Front brakes won't release
Do you know if the master cylinders you’ve purchased are specific to front discs? Drum brake type will have a residual pressure valve designed to maintain pressure…I’m thinking this is your issue.
Sometimes an easy way to tell is that the disc master cylinder will often times also have a larger reservoir for the front/disc brakes since they compensate for pad wear over time vs a shoe setup that has to be adjusted manually to compensate for the lining wear.
Here’s a quick side by side for comparison:
Do you know if the master cylinders you’ve purchased are specific to front discs? Drum brake type will have a residual pressure valve designed to maintain pressure…I’m thinking this is your issue.
Sometimes an easy way to tell is that the disc master cylinder will often times also have a larger reservoir for the front/disc brakes since they compensate for pad wear over time vs a shoe setup that has to be adjusted manually to compensate for the lining wear.
Here’s a quick side by side for comparison: