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MG MGB Technical - 72B Brake Pressure Failure Switch Fixed

Ever since I got my 72B a few years ago it has bugged me that *everything* electrical works perfectly except the brake pressure failure switch. The warning switch on the dash was OK but the switch on the brass body assembly was shot - the contacts had corroded off and the part is NA (Moss #141-725).

I had a switch (#181-955) that would fit in other models - later Bs, midgets and likely others but the threaded insert that fits into the body was too long for my car.

Tonight I was playing around and modified the switch by cutting it down. I used my Dremel to first slice off about 3/8" of the plastic threaded portion. This exposed more of the plunger rod which I cut off to match the length of my old switch. I then rounded it off and polished it a bit and it fits perfectly and it works just fine. (Although for how long who knows?) I tested by bleeding my brakes.

I know this part is considered useless by many but I wanted to pass this along as a possible solution.

Greg Smela

It's nice to know that there are creative solutions to some of the "NA" parts problems that we encounter. Good tip.
R. L Carleen

Greg,
I have done the same to the pedal box mounted brake lamp switch when it wears away even with the end of the threaded shank.

One has to wonder tho, why did yours was so short?? Was it worn or just manufactured too short? If wear, then would that mean that the shuttle that operates it was sliding back and forth all the time?? Probably not, but I was just curious.
Bob Muenchausen

Bob -

I think the original part just had a shorter shank by design. My original part isn't worn at all. The few used switches I've come across for that model year are all the same length - and all are suffering from missing/corroded electrical contacts.
Greg Smela

I'll have to come back to this thread after I get all my major stuff done. I do like to have everything work. The wonders of "Dremeling"......last used mine Friday night to cut the top off a brass drain access plug in some house plumbing that had corroded immovably...then cut some "pizza slices" in the top....tappped it with the cold chisel a few whacks and out she came. Would have been sooo much harder with just the chisel.
J.T. Bamford

This thread was discussed between 24/07/2004 and 26/07/2004

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