BRAKE FLUID ALARM
- The TE3509 is an electronic brake fluid
sensor that fits in place of the standard cap on the Lockheed master
cylinders fitted to many British cars of the 50s, 60s and 70s*.
WHO SHOULD USE IT?
- The TE3509 is a significant safety
enhancement for classic cars that are not fitted with a brake fluid
- It is particularly valuable on vehicles
with single braking systems and secondary servos where a servo seal
leak can result in rapid brake failure when all of the brake fluid is
drawn out of the system by the inlet manifold vacuum.
- Low fluid level simultaneously flashes a
red LED panel lamp and sounds a bleeper
- High reliability with no moving parts, no
contacts and no filament lamps
- Suits negative or positive earth 12V
- Easy installation with no necessity to
solder or crimp
- Pluggable connector allows easy Master
Cylinder cap removal
- Confidence check bleep and flash at
- Response time less than 1 minute
- Sensor projects only 10mm above the
standard Master Cylinder cap height
THE CONTENTS of your KIT:
ITEMS YOU WILL NEED:
A drill plus general tools, including
- 3.2mm/1/8” and 2.5mm drill bits may be
required for fixing screws and also for the pilot if panel mounting the
- If panel mounting the LED indicator, the
required hole is 14mm; the best way to drill this easily and neatly in
a thin panel is to use a step drill (make sure it has a 14mm section
and you stop at that step!).
- A 17mm ½” drive socket is ideal for
tightening the LED back nut (use the socket alone as a hand tool).
- A knitting needle or similar thin rigid
rod is useful for threading cable through bulkhead grommets – tape the
cable to it near the end avoiding any abrupt steps.
- By inspection or meter, establish whether
your car is negative or positive earth. British cars after c1967 will
be negative earth while those before may be positive earth but may have
- Referring to your car manual or by using a
meter establish which connection at your fuse box is fused and ignition
switched – we will call this the hot tab.
- Decide whether you want to use the
supplied LED housing or discard it and panel mount the LED.
- The LED/beeper/housing mounting positions
should be chosen to be within the pre-made cable length.
- For safety it is now advisable to isolate
the battery before commencing installation.
INSTALLATION, GENERAL: (for detailed
instructions for MGB GT V8 see accompanying instructions from Victor
Smith; instructions for other models may be available from the TE
- Fix the beeper and, if reqd, the LED
housing using the ST screws or double sided sticky pads provided. The
beeper and sensor cables exit the LED housing via notches in the back
face. The beeper can be conveniently mounted on the LED housing.
- If panel mounting the LED indicator, note
that the positive terminal is brass and the negative is nickel. This
may not be visible after installation so orient the lamp in a known
position, eg positive at the top.
- If you’ve re-mounted the LED, replace the
0.110” Faston connectors – the orange wire is positive and black is
- Temporarily remove the orange and black
cables from the sensor connector. Thread them through a bulkhead
grommet and re-connect ensuring all connections are as in the diagram.
Lay the cables near the Master Cylinder (MC) and loosely ty-rap into
- In the region of the fuse box find a
suitable earthed screw/fixing bolt (ideal dia ≤ 5mm) that can be used
to attach the earth “Faston” tab. Alternatively drill a 3.2mm/1/8” hole
into a suitable place in the body and use the No 8 ST screw provided.
- Lay in the red and black cables, Faston
connectors near the fuse box and earth tab, running
along a loom or other suitable route to the region of the Master
Cylinder. Loosely ty-rap into place.
- Wrap the spiral insulation around the
wires from the connector to where the cables will be secured.
- Connect the + and – Fastons at the fuse
box. If negative earth, connect – to the earth Faston tab and + to the
fuse box hot tab; vice-versa for positive earth. The piggy-back
Faston allows you to connect the new lead even if there are no spare
- Dress the cables, “losing” any excess
cable by looping. Position the connector and tighten the ty-raps. Cut
off excess ty-rap tails leaving ~ 5mm
- Carefully check the installation against
- Re-connect the battery and plug-in the
fluid sensor - note that the plug is inserted screws uppermost. Leave
the sensor assembly resting on the Master Cylinder (MC). The LED/beeper
should be off.
- Switch on the ignition. There should be a
momentary LED flash and a beep. After approximately
30s the alarm should start to flash the LED and sound the beeper (it’s
not immersed in fluid..) If there is no flash/beep but the PCB
overload LED is flashing the orange and black lines are shorted.
- Switch off the ignition, unplug the
sensor, remove the MC cap and top up the brake fluid. Now screw on the
brake fluid sensor and re-connect.
- Switch on the ignition. There should be a
momentary flash of the LED and beep followed by a continued silence as
the fluid sensor is now immersed in brake fluid. Installation is
UNPLUG THE SENSOR CONNECTOR BEFORE UNSCREWING THE MC CAP
FOR ROUTINE INSPECTION/TOPPING UP
CHECK THAT THE PCB BREATHER HOLE IS CLEAR (0.6mm hole under the “c” of
TE Electronics). If blocked, unplug sensor and clear hole with a short
If you have a problem with your TE3509 Brake Fluid Sensor
Kit, or have a suggestion for improvement, please
contact us: contact details are at the head of page 1.
Your TE3509 Brake Fluid Sensor is guaranteed for 12
months. Please return any faulty devices to TE Electronics Ltd with
your return address and a brief description of the problem.
If you have fitted your kit to a model not
currently listed we’d like to hear your experiences and
recommendations. Perhaps we could even persuade you to become the
author of the detailed instructions for your model!
OTHER TE ELECTRONICS PRODUCTS
TE Electronics manufactures niche market
and custom electronic equipment for the AV, SCADA,
telecomms and automotive industry.
Other automotive products include
the TE3518 “Smoothie”
Battery Conditioner which is compatible with voltage monitoring car
the TE3519 solid state
contact replacement for SU Fuel Pump contacts
the TE3520 Coolant
Please contact us if you have a problem that you think
could be solved by some custom electronics. We are always pleased to
hear of your “Solution Opportunities”!