1 Swap in a new set of shoes, reconnect the brackets & springs, put the drum back on and youâre done.  Thereâs no need for compressors, or opening fluid lines to retract pistons with these setups. As a matter of fact, replacing brake shoes on some vehicles can be accomplished in under 2 minutes, once the drum is removed.
The bicuspid valve, sometimes better known as the mitral valve, allows blood to flow in only one direction (assuming it is functional) from the left atrium to the left ventricle, it prevents blood from flowing back from the left ventricle into the left atrium.
1 When the ventricle is full, the tricuspid valve shuts. This prevents blood from flowing backward into the atria while the ventricle contracts.  As the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.