How to remove 1950 B2B master cylinder

[Iowaboy]

Got my 1950 B2b truck running well after 23 years setting, now to tackle the brakes. The pedal goes all the way to the floor. Topped off the reservoir and still does it.

The fluid level drops very little when pushing in the pedal, so i assume the fluid is going around the plunger seal?

So, i am ready to pull the master cylinder and replace or rebuild depending on how it looks. IF I CAN GET IT OUT!

I have read the posts on removing the MC from vehicles, but i have not found any on removal from a 1/2 ton truck. Do i have to remove the floor panel below the clutch a  brake pedal and remove the entire assembly or both pedals from below? Is there any way i can disconnect the MC plunger shaft from the MC body and leave it in place, then remove the MC from the  engine compartment side? HELP! 

 

[Merle Coggins]

From under the hood, and/or under the truck, disconnect the brake line and remove the bolts that hold the M/C to the bell housing. It'll come right off. No need to mess with the pedals unless you need to work with the push rod.

[JPP]

Don’t remember this being a big problem but I would get that starter out of the way first then the rest will seem simple. 

[Iowaboy]

That is great news that i can remove the MC without messing with the pedals. Thanks members. 

[Jj1981]

Be careful if u do take the starter longest hour of my life trying to get the bolts back in. I'm interested in what u find post back if u rebuild I'm about to do the same with the same truck good luck

[Charlie Stephenson]

Brake fluid evaporates.  Just pump the pedal about an inch "many" times the fluid will go down, the master cylinder is air locked, sounds easy when you say it fast.  Maybe this will work for u maybe not, but is sure beats getting out the wrenches. Charlie Stephenson

[Jj1981]

So if the truck has been sitting for that long and the master cylinder is dry is it worth trying the system or automatically needs he cylinders rebuild including the master

[Iowaboy]

So i pulled the MC out and put it in a vise. I filled the reservoir and used a big screwdriver to push the piston in and it squirted fluid out, strongly. Does this mean the MC does not need to be rebuilt after all. When it was in the truck i could not feel any pressure on the pedal at all, it went all the way to the floor. Maybe i should have unscrewed the brake line somewhere to see if fluid would come out.  

[Jj1981]

Very interested in you're progress please keep us posted

[Jerry Roberts]

Your truck has been sitting for 23 years , most likely everything in the braking system will have to be replaced or rebuilt . If you want to fiddle with your master cylinder to see if it will hold pressure , you can make a plug from a portion of a brake line so that the fluid doesn't run out when you apply pressure to the piston .  

[Iowaboy]

I mounted the MC in a vise and put a pressure gauge at the end of a pipe screwed into the hydraulic fitting on the bottom. I filled the reservoir and actuated the piston in the bore by pushing on a steel rod with my chest (piece of plywood to protect to protect chest), I got up to 80 psi and held it there for about 30 seconds. This confirmed to me that the MC should be ok. 

I put the MC back in the truck. Pedal still went to the floor, the fluid level drops in the reservoir. I opened the bleeder on the passenger side front wheel, attached a piece of 1/4 inch clear tubing, and pushed the pedal down several times with my hand. I got fluid in the hose. That's as far as I've gotten. Difficult to trouble shoot with one person bleeding brakes. 

Whats really got me going is this truck has some sort of brake valve manifold that is mounted to the steering column just under the  steering wheel. The brake line comes out of the MC up to this valve manifold and through it then down to the tee connection that feeds the line going to the front and back wheels. The manifold has a pressure gauge and a hand actuated lever, which I think restricts the flow of brake fluid through the brake lines. 

If some one could tell me or link me to the process for posting photos, I could post pics of the manifold and the truck.

My father in law used this truck to haul groceries and pipe fittings way up into the Colorado mountains west of Rifle, Colorado for Mobil Oil, and its predecessors, while they were drilling up there, he did this for at least 15 years. I rode with him several times up in the mountains and watched him use this brake but don't know how it worked. Seems to me he only used when going down the hills.