whatsup everybody, so i ran into an issue where my brakes dont work as well at low speeds. my car brakes perfectly fine from 5+ mph but below that the brake gets very stiff and my brakes start to make a clunking noise. and it dosnt happen every time im going at low speeds, i say one out of three times it does it... does anyone know what this could be? not gonna drive my car just to rear end someone someone please help thanks

 

The cars has power brakes that utilize engine vacuum for the power assist. At low engine speed, the vacuum is not as great. The power brake unit "stores" vacuum for these situations.

Check the hose that goes to the power brake unit. It could be dried up and cracked, it should be soft and flexible. Other possibilities are the check valve on the power brake unit that the hose connects to. The power brake unit itself could also be the problem.