Stock brake system?

[vacca rabite]

I am almost done replacing all my brake lines. But I have come across something that is confusing to me.

from the top of the master cylinder, there is a hose that goes into the air cleaner and then into a port on the engine. Is it supposed to run this way? Did someone refit my truck with some sort of power brakes, or is this how the stock system is run.
Master Cylinder. Hose that goes up goes to the air cleaner, other hose goes to the pump thingy. The hose that goes to the pump is TOTALLY shot.


Where the hose attaches to the air cleaner.


What is this?


Assuming that this is the stock set up for a 68, what do these hoses do? Should I cap them, or buy new hose and clamps and rebuild?

Zach

[ryanroo]

that pump thingy is the vaccum pump that is an integral part of the fuel pump. that hose i would guess runs inside the cab and up the windsheild frame, to your wiper switch. powers the vaccum wipers. the other hose is just a vent to for the master cylinder
Ryan

[george walker]

To make the veh. waterproof a sealed source of air is needed for all components, the master, the dist, the axles. If you follow those lines they go to all those places. The other lines are the vac lines to an from the vac side of the (double action) fuel pump to run the wipers. They go from intake manifold to vac pump to wipers

[Binford]

Vacca...are you planning a stock restoration or upgrading components for reliability and safety? If the latter, I would *highly* recommend doing a master cylinder swap. There are a few threads on this in the Modified forum. It was quite literally a plug-n-play operation that took me all of an hour, once I got the parts I needed together. Right now, if you have a failure of any of your brake lines, you have a complete brake system failure. The master cylinder upgrade gives you two systems--front brakes operate separately from the rear brakes.

[randyscycle]

The connection to the top of the master cylinder is as George put it a vent. The diffs, the master cylinder, the transfer case and the transmission all are vented together for deep water fording. Have a look underneat than you can follow all the lines to a central point from those vents if all the hoses are still there and intact.

THe hose from the top of the fuel pump/vacuum pump is for the vacuum wipers, and goes inside the cab to the wiper switch/valve and on tot he wiper motors.

[brute4c]

The venting of the master cylinder and all the gear boxes anbd the motor are for fording...if the truck does not have a fording kit, then up to 3 feet of water can be forded. If the truck has the fording kit, 6 feet can be forded and with that fording kit comes a valve that uses crankcase pressure to pressurize the engine, gearboxes and the master cylinder...better when fording to have pressure pushing past the seals from inside the part in question and going out into the water than it is to have the water just pushing in...

[vacca rabite]

^^^
That is what it is. The line I took the picture of does not run into the cab for the wipers - it runs from that pump to the MC. I believe that it is part of the deep water fording kit.

However, given that the line had a big void in it from resting too long against the engine block, I doubt that it was still functional.

Zach

[george walker]

Well there is a vent line for the fuel pump also, it runs from the fuel pump an is tee'ed in w/ the other vent lines.

[brute4c]

The vacuum pump better not be running to the master cylinder...that is not good.

The master cylinder, fuel tank and fuel pump vents all go to the air cleaner horn.

One side of the vacuum pump, the top 2 lines on the unit, says Manifold on the housing, should e hooked to the drivers front of the head to the vacuum fitting there...the other, marked Wipers, needs to be hooked to the wipers.

Basic vent diagrams are here:

Early style, carb mounted air cleaner, no governor:
http://www.m715zone.com/vb/view.php?pg=early_vent

Late style, large under hood aircleaner with governor:
http://www.m715zone.com/vb/view.php?pg=late_vent

[vacca rabite]

The vacuum pump better not be running to the master cylinder...that is not good.

The master cylinder, fuel tank and fuel pump vents all go to the air cleaner horn.

One side of the vacuum pump, the top 2 lines on the unit, says Manifold on the housing, should e hooked to the drivers front of the head to the vacuum fitting there...the other, marked Wipers, needs to be hooked to the wipers.

Basic vent diagrams are here:

Early style, carb mounted air cleaner, no governor:
http://www.m715zone.com/vb/view.php?pg=early_vent

Late style, large under hood aircleaner with governor:
http://www.m715zone.com/vb/view.php?pg=late_vent

Huh, my truck is done wrong, then.

As you can see from the picture, the top of the MC has a hose that splits into a T fitting. One end of the T goes to the air horn, the other end goes to the vaccum pump.

So in a stock form, the MC should only have one hose going to the air horn, right?

I wonder where the line feeding into the T is supposed to go? Is it trying to run up to the air horn as well? At current there are only 2 hoses going to the horn.

Zach