I’ve already had to replace the master cylinder once, presumably because dirt and dust got into the push rod hole, which caused it to leak inside the car. So, to stop this happening again I needed to intall the push root boot.
It’s a pain in the a$$ to try and install it whilst the master cylinder is in the car so I drained the brakes (I needed to do so anyway so I could remove the rear end from the car) and removed the cylinder from the car. Once the push rod was pushed through the boot, the boot is stretched to fit on the end of the master cylinder and the entire thing is pushed through the firewall and bolted back up. Job done 🙂