I guess the first tip would be to adjust them often, even if they don’t need it, so the adjusters don’t freeze up. Going around during every other service job would be enough to keep them free.
So many times the brake adjustment is forgotten about and then they stick and as the linings wear the wheel cylinder travel exceeds its limits and they start to leak. Then you lose your pedal pressure from the loss of fluid and air entering the system.
Troubleshooting a hydraulic brake system can be tricky sometimes, but starting with the obvious things first and work your way into the system. First check the fluid, is there any in the master cylinder?
If it’s low start checking around for wet wheels, wet master cylinder, or fluid coming from the booster or a possible leaky hose or steel line. While checking lines keep your eye open for kinked lines-there must not be any sharp bends!
Once you’ve found your leak, it’s just a matter of R&R and then setting up the brakes and bleeding the system. But lets say the master still had fluid and you couldn’t find any wet areas, then what?
Well, I would say then the brakes are in need of adjustment, so first go around jacking up each wheel and adjusting each adjuster evenly until tight and backing off 4 clicks, now go try the pedal, better? But not quite normal?
Better check the vac on the booster next, I check in reverse starting from the booster working to the engine, a lot of times the check valve will be restricted which you will find out if your vac is less than 15 at the booster, if the vac has good vac but everything else checks out the booster may be next.
You can pressure up the brake pedal and start the engine if the pedal falls the booster is working, if the pedal rises and gets hard the booster is not.
Now these are not text book methods because every situation is different and it seems everyone has their own method, these are just some that I’ve found to be helpful.