replacing master cylinder on 50 pontiac help

Replacing the master cylinder on my 1950 pontiac chieftain this week. Have been dreading this since it is under the floor and have never worked on one like it before.
Any tips I should now before I start?

How do you fill the stupid thing once I get it in there? Looks like there is no room.

Does it bleed like modern brakes with the cylinder on the fire wall system?

Thanks for any help.

 

number one, it is not fun removing it, but it is do-able.
number two, there is a cap or cover in the floor that is removable to get at the lid of the M/Cyl when it is in the car, Bench bleed BEFORE you install the new one.
Pressure bleeder is the best. Bleeds the same except you cannot just open the bleeder and let it run because the m/Cyl is below the level of the wheel cylinders.
need to have a pressure bleeder or a helper.

good luck

 

Thanks for the info.

Sorry, define bench bleed? Have never done that before.

Also no plate on the floor boards. Have been putting this off for some time knowing I will have to screw around without easy access.

Assume I bleed it off of the car, how much fluid am I going to lose once I try and shimmy it in, then remove plugs? Is it even worth the mess?

I did buy a pressure bleeder knowing I am doing this by myself.

Thanks

 

lock it in a vice on the bench, there should be little plastic tubes and screw in plastic fittings in the replacement box, put those on the new master cylinder looping back into the reservoir, fill with brake fluid, and using a push rod or a long bolt (some people use a screw driver) push the plunger in several times till it no longer bubbles in the reservoir.
at that point it is bench bled.
yes it will leak some out but it is a LOT less work to do it that way than it is to chase air through the entire brake system.

and I can pretty much guarantee you there is a removable panel somewhere there on the floor above the master cylinder. if not then you should cut out an opening to make it accessible and then make a sheet metal cover for that opening, Neater is better.

 

Thank you once again.

Cool car bye the way.

 

My 55 Pontiac has a similar m/c under the floor.I use a pressure bleeder to bleed the system;no problem.All I did was get a spare m/c cap and drill a hole in it and tap in a standard air fitting that corresponds to the fitting on the bleeder.There is plenty of room(at least on the 55)to attach the fitting on the bleeder to the fitting on the cap.
I'm currently having a problem with a soft pedal on my brakes and likely will have to either replace or re-build the m/c. Biggest hassle for me is getting this 68 year old body under the car to do it.

 

on the 50 pontiacs the mc is actually under the steering column there is a panel on the floor near the brake pedal to access it if you look under hood you can see it but floor panel is easier access

 

I've done my '46 Chvey, '50 Chevy, and '55 Pontiac and they're not difficult, just a pain to bleed if not bench bled. If you don't bench bleed, get a friend with a good leg and stamina!