w114 parking brake
 

parking brake marginally holds vehicle how do you adjust to make parking brake hold better??

Start by removing one lug bolt from each rear wheel. Rotate the wheel while looking into the lug hole with a light until you see a start adjustment wheel. Use a straight screwdriver to tighten the star adjuster until the wheel will not turn then loosen the star adjuster three teeth. Repeat on the other wheel.

Check the brake operation and then test drive the car checking that the wheels do not overheat.

Good luck!!!

There's also a cable adjustment underneath the car...

Tomas7 is correct. The wheels should be done first followed by the cable he mentioned. It might be necessary to slacken the cable first if it is too tight. Do both adjustments and several times, drip some THIN oil down the cable just above where it comes through the floor by the Ebrake pedal.

Good luck!!!