Superformance clutch slave

[wanab5150]

We just did the Moro Bay trip in the Cobra last weekend. Right at 800 miles for us since we live in Roseville.

The car has been parked all week until tonight we went to dinner / car show in Folsom. On the way over I told Deb the clutch felt spongy. When we got there the slave reservoir to the clutch had only about an eighth inch of fluid and a pool on the ground. We matched our speed to the signal lights so as not to use the clutch......Once home the only fluid left was what was in the line and on the driveway.

THANK YOU LITTLE COBRA FOR MAKING THE 800 MILE TREK LAST WEEKEND AND WAITING TO BE HOME TO BREAK!

This may have something to do with Scott (Scooter)and Danette tampering with my car in Moro Bay...I have photographic proof!

Now, anyone know what slave this is.....or a replacement? I would also like a real pushrod to replace the one I made 8 years ago????? tom

[mr. G]

yo wanab5150
here's the part number that was installed in my car #3041 from summit racing #BCK-072-9514 it's a generic slave, problem was from misalignment turned the bore of the slave into an egg shape….

[vatdevil]

Clutch slave choice is by the builder. For my car, 96-98 Suziki Samari

[Mark IV]

What engine/trans/bellhousing do you have? As said, the slave is the choice of the installer. SCOF has pictures of of some of the most common units used.

Without a picture of your we would just be shooting in the dark.

[wanab5150]

After researching everyone else's part numbers it's clear Superformance uses what ever slave in on the menu of the day. After several tours on the internet I stumbled across a Duralast slave part# 12413 that was a match. On Rock Auto 's website they had the same slave listed as being produced by 8 different manufactures. They all cross referenced each other and the slave is a generic to be used on whatever vehicle you think it will fit.

I found mine on line at Auto Zone for a whopping $14.99 with a non adjustable clutch rod. I do not understand the non-adjustable clutch rod?????? I put the slave back on with the 6 shims that space the slave back from the mount as it was when I removed it. Before I ran a double nut back and forth to adjust the clutch....now I'm thinking I just got lucky. It is buttery smooth and perfectly adjusted. I'm thinking that if it needs adjustment in the future I just have to either add shims or remove shims to the slave. Does this make any sense to anyone else. Everyone I've talked to has an adjustable rod that they made from a grade 8 bolt like I had before this. Hmmmmmmmmm !

[Mark IV]

Originally Posted by wanab5150

After researching everyone else's part numbers it's clear Superformance uses what ever slave in on the menu of the day.

Remember it is not "Superformance" but the installer or owner who selected the slave. And because the slave cylinders are typically from a production vehicle they don't have an adjustable pushrod......do you think GM etc. do a "how does it feel now" adjustment on the assembly line?

[wanab5150]

Smart Ass.......
I would have eventually figured it out, but it may have been next September at 3am that it would have popped into my head.

[sn8ke2]

Has anyone used a concentric slave setup on their Cobra? It looks like a viable solution to the asymmetric loading of the slave cylinder push rod. I have been through 3 slaves on my Superformance Mk3 and am curious as to whether a concentric slave is the answer to the asymmetric loading.

[DanEC]

Do you have an example of one? I’m not familiar with it.

Edit - never mind, I guess you’re looking at internal slave cylinders. I had external on my mind.

[Sawdust]

For what it's worth I used a slave cylinder from Napa. Part #73168

[Mark IV]

We tend to not like HTOB on these cars. When they fail (and they will...) you must pull the engine or perform some fun contortionist moves to replace. A properly aligned push/pull slave will perform well for years. You do need to change the fluid every few years as it absorbs moisture and the location close to heat sources degrades the fluid. https://www.facebook.com/TimeMachine...type=3&theater

https://www.facebook.com/TimeMachine...type=3&theater

[sn8ke2]

https://duckduckgo.com/?q=diagram+of....jpg&ia=images
It rides on the input shaft of the transmission; eliminates clutch fork.

[sn8ke2]

Originally Posted by mark iv

we tend to not like htob on these cars. When they fail (and they will...) you must pull the engine or perform some fun contortionist moves to replace. A properly aligned push/pull slave will perform well for years. You do need to change the fluid every few years as it absorbs moisture and the location close to heat sources degrades the fluid. https://www.facebook.com/timemachine...type=3&theater

https://www.facebook.com/timemachine...type=3&theater

htob ?

