Master Cylinder Question
Thread Starter
Instructor
Joined: Nov 2005
Posts: 230
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From: Bridgewater, Nova Scotia, Canada
Master Cylinder Question
Hey all, I bought a new master cylinder generic type suppose to be for power brakes. It has a 1" bore. my old casting is a 1 1/8" bore. Can this be used for power brakes or is it the wrong one. And yes I haven't learned my lesson yet, I got it off ebay.
Thanks
Thanks
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
I asked the same question when I was buying a new one a few months ago. The answer was that a 1" would need more piston travel to stop than a 1 1/8" bore. I then bought a chrome m.c. from the partslady on eBay. When I finally got around to putting it on last weekend, I learned that the fittings were 3/8" and my lines had 1/2". Now I question what size bore I really have. 
Anybody want to buy a chrome m.c.?
I recently bought a new GM m.c. that I am going to paint black with epoxy caliper paint.
Anybody want to buy a chrome m.c.?
I recently bought a new GM m.c. that I am going to paint black with epoxy caliper paint.
Team Owner
Joined: Jun 2000
Posts: 38,923
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From: Southbound
Cruise-In II Veteran
Safety Car
Joined: Oct 2004
Posts: 3,920
Likes: 731
From: Youngstown Ohio
Definitely the wrong one. The smaller bore MC will cause your pedal to go to the floor, not allowing enough fluid pressure in the lines for stopping......very unsafe condition.
Thread Starter
Instructor
Joined: Nov 2005
Posts: 230
Likes: 0
From: Bridgewater, Nova Scotia, Canada
I asked the same question when I was buying a new one a few months ago. The answer was that a 1" would need more piston travel to stop than a 1 1/8" bore. I then bought a chrome m.c. from the partslady on eBay. When I finally got around to putting it on last weekend, I learned that the fittings were 3/8" and my lines had 1/2". Now I question what size bore I really have.
Anybody want to buy a chrome m.c.?
I recently bought a new GM m.c. that I am going to paint black with epoxy caliper paint.
Anybody want to buy a chrome m.c.?
I recently bought a new GM m.c. that I am going to paint black with epoxy caliper paint.
I'm gonna try to rebuild my old MC unit if it will clean up.
Thanks all for the input.
Burning Brakes
Joined: Jul 2006
Posts: 1,047
Likes: 12
From: SoCal
IIRC, 1" bore is used with manual brakes.
1 1/8" bore is used with power brakes.
However, both types of MCs for Corvettes use the same size fittings (so yours seems totally wrong).
But I have found that you can use a Corvette power brake MC (1 1/8" bore) with manual brakes, which is nice because I haven't found a chrome MC with the 1" bore for manual brakes (which is what I have in my '72). Seems that they only make chrome MCs for power brakes...
HTH
1 1/8" bore is used with power brakes.
However, both types of MCs for Corvettes use the same size fittings (so yours seems totally wrong).
But I have found that you can use a Corvette power brake MC (1 1/8" bore) with manual brakes, which is nice because I haven't found a chrome MC with the 1" bore for manual brakes (which is what I have in my '72). Seems that they only make chrome MCs for power brakes...
HTH
Last edited by VCuomo; Apr 6, 2007 at 06:59 PM.
Safety Car
Joined: Sep 2005
Posts: 4,212
Likes: 643
From: Orange County Ca
I believe that you can get both to work. The 1" bore will have a longer travel, but will deliver more pressure. Origional cars with skinny tires didn't need more clamping power, because they would lock up easily, but with newer, wider tires, you may be able to use more force for quicker stopping.
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Thread Starter
Instructor
Joined: Nov 2005
Posts: 230
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From: Bridgewater, Nova Scotia, Canada
I found another problem with the new unit, the pushrod out of the power booster went into the origional MC an inch or two. On the new one it only go's in a quarter inch or so. Too many things different here to make this work so I'm gonna try and get the proper one. Anyone have a good source for a low price on the proper one. Yeah I know,maybe if I wasn't such a cheapo I'd have the right one in hand but my budget is already broken and this should be the last item.(famous last words)
Le Mans Master
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From: Omaha NE
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Corvette Central has one for $79...........
Thread Starter
Instructor
Joined: Nov 2005
Posts: 230
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From: Bridgewater, Nova Scotia, Canada
Dropped into my local CarQuest today, for fun I asked the price of a MC for a 72 Corvette. $47 CDN! Order one in please and thankyou. Sometimes you find parts in the most unexpected places. I'll believe it when I see it.
Safety Car
Joined: Oct 2004
Posts: 3,920
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From: Youngstown Ohio
It's probably the right one....... believe it or not, Auto Zone has them, too.
Thread Starter
Instructor
Joined: Nov 2005
Posts: 230
Likes: 0
From: Bridgewater, Nova Scotia, Canada
Picked up the MC today, fittings are all correct and the plunger is 1 1/8". Looks like its sleeved to. I've got a few things from CarQuest now that I didn't expect I would. Trouble is going there first instead of checking eBay , gotta get back into the pre-eBay mindset.
I'll give the other one to my brother for his 68, after 20 yrs of storage I think he's gonna need it.
, gotta get back into the pre-eBay mindset.I'll give the other one to my brother for his 68, after 20 yrs of storage I think he's gonna need it.
Last edited by 72350auto; Apr 10, 2007 at 07:26 PM.