Manual Disc master cylinder

[dmjlambert]

Originally Posted by Steeveedee

If it doesn't say anything about a booster on the SPID, it came with manual disc brakes...unless there was an option that ended up including power disc brakes without calling them out on the SPID. The reason I say that is because I have 16.5" wheels on my truck, but it doesn't say anything about them on the SPID. I suspect that this was because they came with being a Longhorn or some thing like that. I don't see any indication that the 61A alternator should be on my truck either, according to the SPID. Maybe that came with UY1 Camper Wiring? It would make sense.

A longhorn is not really fully in the C-10 family because it has a 1 ton frame, is that correct? I suspect they only had power brakes, just like C-20's. So yes I agree/suspect power brakes came with being a Longhorn. Wouldn't surprise me at all.

[Steeveedee]

True enough. In all the discussions I've seen about this here, I believe that the consensus was that all 3/4T and up trucks came with power brakes standard. But I might be remembering that wrong. It sure would be nice to be able to talk to the sales managers I knew when these trucks were new and I was working there. They could shed a lot of light on the subject, I bet.

This of course only applies to '67 and up I suspect, because there seem to be a lot of manual brake 3/4T trucks in the '60-'66 forum.

I worked on hundreds of vehicles in new-car get ready, and remember that I've only ever seen ONE car with manual disc brakes. It was a '71 Chevelle. I remember because that was quite a surprise when I drove it. It stopped fine, but had a bit higher pedal effort, like a drum/drum vehicle would have.

[hjewell2]

subd

[Keith Seymore]

Adding the '71 and '72 engineering brake charts here, per request (focused on master cylinder information):

[Resto-Rand]

I just logged on to the site after a year and can't believe this thread. I have a 1971 C10 with manual front disc / rear drum. It has no part number on it that I can see. It is for sure stock as it came to me that way a million years ago. I paid $1700 for the truck so it's been awhile since I purchased it for work.

It has a larger front res. and different sized lines for front and rear.

Not being too knowledgeable, I'm assuming I cannot measure the bore with it still installed?

[dmjlambert]

I think you would have to remove the master cylinder to measure the bore. I re-read the whole thread while trying to ignore all C-20, C-30, and longhorn info because those always came with power brakes and were plumbed differently.

Summary: According to the documentation Keith Seymore posted, manual and power both have a 1-1/8 bore size. I have heard before and seen posted on this thread the power master cylinder has a shallow push rod hole and and manual master cylinder has deep push rod hole. On C-10 the front reservoir is for front brakes, and for disc/drum setup the larger reservoir and smaller tubing size is for disc. So it looks like 54blackhornet got a good new master cylinder for C-10 manual disc/drum.

The next thing I would be interested to see is measurements and photos from actual C-10 71-72 trucks with and without power brakes. Measure and photo the pushrod clevis attach point to brake pedal lever pivot point that jocko mentions in post #55.

Somebody with factory power brakes on a 71 or 72 (C-10 only) measure this distance


And somebody with factory manual brakes on a 71 or 72 (C-10 only) measure this distance


I suspect they are the same but would like to know and for the measurements to be documented. Like Steeveedee and BigBird05 mention these are just illustrations by humans. It would be great for measurements to be made, and only from 71 and 72 C-10s that are suspected to be original, not conversions of earlier years and not from trucks that have been converted from manual to power.

[dmjlambert]

It looks like 54blackhornet got the correct master cylinder from NAPA for non-power C-10 disc/drum because it has a deep pushrod hole, 1-1/8 bore, and larger reservoir in front for the front brakes. The part number was M36280, not MC36280 like I said above and it's not Raybestos. I was confused, apparently, and looking at the pictures of the box that Greasey Harley got. Anyway, this is what 54blackhornet pictured for Napa part M36280:

It appears to be this one: https://www.napaonline.com/en/p/NMAM36280

That is not the same as what Greasey Harley got from Federated, Raybestos part MC36280, because the Raybestos one does not have a larger reservoir for front disc brakes, although it may otherwise have the same specs.


Something has been bothering me about this thread for the longest time, but I couldn't figure out exactly what, and I finally figured out what was bugging me. The huge majority of pictures on the Internet of 67-72 Chevy C-10's with disc/drum setups have master cylinders with same size reservoir for front and rear. Most conversion kits pictured for sale also have same size reservoir for front and rear. Of course 100% of the kits have power boosters as well, but that's just because that's what sells. But I wonder about the reservoir sizes.

[volksworld]

i think whats going on is that the aftermarket disc conversion master cylinders with the equal resevoirs f&r are sourced from corvettes that were 4 wheel disc ...so yes the resevoirs are equal in size, but much larger in volume than a drum brake resevoir would be

[dmjlambert]

Hi 54blackhornet, I was wondering if you have an update. Did you make progress with installing that NAPA part M36280 new master cylinder in your non-power-brake 1/2 ton C-10 disc/drum setup with deep pushrod hole, 1-1/8 bore, and larger reservoir in front for the front brakes?

[dmjlambert]

I'll give an update for this thread in case anybody searches for this information and wonders what is the master cylinder that works for manual disc brakes. There is no such thing as manual brakes on C-20 and up, so this is just C-10 info.

I installed NAPA part M36280 new master cylinder in my manual-brake 1/2 ton C-10 disc/drum setup. The master cylinder has deep pushrod hole, 1-1/8 bore, and larger reservoir in front for the front brakes. This appears to me to be the most technically correct part for manual disc/drum brakes for 71-72 C-10. This is for my 1969 C-10 with manual all-drum brakes upgraded with used 1971 spindles and front disc brakes and rear drum brakes, a used 71-72 steering center link, and new 71-72 tie rods and ball joints, and front pre-bent tubing for 71-72 from Inline Tube.

After reading forum posts about the very common Chinese brass block style proportioning valves leaking and/or not working right, I decided to buy a used 71-72 proportioning valve and send it to White Post Restorations to have it rebuilt/restored. My setup works well, didn't require any modifications to the brake pedal or push rod. I have no conversion or kit parts on the truck for this upgrade, just use normal 71-72 components. Except: I do have "conversion" 5-lug rear axle shafts for my 1969 12-bolt differential, and I have new fabricated front hose brackets or tabs for attaching the hoses to hard lines at the front of the front crossmember.

Brakes feel very good and require a less pedal effort than my previous all-drum setup.