Manual Disc master cylinder

[sammywells]

Working on a 1968 C10 with 1972 frame. Stock disc/drum brakes. I've searched the forums and the answers vary. I want to go with manual brakes but can't seem to find a master cyinder for stock manual disc/drum. I can find one for power disc/drum. Does anyone know if there is a stock manual disc drum master cylinder made or do i just use the one for power. I would think the bore would be a bit smaller for manual.

[54blackhornet]

I just bought a master for my 71 with original front disc’s. I got it from Napa. They list one # for both power & manual. I rechecked this to be sure. I have not installed it yet. Supposed to have a plug you remove for manual application..

[Steeveedee]

I'd be interested in seeing how that would work. Those master cylinders have different bore diameters IIRC.

[54blackhornet]

Only for manual/ manual set up.

[sammywells]

Originally Posted by 54blackhornet

Only for manual/ manual set up.

By manual/manual do I mean manual brakes and manual shift
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[68Gold/white]

Just bought a new M/cyl for a 71/72. My Napa guy says it fits manual or power. He's not a novice rookie/bumpkin.
Now if Napa's listing is correct???
I plan to run manual disc on my 67 and 68

[jocko]

I have no idea what manual/manual means. And just because a counter guy says it fits both applications (which it will), it does not always mean a part is "designed" for both applications. There is a difference between a 72 C10 power brake system master cylinder and a non-power brake system master cylinder - and some parts houses carry separate part numbers and list applicability based on power vs. non-power. Believe bore dia is different as mentioned above - and also that the depth of the depression in the back of the piston varies between power (shallow) and non-power (deep). Here is an LMC example:

[dmjlambert]

68Gold/white, So what is the Napa part number or manufacturer part number that Napa sold you? Did you also get a stock proportioning valve or other parts for the conversion from them? Please let us know how it works out. I would be interested in that conversion someday.

[68 P.O.S.]

From what I've read on this forum, the master cylinders for our trucks are either 7/8", 1", or 1-1/8" bore. The 7/8" is for manual brakes and the 1-1/8" is for power brakes. It looks like the 1" bore can be used for either.

[sammywells]

I just looked up the napa m/c. They only list the 1 1/8 bore. Have yet to see a bore size of 7/8 unless it's for drum maybe. The only one for 1 inch is for aftermarket M/C from what i can tell so far. Could it be that they used to make and now they just don't.

[54blackhornet]

I was referring to manual drum/ drum , front and rear..sorry ? They call for a different master.

[jocko]

Originally Posted by 54blackhornet

I was referring to manual drum/ drum , front and rear..sorry ? They call for a different master.

Ah, duh, I got it now - thanks for clarifying, wasn't thinking front/back.
Curious if the plug you mentioned was in the back of the piston facing the firewall - if so, then that really does sound dual purpose (i.e. would support the short intermediate pushrod used with a booster, or, removed, the long pushrod for the non-power setup).

[RichardJ]

CPP is the only one I've seen with a removable plug.

Original type MC have deep hole for manual and shallow hole for vacuum power boost.

Bore diameter is a different issue. 1 1/8" bore without power assist may require a considerable amount of foot pressure.

[chev-obsession]

Go to Napa ask for a New brake master for a 75 C10 (less expensive than 71-72 and same dimensions. Put it up to a booster or not if you want manual brakes. To my knowledge there’s no difference between power and manual brake masters.
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[KQQL IT]

Look at an 84 c10 manual brakes master cylinder
Aluminum body plastic reservoir

[KQQL IT]

This

[68Gold/white]

Originally Posted by dmjlambert

68Gold/white, So what is the Napa part number or manufacturer part number that Napa sold you? Did you also get a stock proportioning valve or other parts for the conversion from them? Please let us know how it works out. I would be interested in that conversion someday.

I will try to remember to get that number when I go home for lunch. THe hole in the end of the M/C piston on mine IS the deep hole. It would have to be to retain the brake pedal rod

I don't believe the 73-up master cylinders have the deep hole in them. THat particular master cylinder was used for years and years on cars and pickups!!!
The Wagner part number for it is (or was, I have not sold auto parts since 1998) F101254 for the new cylinder or R101254 for the re-man. I don't use re-man master cylinders, any more, EVER...

[68Gold/white]

Originally Posted by dmjlambert

68Gold/white, So what is the Napa part number or manufacturer part number that Napa sold you? Did you also get a stock proportioning valve or other parts for the conversion from them? Please let us know how it works out. I would be interested in that conversion someday.

