Hacking the Upper Half of Your Lotus Europa Master Brake Cylinder

I'm new to automotive customizing and the aluminum threaded cover for my original Lotus Europa brake master cylinder sovy device is no longer available. From years of pauper existence, I have've had to hack what's broken, usually to positive results.This is no different.

The original design is as simple as they get. A cork, attached to a rod with a metal washer attached to it, floats in the brake fluid reservoir. As the fluid level drops, the cork drops as well. When the washer gets low enough, it comes to rest on 2 contacts, closing the warning light circuit... Simple.


Unscrew the heavy billet aluminum piece from your plastic brake fluid tank and let's get started.

Step 1: What You'll Need

The first thing you'll need to find is a cover that fit's the original billet aluminum housing. Plastic is a much better choice than the original aluminum. As you can see, the original cover portion of the unit on my car lost the electrolysis battle. A plastic replacement will be less bothersome in the future. I used the cover from a spice bottle.

You'll also need four #6x 3/8" sheet metal screws.

If your car is stock, and you want to keep it that way,. If your car is concourse, you'll have to find an aluminum screw-on cap.You'll also want to eliminate the screws and clean up or replace the original hardware.

Grab a screw driver, sharp knife and/or Dremel tool, various cleaning materials and we're off to the races.

Step 2: Pry the Part Apart

The original plastic parts of the sovy switch were held together with threaded rivets. These are easy to remove by prying the upper and lower plastic part apart. This switch has virtually no delicate parts or springs that can fly off or get lost if you do this. The rivets will simply back out of the lower plastic portion and the parts will separate. On mine, the float stabilization rod had rusted to the plastic cover, so I had to gently twist it with a pair of pliers until it broke free.

You can toss the rivets, but save the contacts.

Step 3: Clean and Repair

The contacts are brass plated steel, so be careful when cleaning them. I used Brasso, which worked quite well to bring them back to life. Again, save the screws for concourse, but otherwise, #6x3/8 screws will work just fine.

I also used Brasso to clean the disk, that's on the rod connected to the cork and operates the switch. The top end of this part, goes through a hole in the cover. This is to keep everything inside aligned. It is a very simple, very reliable design.

For whatever reason, the upper portion of this rod was horribly corroded on my unit. It was rough and about 3/4 of it's original diameter. Rather than replace it, I slipped a short piece of heat-shrink over it to cover and insulate it from whatever had been working on it. I cleaned out the hole it had corroded itself into and took everything over to the sink for a thorough cleaning.

Step 4: Now, Go to Work

There are a ton of donor caps available.Fortunately for me, my wife generously donated the top from a jar of Lemmon Pepper for the task. Unfortunately, she didn't realize she had donated it until the job was finished.
Find a cover that fits tightly over the billet threads. You may need to reduce the height of the threads on the inside of the cover like I did. It's better the cover fits too tight than too loose. Take your time, and slice away a narrow strip of plastic from the top edge of the threads until the cover threads snugly onto the billet.

You'll also need to cut the top surface away where the lower half of the parts you just cleaned can poke through.

Once that's done, fit the switch components through the cover's opening and the cover threads onto the aluminum billet, you can start to put everything back together again.

Step 5: Re-Assemble

If you're building your car for shows, you'll want to clean the rivets and original screws (judges have been known to subtract for not having the correct screw or in this case, rivet in place).

1. screw the contacts in place. The end of the contacts will need to rest beneath the disk on the rod.
2. Slide the top over the upper portion of the rod and screw or rivet that back into place.
3. Screw your new cover onto the billet and if the rest of the brake system is like mine, get ready to tackle the lower half.

Hope this helps.

bfk