Leaking Brake Fluid

[auzziez]

I haven't had a chance to research this yet, but I plan to get underneath the car this weekend. I was hoping that I could get some ideas on possible causes before starting.

The details, HLS30-17269 build date 12/70. Stock braking system. The rear reservoir (one closest to the firewall) ran dry, the front reservoir was slightly low, but was still 3/4 full. No visible signs of leakage around master cylinder or master vacuum. There are signs of leakage under the car, dripping down onto the top of the transmission, with splash moving toward rear of the car on the passenger side. No visible leakage on either wheel brake calipers or cylinders (looking through the slots in the mag wheels) .

My initial thoughts are that there is a leak in the main brake tube that runs from the brake master cylinder to the rear wheels, which I believe runs down the transmission tunnel above the transmission.

Is this tube a solid piece between the engine compartment and rear wheels? Does anyone know if there are any valves or connectors in that tube between the master cylinder and rear wheel proportioning valves.

Jumping to worst case scenario, If there is a leak in the main tube, can this be replaces with parts available at my local AutoZone?

Any thoughts would be appreciated.

[JohnnyO]

Is this tube a solid piece between the engine compartment and rear wheels?

Yes

Does anyone know if there are any valves or connectors in that tube between the master cylinder and rear wheel proportioning valves.

Pretty sure there are no valves in the middle.

Jumping to worst case scenario, If there is a leak in the main tube, can this be replaces with parts available at my local AutoZone?

Yes, if you can bend lines. Autozone or Napa has the correct lines. Get 2 lengths of BLJ-60 and 1 each of the shorter BLJ-12, BLJ-18 and BLJ-24 lines. You will also need something to connect them in the middle. This should get you close to the proportioning valve.

You could also bend the entire line out of 3/16" line but I am not sure you would get it re-installed without dropping the tranny. Autozone has the correct nuts, I believe they are M10. Let me know if you need the part number.

Any thoughts would be appreciated.

Keep in mind this is not a fun job. The tranny and rear diff will be in the way and you will probably have to cut the existing line (after you confirm that it is leaking) to get it out. There are 2 fuel lines on my 70 that also run back on the same route and the brackets hold all 3 together so you will be fighting them when you put them back in too. You might even consider dropping the drive shaft and differential to make it a little easier to get around under there.

I would venture to guess that somewhere near the parking brake mount is where it is leaking. There are a couple places for it to rub there.

Good luck.

[auzziez]

Thanks Johnny'O. Great Information Mate. I'm always up for a challenge.

[JohnnyO]

When you start searching for the leak remember that, just like a leak in your water pipes, the fluid will travel downhill before it drips. So if you are getting drippage around the back of the tranny it may be leaking just past the firewall and traveling down the line until it levels out or hits a line holder.

It will definitely be a challenge.

[SteveJ]

Did you check the inside of your car for evidence of leakage?