Clutch master cylinder replacement for SBC application? (1 Viewer)

Joined
Jul 16, 2016
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Charlotte, NC
Our '72 has a SBC conversion using the GM 4-speed/ xfer case setup. I just noticed that the master cylinder is starting to leak on the inside of the cab.

The master looks to be original, or close to it. Which master should I buy? Or, should I just get one of those kits from SOR that come with a new master/ slave/ lines/ hardware?

Thanks!!
 
Joined
Apr 2, 2008
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Victoria, BC
I've rebuilt mine twice in 28 years. The kits for a '74 include new seals and a piston for < $30.

The lifespan seems to be about 11-12 years. Usually it's recommended to replace it every 10 years.
 

Mopdog

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Jul 18, 2010
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There is the option to use an early brake master as a clutch master as well. It bolts right up and increases the amount of throw over the original clutch master.
 
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Jun 5, 2007
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Brea, Calif.
^^^ But then takes about 30% more leg muscle pressure to use, could become a problem when holding in clutch at a red light ???
 
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Mar 14, 2011
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Seattle
x2 on the SOR combo. I was having trouble getting enough throw from the later model clutch master/slave for my SBC setup. Got the SOR kit and it solved my problem, using a standard chevy clutch setup. Best I can tell, it is just an earlier model master. It's nice that it comes with new lines.

It does require a bit more pressure than the later model master, but honestly I found the later model master to be too soft. The pressure doesn't bother me at all, and it's a lot simpler than replacing your clutch with a special unit that requires less throw. But I can't speak to what it's like when using an early model brake master in place of the clutch master. My udnerstanding is that the brake master has a bigger bore than the earlier model clutch master (1" vs 13/16", I think)
 
Joined
Jul 16, 2016
Messages
85
Location
Charlotte, NC
I've rebuilt mine twice in 28 years. The kits for a '74 include new seals and a piston for < $30.

The lifespan seems to be about 11-12 years. Usually it's recommended to replace it every 10 years.

Could you post the correct source/ part number for this kit?

Thanks for all the replies so far.
 
Joined
Jun 8, 2008
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San Diego
^^^ But then takes about 30% more leg muscle pressure to use, could become a problem when holding in clutch at a red light ???

Holy cow, only 30% more!?!?
It felt like 2x! I ran it like this for some years and it was exhausting after a day on the trail. 😳
Went with a stock system and your clutch/pressure plate, and it's smooth and easy like butter.
 
Joined
Apr 2, 2008
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Victoria, BC
Could you post the correct source/ part number for this kit?

Thanks for all the replies so far.
I’ll have a look for a P/N, unfortunately no link.

When I was looking for the kit I stumbled across this... looks like a new Asian one...
364B0B35-4094-4F06-B504-F9E05F138967.jpeg
 
Joined
Apr 2, 2008
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9,731
Location
Victoria, BC
I’ve had good luck with ‘74 clutch components. I no longer have bore specs... however years ago I found that the bores created somewhat more stroke than other combinations without going to the extreme of a 1” brake master cylinder.

Combined with a SS braided line to connect the master and slave. The LUK clutch has been serving me well for 24 years and now a second 350.
 

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