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my new McLeod RST clutch wont fully disengage

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I decided to have my Ford dealership technician install a McLeod RST and steel flywheel in my 12 Boss in order to solve high RPM lockouts at trackdays. He used a new throw out bearing and pilot bearing. The high RPM lockout issue is gone, but the problem I'm having now is on startup. I start the car in neutral, and it doesn't want to shift into 1st or reverse without forcing it. with the engine off, it will shift into 1st or reverse smoothly. If I start the car with the shifter in reverse and clutch pedal to the floor, the car creeps backwards. My mechanic has bled and re-bled the system 3 times, with no improvement. Not sure what to do now? Anyone have any idea what's wrong?
 
That's got to be an installation problem. I'm not sure of the exact specifics but there is a spacer in there and if the incorrect one is used the clutch will not fully disengage. Hopefully someone with the specifics on that issue will chime in.

@ArizonaBOSS
@Grant 302
 

steveespo

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There may or may not have been a spacer behind the throw out bearing originally, if the mechanic did not reinstall it then there is the issue. The throwout bearing could be the wrong part, GT500's are shorter, or it could be defective. Finally the 1st disc of the clutch could be bound up under the floater plate. This will not allow the clutch to release fully even with the pressure plate retracted. Sadly the only way to check is to pull the trans and reassemble it per McLeods instructions.
 

ArizonaBOSS

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Ian; steveespo above covered the primary possible causes. On the 2011-2012 cars, a 1/2" (or so) thick billet spacer is used from the factory to keep the slave cylinder the correct distance from the clutch. On the 2013+ cars they built this "spacer" into the casting of the transmission itself. If you don't include this in the installation, you are going to have symptoms as you described. I have (stupidly) done this and experienced the same stuff.

Alternately, if the pressure plate is somehow cracked as-new or mis-installed you may have similar issues.

Let us know what you find out...but unfortunately I would believe that the transmission will have to come out again.
 

mattlqx

Mustangless
I still have night terrors of having to remove and reinstall the trans after clutch replacement because of the things not being assembled quite right. Granted, those are memories of an E30.
 

captdistraction

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Look at the side of your trans housing on the driver's side. What's the part number? that will dictate the spacer usage.

That said, the mcleod clutches are very picky on throw out distance, if you add a spacer carefully measure it. I have a shim from RAM clutches if you end up needing one, but I recommend measuring the engagement depth to be sure its correct (which unfortunately involves removing the transmission as well).

Its worth getting right, as you can destroy the clutch and associated hardware if not.
 

302 Hi Pro

Boss 302 - Racing Legend to Modern Muscle Car
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Yes, your problem is directly related to incorrect T/O bearing clearance/spacing.

Any time an Aftermarket clutch assembly is installed careful measurement to T/O travel is required.

She creeps in gear with clutch fully depressed is because of insuffectnt T/O travel distance. This must be adjusted for full disengagement and still maintain clearance so the T/O bearing does not contact the pressure plate fingers when released.

In other words, the T/O bearing must NOT ride the PP fingers, you need 1/6" clearance minimum.

Check the new Hyd T/O Part number for your application.

Good luck and keep us posted,
302 Hi Pro
 
Got the car back today from a local transmission shop owned by a friend of mine. It finally shifts like it should, no trouble getting 1st or reverse at all, and shifts buttery smooth. What finally fixed my problem? 40 thousandths shims between the flywheel and pressure plate. Sounds strange, but it seems to have worked. I have a trackday this Sunday the 21st at Pocono with Hooked on Driving, will let you know how the car performs.
 
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Got the car back today from a local transmission shop owned by a friend of mine. It finally shifts like it should, no trouble getting 1st or reverse at all, and shifts buttery smooth. What finally fixed my problem? 40 thousandths shims between the flywheel and pressure plate. Sounds strange, but it seems to have worked. I have a trackday this Sunday the 21st at Pocono with Hooked on Driving, will let you know how the car performs.
What shop did the work?
 