Napa part number M2062. Bore appears to be 1-1/4" hole in piston is about 2 inches deep. No plug to convert to shallow piston, only plugs for bench bleeding...

[sammywells]

Judging from the reply's there is no one master cylinder for manual disk brakes for a 72 c10. I just don't want to have excess pedal pressure to get it to stop. Maybe I need to rethink the manual brakes.

[68Gold/white]

Originally Posted by sammywells

Judging from the reply's there is no one master cylinder for manual disk brakes for a 72 c10. I just don't want to have excess pedal pressure to get it to stop. Maybe I need to rethink the manual brakes.

I'm not going to install my m/cyl for a while. Have read many here that liked it.

I will start a thread, asking that question!!!

[dmjlambert]

I would love to see a thread about conversion of front manual drum brakes to front manual disc brakes using as many as possible car parts store parts or original equipment traded parts from 71-72+. I am interested in stock height, and love the feel of manual brakes.

[jocko]

Originally Posted by sammywells

Judging from the reply's there is no one master cylinder for manual disk brakes for a 72 c10. I just don't want to have excess pedal pressure to get it to stop. Maybe I need to rethink the manual brakes.

Yes, there is. LMC # 34-4018 is specifically for a stock 71-72 C10 non-power, disk/drum setup. The link is provided in post #7 (the blue underlined text) $59.95

While I'm not a massive fan of LMC, they don't manufacture master cylinders, they just sell them like anyone else does - and the fact that they list power, and non-power master cylinders for a 72 C10 under different part numbers means they at least understand there is difference - which puts them light years ahead of the other suppliers. I've always trusted Napa too, but original 72 C10s had different MCs for power and non-power applications, so if there is a seller out there that realizes this, I'd have a warmer fuzzy going with their part # for a non-power setup than rolling the dice on one about which a parts guy just said "they're all the same" when they are not - for several reasons outlined above. I've had much better luck with LMC than CPP for brake parts, believe it or not. I too would prefer to purchase one at a local dealer like a Napa, but if you (now) know that there are two separate MCs for two different applications - I'd personally prefer to go with the vendor that understands the system.

Having said all that - if you don't want excess pedal pressure, it sounds like you actually want power brakes. You can easily buy a booster at any parts store and source the stock bracket/links/etc from the parts board here from someone parting a truck, or go with member CaptainFab's custom booster bracket that will tuck everything closer to the firewall. 5th picture down in this thread

[BigBird05]

I bought my power brake bracket/link for my 72 Truck from Classicmuscle.

[dmjlambert]

Originally Posted by KQQL IT

Look at an 84 c10 manual brakes master cylinder
Aluminum body plastic reservoir

Do they have the same depth pushrod hole as the 67-70 manual brake master cylinder? Will anything need to be done in the cab?

[Steeveedee]

Originally Posted by jocko

Yes, there is. LMC # 34-4018 is specifically for a stock 71-72 C10 non-power, disk/drum setup. The link is provided in post #7 (the blue underlined text) $59.95

While I'm not a massive fan of LMC, they don't manufacture master cylinders, they just sell them like anyone else does - and the fact that they list power, and non-power master cylinders for a 72 C10 under different part numbers means they at least understand there is difference - which puts them light years ahead of the other suppliers. I've always trusted Napa too, but original 72 C10s had different MCs for power and non-power applications, so if there is a seller out there that realizes this, I'd have a warmer fuzzy going with their part # for a non-power setup than rolling the dice on one about which a parts guy just said "they're all the same" when they are not - for several reasons outlined above. I've had much better luck with LMC than CPP for brake parts, believe it or not. I too would prefer to purchase one at a local dealer like a Napa, but if you (now) know that there are two separate MCs for two different applications - I'd personally prefer to go with the vendor that understands the system.

Having said all that - if you don't want excess pedal pressure, it sounds like you actually want power brakes. You can easily buy a booster at any parts store and source the stock bracket/links/etc from the parts board here from someone parting a truck, or go with member CaptainFab's custom booster bracket that will tuck everything closer to the firewall. 5th picture down in this thread

Well said! There's a lot of confusion about the difference between power and manual brake master cylinders, and it persists. I do have power brakes on my truck, but am aware of what happens to pedal pressure when the system fails. Our Astrovan had a fuel pump fail, so the hydra-boost of course wasn't working when the engine quit. My wife was driving it and managed to get off the freeway and get it stopped without a crash. I can stand on the pedal in the truck in case of booster failure, but there is no way that my wife could do it and make it stop well. As a result, she has no interest in driving it while pulling our travel trailer.