drum to disc on 73 S2

NewcScout

NewcScout

Member
Hey ya'll

ok, so I'm going from drum to disc on my 73 s2.

Got what was told to me as the disc/drum mc. Plus a proportioning valve off a 77 with disc/drum.

Here's my question:
in the mc - which is the front reservoir and which is the rear?

On the proportioning valve - which is the front and which is the rear?

The manual doesn't seem to have the later years proportioning valve and mc data in it.

A picture from someone would be great if possible.

Thanks guys.....


Drew
 
The large reservoir is for the disk. The piston is much larger on a caliper than on a wheel cyl. Therefore uses more fluid. Did your Scout come with a prop. Valve? I can get a pic of mine tomorrow.
 
Thanks scoutitout,

that's what I figured, and went ahead and did this. Does it look right to you?

Thanks again for the help.


-drew

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Well, fatherly duty's abound and I haven't got the fluid in yet. :(

I hope to fill it, bleed it, and stop it in the next couple of days. I'll report back then.....

Thanks for the help...


Cheers,
drew
 
One comment, a vertical coil in the brake line gives a location to entrap air bubbles. A horizontal coil serves the same purpose as the vertical coil (allows for relative movement between components) and does not trap air. You want the hard line in the loop or coil to descend towards the brake caliper/cylinder to allow free flow of brake fluid when gravity bleeding....or to allow air to escape up the line to the master cylinder to escape to atmosphere.

Otherwise, you have a nice installation there.
 
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1975ih200 said:
one comment, a vertical coil in the brake line gives a location to entrap air bubbles. A horizontal coil serves the same purpose and does not trap air. You want the hard line in the loop or coil to descend towards the brake.
Click to expand...

One time on extreme 4x4 ian said to mount a trans cooler with hose connections up. The same reasoning was given, air could get trapped in the cooler if the fittings face down. Here's my question, in a pressurized fluid line, how can air stay anywhere? Once the pressure is greater than that of gravity the air would be pushed out of the line.
 
Scout-it-out said:
one time on extreme 4x4 ian said to mount a trans cooler with hose connections up. The same reasoning was given, air could get trapped in the cooler if the fittings face down. Here's my question, in a pressurized fluid line, how can air stay anywhere? Once the pressure is greater than that of gravity the air would be pushed out of the line.
Click to expand...

I'm no expert, but a couple of things here.
1. Brake lines only have pressure in them when pedal pressure is applied. If there were constant pressure, then the brakes would always be partially applied.
2. The pressurized tranny lines are only pressurized when the vehicle is running. They go to 0 pressure when the vehicle is off. So bubbles will collect in "trappable" areas when the pressure stops and the fluid flow stops.

I guess both lines could get air in them. However bubbles in the brakes lines can find their way back up into the mc if there aren't any loops in the way.

There shouldn't be any air in the brake lines ever. If air is getting in, then fluid is getting out. This is mostly a method for making bleeding easier and making sure any bubbles that May occur can find their way up and out the mc. I think.
 
Scout-it-out said:
one time on extreme 4x4 ian said to mount a trans cooler with hose connections up. The same reasoning was given, air could get trapped in the cooler if the fittings face down. Here's my question, in a pressurized fluid line, how can air stay anywhere? Once the pressure is greater than that of gravity the air would be pushed out of the line.
Click to expand...

A. As for why ian of extreme 4x4 places hose connections "up" in a pressurized, flowing fluid circuit.....I would suggest that you ask ian. You can then also ask him how he installed a truck oil pump on a sv-8 engine with a Scout oil pan. Edit: I am sure a lot goes on in the builds that is not on camera or broadcast due to time limitations. Tv shows are only about 20 minutes long (for a half hour show) due to commercials, so obviously content suffers. Edit: 1. How would you know an air bubble was in the trans cooler lines? 2. And who cares? The air will flow with the fluid and return to the auto trans pan. 3. So what? No harm done.

B. As for automotive hydraulic brake system, non-abs, the fluid does not circulate or flow, it is a medium that only transmits pressure from the master cylinder to the wheel cylinders and/or brake calipers. There is very little movement of the fluid itself, most "movement" can be prescribed to the expansion of the flexible brake hoses under pressure. The brake fluid only "flows" to fill the areas in the brake cylinders as the brake friction surfaces wear and require more cylinder stroke to accomplish their braking action. Hence, air is easily trapped when the system is open for maintenance, and will seek the highest level if not bled out properly. Having a permanent vertical loop or coil in the brake lines gives air a place for air to hide, which May be difficult to bleed out properly. The hydraulic brake lines should have a slight drop from the mc to the wheel cylinders to allow free flow or gravity bleeding with the bleeders open. A horizontal coil to allow for body movement will allow that flow under gravity alone, a vertical coil will not.
 
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1975ih200 said:
if not bled out properly
Click to expand...

I can appreciate this, thank you! I remember seeing coils on factory cars but I didn't remember the orientation of the coils. I thank everyone for correcting me respectfully!

Regarding ian, they showed the rebuild kit on a table but when the engine is going together he used the old pump.

The trans cooler still doesn't make any sense to me. The cooler I'm thinking of is kind of back and forth flow. Kind of "w" where the fluid comes in, flows up and down and back out the same end. If the lines in are up or down there are still the bends in the cooler that are up! For what it's worth, my ps cooler and trans coolers are both mounted lines down:dita:
 
Well, I reoriented the relief coils horizontally and bled them through.

Went on the test drive and laid down a sweet 4 wheel skid!! Success!!

It's odd having breaks and being able to stop.... Novel idea....:out:

thanks for the tip 1975ih200!!
 
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