I've done a lot of research on this, and read dozens of prior posts on the subject, but still haven't come up with a definate conclusion. I'm hoping someone can help me out and speak from experience. I took a complete front brake system, with master cylinder, from a donor 69 Camaro. It has what appears to be the original master cylinder on it, casting number ends with "310". It is the small body cylinder, with equal volume front and back. From what I can tell this is the correct master cylinder. It's pretty rusty and I can't move the piston (without using a hammer) so rebuilding it is probably going to require a new sleeve, so I';d like to just get a rebuilt unit.

Here's my problem. I went to two auto parts stores looking for a replacement. The one they show for manual and power disc brakes has a 1-1/8" bore. Mine is a 1". The one they list for manual drum brakes has a 1" bore and physically looks identical to mine. I think the part # was R11505 Bendix. I did buy that one, but kept my core for now until I can confirm this new one will work. Can anyone tell me if this would have the proper internal components for my disc/drum set-up? I also have the dist block mounted under the master cylinder. It has about 5 or 6 lines going into/out of it and and electrical connection. I have most of the original front to rear brake line, and it is the one-piece style, without the valve under the body.

Will this work properly, or do I need to keep looking for a different master cyl? I have no way to know if the brake system was functioning properly on the donor car, since it was just a bare body and frame when I got it. I guess someone could have put the wrong cylinder on it many years ago.

I need to run manual brakes, because my engine won't produce enough vacuum to operate power brakes, so I want to make this work.

I hope somebody can shed some light on this for me.

Thanks!

Jeff

This should actually be in the suspension forum.

Anyway, manual drums get a 15/16" bore ( think), manual disc gets 1", and power disc gets 1.125" bore. The manual disc master has different sized reseviors, the larger being for the front discs. Power disc masters (1.125" bore) has equal sized masters, unless you have a Bendix booster.

So you want a 1" bore, but you need to get one with a larger resevior for the discs. The one that you got looks to be for a power drum setup. You need a MC off of a '67 Camaro w/ manual discs, and these have the proper volume for the discs and has a 1" bore.

Also, are you sure you don't have enough vacuum for a booster? I have about 10"hg, and the power brakes work great. Think about how much vacuum the Z/28's had.

Sorry, it's my first post and I must have been looking at the Body Shop when I sent it. Anyone know how I can move it?

When I got home I dug through some more old parts and found a M/C that has the big/little reservoirs on it and has a 1" bore. I'm now wondering if this is actually the one that came with the car and I had the other one confused with it. I'll head back to the parts store and try to match this one up.

I tried to look up a 67, but they don't show manual disc/drum. The 69 shows 1-1/8" for both power and manual, which I know is not correct. I think I'm on the right track now anyway. I was looking for one with equal sized reservoirs, but that's not right.

As for running power brakes, I had this motor in a 71 Chevelle about 7 years ago, but can't recall how much vacuum it had. I don't think it was much. The Chevelle had manual drums on all 4 corners. It's a 406 small block with a very agressive solid roller cam. 256/267 @ .050", 292/304 advertised duration, .651/.651 net lift. ATI supercharger and air to water intercooler through a 750DP. Made 670HP/600FT/LBS on dyno with 93 octane and ran 10.50's in the Chevelle through the mufflers with 3.73 gears and DOT slicks.

If anyone knows an inexpensive/simple way to get these brakes working, I'd like to hear from you. I'm not concerned about "original" appearance. I'll also be plumbing a line-loc to the fronts. Not sure if this original Prop valve is any good, so I might need to get a different one. Maybe an adjustable one?

Thanks,

Jeff

There Is No manual discs on a 69 car from the factory they are all power. It takes a 309 master with US stamping on the front for the original factory master. Sounds like the one you have is for a power or manual drom brake car.

"There Is No manual discs on a 69 car from the factory they are all power."

Did the window sticker show both J50 and J52, or did J52 include J50?

the 310 is manual drum/drum master. It has a 1" bore.
the R11505 is also a drum/drum 1" bore master.
68-9 camaros did not come with manual disc.

IF 69 had come with manual disc, it would have had a 1 1/8" cylinder.
The reason the 67 front disc cars had a 1" cylinder for manual brakes is they had smaller displacement calipers than the 69-81.
The reason the 1970-81 front disc cars had a 1" cylinder for manual brakes is they had a shorter pedal ratio.

Get a master for a manual disc Corvette of the same year. It has a 1" bore.
If the pedal travel is too much for you, get one for a power brake corvette for the same year. It has a 1 1/8" bore and is the same cylinder listed for 69 camaro w/ front disc/delco.

I could be wrong, but I don't think the Corvette MC will work. Disc brakes require more fluid to operate than drum,..and of course Vettes had 4-wheel disc. The Corvette's reservoirs would not be set up for disc/drum.

