Brake Switch - Hydraulic to Mechanical

[rogerotto66s]

Considering converting my MK1 from a Hydraulic to a Mechanical brake switch.

Not much fun trying to fiddle with the frame mounted switch.

I can not find any topics which address this conversion.

Any pictures and help would be appreciated.

[Spider]

I don't like to steer traffic away from this forum, but you can have a look here for a very easy simple solution without the need to remove the pedal box or drill holes in awkward places;-

https://www.theminiforum.co.uk/forums/t ... onversion/

[minibitz]

Easy!

You will need to fabricate an L shape bracket to hold the pedal switch. This can then be bolted to the pedal box inside the car. Then it's simply a case of running the existing two wires going to the hydraulic switch inside the car to the pedal switch.

My suggestion would be to take a peak inside a later mini equiped with a pedal switch. Once you have a visual it will all make sense.

[minibitz]

Too slow, looks like Spider hit submit while I was still typing.

[Spider]

Too slow, looks like Spider hit submit while I was still typing.

Sorry mate ! 40 lashings to me !

[LarryLebel]

If your concern is the reliability of hydraulic switches using silicon brake fluid, Harley Davidson motorcycle versions seem to be much better. The HD part number is 72023-51E.

[Peter Laidler]

My Cooper S has been using Silicon brake fluid since 1986 so I wouldn't let it worry you.

As a matter of probably little interest, the brake fluid - of whateer sort you choose - won't reach the rubber diaphragm within the hydraulic brake pressure switch. That's because of the position of the switch, ABOVE or at the top of the column, there will always be an air gap between the column of brake fluid and the diaphragm/seal. The brake fluid pressurises the air gap which operates the switch

[rogerotto66s]

More concerned with safety and reliability. Sometimes the lights come on, sometimes they don't. Brake fluid not an issue since I am using DOT4.

[Peter Laidler]

That's a strange reason to change brake fluid if I might be so bold as to say so. You cannot compress a liquid - it's a basic law of physics. There must have been another reason - but silicon brake fluid wasn't the cause of the crap brakes!

[rogerotto66s]

Question regarding wiring. My thought was to place the new G/GP wires in a sleeve (like headlights) and connect one end to the existing hydraulic switch wires and the other end (through the bulkhead) to the new mechanical switch on the brake pedal.

What is the preferred route for the wires through the bulkhead as well as their length?

[Spider]

If you feel like spending a little time on it, you can pull the wires back through the loom and route them with the other wires going through the bulkhead.

The Green comes from the Fuse Box and the Green / Purple runs right past the point in the bulkhead where the other wires come through. You can pull them back to there and then tie them in with the other wires coming inside. I've done this a few times and the wires don't need extending at all.

[rogerotto66s]

If you feel like spending a little time on it, you can pull the wires back through the loom and route them with the other wires going through the bulkhead.

Spider, thanks for point out this option.
I would prefer my approach which would easily allow reverting to using the original hydraulic switch.
Just looking for best/easiest way to get wires through the bulk head.
Initial inspection suggests a vertical/horizontal hole near the heater hoses which run into the passenger compartment.

[850RS]

I wanted to do the same swap to mechanical. I drew up a bracket in fusion360 and had a few laser cut and cnc bent. Happy to send you one if you would like.

[swifty]

That’s a very neat bracket but if fitting in a mk1 or 2 the fat heater tube will be squashed and hitting the wire terminals…. Shirley

[850RS]

That’s a very neat bracket but if fitting in a mk1 or 2 the fat heater tube will be squashed and hitting the wire terminals…. Shirley

Ah- good point. I’m running this switch in a right hand drive stripped out racecar without a heater.