15/16 Master or 7/8 Master

[70 LS1]

What cars came with either a 15/16" or 7/8" master? Where else can I get one of these sizes?

[CurtiSS 69]

The 77 Chevy Malibu with a 6 cylinder and manual brakes has a 15/16" diameter master cylinder.

Regards

CurtiSS 69

[David Pozzi]

Early 70's small ford models use 15/16" and 7/8". They have a longer stroke than the Malibu which I was going to use, I got the Ford MC instead. The Ford MC's have slightly narrower bolt holes, I had to file out mine to fit, and the brake lines attach on the engine side.

Baer sells a master cyl that is 15/16" and has ports on the driver's side, bolts right up to GM cars.

[andrewb70]

There is also the quick take up MC from the S10. David knows more about it than I do. However, I think I am the only one that has ever gotten it to work properly...LOL

Andrew

[70 LS1]

Any more info on the S10 master? What size and what years? And what is a quick take up master?

[70 LS1]

Early 70's small ford models use 15/16" and 7/8".

Would these be suitable for a disc/disc setup? Any specifics on which models would work?
thanks

[andrewb70]

Any more info on the S10 master? What size and what years? And what is a quick take up master?

Do a search on this site. There are at least 2 or 3 long discussions with a ton of information. Google quick take up and you will find some more reading.

Andrew

[MarkM66]

The 77 Chevy Malibu with a 6 cylinder and manual brakes has a 15/16" diameter master cylinder.

Regards

CurtiSS 69

That's what I'm using. C4 front, LT1 camaro rear.

[Neil B]

I'm pretty sure some of the late 80's Camaro/IROC Z's used 15/16" (24MM) bore master cylinders too.

[silver69camaro]

Wilwood will be coming out with a 7/8" aluminum MC in the very near future. It bolted right up to my firewall and brake pedal without any modifications.

[kball]

Here's a good article. I found this when I was looking for the same for my chevelle. http://www.chtopping.com/mustang.html

[David Pozzi]

Would these be suitable for a disc/disc setup? Any specifics on which models would work?
thanks

Wagner cast iron master cyls

F104473 13/16 Manual brake, Ports on engine side file mounting holes to fit chev. Ford Escort 81-83

F99084 7/8" Manual brake " Ford Fairmont 78-81

F81630 15/16" Ports away from engine, not sure about mounting hole fit, or if for manual brakes.
From Ford Granada 75-80, Maverick 74-77, Mustang 75-78,

[67jeff]

just to make sure, were talking about manual brake applications (no vac booster, no hydraboost), right?

what about this one

Raybestos # MC 39027 (L.H.) (cast iron) 7/8 bore (L.H.)
'76-80 GM Monza • Sky Hawk • Starfire • Sunbird

its from that mustang article above

also, is this a quick take up (dont think so, but wanted to ask)?

thanks

[SHANE 73Z]

Jeff,

What kinda car??? Just looked 70 vette.

What is the pedal ratio?? Most of the cars (1st gens) running the bore sizes you mentioned have a 6:1 pedal ratio. If you have a lower pedal ratio (like my car 5:1) you will not like the brake performance.

I am running 3/4" masters presently & will be trying a .7" diameter this year to try to get a little more line pressure. If that doesnt satisfy, I will be looking at doing some pedal mods.

Shane

[67jeff]

Shane,

I have a 67 Camaro that came with manual disc/drum brakes. Ive got a master cylinder on there now that is probably an 1" or better (larger)and ive never been in a real hard stop, but i can tell that id have to stand on it to get it to perform.

Id like to do the touring classics type setup (twin 40mm pbr C5 calipers) in the front with 97ish camaro rear discs in a manual mode, but after reading quite a bit, i think id need a 13/16" (or at most a 7/8) to give me the "front cylinder ratio" described here

http://corner-carvers.com/forums/showthread.php?t=21615&page=1&pp=40&highlight=manual+brake+thread

this makes sense to me, but is really just numbers to me because i dont know what i personally consider acceptable foot force (100-150 or more lbs) when braking.

i do know that with my new motor (planning a procharged 496) that i want to be able to stop quick and i dont want the master cylinder bottoming out.

do you know if these master cylinder (the ones that david pozzi and others referenced) are of the quick take up kind? or will they have plenty of travel and not bottom out during a hard stop?

The other thing i want to know is why does the Touring Classic setup with C5 PBRs recommend a 1" or 15/16"? using the math above, that just seems way too big.

thanks

[70 LS1]

SHANE 73Z - Pedal ratio is 6:1. I actually talked with a guy at Tilton and he recommended 7/10 for the front and 13/16 for the rear. Took into consideration, car weight, weight distribution, tire size, wheelbase, caliper and rotor size. Looks like I will try a dual master setup. Besides it gives me an excuse to buy some more cool parts.

Thanks for all the responses.

[SHANE 73Z]

Jeff,

I am running the Touring Classics rear kit on my car. They seem to be pretty sharp guys and I would not be afraid to start with their recommendations. This is just like any other part we buy for our car, we educate ourselves as best we can & start from there.

As far as the above mentioned masters the only one I am certain is a quick take up is the S10 unit. In the C-C thread there was quite a bit of good info, on OEM masters/sizes if you read far enough. I have never calculated the MC sizes using that formula. I calculated mine starting with an assumed 6:1 pedal ratio and then calculated MC bore size (piston area) as approx 20% of the front caliper bore size (again as piston area). I found out after selecting 3/4" MCs that my second gen is a little light on pedal ratio.

70 LS1,

Tilton sounds like they are pretty much on the mark. I am running a dual master setup from CNC brakes that adapts to the stock pedal. This allowed me to avoid the problems of hanging a race pedal arrangement. The other nice thing about the dual MC setups is the fact that most of the MCs available are interchangeable, meaning that you can swap between brands even. I am replacing my CNC masters with Wilwoods for example.

Heres some links to some cool stuff.
http://cncbrakes.com/cncbrakes.com-asp//sra.asp?grp=sra&subgrp=d&series=240&subseries=

I purchased my CNC stuff through JMC Motorsports.

Take care,
Shane