But you could call one of the aftermarket co's,..Baer or Willwood or somebody,..they'll have something.

I guess you'll have to take that up with acdelco. They list the 18M72 for both disc/disc and disc/drum applications.
http://www.oewarehouse.com/Merchant2/merchant.mv

catalog/vehicle list, 18M72

I appreciate the help so far, but I'm still a little confused. Everything I've read, in the posts that I've searched, leads me to believe that a 1" bore is needed on a manual disc application, to make more pressure (and make up for the lack of power assist). Now I'm being told that 1-1/8" will work?

Can anyone answer this question? What is the relavance of deep and shallow holes in the piston for the pedal rod? I'm guessing power had shallow and manual had deep? If that's the case, then this confuses my situation more. My M/C (1" bore with big/small reservoir) has the shallow hole. I mocked it up on the car and would push the piston in about 1-1/4" by the time it was bolted down, so it obviously won't work, even if I found an identical unit. The pedal is set up in the manual position (rod in upper hole) right now and is adjusted to almost the shallowest position. If this really is a power M/C (because of the shallow hole), why would it have a 1" bore? That seems to go against everything that everyone has told me.

I went to the parts store yesterday to try to find a M/C with big/little reservoirs, and a 1" bore. We couln't find anything in stock, so I ordered one that might work. It's for a 73 Malibu with manual disc. It didn't mention bore size, but I'm guessing it's 1". The one for a power appilication noted it was 1-1/8". It had a foot note saying it was supplied with a pedal rod. The reservoir configuration is backwards from the older Camaro's, in that it has the rear brake (small) reservoir on the front. Not a big deal since I'll be fabricating lines myself anyway. It's supposed to be here tomorrow (Sunday) so I'll report back what I find. Unfortunately the car is a few months away from running, so even it it physically fits, I won't know how it functions for a while.

Manual masters can have the shallow hole if they used a shorter pushrod with a retaining cup. 67-9 Camaros all list OE as having a deep hole whether manual, power, disc, or drum.

1" bore is correct for 1967 Camaro manual disc.
1 1/8" bore is correct for 1967-8 Firebird with manual disc.
There is no correct master for 1969 manual disc.

Most prefer the 1" master. 1 1/16" - 1 1/8" would actually give it almost identical overall ratio to other manual disc GMs. GM wouldn't use a 1" master with that pedal ratio and those calipers. That doesn't mean you can't. I did.

The 2ndgen 70-81 Fbody used a 1" bore for manual disc BUT it had a Lower Pedal Ratio. The Overall Ratio was nearly identical to the cars with the 1 1/8" bore manual master, and to the 67 camaro with smaller calipers.
overall ratio=hydraulic ratio x pedal ratio

The malibu master should work IF it has the deep hole.
The pic I looked at of one shows it should, but the ports are reversed. Front brakes will hook up to the rear port if it looks like the pic I saw (large resivoir in back).
I would use the manual corvette master if i was you.
I have one on my 68 firebird with single piston calipers.
The 1" master does not a firm pedal make, but it's not bad. The difference from the 1 1/8" I had on there as far as pedal effort is not significant IMO. I am leaving it until i can find the correctly coded 1 1/8 master (power corvette used same master, different code)

If I follow your advice and use the 69 Vette manual M/C as you did, what would I use for a prop valve? The one I have is the long-narrow style that mounts under the M/C with a bracket. It's not the small-rounded style that I've seen in some pictures. It also has the rubber button on the end. Will this work with the 69 Vette and 73 Chevelle M/C's? I'm curious as to how you have yours set up, since you say it works well on your 68 with single calipers. Do you have that other valve mounted on the frame under the drivers seat area too?

The master cylinder doesnt care which valve you use.
The rest of the car does.

The combination valve you have will work fine. It takes the place of the round valve (rubber button) and may also have a rear proportioner in it (valve under driver's seat).

If the last 4 digits on the valve are 7177, it might not have a rear proportioner in it. Many cars had none. High front end weight, high weight transfer, or large rear brake cars generally need one.

If the last 4 digits are 9419, you can actually go up to 15/16 rear cylinders from a late 70s 2nd gen.

I have not installed any valves yet. I have light front end weight (6cy) and 7/8 rear brake cylinders. On my shelf i have the front round valve, the rear under seat valve, an adjustable rear valve, and a 9419 combination valve, as well as an extra stock differential switch.

Can't see a number on my valve. It's pretty rusty. I'll take the bracket off so I can clean it up, maybe I'll find the number then.

Could I run without a valve at all? Just make two left/right distribution blocks from "T"s and add an adjustable aftermarket valve in the rear line? I'm starting to think that might be the easiest way to make this all work. My front end isn't light, I have a small block with Alum heads, but AFR's are almost as heavy as stock iron heads. I also have the ATI supercharger and intercooler, with all of it related plumbing. So I'm probably heavier than a stock small block, but lighter than a stock big block.

yes, split the fronts with a T, and put and adjustable in the rear line. That's all you need.
You wont have the dash idiot light anymore.

