There has been talk that suggests that manual brake bleeding over-extends the master cylinder (pushing the cup/seal deeper than normal into the bore) and damaging the master cylinder seals (if the bore is corroded).

This could lead to a poor master cylinder seal and a soft pedal feel.

I've manually bled car brakes for years and never had an issue but I vacuum bleed brakes now after reading that!!! It's also easier and a one man job - like pressure bleeding.

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Wayne
2005 BMW X5 3.0d (b 02/05)
2001 BMW F650GS Dakar (b 06/01)