I'm having a difficult time getting my brake master cylinder linkage apart. It has a cylindrical end rod with a cross pin inserted through a yoke, with the rod end in between the yoke shoulders(shown in picture). With the rod disconnected from the master cylinder, the rod and pin rotate easily with respect to the yoke, but the pin is stuck tight in the rod end. Is this a designed press fit between the pin and rod end, or is it more likely rusted together? I have tried penetrating oil with no luck. Is the next logical step using heat, or am I missing something? Any advice will be appreciated.

 

 

Thanks, that's what I needed to know. I am going to try to coax it with a C clamp and a large socket over the headed end against the leg of the yoke. .

 

Of course heat will always help!! Grab the "blue wrench" and have at it.

 

Mine wouldn't come off either so I managed to unscrew it and rebuild the master cylinder that way.

My questions is(not to hijack your thread) how do you property adjust the master cylinder? The threaded part?

 

I had a simuliar situation a couple of years ago. What I did was disconnect the wires from the brake light switch, disconnect the lines from the brass 3 hole fitting in back of the master cylinder, then I loosened the brake master cylinder mounting bolts, pulled them out, and then lowered down the master cylinder as a unit from the frame rail. Once you do that, you could pull away the master cylinder from the master cylinder push rod and eyebolt assembly. If I remember correctly, there is nothing retaining that master cylinder push rod. It just slides in (or out) through the rubber boot and pushes on a piston when brakes are applied.

I did try rebuilding mine once. It was leaking before I rebuilt it. And even though the brakes worked great afterwards, it still leaked. So I ended up just buying a new one for less than $100. I should of just done that in the first place.

One more thing, when either re-installing the rebuilt one or a new one, do not forget to bench bleed the unit before re-installing it. Put it in a vise, have 3, 3/16" brake line fitting plugs available but install 2 plugs in the ports for the brake lines, take the third open port, attach a 3/16" fitting using a clear hose and run that hose (with the fluid reservoir cover off) back to the master cylinder fluid reservoir. Fill it 1/2 full with fresh brake fluid, make sure the end of the hose is completely cover in brake fluid. Take a phillips screwdriver, slide it into the rubber boot, and slowly stroke the brake cylinder piston until you see the bubbles disappear in the clear hose. Now remove the hose from the rear 3 way fitting, in it's place thread in the 3rd 3/16" plug, then carefully re-install the master cylinder cover. Take it back to the truck, and reinstall it in the reverse order you re-moved it. After you get it remounted and reconnected to the brake pedal, remove one plug at a time and reconnect one brake line at a time. When that's all done, then fill the master cylinder full, then proceed to bleed the entire brake system. Keep in mind you don't want to let the master cylinder run dry in the process.

BTW:

CPP gives away brake master cylinder bleeder kits at car shows that have all the plastic fittings and clear lines you need. If you don't have one, call them at 714-522-2000 and I bet you they will send you one.

 

I just adjusted it until I had a bit of play at the top of the stroke and firm pedal with room to spare to the floor.

 

I did the same to get the MC off. I used a bit of vaseline on the old rod where it went through the new boot and it adjusted OK. Thanks for the tip on bench bleeding.

 

HI Art,

Glad it helped!