850 brake pressure switch

I have had to replace 3 brake pressure switches on the 850 model Volvo over the past few years, this is the pressure switch that screws into the main master brake cylinder that operates the brake lights. These have started to weep brake fluid, this in turn drips onto the exhaust causing a sweet smell in the car.(can be or can be mistaken for the heater matrix weeping). It seem that the moulded plastic body on these switches or the join between the plastic and the metal parts is failing. My Volvo agent will not sell this switch on its own, so you have to buy the whole master cylinder assy, so far I have managed to get this switch from my local breakers yard. Has anyone else had this switch fail on their 850 / V70 car ? My concern is that if this pressure switch fails completely the car will have no brakes.

ttfn......Alistair

Hi Alistair,

I had a 1996 850 for 10 years, only sold it recently, and I had no problems at all with the brake light pressure switch. Perhaps you should buy a new switch and try that. You might be able to get one from somewhere other than Volvo if they won't sell the switch by itself. Brake light pressure switches are pretty basic. I'd be surprised if you couldn't find something suitable. Even if you had to "transplant" the electrical connector to another switch. Something like this

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(0536738790 providing the thread is compatible. You wouldn't be left without brakes if the switch failed as the braking is a split system. According to my Haynes Manual, it's divided front and back, and in the event of a failure the brake pedal will travel further and be harder to push, but you'd have something left. And you'd alway have the handbrake left as well (only joking, I wouldn't rely on that to pull me up). But of course you don't want to wait for this to happen.

Regards Barry.