When I apply the brakes on my 93 Cutlass the pedal is very soft and the left rear wheel locks up. I checked the rear wheel brake cylinders and front calipers and there are no leaks and the master cylinder is full. The power booster appears to be in good shape. Any help or suggestions are appreciated.

 

The springs sound like they are on the way out. I'd start by replacing springs and shoes on both sides, inspecting the drums and flushing out all the old fluid. As for the soft pedal if the above does not fix it, I'd test the booster with a vac pump & gauge, and see if it holds.

 

Is this supreme or ciera does it have ABS? Because all of the parts houses are stating that 3.1 or 3.4 supremes came with rear disc.

Pat

 

My mistake, 91 Cutlass Ciera, 3.1. Rear drums are smooth and shiny, the shoes look barely worn. Removed all dust, checking springs today. Thanks.

 

If it was the booster the pedal would be hard to push right? Also push and hold the brake dose it slowly go to the floor? If it does how slow?
Railguy

 

Pedal goes almost immediately to floor. Pretty sure it is the master cylinder, still not sure why left rear wheel slides.

 

Pull the vacuum tube off the Booster, attached a vac gauge to the booster pump to -20 and walk away for 15 min. come back if the gauge has dropped you have a leak in the booster. Another cause for one wheel to lock up and not the other is air in the line will compress making that line not "bite" as hard as the other.

 

Does the master cyl have 2 or 4 lines attached?? If you have 4 the wheels are split up the right front and the left rear use one part of the MS the other feeds the left front and right rear. Good luck.

Johnny