The Stovebolt Site Forums The Shop Area Engine Shop Trying to find Master Cylinder - will this work?

I am gearing up to do the brakes on my '71 C10 and I have run into a bit of a dilemma. This truck has manual brakes and after running to various parts stores all that keeps coming in is a master cylinder that is for a truck with power brakes. In the stores they don't even list an option for manual brakes in their computers. As a reference, this is the one I need and this is the one I keep getting. The one for power brakes will bolt up, the lines will hook up, but the piston bore is shorter and the sizes of the reservoirs are different. So, will the power brake master cylinder work on my truck or will I need to keep hacking away until I finally get the one I need? The really big problem is that I need to do the brakes now, they are starting to fail but this truck is my sole transportation so I can't be sitting here waiting a whole lot longer. I'm tempted to just bolt up the MC for power brakes and give it a shot, but I thought I'd ask for some opinions first.

I checked the Napa catalog & sure enough it doesn't show anything for manual brakes. The size of the cylinder bore would be the big factor. If the bore of the replacement is larger it would be no good. It takes a lot of pressure to operate disc brakes. With a larger cyl it would take more. If it is the same or smaller it would work. Maybe you could take the casting number off the old cyl. & a good parts man could match it up. If you could get a kit they are not that hard to rebuild.

Hy Bears63, your 71 is the first year for front disc brakes, does it have front discs, or is it still all drum brakes? The master cylinder listed for a 1970 C10 with manual brakes is Napa p/n UP36239 $78.49 thats a new cylinder, they also list p/n SS4736239 $37.49 also a new cylinder, and p/n TS101329 $29.89 + $11.10 core that is a reman. cylinder, these are all 1" bore. 1971 C10 with power brakes [no non power brake option listed] p/n UP36280 $71.49 that is a new master cylinder, also p/n SS4736280 $37.49 also a new cylinder, and p/n TS1013399 $26.79 + 11.10 core, that is a reman. cylinder, and p/n TS101511 $34.99 + $16.70 core, also a reman. cylinder, these are 1 1/8" bore, hope that helps.

My truck does have the front disc brakes. Also, the info that I have is that both master cylinders I was looking at have the same 1 1/8" bore size. I had looked at '69 and '70 master cylinders and the size difference was considerable, to the point that I wasn't comfortable trying them out. I think I will try out the one I have and see what happens. I am definitely going to take down the casting number off the old one and hold onto it though. Thanks a lot for the info, guys. It's appreciated!

Just found out some interesting info today. There is a reason why there is no manual brake master cylinder option listed for a '71 1/2 ton. Although there are 2 styles of master cylinders they are both 100% interchangeable. So long as the part is for a 1/2 ton pickup it will work just fine with either manual or power brakes. So, I went through all the hassle of running around for the "right" master cylinder when I had the right one from the start. Well, now I know and I had to let everyone else know too.