Brake light?

[JerryH]

The brake light has turned on on m 78. I know this is not due to the E-brake switch because the light changes intensity when I pull the E-brake handle.

I know I've got an issue with my brakes as I've had to top off my brake fluid level a couple of times during the past couple months. I'll be going through my brake system soon--I've got to find where the fluid is going. But, what makes the brake light turn on? Where is the sensor located? What is it sensing?

Thanks for your help...

-J

[ORFORD2004]

Oil level in your tank

[vandor]

Your brake fluid level is low.
There is a float and a switch in the brake fluid reservoir cap. When the float drops it closes the contacts and the light comes on.

[124JOE]

hop in and push the pedal 7or8 times,look under the car for the puddle.
if you dont get one look under the dash behind the pedal for a trail
hopfuly you dont blow a line

[JerryH]

I've got two separate reservoirs for brake fluid. Both have caps, but neither one has a float or a switch. I still don't know what is turning on the brake light.

Joe, I'll use your technique for finding the leak. I purchased new brake lines so I don't need to worry about blowing a line. I've been considering changing out the master cylinder as well-- mainly because they're inexpensive and it looks like a relatively easy job.


-J

[vandor]

I've got two separate reservoirs for brake fluid. Both have caps, but neither one has a float or a switch. I still don't know what is turning on the brake light.

Are you sure you have a '78? The separate reservoirs came 1974 to early 1977.
Under the master cylinder is a block with 4 brake lines going into it, and also has an electrical wire connection.
If this unit senses a pressure difference between the front and rear circuits, it will ground the wire and turn on the brake light on.
When they are old sometimes they are hard to reset. They are also prone to leaking. I have eliminated them from several cars by using a front left metal brake line from a newer Spider, and running the rear line straight to the master cylinder.

[JerryH]

Sorry guys, my car is a 76. My previous Fiat was a '78.

Csaba, you pegged it. There is a block mounted on my sidewall just as you described. The reason that I didn't see it is that that is where I stuff my dipstick wiping rag. I'll check it for leaks. I'll report what I find.

Thanks for your help.

-J

[JerryH]

Now that the warmer weather is here, I've cleaned the brake fluid pressure sensing block and sure enough it appears to be leaking where the electrical connection is made. I'd like to get rid of this block--it's a nuisance. I've also purchased a new master cylinder that I plan to install. Here's my plan:

1. Purchase and install a later model fluid reservoir which uses a float sensor on the cap. Anyone got one of these for sale?
2. Install the new MC (I understand that I should 'pre-fill' the new MC with fluid before installation).
3. Install new lines from the reservoir to the MC. Is it okay to use fuel line here?
4. Replace the front left brake line as Csaba recommends. Where can I source one of these lines?
5. Bleed the brakes and drive!

Question 1; Is this a good idea? Any recommendations?
Question 2: I have 3 'hard' lines coming out of my MC. Where do these lines go (see photo below)? Which one needs to be replaced (front left)?