Losing Break Fluid

[evrenosogullari]

Hello
Sorry if this is a redundant discussion... I haven't been able to find exactly what I need for this...

Fiat 1980 Spider Fuel Injected....

Basically the break light has been coming on and I'm noticing break fluid going kind of fast. A sidenote: my emergency break has never worked since I got the car and I understand that the cables have zip tied off to the side for the time being (another topic).

I refill it with DOT 4 break fluid and 2 or 3 days later the light comes back on, and when I look in the canister, its leveled down halfway.

I don't see any obvious leaks around the tube leading out of the break fluid canister or anywhere near the engine. Tried to get a look at the calipers (i'm not exactly sure where they are!), but I don't have a lift or anything so its just me kneeling under the car... don't see any leaks.

I have some places to drive tomorrow so I guess i'll just be refilling the break fluid until I can get it figured out... hope that's not dangerous?

Any help would be greatly appreciated!

[kilrwail]

Well it is dangerous. You should find the leak and fix it before you have an emergency. Look at the paint under the brake master cylinder. If the paint is bubbled and peeling that's a good indication that your master cylinder is leaking and should be replaced. Brake fluid is very hard on paint. Also look at the ground inside each wheel for evidence of a leak at one of the wheels, which is less likely. If there's a puddle inside the left front wheel that's probably caused by fluid running down the frame rail and spindle from the master cylinder before dripping to the ground. If you don't know how to replace the master, get some help - it's not difficult.

[18Fiatsandcounting]

I agree with Peter that the leak needs to be found and fixed. Brake fluid doesn't just disappear, and so if your fluid level is dropping that fast, you've got a leak somewhere. With no leaks, the brake fluid level should be constant over years.

Any tire or brake shop should be able to put your car up on a lift and find the leak for you, and you can decide how to fix at that point.

-Bryan

[evrenosogullari]

Thanks for the advise here...

Mechanic checked under the hood, around the pedals, and then took the car up on a lift. He said he wasn't able to see any leaks. Maybe its something subtle?

Would you recommend just swapping out the master cylinder to be safe? In that case any idea where to grab a nice new one?

I'm going to see if the level does actually go down again in the next couple days or I was dreaming... and if so maybe take it back for a harder look

[18Fiatsandcounting]

I'm going to see if the level does actually go down again in the next couple days or I was dreaming... and if so maybe take it back for a harder look

Let us know, and if the fluid level in your brake fluid reservoir is going down by half over several days, there's something going on. I wouldn't start replacing parts until you find out what.

One possibility is the rear brake compensator (regulator) that is near the passenger side rear wheel. Another is the flexible center brake hose, that goes between the underside of the body and the rear axle. Both are sometimes overlooked.

-Bryan

[SteinOnkel]

Thanks for the advise here...

Mechanic checked under the hood, around the pedals, and then took the car up on a lift. He said he wasn't able to see any leaks. Maybe its something subtle?

Would you recommend just swapping out the master cylinder to be safe? In that case any idea where to grab a nice new one?

I'm going to see if the level does actually go down again in the next couple days or I was dreaming... and if so maybe take it back for a harder look

Fire him immediately. Any mechanic that lets you drive off with a car that needs its brake fluid replaced that frequently does not deserve the title.

Good gracious, sometimes I miss Germany's biannual tech inspection...

[evrenosogullari]

Fire him immediately. Any mechanic that lets you drive off with a car that needs its brake fluid replaced that frequently does not deserve the title.

He's kind of a local guy on my block who helps me out here and there... taking the car to a 60-year-old italian guy in LIC next week who might know better about all these things.... Will post any interesting developments....

[18Fiatsandcounting]

Good gracious, sometimes I miss Germany's biannual tech inspection...

I have found the holy grail, someone who speaks favorably of the TÜV...!

-Bryan

[DieselSpider]

Unfortunately some of the rubber parts in the braking system on the Spider may not react well to DOT 4 brake fluid including the brake hoses which can weep fluid their entire length and just appear moist without appearing to be leaking. Yes some of the manufactures are now using rubber parts that hold up better to DOT4 however not all are and you would have to verify that all the rubber seals and hoses have been upgraded.

Previous owner of my car needed the brakes bled after he did some repairs himself and they flushed out all the DOT3 with DOT4 while bleeding the brakes and a few weeks later the new master cylinder and New Old Stock Hoses he had just put in all had the rubber start to fail in them and begin leaking. The new master cylinder and the rubber hoses at all the wheel positions had the rubber turn to putty and had to be replaced along with the new hoses between the brake fluid reservoir and master cylinder when I purchased the car.

[18Fiatsandcounting]

Unfortunately some of the rubber parts in the braking system on the Spider may not react well to DOT 4 brake fluid including the brake hoses which can weep fluid their entire length and just appear moist without appearing to be leaking. Yes some of the manufactures are now using rubber parts that hold up better to DOT4 however not all are and you would have to verify that all the rubber seals and hoses have been upgraded.

DieselSpider, are you thinking of DOT 3 vs. DOT 5? I always understood DOT 3 and DOT 4 to be fully compatible since both are glycol ether formulations, with DOT 4 being higher boiling. DOT 5 is silicone based which is definitely NOT compatible with the Fiat brake systems.

-Bryan

[Nut124]

I have been using DOT4 for over 20 years. No leaks.

[rridge]

I would remove the carpet and the padding under it on the driver's side and check that a leak is not following the brake actuator through the hole and running down the inside of the firewall.

[evrenosogullari]

So took the car finally to someone named Giovanni in LIC who is very old and from Sicily....

Seems (as mentioned here!) that the master cylinder was decrepit and leaking back into the "pump" (?), which is now full of break fluid. That's why there was no visible leak anywhere. He's going to put a new master cylinder on there and buy a new pump (because when the pump fills with break fluid it apparently also causes a rubber lining in there to weaken), and drain it of fluid...

I have faith that he'll be able to fix it.... hope that helps someone else who has a similar problem...!

[18Fiatsandcounting]

Seems (as mentioned here!) that the master cylinder was decrepit and leaking back into the "pump" (?), which is now full of break fluid.

Credit goes to rridge for mentioning this potential problem, and it sounds like you're on the way to having it fixed. Just a note for posterity: The "pump" is officially known as the brake booster, and its function is to assist your foot effort when pressing the brake pedal, so you don't have to push as hard.

The booster works off engine vacuum from the intake manifold. When the brake pedal isn't being pressed, the pressures (vacuum) on both sides of the diaphragm inside the booster are equal, so it doesn't provide any braking action. When you start to press the brake pedal, the side of the diaphragm towards the rear of the car opens up to outside air, and this pushes against the diaphragm and supplements your pedal effort in pushing the pistons inside the master cylinder.

Cool, eh?!

-Bryan