Fabman

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I would love to hear more about this from those in the know:
When I bought my Hyper single and Magnum XL I got an email from Kohr saying that I might need a spacer....when I called for clarification then I got, "Naw, you probably won't need a spacer".
Now that the car runs, I was able to put it in gear while running on the rack and that works (haven't driven it yet or tried reverse but 1st works) and it seems like the first part of the pedal travel is pretty low pressure and about halfway down it feels like a real clutch. Not sure if this is part of how those clutches feel or if I need a spacer or what....
 

steveespo

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I would love to hear more about this from those in the know:
When I bought my Hyper single and Magnum XL I got an email from Kohr saying that I might need a spacer....when I called for clarification then I got, "Naw, you probably won't need a spacer".
Now that the car runs, I was able to put it in gear while running on the rack and that works (haven't driven it yet or tried reverse but 1st works) and it seems like the first part of the pedal travel is pretty low pressure and about halfway down it feels like a real clutch. Not sure if this is part of how those clutches feel or if I need a spacer or what....
Chris Wynne knows the ins and outs with these clutch/transmission combos. @captdistraction
 
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I would love to hear more about this from those in the know:
When I bought my Hyper single and Magnum XL I got an email from Kohr saying that I might need a spacer....when I called for clarification then I got, "Naw, you probably won't need a spacer".
Now that the car runs, I was able to put it in gear while running on the rack and that works (haven't driven it yet or tried reverse but 1st works) and it seems like the first part of the pedal travel is pretty low pressure and about halfway down it feels like a real clutch. Not sure if this is part of how those clutches feel or if I need a spacer or what....
I initially installed my Hyper Single with the stock GT slave cylinder. When I dropped the trans to overhaul the synchros, the slave cylinder fell apart as soon as the trans was separated from the clutch. The clutch engagement is at the very top end of the travel (when you first start pressing). The bottom half of travel does nothing - meaning you have to let off the pedal a long ways before it starts to engage. I installed the Maximum Motorsports clutch travel limiter, and then switched to the Kohr spacer and GT500 slave cylinder. Pedal feels roughly the same with both, but it won’t overextend the slave to the point of damaging it now.

A bit more detail on what I found here:

Post in thread '@4o6racing'
https://trackmustangsonline.com/threads/4o6racing.16296/post-251497
 

captdistraction

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Chris Wynne knows the ins and outs with these clutch/transmission combos. @captdistraction
So what Kohr was mentioning is you have one of two options:

The oem "long" slave and no spacer - this technically works, though I found certain clutches need a small thin spacer to get the engagement on the middle - though caution over-engagement is a thing as well. This setup would wear the slave out quickly, especially if you drive the car onto a trailer.
1616684223829.png
Kohr sells a large aluminum spacer to be used with the GT500 "short" slave cylinder. They found the short slave to be beefier. It is- its rated for 2500NM of force (effective) vs the long slave of 2300NM.
1616684155299.png


Somewhere I have a setup diagram with measurements taken with an Exedy HyperSingle clutch, but basically you want to follow something like this to get the setup:
1616684433333.png

There's more to it, you want the engagement specs from the clutch and match that to the stroke on the slave cylinders to make sure you don't over-engage or under; but hopefully there's some helpful info here.
 

Fabman

Dances with Racecars
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Pleasanton: 1/2 way between Sonoma and Laguna Seca
So what Kohr was mentioning is you have one of two options:

The oem "long" slave and no spacer - this technically works, though I found certain clutches need a small thin spacer to get the engagement on the middle - though caution over-engagement is a thing as well. This setup would wear the slave out quickly, especially if you drive the car onto a trailer.
View attachment 63829
Kohr sells a large aluminum spacer to be used with the GT500 "short" slave cylinder. They found the short slave to be beefier. It is- its rated for 2500NM of force (effective) vs the long slave of 2300NM.
View attachment 63828


Somewhere I have a setup diagram with measurements taken with an Exedy HyperSingle clutch, but basically you want to follow something like this to get the setup:
View attachment 63830

There's more to it, you want the engagement specs from the clutch and match that to the stroke on the slave cylinders to make sure you don't over-engage or under; but hopefully there's some helpful info here.
This would have been great info to have before we put the transmission in. I'll definitely hang on to this. Thanks!
 
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Would the lack of a spacer be an issue for the s550? I’m having the same exact issue as the OP but instead I have a Hyper Single. My TOB was replaced under warranty but I don’t have the sheet in front of me to see the Part Number.
 

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