1970 C50 Brakes

[bts2]

Sorry for the noob response. I am familiar with hydroboost where there is either a gas accumulator or electric motor as backup. Since I don't have a donor, I'm going off of diagrams and random pics that indicated an electric motor backup for the hy-power option, whereas the dual-power option has the traditional vacuum booster behind the hydro-boost. I'm still learning - if you have pics of the setup under the hood, that would be awesome. So it goes like this:

pedal-rod-hydraulic booster-M/C-balance valve-wheel cylinders. Guess I need to hit a junkyard. There's a rod in between the booster and MC right?

[84rzv500r]

the medium duty Hydra-boost has no nitrogen charged accumulator...

yo u can google and/or ebay to get pics and specs for the components.. it matters a bit what size slave cylinders you have...

[bts2]

thanks - i've googled away and found pics of the booster and MC but not the whole system. I don't want to go on a parts bin shopping spree without understanding the whole system first. I'll keep looking for pics of an actual truck or look around the yards here. I gotta pull the old stuff out too from the 1970 to get the bore diameters and such.

[bts2]

Guys, further research here... the 83-87 Hy-power brakes have an electric motor under the hydraulic booster to back up the boost when there is no flow from the steering pump (engine off, pump failure, blown line...) The other brake option those years is "Dual power" which uses both a vacuum booster AND a hydraulic booster, where each backs up the other.

Now, mind you, I haven't laid hands on either yet but I have talked to the rebuilders and got several system diagrams. See attached shot from the Chevy Medium Truck 87 Service Manual.

Are you guys sure about the no electric motor backup ?

Colgad, can you post pics of your 67 booster setup - would be awesome to clear up my fuzzy mind.

[colgad]

Here is my setup on my C10. The Gold cylinder on the lower Left is the hydraulic reserve (see diagram). I have an adjustable proportion valve for the rear brakes and an adjustable pressure valve to give me a better steering wheel feel. The gauge is the pressure to the rear.

[bts2]

Very nice setup! I think I'm going to copy this for my '73 K-5. Did you use the same setup on your C50? I know it's gone now, but do yo have any pics of the booster on it?

[colgad]

On my last C50 it was vacuum.

My current C50 under construction is yet to be determined. Since my current C50 will have TopKick 4 wheel disk which all have 2 2.3" pistons, the requirement of a dual Master Cylinder with at least a 1.5" diameter bore is needed.

Hydroboost may be my only option. It's a little more expensive but takes up less room.
I plan to remove the 327 sometime in the future and put in a 454 I have but for now the 327 will get me around.