Moisture trapped in old brake fluid can cause the brake fluid to boil within the system during heavy brake use. Once brake fluid boils, it releases air into the system. This is one of several ways air becomes trapped in a hydraulic brake system. The most obvious way to fix this is replacing a leaky brake line. The bleeders on the wheel cylinders or caliper pistons are the most practical way to release air from a hydraulic brake system. However, after many years of rain, snow, and corrosive salt, the bleeder is tough to open.
Instructions
- 1
Brush the brake bleeder clean with a wire brush. Spray penetrating oil on the stuck brake bleeder, and tap the bleeder lightly with a small hammer.
2Insert a six-point box end wrench over the brake bleeder, and apply slight pressure, in both tightening and loosening. Apply heat with an electric heat gun; sometimes this is enough heat to break it free, before trying a torch.
3Apply heat to the bleeder with a concentrated flame from a mini torch or a fine brazing tip on an acetylene torch. Do not let the bleeder get too hot; once the bleeder is red, take away the heat. Let it cool.
4Spray more penetrating oil over the bleeder. Insert a six-point box end wrench over the bleeder, apply a slight pressure, and try to move the bleeder in either direction. Do not twist the bleeder off.
5Reheat the bleeder until red just begins to show. Let it cool, and once again spray penetrating oil on the bleeder after it cools. Put the six-point box end wrench over the bleeder, and apply ample pressure to loosen the bleeder.
6Repeat Step 4 until the bleeder is loosened.
