The rear brakes in Korean cars are very weak, and reliance is on the front brakes. The problem is with the brake booster not pushing oil to the rear brakes, unlike the front, which receives oil and grips better than the rear. The known brake distribution is 70% front - 30% rear. But the car gives you 70% front and the rear is weak, giving you 10%. When you brake, the car dips in the front and rises when accelerating. You don't feel in control. The biggest proof is that the rear brake pads don't wear out, unlike the front ones. Solution ✅ The problem is likely in the rear valves located in the brake booster or the master cylinder. They are disassembled and cleaned. There's something called a "check valve" that needs to be checked. There's also a spring you can bypass. Bleed the brakes, and they will work excellently with a noticeable difference. Cars like Optima, Sonata, Elantra, etc. ... those from model 15 and below, without ABS.