

I was very surprised by your experience, I have a twin disc clutch, master on my bike and a proportioning valve on the Pantera as well, the tec service I had was exceptional and they are very familiar with our cars?

quote:

Originally posted by Panterror:
I can see Larry has been the route as well. My file will addresses precisely what Larry is describing....Being the obstinate soul that I am, I didn't give in, but it took some effort. I just spec my own components now and don't bother with kits because I usually spend as much time and effort fixing the kit as do starting from scratch.

Best,
K

I have one on mine with zero problems. On top of that, if I do, this is the easiest car in the world to get the trans out! I have heard that many who installed them which failed did not get the adjustment set right.

quote:

Originally posted by pantera chris: I was very surprised by your experience, I have a twin disc clutch, master on my bike and a proportioning valve on the Pantera as well, the tec service I had was exceptional and they are very familiar with our cars?

Not sure if you are referring to the McLeod hydraulic slave or just their products in general. My comments were in regard to the McLeod (slave cylinder not master) TOB in the link the Original Poster posted, and perhaps they were having a bad day, but it actually was three bad days over the course of 3 weeks because that’s how many separate calls and iterations it took.

As I mentioned I phoned to speak with them about their kit and got the usual assurances but they would not sell to me direct and referred me to Jegs and Summit with a part number. When it came there was no spacer included in the kit. After a few futile phone calls with Scummit they sent me back to McLeod. McLeod said was oversight. –OK Fair enough; it happens. They sent one to me. It was the wrong spacer. When I called them and explained the problem, they sent me another one…….the same wrong one and they either had ignored the conversation or they had a stock of incorrect parts under the ZF spacer part number! When I called and emailed pictures of the problem they told me they had never had a complaint and couldn’t help me…….I had already concluded the latter by that time.

The picture below is the spacer they sent me (twice).



The problem is obvious right? The slots were clocked improperly to clear the bolts on the ZF input shaft collar. All ZFs are the same in this regard and the bolt heads are not evenly spaced at 120 degrees apart. It also was the incorrect height, and yes, it was their clutch too. Now I could have just chucked it and turned it to the correct height, and milled the slots wider, but the only thing that made it a Pantera kit over just buying their hydraulic slave was the spacer and two hoses, which by the way were strange lengths and not useful so I tossed them in my used parts stash. Anyway, there were other issues too but it’s all in my little write up, and as I’m sure you can tell, I’m still grumpy about it.

Here’s a picture after my mods and final install.



Here’s another McLeod story. I’ve run street Twins in my cars and Pantera for the last 15 years. Here’s a cut and paste I previously wrote on that experience and a little history on that products evolution. I offer it just in case some else has an old Street Twin, and perhaps to further understand how I’ve formed my opinion. –Better get a cup of coffee.

I bought by first McLeod Twin Disc clutch from Dennis at Pantera Performance in 2001. I also visited the idea of the hydraulic TOB with him at that time but declined. I considered it again around 2003-2004 on another engine build didn’t opt for it because I just couldn’t go away from external access to the slave cylinder…..It’s a lonnnnng story but there may be something to be learned from it so here it goes:

Dennis was working with McLeod to adapt it their street twin to the Pantera around 2000. It required the usual tweaks, just needed to make sure there was no bell interference from the PP and actuation arms, and of course properly engage the TOB. I believe he offered the hydro TOB well before that time. He told me my Twin was one of the first two he had sold for a Pantera. I was a bit hesitant because it was expensive but I was going to buy an aluminum flywheel anyway and Dennis was eager to get a few in the field so he said he’d make it worth my while and I bought it. That was about 2001. It was a very nice piece and quite a bit lighter than my unit at the time, but this is basically all a function of the aluminum flywheel. The engine I had at the time was externally balanced so the aluminum flywheel is too. All my engines since have been internally balanced.

So back in this time, all McLeod Street twins had a proprietary flywheel specific to the Street Twin, and the external balancing was done by slugs pressed into the flywheel instead of bolt on weights that change neutral to whatever balance as in today’s models. The other major difference, at that time, all McLeod street twins had pin drive instead of strapped floater discs they sell now.

I did not do the clutch install as my car was at PPC at the time. When I eventually got the car on the road, initially it ran beautifully, shifted like butter and the clutch held like a vice. However, over time, and I’m talking a few years, the shifting quality began to degrade and it started to hang up. Not bad but you could feel the tension pulling it out of the lower gears and eventually it started clanging the synchros a bit in 2nd and third gear. I was told my ZF might be getting tired but it had just been rebuilt by Butfoy. I noticed when it was cold, it still operated very smoothly but the hotter the day and harder I ran it, the more symptomatic it became. It seemed highly correlated to operating temperature so I removed the bell housing site window cover I had installed and it actually made a noticeable difference in that it took longer to run it to the point where it acted up.

