TE low brake fluid detector - a vital safety device for an MGBGTV8
Bob Owen (Blaze 1675) from Berkshire suffered one of the brake servo failures we have reported over the last few years and decided he would like a little more warning if the brake fluid loss might occur again! He was well placed to create an electronic sensor which fits on the brake fluid master cylinder cap as he runs an electronics business. This kit will be launched at Silverstone in July 2005 so V8 enthusiasts will be able to see a demonstration unit and buy one. (Jun 05)

View of the printed circuit board of the TE low brake fluid sensor showing the electrical connection. The unit is fixed to a plastic cap on top of the brake fluid reservoir. (Photo: Bob Owen)

The need for this kit is clear - we have had over four reports of total failure of servos on V8s which are reported in the V8 Workshop Notes series - see a free copy on the V8 Website. When we say "total failure" we mean a complete loss of brake fluid swallowed by the servo so it is a serious safety issue. If you have had this type of failure, your spine stays cold for ten days afterwards! As Factory MGBGTV8s pass the 30 year age barrier it has to be prudent to have your servo checked by a skilled specialist and if necessary have a replacement servo fitted. As a reassuring backup Bob's device, known as a TE low brake fluid sensor, provides not only a reassuring confirmation of a correct fluid level each time you start the car - both an audible bleap and a confirmatory light - but also should the fluid level drop at any stage, then a flashing light and a bleap come on with gusto giving you the earliest warning that you should stop the car as soon as possible.

The TE low brake fluid sensor kit can be used with 12V negative or positive earth cars and fits only the metal type of Lockheed brake fluid reservoir with either the original metal cap or the later nylon cap we see on V8s. A variant of the sensor is being produced for the later plastic replacement brake fluid reservoirs. It will also be useful for the many more MGB and MGC enthusiasts in the UK and overseas. The kit comes in a pack with all the parts and comprehensive fitting instructions together with a copy of a V8NOTE33 which describes the author's experience of fitting one of the kits in a V8. By the way V8NOTE331 is the first V8 Workshop Note in the new Volume 10 of the long running and popular series based on members' spares and maintenance tips.

TE Electronics Ltd
Tel: 0118 933 2533 & Fax: 0118 933 1224
(note we use this email address format to block spammers automated email address harvesters, just use @ as usual)

Neat electronic sensor under the cap of the brake fluid reservoir monitors the brake fluid. (Photo: Bob Owen)

The alarm signal is a rapid flashing of a red LED
plus synchronised bleeping. At switch-on of the ignition there is a short flash/beep to indicate that the sensor is active. The sensor operation is thermal. The sensor element is a small metal cased device 5mm dia x3mm which is surrounded by a larger metal protective shroud attached to the cap. The alarm goes off within 1.5 minutes if fluid doesn't surround the sensor. The delayed response makes the unit proof against false alarms from fluid displacement such as might occur when cornering or braking hard.

The electronics are built onto a hexagonal pcb which takes the place of the push-on lid on the standard plastic cap. The components are mostly surface mount (ultra miniature) types which fit into the void in the cap. The pcb has a 0.6mm dia vent hole which communicates to the reservoir via a small slot in the sensor connector assembly, simulating the original vent path. The three wires to the unit (chassis, +12V and Indicator) are connected to a plug so that the cap/sensor is easily removed to top up fluid levels. The unit is protected against surge voltages, reverse connection and short circuit of the LED indicator/bleeper or cabling. The aim is for simple and foolproof installation!

The alarm signal is a rapid flashing of the red LED which can be mounted in the dashboard or other convenient location plus synchronised bleeping. You will see Bob has also installed a cooling fan override switch and green LED. (Photo: Bob Owen)

This device is probably one of the most useful contributions to the V8NOTES series.