It's starting to sound like that's the way to go for my situation. I forgot that I would only need one "T" (for the front), since the rear splits at the back of the car. Should make plumbing the line-loc a little easier and cleaner too, this way. My original valve is pretty nasty looking and I question if I could even get it working properly anyway.

Thanks for the help!

Just to clarify,..according to Bendix, 4-wheel disc brakes for 69's (JL-8)required a different master cylinder than the others. Also, Vette MC's of the same years show to be different from Camaros.

Here's an excellent source for info and parts:

http://1967-81camarocarparts.com/pdf/F1_67-69/F1_05%20brakes.pdf

Good luck!

They are still the same casting #s.
The 5469489 pt# was used, correctly and according to your link, 68-69 for 4wl disc, and also for 67-68 disc/drum.
The 5469489 part# used a 5460346 cast. Same as Corvette.

The 5469489 part# has an SA code on the front.
The Corvette had a PG on the front.
Same cast.
Same primary piston.
Most likely a different secondary piston.

I doubt you'll find aftermarket with different secondary pistons. They all use the 3 ring length. (3 ring was FR, GA, WT, US, ?)

69 disc/drum cast was 5468309. You'll find the part number on your link.

Please show me the different GM corvette part #s. I need for my research.

The current Bendix 69 4whl disc part R11494 is traditionally a disc/drum casting... rectangular, large front, small rear. I'm sure it works. It is also listed as fitting about 60 different disc/drum vehicles, including 67 Firebird (never came with disc/disc), but only the One disc/disc vehicle..
Their disc/drum R11372 and new 11372 cast is the same # as they list for disc/disc Corvette, and disc/drum 69 Camaro.

Strange huh? Just to clarify.. or confuse ;) I'm confused.

The Corvette master cylinder won't work with a disc/drum system - it doesn't have a residual pressure valve in the rear system outlet.
:beers:

Neither does the disc/drum master 69 and later.

Neither does the disc/drum master 69 and later.

Yes, it does. The "US"-stamped master cylinder has a residual pressure valve mounted behind the brass tube seat in the rear outlet; you have to remove the tube seat to see it.

:beers:

Do you have one?
I had a 69 GA stamped 309 cylinder without one. (firebird) I did add one when I rebuilt it.

The residual valves are not listed for the 69 model.

The new and rebuilt 69 corvette disc/disc and Camaro disc/drum masters interchange according to their manufacturers, including AC Delco.

If you can gravity bleed your brakes, you do not have a residual valve in that circuit.

My rebuilt 68 drum/drum master i found out had no residual valves in either circuit. I checked for them when i removed it last year. It had been on there since 1989 w/ no problems. I checked for the valves and they were not there at all.

The distribution block also has no residual valves. I checked.

The MPbrakes combination "proportioning" valve also has no residual valve, even though they say it does. I have one. I checked.

Bendix lists their new 11372 master for these vehicles:
CHEVROLET back to top
1969 CAMARO
1967 - 1976 CORVETTE
1968 - 1969 CHEVELLE
1968 - 1969 EL CAMINO
1969 CHEVY II


This is a 1.125" bore, dual bail, deep pushrod cylinder.

ACdelco used to list their Corvette 18M72 for the camaro and corvair, but they recently changed the listing. It is still listed for the other above vehicles, and some 1970 disc/drum cars too.

I have a Bendix rebuilt disc/drum master for a 1970 camaro on my shelf, listed for a host of disc/drum vehicles. There is no residual valve. I checked.

Might be too late but MP Brakes has a Corvette style M/C for manual disk/drum with deep 1" hole. Part # MC390360M $90

Well, I've got a new problem now. I bought the 73 Malibu M/C which appears that it will fit and function properly. Only problem is that when I installed my roll cage (7 years ago) and ran bars through the firewall, down to the front of the subframe, I didn't have a master cylinder on the car at the time and it caused a problem now. This one will fit, but the tube runs along where the brake lines would assemble into the unit. Too close to make a sharp bend in the line and I'm not sure even if I could find a 90 degree fitting, that I would want to use it for this application. I know I've seen a M/C with the same configuration as the Malibu, but with the lines coming out of the passenger side of the unit. Anybody know what application might have used this M/C, so I can look it up at the parts store? We tried 60's and 70's era trucks, Nova's Impala's and a bunch of others, with no luck.

Any ideas?

