1986 240 brake failure light on after MC replaced

[steelbox]

Had a brake failure and after that had a new master cylinder replaced but the brake failure light didn't go off, so how do i fix that? Thanks!

[steelbox]

The brake failure light was solved by bleeding the brakes. The light goes off, but then comes back on again after several miles. Bleed the MC or what the mechanic said was balance the MC. So far so good, time will tell! I guess if that doesn't work last resort will be to replace the MC ( which was done one year ago) The light has been on for a year. This is my nephews car and uncle me is selling for him as he is returning to London. Thank you!

[jimmy57]

The trick is to have someoen keep firm pressure on brake pedal and you bleed at lines at MC. Only bleed one at at a time on each pedal application. There is a pin in the junction/safety switch manifold and you are trying to get that pin to center by having pressure imbalance push it over.

[steelbox]

Thanks again!

[steelbox]

well after bleeding MC yesterday and 30 mi. later the brake failure light came back on again. I guess ill bleed the two lines (or all three) coming out of the MC if that doesn't work then Ill replace the MC. Any other suggestions on this matter would be appreciated, thanks!

[steelbox]

No brake failure light on...I disconnected the the wire at the junction under the left side of the undercarriage. Probably not the best idea but the brakes work well so Im thinking the connection was faulty!

[SteveD]

Have you tryed bleeding at the wheels,starting at farest to closes. Sound like air pocket in line,causing uneven pressure,which give light

[93Regina]

well after bleeding MC

Brake bleeding has to be learned; read item 3 here.

This item 3: When the brake fluid becomes clear, direct your partner to hold the pedal to the floor.