Slave cylinder shimming

[Rick Simons]

Good job!
Yea, that lip on the slave is just there to keep it together in the box. Once installed, the clutch should not let it extend anywhere near that. If it is shimmed correctly.

Thanks Juice!

 

[Rick Simons]

I don't recall if I mentioned it, but I have 24mm of preload with a .375" shim, so a big thank you to those who shared the preload info. On a side note, my high rpm 2-3 shift that used to be hit-or-miss is now silky smooth.

 

[GlassTop09]

I don't recall if I mentioned it, but I have 24mm of preload with a .375" shim, so a big thank you to those who shared the preload info. On a side note, my high rpm 2-3 shift that used to be hit-or-miss is now silky smooth.

Good stuff!
If I read your postings correctly you installed an Exedy Mach series aftermarket (non OE) clutch setup using a single organic clutch disc, correct?

If so, then I plan to use your TOB setup info on my next replacement as I have an Exedy Mach 500, Stage 3 Grooved PP\Clutch Kit on an Exedy HP CM Flywheel installed & I had some slight clutch drag on disengagement (I didn't install it....had it installed by the local Ford dealership so I know they treat all these like an OE setup thus no preload check) that I "fixed" by installing the 13-14 GT500 clutch master cylinder but will be better done by actually shimming the TOB. I read in Exedy's sheet that came w\ my Mach 500 series setup that they designed this series specifically to have a low pedal engagement so it would be suspect to have some potential clutch drag disengagement issues w\o some type of shim installed......but Exedy doesn't say anything about adding any shims. My install results proved otherwise.......it does need some size of shim added.

I noted in rocky61201's posting that he also installed an Exedy flywheel w\ a Luk Clutch\PP kit setup & all good using .312" shim.... Both his, yours & mine are 4.6L V8's w\ a TR3650 trans thus the trans housing depth is a std depth within manuf tolerance of approx 3% so is close enough, the separator plate is a std thickness as well as is the 4.6L crankshaft 6-bolt flywheel mount dimension so it appears to me from y'all's work that I should be good using either a .312" to .375" shim w\ an Exedy Mach series non-OE single organic disc clutch package w\ a TR3650 trans.

 

[Bigearl]

In case anyone besides me is curious, here's what the guts of the slave cylinder looks like. Pretty fragile looking IMHO. All that keeps the piston/bearing from sliding over the end of the tube is a little raised lip. No wonder they blow apart so easily.

View attachment 80619

Got it all back together Saturday night, and test drove on Sunday; perfect! Pedal has about 25mm of free play, and engagement starts about 50mm off of the floor. I have about 250 miles on it now, so far so good.

I know this is an old post but did you shim in the end and by how much if you did?
My apologies did not see page 2. Thanks for the excellent info.

 

[moooosestang]

Btw the problem with upper rpm shifting is rarely clutch related. It's due to motor/trans torque rotation relative to a non driveline (body) mounted shifter.

The oe hydro motor mounts are shot around 75-100k. Get some poly or prothane motor mounts thats step 1 to helping everything in line when high rpm shifting.

You seem to be bumbling around in the dark with your threads, tons of experience and threads to look through on here.

This^^^ Get torque limiters and or stiffer motor mounts and your high rpm shifting will be butter smooth. No reason to shim the slave if everything is stock. Some people may have high rpm shifting problems from not properly bleeding the clutch too. I would get a vacuum pump that attaches to the master cylinder to properly bleed it. My clutch is spec with spec flywheel and it starts to engage somewhere in the middle of the travel. Be sure you have a ford OEM slave! don't use any of the aftermarket crap.

 

[Caden]

Hey strangers, just thought I would add some more data here for future folks trying to figure out their preload and how much to preload. My T56 XL swapped 3 valve popped two slave cylinders before i could even get it out of the garage, so i finally decided to measure my preload (which my clutch manufacturer, Exedy, kept insisting i did not have to do), turns out i was only getting .2" of preload! In order to get close to 1" i shimmed it with a .75" shim from Tick performance. In order for the slave fluid tube to clear the bellhousing with the giant shim, i had to bend it a bit, which was easy to do by hand.

As far as driving goes, my clutch feels great, its not slipping at all, and its all at the top of the pedal making slow speeds easy. If anybody has questions about manual swapping an auto, installing a T56 magnum, or slave cylinders, i'm not a professional but you can certainly feel free to ask me!

 

[Juice]

Hey strangers, just thought I would add some more data here for future folks trying to figure out their preload and how much to preload. My T56 XL swapped 3 valve popped two slave cylinders before i could even get it out of the garage, so i finally decided to measure my preload (which my clutch manufacturer, Exedy, kept insisting i did not have to do), turns out i was only getting .2" of preload! In order to get close to 1" i shimmed it with a .75" shim from Tick performance. In order for the slave fluid tube to clear the bellhousing with the giant shim, i had to bend it a bit, which was easy to do by hand.

As far as driving goes, my clutch feels great, its not slipping at all, and its all at the top of the pedal making slow speeds easy. If anybody has questions about manual swapping an auto, installing a T56 magnum, or slave cylinders, i'm not a professional but you can certainly feel free to ask me!

As I said before, Ford set up this slave to operate at the very edge of the piston travel. Probably to allow for max clutch life. As the clutch wears, the operating range slowly moves towards the trans, but it will never "bottom out" the slave cyl. Yes, it has way more travel than it needs.

 

[Midlife Crises]

Measured all my stuff yesterday with the slave installed on the transmission, clutch/PP installed to the flywheel and everything torqued to spec. I'm seeing about 2 11/16" from the bellhousing face to the TOB face, and about 3 1/8" from the block plate to the PP fingers. So, a difference of 7/16".

So I'm guessing I need a shim but what I'm not clear on is how much of a shim. I've seen that you're supposed to have around 1", but I've also seen where people said the actual travel is only 1/2"...so I'm not totally clear. Now granted I didn't measure the stock stuff before I took it out but this is an OE replacement clutch kit so everything should be similar and it had no shims. I will say that on the stock clutch you had to push it all the way to the floor to make sure it was completely disengaged. Never really had any problems shifting though.

Would a a single 3/16" shim be enough?

If I had your measurements I would add a 1/4” spacer purchased from Summit Racing and 1/4” longer bolts from the hardware store to mount the new slave and spacer. You will have plenty of travel and it will not place a higher load on the throwout bearing. The slave has its own internal spring so the load is the same wether it’s compressed 3/8” or 1” when at rest. The spacers from Summit are machined on both sides to match the tranny and slave unit so they do not misalign.