Pressure Activated Brake Light Switch- Any Solutions?

This only applies to early cars. It pertains to the brake light switch that is located on a "T" fitting in the hydraulic system. When the brakes are applied, the pressure closes the switch and the lights activate.

I seem to go through 2 or 3 of the pressure activated brake light switches every year. Its not that they are hard to change or all that expensive, but between not knowing and the stash running out, I spend a lot of time with no brake lights. Not a great idea in todays driving environment.

I do run silicon brake fluid, which may or may not have anything to do with the failure rate. I am not ever going back to paint stripper in the lines!

Has anyone found a substitute in the industrial applications world? Any other suggestions?

Pete

I don't know if it is feasible, but could you move to the modern dual circuit master cylinder and use the newer pressure module (which is also used on Mustangs, I think). Those switches seem to last forever and only require an O-ring to rebuild. it would also be safer to have a dual circuit brake system.

Just an idea.

Where are you getting your switches?

Install a relay in the circuit, the switch will last longer, see the Dave Dubois in the library section.
http://www.mgexperience.net/article/brake-light-relay.html

Clifton

throw it on the counter at a napa store and tell him to match it..most have 1/8
npt threads..get the good stuff..

I got one from NAPA this Spring while on the road. Someone on the list here is a Volvo guy and he said that it crosses with the brake switch for the volvo 122. He then said to get the Volvo branded one from the dealer as it was MUCH better.

http://www.napaonline.com/masterpages/NOLMaster.aspx?PageId=470&LineCode=ECH&PartNumber=SL147&Description=Stoplight+Switch

http://www.ipdusa.com/Volvo-122/Brakes/Brake-Pressure-Switch/p-71-85-989/

Cant seem to find the Volvo branded one tonight.

Same as early VW switch.

Thanks all... Since we actually have NAPA in the great white north, I will be there tomorrow.

I have sourced these from the M place and the V place and from any flea market I go to. I really did have a stash of them. I really wish I knew the failure mode. May disect this last one.

Pete

Like Clifton said, install a relay. You will never have to replace the switch again.

On one of the cars I use the Alfa mechanical switch. It's soooo easy and infallible. The pedal arm touches it and the lights come on. Basil

When I build mine, 65-67, I am using an early 70's pedal cover with the mechanical switch and plugging the switch hole on the 4 way. These were parts I had laying around and I think it looks cleaner.

Zaque

Aah - you had me confused - I thought you meant a pressure loss switch. I didn't know the old Bs triggered the brake light on hydraulic pressure.

NAPA had the part ready to go. It looks a bit different than the one I had, so lets hope it last a bit longer. I may dissect the old one to see if the problem is silicon fluid getting behind some kind of seal.

Not only did they have it ins tock, but it was cheaper than the britt suppliers!

Pete