This has ports on both sides: Part #: MC390834M $119 http://www.mpbrakes.com/uploads/content/2006%20catalog.pdf Page 16 of their catalog. If you search for the part # it doesn't show up, but it's in the catalog.

or MC390387M ports on right side, page 36 of catalog or here: http://www.mpbrakes.com/products/product-detail.cfm?product_id=534

good luck

Here's an update for anyone else who might run into this issue. I found a M/C for a 76 AMC Matador (other years and AMC models listed the same one as well) Cardone # 101492. It has ports on the engine side to clear my roll cage tubing, and is for a manual disc/drum car, with the deep bore for the pedal rod. The only difference from what I was originally looking for is that it is 1-1/8" bore instead of 1". From what some of you guys have told me, that shouldn't be too much of an issue though. It cost me about $30.

Thanks to everyone who responded with advice!

For manual disk/drum brakes use a 1" bore the drum/drum M/C is to small. There were 600 or so manual disk/drum cars made if you don't have the right M/C now you won't find it. Use the 70 Corvette Disk/Disk manual 1" M/C it does not have a residual check valve but you may not need it, some had one and some did not. Try it with out first, if you have a low pedal then add a residual check valve in line. it just holds the drum brake springs from returning the shoes to far. I also think that the 70 camaro M/C will work but it has a small reservoir. If you need more help contact David Pozzi. I went through the same thing and this is what he had to say.

This is some coped e-mails so it's a little gooffe.

Dave I have been looking for a master cylinder for my none power 67
with front disc and rear drums. I located a one at Kragen Auto
Parts.($48.00) It's a new not a remanufactured unit, and they insist
that it is for Disc/Drum it has the 1" bore but it also has a small
reservoir, and a single bail clamp just like the Drum/Drum unit. Since
I don't know much about the internals, and none of the parts guy's do
ether, I don't know what to look for for a residual pressure valve
for the front side. (1) If it has a residual pressure valve in the
front it will wear out the front pads right?

Don't use this one, it's a drum type. It probably has a residual pressure valve and will wear out the front pads.

(2) How do you tell if a master cylinder has a residual pressure valve
or not? (3) Can you see the residual pressure valves in the outlet
holes on all the master cylinders?

It's a little black rubber device about the shape of a pencil eraser just behind the brass seat in the master cyl port. You can see it if you have a good inspection light, or stick a toothpick in there and it won't go far and will feel spongy.


I have also located a rebuilt Disc/Disc unit for a 70 corvette with a
large reservoir, and duel bail for near $25.00 I have a question about
that to. You said in you're e-mail to me that: I'd use an adjustable
proportioning valve in the rear brake line and I wouldn't put any
residual pressure valve in the rear line. (4) So if I don't use a
residual pressure valve in the rear line, won't the rear brake shoes
back away form the drums due to the springs and lessen the usefulness
of the rear brakes?

10 lbs of residual pressure is usually used by GM, it is used to keep the wheel cyl seals pressed out and sealing, it is NOT for keeping pressure on the return springs. THAT would take way more pressure and you would not want that.


Next question goes with ether master cylinder,
(5) should I use a
combination valve?

NO

(6) Could I use a 1970 or later combination valve
and skip the adjustable proportioning valve?

You can if you want to go that way. It usually costs more and there is no adjustment if the proportioning isn't just right for you.

(7) Does the combination
valve have the residual pressure valve in it, or are they in the master
cylinder?

The residual pressure valve should be in the master cylinder. I have heard the wheel seals were changed to not require a residual valve sometime around 1969 or 1970 but have no proof this is correct. It would mean that all the fuss over residual pressure valves is for nothing. David

Thanks again for your time
Jack
jackswanson@verizon.net



On Dec 30, 2005, at 9:25 PM, David Pozzi wrote:

A good manual master cyl for disc is a 67 Camaro manual disc master
cyl. GM only made around 600 that way so many parts sources won't have
that one. A 70's Corvette is identical except they have no residual
pressure valve for the rear brakes. I'd use an adjustable
proportioning valve in the rear brake line and I wouldn't put any
residual pressure valve in the rear line. If your rear wheel cyls
start to leak a little, you can buy a residual pressure valve and
install one in the rear line, something close to 10 lbs is needed.
Good luck with your Camaro, David

Jack Swanson <jackswanson@verizon.net> wrote:

Hi David

My name is Jack Swanson, I live in So. Ca. I have a 67 camaro that I
am
putting 69 front disc on. I have all but the master. I have been
looking for a 69 master but cant find one for none power. I see on
your
web site that a 70 can be used. My question is, does the z28 master
work the parts guy says it's for 4 wheel disc, or is there a down side
to using the 70 1" none power unit other than the look, and what
combination valve can I use or does it matter. I mostly use this car
for bracket racing but it does see a little street use. This means I
do
use the breaks hard at the top end @ 115 MPH so I don't want it to
brake unevenly. It would be ok if the front lock first but best if
they
are even.
`
Thank You for Your Time
Jack



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