[eschaider]

Something you want to keep in mind as you do your slave selection and replacement is slave cylinder diameter. Your SPF very likely uses a 0.875" clutch master cylinder like mine. Your slave ought to be a minimum of 0.875" or better yet 1". The slave I used in my car is 1.0625".

When you go to a 0.750" slave from a 1" slave you pedal pressure required to depress the clutch will increase. Here is the impact of changing slave cylinder diameter on pedal pressure. The model uses a 0.875" diameter slave and master as 1.0

• A 0.750" diameter slave will increase felt pedal pressure by 36%
• A 1.000" slave will decrease felt pedal pressure by 23%
• A 1.0625" slave will decrease felt pedal pressure by 32%

To put this in perspective;

• If you had a clutch with a 2400 lb plate, a 0.750" slave cylinder would produce a 36% increase in felt pedal pressure and is what you might expect to experience if you put in a clutch with a 3200# plate load. If you have never driven a car with one of these clutches, they give you cramps in your left leg and cause it to tremble uncontrollably in stop and go traffic.
  
• If you had the same clutch with a 0.875" slave cylinder your clutch would feel like a heavy duty but tolerable clutch for many but not all drivers.
  
• If you had the same clutch with a 1.00" slave cylinder it would feel like a light pedal in a showroom stock automobile and be possible for mere mortals to drive.
  
• If you had the same clutch with a 1.0625" slave cylinder it would feel like a clutch in some proletariat euro import and be drivable by anyone (read your wife).

Choose wisely ...


Ed

[S1965C]

Originally Posted by sn8ke2

htob ?

Hydraulic Throw-Out Bearing

[twobjshelbys]

HTOBs seem problematic. When I had my car I had clutch issues and they all revolved about the HTOB being misaligned and thus eating the rubber seals. It was practically impossible to fix and I finally gave up and went to the practical and cheaper external slave and never had a problem after. After some research here I found Mike Forte's kit. I never regretted the change.


"proletariat". You're aging yourself by using that word. It's probably not even in the history book vocabulary now.

[eschaider]

Originally Posted by twobjshelbys

... "proletariat". You're aging yourself by using that word. It's probably not even in the history book vocabulary now.

I'm already older than dirt Tony, but you're right. Seems like old habits die hard


Ed

[sn8ke2]

Originally Posted by eschaider

Something you want to keep in mind as you do your slave selection and replacement is slave cylinder diameter. Your SPF very likely uses a 0.875" clutch master cylinder like mine. Your slave ought to be a minimum of 0.875" or better yet 1". The slave I used in my car is 1.0625".

When you go to a 0.750" slave from a 1" slave you pedal pressure required to depress the clutch will increase. Here is the impact of changing slave cylinder diameter on pedal pressure. The model uses a 0.875" diameter slave and master as 1.0

• A 0.750" diameter slave will increase felt pedal pressure by 36%
• A 1.000" slave will decrease felt pedal pressure by 23%
• A 1.0625" slave will decrease felt pedal pressure by 32%

To put this in perspective;

• If you had a clutch with a 2400 lb plate, a 0.750" slave cylinder would produce a 36% increase in felt pedal pressure and is what you might expect to experience if you put in a clutch with a 3200# plate load. If you have never driven a car with one of these clutches, they give you cramps in your left leg and cause it to tremble uncontrollably in stop and go traffic.
  
• If you had the same clutch with a 0.875" slave cylinder your clutch would feel like a heavy duty but tolerable clutch for many but not all drivers.
  
• If you had the same clutch with a 1.00" slave cylinder it would feel like a light pedal in a showroom stock automobile and be possible for mere mortals to drive.
  
• If you had the same clutch with a 1.0625" slave cylinder it would feel like a clutch in some proletariat euro import and be drivable by anyone (read your wife).

Choose wisely ...


Ed

Thanks for your reply. Seems like a logical explanation; do you know of any 1.00" units on the market?

[eschaider]

Originally Posted by sn8ke2

Thanks for your reply. Seems like a logical explanation; do you know of any 1.00" units on the market?

Here are a few 1" bore Dormans I dug up a while ago;

CS19097, CS33723, CS36170.

Get a Dorman catalog or go to Summit and check out the listings there.



Ed

[saki302]

Forte recommended the .750 slave on my superformance.

I like it. But my friends call it a 'one driver car' for some reason ��

-Dave