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CNC Clutch setup leaking at master already? Less than 1K miles.

2645 Views 30 Replies 7 Participants Last post by  slow-poke
I was digging around under my pedals, and I felt some fluid around the MC. It's a CNC, 3/4" if I recall (And it's been about 5 years). I believe the slave to be 7/8?

This is on a T5. I am unsure of what clutch is in there (I remember it being FRPP, but beyond that, no idea). VERY hard to push down.

Anyone had a CNC brand master failure? It hasn't failed yet, but... I do not recall if I got the aluminum or the steel version. But the aluminum one would be sleeved I imagine, so is there a strength difference? (And of course, there are rebuild kits).

1000ish miles, but an extremely hard clutch pedal.. I have to dig into the clutch, one day.. Hopefully not this summer!
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Bartl - Can you ruin a master cylinder by pushing it too far? We have our hydraulic clutch installed but haven't driven it yet. It appears to work fine but the master definitely bottoms out before the pedal hits the floor. Should that be a concern? Is there a way to prevent that?

Thanks,

Bob
I know the feeling. I use to have a clutch that was an on/off switch. Wilwood master w/ McLeod hydraulic bearing. Definitely not fun.



Back to the question at hand. So I made one bad assumption and hope I'm not making another. I reread which master cylinder you used. I had assumed you used the master CNC supplied to JMC. The next assumption I'm making is that this is installed in a 65-6. Is that correct? If so, did you use the part below with the master you bought from CNC to angle it up towards the original clutch rod hole in the pedal? I'm thinking if not, you had to drill a hole in the clutch pedal 1" lower than where the factory clutch rod goes and that would definitely increase pedal effort. The size master you chose seems to be correct for the application. My brother-in-law's clutch kit is 3/4 master, 7/8 slave (nice easy pedal) whereas my brother and I have 3/4 for both (little more feedback). Another thing is the masters can be temperamental if the pushrod travel is not parallel with the bore through the full stroke. I'll wait to see the picture(s) so I don't give bad advice.
Daze cars has a master cylinder rod and an offset rod adapter to let you install the master straight on the firewall and use the original push rod hole on the pedal. I have it. Works great.

Bob
M
A M/C with slightly more stroke (about 1.5-1.7") would be better suited, but I have not found one.

If Tilton, Wilwood, CNC were to offer a M/C with more stroke, I would buy one tomorrow.
The one I installed is 1.4" stroke, 13/16 bore.

It feels like it requires more pressure than I'd like, but we haven't driven it yet so we'll see. The Slave is CNC 7/8" bore slave.

http://www.summitracing.com/parts/WIL-260-11972

Pic in my car:

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The one I installed is 1.4" stroke, 13/16 bore.

It feels like it requires more pressure than I'd like, but we haven't driven it yet so we'll see. The Slave is CNC 7/8" bore slave.

http://www.summitracing.com/parts/WIL-260-11972



I'm surprised that M/C will provide enough volume to fully disengage the clutch.[/QUOTE

Why? The daze mc is 3/4" bore, and I don't think it's stroke is as long either.. Math says I get like 1.3"+ stroke at slave, which seems plenty to me. I'll measure on Saturday.

Bob
Do you have any preload on your clutch fork? my understanding is 1.4" stroke at the slave should be more than enough. Sounds like you have way more experience than me, so I'm relying on what I have researched. I bled with a pressure bleeder from the slave up.

Bob
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