Over time (we’re talking 8 years) it continued to act up occasionally and degrade to the point where last year, if I took it out and ran it very hard on a Summer day, a couple times it got so bad I could not even get reverse or first gear while sitting still. I’d have to shut it down, put it in gear and start the engine with the clutch engaged. Well at this point I’d obviously had enough of it but knew I’d have a go at it during the planned engine swap, thus the current go-around I’m having with the McLeod for the RST install.

So of course over this time I was engaged with Dennis and McLeod multiple times. I got fed a steady diet of the idiot questions; did you bleed your clutch, have you checked your slave and its stroke, have you checked the clearance between discs with a feeler gauge, are you over stroking the master. I had previously checked all those things over and over. Dennis even had me change my CNC master cylinder because he had had some problems with them over the years. I called Mcleod no less than six times over this period, spoke with their experts, and got fed a steady diet of the same idiot treatment by them.

OK, here’s why you read all this. A while after I pulled my engine for this swap, and removed the clutch I eventually took the old clutch apart on the bench and had a close look at it. Remember above when I said the old Twins were pin drive? Well the floater is a Blanchard ground plate about ¼” thick with three ears with holes the pins engage so the floater can slide on them when actuated and transmit torque through the pins which are bolted to the flywheel. Upon closer inspection I notice the drive pins look a bit deformed. They mushroomed a bit under the nut that secures them and the diameter was visually not consistent along their length. So I take one of the pins off to have a closer look and discover they are plastic!!! No kidding...plastic!!! So you have a ¼” thick plate bearing against three ¾” diameter Delran pins to transmit in my case then ~550 ft-lbs. The Twin clutches were rated for much more.

I instantly realize the problem began feeling a bit angry (this seems to be happening more often these days) thinking back to all the conversations I had with the McLeod tech line on the subject over the years. So that night I do some web surfing on a couple gear head websites I frequent, search McLeod Street Twin in those date ranges and easily get many hits with similar problems and complaints about McLeod Street Twin at that time. It turns out McLeod actually recalled them for these very reasons. Now I feel like a dumbsh!t and am also getting more PO’d because McLeod had to have known about this issue all that time I was calling them….is apparently was common knowledge.
So in the middle of the slave cylinder fiasco, I took the opportunity to take this issue up with the same tech guy I dealt with on that matter. I tell him the whole story (except the bit about my discovery upon recent inspection) and ask if he has any idea what may have been causing such a problem. He would only say my clutch was obsolete and all Street Twins now are strapped floaters now not pin drive. So when I told him what I had observed about the drive pins and actually asked if McLeod ever had any problems with Delran drive pins on pin drive Twins, only then does he come clean and explain that McLoeod started selling the pin drive Street Twins with Delran pins because the floater plate would rattle on the steel pins when folks revved the engine with the clutch disengaged. People with street cars complained. The Delran pins solved the noise issue. However, the material properties of the Delran were not able to withstand the contact stressed induced by the floater, a condition which was of course aggravated by elevated temperature. Do you think the floater ever gets hot from clutch friction? This is what led McLeod to develop the strapped floater design.

I asked him if the old Twins performed well with steel pins, if they had any pins, and if so how much they were. He said yes, they performed flawlessly with them, they have them in stock, cost a couple bucks a set, and he would throw a set in with the spacer for my current set up which of course he never did, but I did get them when I got the (wrong) spacer.

So here is the morale of the story. All that time, I was being afflicted and aggravated by a problem well known to McLeod that they would not disclose to me in multiple tech assistance calls, presumably because they didn’t want to warrant their product. The fix was penny parts....I mean three ¾” diameter steel stand-offs with a mounting hole in the middle. I could have made three on the lathe in 15 minutes. Even when I brought it to their attention on the recent debacle, I had to specifically ask about the problem and the Delran pins to get them to acknowledge the issue.

So you may also assume the other moral to the story is I’m a glutton for punishment and why in the Hell would a buy from McLeod again? Answer: I had already made my purchase before discovery of all the above, I want to get my car back together or everything would go back. The products I bought look to be of very nice quality. Their tech support.....well opinions may vary but I think you can guess where I sit on that subject. I certainly hope for them, I’m the exception not the norm.

...long storry :-)
i think , cutting the spacer is not the right way. You have a angle of the bottom and the holes in the spacer are to big, I guess.
I hope that MC-LEOD send me the right spacer.

quote:

Originally posted by GT4Peter:...long storry :-) i think , cutting the spacer is not the right way. You have a angle of the bottom and the holes in the spacer are to big, I guess.

