Seperating master cylinder piston from pushrod (66 Polara)

[northeast eric]

Hi all, new member from CT. Any tricks to separating the brake pedal pushrod from the MC piston? It's obviously a press fit onto the ball end of the PR... I figure just manhandle it and pull it apart, maybe heat up the piston a bit to expand it. I searched the forum first and nothing about it. Looking at the FSM, it says to not to separate the two. But the rebuild kit I ordered comes with a new piston. Should I leave the piston on and try to slip the secondary seal over the front of the piston? any advice?

thanks.

 

[Fratzog]

Welcome aboard. I've never tried a rebuild kit. Have only replaced MC. I'm sure someone here can help though. How about some details and pics on your ride?

 

[northeast eric]

thanks. I will post some pics tonight when I get home.

 

[Mopar mike]

Pics when i remowed my MC, Polara -67.

 

[cm23uoc]

thanks. I will post some pics tonight when I get home.

Where did you order the rebuild kit ?

 

[70bigblockdodge]

Welcome to the site, are you talking about a manual brake car because a power brake mc should come right off, a manual brake has a rubber collar on push rod can be tough to get out sometimes just pull straight, you can put some brake clean in where push rod goes in it works like lube on rubber, oil in there it may help but it may ruin rubber collar which should be replaced anyway.

 

[70bigblockdodge]

I would leave piston if it isn't scored real bad the seal does the work the piston puts the pressure on the seal evenly

 

[mobileparts]

If you are rebuilding a manual brake master cylinder -- the single master cylinder with push rod -- of the 1963 - 196 era,
you must grip the push rod in the bench vise -- and use a rubber mallet to knock the master cylinder off the push rod....
It is "kinda' backwards" but that is the way it gets done -- you will not be able to generate enough force by holding the
master cylinder in the vise --- you must knock the master cylinder off the push rod..... Happy rebuilding....

 

[Clover]

Back in the olden days, we would leave the rod attached to the brake pedal, unbolt the master cylinder from the firewall and then just pry the master off, using a prybar wedged between the master and firewall. Nowadays, I put the rod in a vice, leaving a 1/4" gap between the vise and master, then use a prybar wedged between the master and the vise to pry the master off. Your rebuild kit should have a new rubber attaching grommet included, as removing the rod from the master will ruin the old grommet.

 

[northeast eric]

Pics when i remowed my MC, Polara -67.

Mike, I have the manual MC with no booster. thanks for the pic.

Where did you order the rebuild kit ?

Ebay special $17, I ordered the only one I found. I'm thinking it's for a booster set up...

Welcome to the site, are you talking about a manual brake car because a power brake mc should come right off, a manual brake has a rubber collar on push rod can be tough to get out sometimes just pull straight, you can put some brake clean in where push rod goes in it works like lube on rubber, oil in there it may help but it may ruin rubber collar which should be replaced anyway.

your talking about the boot on the pushrod right? that's getting re-used so it's staying on.

If you are rebuilding a manual brake master cylinder -- the single master cylinder with push rod -- of the 1963 - 196 era,
you must grip the push rod in the bench vise -- and use a rubber mallet to knock the master cylinder off the push rod....
It is "kinda' backwards" but that is the way it gets done -- you will not be able to generate enough force by holding the
master cylinder in the vise --- you must knock the master cylinder off the push rod..... Happy rebuilding....

Back in the olden days, we would leave the rod attached to the brake pedal, unbolt the master cylinder from the firewall and then just pry the master off, using a prybar wedged between the master and firewall. Nowadays, I put the rod in a vice, leaving a 1/4" gap between the vise and master, then use a prybar wedged between the master and the vise to pry the master off. Your rebuild kit should have a new rubber attaching grommet included, as removing the rod from the master will ruin the old grommet.

It's been separated since before I first posted, the MC came apart easy. I need to post some pics to show you guys what I'm talking about. not enough time in the day....

 

[northeast eric]

here is a pic of the car

this is the exact style of MC I have, no booster.

The rebuild kitbought off Ebay, I'm wondering if I ordered the wrong one.
This is the push rod assembly. I am trying to remove the piston from the pushrod. like I said the FSM say not to remove the piston. I guess I should have bought this assembly...

 

[Clover]

Just reuse the old piston unless it's damaged.

 

[northeast eric]

Just reuse the old piston unless it's damaged.

So It wont damage the seal pulling it off the new piston and slipping it on the old one?

 

[MrMoparCHP]

Two ways that have worked for me.
1. Leave the master installed and jerk the pedal back

2. I've had better luck just splitting the piston in two, hacksaw and a chisel