Vacuum hose routing for brake booster

[Scarlett77camaro]

Hey guys! I just installed a new brake booster for my 1977 Chevy 250 in-line 6 but I don’t know where to route the vacuum hose for it. The one I replaced had the hose disconnected and I don’t know where it goes. Also in case it goes into a port on the carburetor I’ve got a Rochester 1-barrel. Would love some help or even a diagram of where to route it. Also maybe I just installed it wrong (crazy if I did seems like it only goes on one way) but the rod that actually connects to my brake pedal seems like it’s too short or something cause it’s not pressing the switch that will actually turn off my brake lights. So now my brake lights are always on. Had to disconnect the battery so it wouldn’t drain it. Would love some help guys and gals!!

 

[CalSgt]

Hey guys! I just installed a new brake booster for my 1977 Chevy 250 in-line 6 but I don’t know where to route the vacuum hose for it. The one I replaced had the hose disconnected and I don’t know where it goes. Also in case it goes into a port on the carburetor I’ve got a Rochester 1-barrel. Would love some help or even a diagram of where to route it. Also maybe I just installed it wrong (crazy if I did seems like it only goes on one way) but the rod that actually connects to my brake pedal seems like it’s too short or something cause it’s not pressing the switch that will actually turn off my brake lights. So now my brake lights are always on. Had to disconnect the battery so it wouldn’t drain it. Would love some help guys and gals!!

Did you already return your original as a core? If not measure the rods and compare.


ETA: IIRC the brake lamp switch should be adjustable by threading it further into its bracket. Also, the tab that makes contact with the brake lamp switch has to be removed to disconnect the brake booster rod, make sure you put it back on correctly.

It’s the silver do-hickey on the upper 1/3rd of the pedal

You must be registered for see images attach

 

[Ricko1966]

There's more to this. 1. brake booster gets manifold vacuum use steel line with short rubber hose as connectors.2. There are 2 adjustments to your pedals(kinda) 1 is pushrod length from the pedal to the booster. The other is the pushrod length for the master pushrod. It has to be right. First .02 clearance between booster pushrod and master with the brake pedal clevis disconnected. Then brake pedal pushrod adjusted to give about 1/2 inch free play. To adjust booster/master pushrod you need to grind the end of the pushrod.

 

[75gmck25]

With a Quadrajet or Edelbrock 4 barrel there is a threaded port on the back of the carburetor base. From the factory there is a metal line (6” long?) threaded into that port and it runs back and over to near the brake booster. From there you have a short rubber line connected to the brake booster. Not sure what type of fitting you have on a 1 barrel carb.

 

[Turbo4whl]

Here is a picture:

You must be registered for see images attach

There is a pipe thread in the intake manifold with an adapter fitting for the metal tube. What can happen on the old 6 cylinder engines, that manifold port gets clogged with carbon from the EGR valve. The parts get rusted and do not come apart. In that case the vacuum booster hose and tube gets moved to another port on the intake manifold.

So your truck may not have the vacuum hose and tube there now. You could "T" the hose to the PCV valve hose. The PCV at the base of the carb also sees manifold vacuum.

 

[Turbo4whl]

Another picture:

You must be registered for see images attach