Well, I discarded the spacers McLeod sent me and made the parts in the photos below. During the whole debacle, I had the opportunity to ask the McLeod technical support guy about their recommended installation. I asked, since the slave cylinder is a loose sliding fit on the input shaft collar, what keeps it from spinning? The reply was simply that in practice it didn’t do that. So if you start the car cold and the grease in the TOB is thick and viscous, or if you mash the clutch at 6krpm, the only thing that keeps the slave slipping and spinning on the shaft is the fact it’s hanging on the hydraulic hoses….right? The reply….. silence, but that is the correct answer; it’s just the hoses that do so and I wasn’t comfortable with that. That’s why I made the adapter as shown in the pictures below. The bolt head that engages the slot on the spacer and the pockets on the back of the spacer engage bolt heads on the ZF input shaft collar so any torque load is carried by those components not my hydraulic plumbing. The round pieces are just bulkhead connectors for the hydraulic lines that install where the cross shaft originally resided.

quote:

I hope that MC-LEOD send me the right spacer.

If you buy from that seller on eBay, you won’t be dealing with McLeod. Based upon my experience, it won't matter. It’s possible they have done their homework for a Pantera/zf install, but looking at their other auctions, I’d say highly unlikely. They just look like a typical online distributor. One thing I can tell you with certainty is that hydraulic slave will need a spacer, and it will need to be a fairly precisely made part. It is not listed as included in their auction.

Good luck, but if you are expecting a bolt-on kit, and in the event you need to manage the purchase aftermath from afar, you may not have a positive experience.

Take care,
K

Kelly,

I have read your very insightful postings on this topic and consider you to have the definitive McLeod hydraulic T/O brg. ZF installation. I do, however, have the same criticism with respect to your spacer, that I had with your 180 degree header: you only made one!

Free spacing between the back of the actuating piston and the aluminum housing is critical. The entire working of an annular hydraulic throwout is sealed by means of a 'quad-seal' in the bore. This special square seal/o-ring contacts the piston on its inside AND the housing bore on its outside. Quad-seals are designed only for linear motion, and the bellhousing, ZF case and flywheel/clutch will all expand with heat. So setting the required free play cold is vital. Note this is NOT clearance between the clutch and throwout bearing-its between the backside of the piston and its seal housing bore. If this space disappears in operation, the constant-contact throwout bearing (spinning with the clutch) will bottom and begin also spinning the piston inside the housing. Within 50 miles, the quad-seal will fail and begin leaking from this unnatural motion!

Well before vendors introduced adapted hydraulic throwout assemblies, I adapted one from Tilton Engineering intended for dirt-track racing to our ZF. The advantages of the annular throwout system are simplicity, a loss of 16 lbs of extra weight and direct motion with no losses- as long as everything is set up properly to begin with. The single disadvantage I've found is, if ANYTHING goes wrong, the ZF must come out to repair it! Mine has been in operation since 1993.

My Tilton provides a lug on one side of the main seal housing, that is anchored to the ZF with a small safety-wired allen bolt. Fore and aft adjustment of the components are provided by threading the whole Tilton seal housing and the custom threaded ZF nose adapter up or down so no spacers needed in this design. Good luck with your custom spacer- as I said, its dimensions will be absolutely critical.

Kelly your spacer looks beautiful!
I have also ordered the kit, because we need something new.
My friends panteras clutch was complete done and also his hydraulic system is hard to repair. Rust did its work in winter.
I hope now that we get the right parts !
I send some email to the tech mail adress and a verry friendly mail from a man called Billy come back. They said that this set should work!
Hope realy that this is true !

quote:

Originally posted by Bosswrench:……..and the bellhousing, ZF case and flywheel/clutch will all expand with heat. So setting the required free play cold is vital. Note this is NOT clearance between the clutch and throwout bearing-its between the backside of the piston and its seal housing bore. If this space disappears in operation, the constant-contact throwout bearing (spinning with the clutch) will bottom and begin also spinning the piston inside the housing. Within 50 miles, the quad-seal will fail and begin leaking from this unnatural motion!

Not entirely clear what you mean here Jack but on the McLeod unit, the only thing that ever prevents the actuator piston from spinning in the housing is the friction created between the quad ring and actuator cylinder housing. When it is pressurized there is a little more friction than when not. Though the McLeod units are “constant run” TOB, that doesn’t mean they are intended to be set up in constant contact with the clutch actuator. According to McLeod their actuators naturally relax .010” when not pressurized though it’s hard to see the mechanism for that because there is no residual valve in the hydraulic circuit. If the installed height is too high and in constant contact then that means the actuator will be bottomed, which I believe may be what you are getting at. This should not occur with a proper initial installed height.

