Replaced all brake lines by professional shop. Good place. Now I bring car home-barely. The engine would run fine at idle. Sitting running the rpm's up two 2500 sounds fine. The drive home was awful. I could'nt get past 40 mph with out the car upfront makeing a loud bumping sound and engine felt like it was trying to fall through on the drivers side. then I would back off the acelerater to 35mph and everything would go back to normal. Now I'm home and find a leak at the center of the back axle. It's the fuel line inside one of those goofy clamps that hold the brake lines also. Would this be the loss of power problem then the surge of engine noise and power? Shifting also was smooth for a 1981 300sd with 135k.