Mazdax605

iTrader: (5)

Hey guys,

In the spring of this year when I got my 79 back on the road I quickly realized that the brake fluid was low while driving it,and having the brake light flash on me a few times. I filled up the reservior,and checked for leaks all over the car.I couldn't find anything,and I park the car in my clean garage all the time in the same place with no stains,or puddles. Everything has been fine until just yesterday when the light flashed on again while on a spirited drive.I popped the hood,and sure enough the fluid is low again.I still can't find any leaks,and I am stumped.The emergency brake still works great so I am pretty sure there are no leaks in the drums from the wheel cylinders,and I still don't see any wetness at any of the wheels,or amywhere on the chassis,or the garage floor.Any help on this would be appreciated.Thanks in advance.

Kentetsu

Feel around on the inside of the rear wheels. That's the most likely place for a leak, at the rear cylinders. The escaping fluid will coat the inside of the wheel, and may not make it down to the floor of the garage at all. Good luck!

steve84GS TII

If you dont find anything in the brakes themselves,check around the base of the mastercylinder.It can leak out the back, into/around the vacuum booster.Wrinkled paint around the firewall and steering box is a good sign that brake fluid has been leaking around the M/C.

I had the same issue a while back with my TII master cylinder.Turned out it was leaking from the unused, active suspension brake pressure switch on the bottom of the M/C.Changed out the M/C with a new one and I havent lost a drop since.

Sgt.Stinkfist

iTrader: (6)

have you pulled the drums yet to actually check? ive seen several cars at my work that had no obvious signs of leaking wheel cylinders on the outside, untill we pulled the drums and found a nasty mess of black goo (brake dust + brake fluid) that never managed to seep out of the drum

Rogue_Wulff

Master cly leaking into the booster. Mine will do that during the winter, when the temp drops below freezing. New MC going on as soon as I get the disc rearend swapped in.

Mazdax605

iTrader: (5)

I am not doubting your idea that it could be leaking into my drum,but wouldn't I notice a lack of holding power with my e-brake if this were the case? I can literally stop the car with the e-brake like I locked up the brakes which I don't think would be possible if I had all that goo inside the drum.

I am going to look into the brake master leaking into the booster,and or inside the car later on today.Thanks guys.

chris wilcox

I've seen them leak into the car, down the inside of the firewall and get soaked up by the underpadding/carpet.
Chris

John64

Ebrakes are mechanical not hydrolic. It is pulled by a cable not the hyprolic pressure of the clutch.

Mazdax605

iTrader: (5)

This I know,but don't you think if the drum was slick from leaking barke fluid that the brakes would not work too well.Like I said the e-brake works great.I am leaning toward a leak at the master cylinder,but who knows.It must not be much of a leak,as it has taken 2-3 months for the level to drop.I know I don't drive the car everyday,but if the leak were bad I think it would drain the fluid down a lot quicker than that rate.Thanks for the help guys I will let you know what I find later today when I get home.

tunafish

I have the same problem, for over a year the brake light would come on the fluid was low maybe once a month then more and more often to the point of 10 miles and refill never a single drop of brake flid was seen (nothing).
Took off the master cylinder last night when I seperated it from the brake booster fluid started leaking out, rusty shity fluid I removed the brake booster dumped out close to 2 pints of brake fluid it was going into the BRAKE BOOSTER! I have ordered a new master cylinder and brake booster what a mess.

Mazdax605

iTrader: (5)

Well guess what the master cylinder is leaking.I found the paint on the booster is peeling,but I don't see anything on the frame rail,or the steering box.Do you think I can just get away with a new master cylinder,or should I replace the booster as well?I would rather not buy a booster,and I am not even sure where I would get one,but I see Mazdatrix has a good price on master cylinders.I didn't have time to look inside the car,but could the fluid leak through the booster,and into the cabin of the car?Thanks for the help guys.

rotarypower84

if is not wet inside the firewall then you dont have to replace the booster just replace the m/c i bought my at checker auto part with life time warr.

tunafish

My Power Booster was the same way the paint was peeling off just under the master cylinder. Its only seeping trust me that fluid is inside the power booster.
The master cylinder is shot and fluid was sucked in to the power booster just because there is no fluid leaking inside the cabin has nothing to do with it. Remove and check it 4 nuts 12mm and 1 cooter pin