Another significant factor in setting the initial installed height of the actuator is allowing for clutch wear. When calculating the installed height McLeod recommends allowing .100”-.150” for this for what they call allowance for the actuator to “self adjust” which really is only a matter of using that much of the available stroke. This is because as clutches wear, the clutch actuator, whether Long or Diaphragm style, grows toward the annular actuator as it wears. If this is not accounted for it can cause constant contact with the clutch actuator as mentioned above. It will also return fluid to the Master cylinder reservoir. If the actuator is full this can prevent the actuator from self adjusting and/or leak fluid in the front trunk. The combination of these two things can cause the actuator and clutch to stay partially actuated and cause clutch slippage on a clutch with normal wear and that still has additional useful life. It also causes the TOB to run constantly.

I neglected to mention earlier that bushing on McLeod unit is adjustable. This is only for fine adjustment and won’t eliminate the need for a spacer. The positive stop on my spacer is designed to float with this adjustment if needed.

Since language may be in play here, a lot of component names and nomenclature get thrown around and sometimes interchanged. McLeod calls their unit a hydraulic throw out bearing which is a bit of a misnomer. In my world, the throw out bearing (TOB) is just the bearing not the actuator and there’s nothing hydraulic about it. When you go to a parts store and buy a TOB, all you typically get is the bearing. The stock Pantera set up has a cross shaft and a fork that bears against the TOB adapter. The TOB is mounted on an adapter and they slide as one on the ZF input shaft collar. These parts all reside inside the Bell Housing. The stock Pantera system also has an external (to bell housing) lever arm and a slave cylinder with some linkage and a return spring. This whole system is what the annular actuator such as the McLeod 1400 series unit replaces, and as Jack mentioned, can save some weight. The stock Pantera system is externally adjustable. The annular actuator is not other than the excess stoke it may have which McLeods calls “self adjustment”. The clutch actuator I mention above is a totally separate mechanism onboard the clutch (actually the pressure plate assy) which may be a Long (three lever arms) or diaphragm style mechanism.

You can go to the McLeod website and download the 1400 series

https://www.mcleodracing.com/c.../instruction-sheets/

I took a look this morning and it has been update with (better) information since I bought my parts. They recommend ¾ bore master cylinder and 6:1 pedal ratio. Most clutches can take a lot of stroke but it still may possible to over stroke some clutches so this should be checked and if needed a pedal stop could be required. One of the members here offered to host the file I mentioned earlier. There are piece part drawings for the parts I made the 1400 series McLeod unit to the ZF and McLeod RST Twin Disc diaphragm clutch. All are welcome to them but keep in mind, you still need to verify the suitability with your particular combination of parts and installation.

Best,
K

quote:

Originally posted by Panterror:...
I have a detailed 20 page pdf “how to” describing what I did to install the McLeod TOB. It’s only 2.3MB but I don’t have a place to host it at the moment. If someone wants to do so and post a link, I will send them the file if they will post the link here.

Best,
K

http://www.slideshare.net/Jose...throw-out-bearing-zf

Very well written!

Hope you don't mind a comment. Did you consider "cam following bearing" instead of a bolt head.

I think this just shows that one needs to either know or MEASURE when installing a component to ensure that it performs as desired. In this case it does seem some basic engineering was not considered.

quote:

Originally posted by JFB #05177:Hope you don't mind a comment. Did you consider "cam following bearing" instead of a bolt head.

Don't mind at all. I just used what I had on-hand. Since it's just a static stop with no motion, and since the alternative was no positive stop at all and just hanging on the hoses, I called it good enough.

Thanks for posting the file.

Best,
K

Does somebody use the willwood master cylinder?
The pushrod is to long and it have the wrong wrench.

Kelly shared his trials and tribulations with McLeod.

I shared my trials and tribulations with McLeod.

I even advised against using the McLeod hydraulic TOB.

Peter, welcome to the club.

Sounds like you already know what you need to do:

Adjust the pushrod to the proper length.

Find the proper adapter for the incorrect "wrench"

Good Luck,

Larry

In the end , it is working

edtit - its working for 1500 miles . now the willwood cylinder is damaged .

who runs the original master cylinder ? Is this also working ? thanks

I use a 5/8" CNC master with mine. No problems.

My Tilton annular clutch conversion uses an aluminum Girling 5/8" clutch master, with bolt spacing changed to fit.

Does somebody use the original master cylinder together with the mc leod clutch zylinder ? I guess it is the same diameter.
Thanks .

I did for a while, until I repositioned the collapsible-sidewall spare up front. The aluminum Girling is shorter and the pressure-out line comes off the body about halfway back giving more space for the spare, plus the Girling is a bunch lighter and rebuildable. The stock iron assembly is known to be very sensitive to moisture corrosion and there's no real rebuild kits.