1968 Need help - Brake Question

[di81977]

Last weekend I pulled the HCS out of storage. It had been sitting since late Oct. Other than adding STA-BIL to the gas and overinflating the tires, I did not touch the car the entire time it was in storage.

Started the car up and the brake pedal went from being firm before storage to going all the way down. Checked the master cylinder and the front reservoir was empty (I did pump the brakes a few times before checking the fluid).

Question - why did this happen, and where did the brake fluid go? I had pans under the car and they were clean, as was the floor. Below is a picture, did the fluid go into the other reservoir?

I have front discs that were converted by a previous owner.

I appreciate all help and direction.

David

 

[PFSlim]

I would have guessed on the floor. I don't think with that master cylinder, it can go from one side to the other. If it was me, I would refill the reservior, check brakes to see if you have to re-bleed. I would guess that if you depressed on pedal with no fluid, it would have put an air bubble in the line.

Unusual I would say.

Paul

 

[DeadStang]

I believe the smaller chamber is for the rear brakes. I suspect that you'd had one or both rear wheel cylinders start leaking over winter and that's where the fluid has gone. Jack up the rear end of the car by the pumpkin and take a look. The inner rear wheels won't be wet as the brake fluid kind of evaporates with time, but you'll be able to tell that something has run down the insides of the housings back there.

 

[di81977]

Took a quick look under the rear. So what is the hose going into the axle do? This appears to be my problem. I had cleaned my rear diff really well about a year ago. What a mess. I still need to pull the wheels and look at the rear drums more closely.

Thanks for the advice.

david

 

[tomcwarren]

The black hose entering the rear axle from vertical is the vent hose (so pressure doesn't build up in your rear end and blow lube out the seals) :wink:

The leak is most likely at the brake line junction just in front of the vent (obscured in your photo). See this shot from another forum:



One of the connections to this junction block is leaking. Probably best to remove/replace all 3, unless you can clean it enough to see exactly where the leak originates from.

HTH,

Tom

 

[di81977]

Tom, thanks for the picture. I looked closer and it appears there are a couple little cracks in the hose right before the junction block. Looks like the hose and junction are relatively inexpensive. The rest of the lines look pretty good, but I have no idea when they were replaced (or if they are even original). For another $38, probably makes sense to replace them with new SS lines.

Thanks again

 

[Ruppstang]

The SS lines can be a bit tough to get sealed because they are so hard. I use the plain steel. Marty

 

[admin]

David,

The leak in your photo doesn't actually look like it's coming from the brake line junction, at least the drip running down the backside of the housing. That looks like it's gear oil from the diff itself. But if you found cracks in the rubber brake line then that's probably your culprit.

The smaller (forward) reservoir in your master cylinder is indeed for the rear brakes, so that logic follows. But as others said, still check your rear wheel cylinders for additional signs of leaking.

And you'll definitely need to bleed your brakes. The reservoir in your 1st pic is dry, which means you probably got plenty of air pumped in there before realizing you were out of fluid. Just filling the reservoir up again may get you passable breaking power, but they should be bled.

I've had very good luck with Speed Bleeders (if your car isn't concours). They replace your bleeder screws and have a one way check valve in them. Once installed you crack one open, connect a tube to a jar to catch the brake fluid, and pump as per normal bleeding procedure. But you don't have the tighten the bleeder between pumps because of the one way check valve. It's true one-man bleeding and makes for a much quicker job.

 

[somethingspecial]

I lost the fluid in one of my non power brake cars recently. I could not figure out where the fluid went as all the slave cylinders were dry with no leaks. I looked under the dash where the brake pedal rod goes into the master cylinder and found the firewall wet. It was the master cylinder that went bad. Might check that while you are at it. Mike

 

[robert campbell]

Ditto on Mike's comment!! Power brake cars will also leak into the vacuum assist cylinder and destroy the vacuum booster rubber diaphragm.

Rob

 

[Ruppstang]

Ditto on Mike's comment!! Power brake cars will also leak into the vacuum assist cylinder and destroy the vacuum booster rubber diaphragm.

Rob

That has happend me two times. I woud not use a remanufactured master cylinder. Better to pay a little more the first time, than a booster too. Marty

 

[di81977]

Thanks again everyone for all the help and advice. After checking out the master cylinder, hoses, line connections and wheel cylinders, I have come to the conclusion that I have LOTS of little leaks.

I am planning to replace the rear hose with the junction box, the rear lines, and one wheel cylinder.

I am pretty sure I can do this myself. Looks pretty straight forward and will give me an opportunity to clean up under the car. Marty, thanks for the heads up on SS lines. Is there anything else I should be aware of before beginning this task? Any special tools needed (other than for bleeding - Jon thanks for the recommendation)? I am guessing the most difficult part will be dealing with the brake line connections.

david

 

[tomcwarren]

A good set of flare nut wrenches is invaluable when working on brake fittings. A tubing cutter and a good tubing bender can come in handy if you are not planning on using pre-bent lines, or need to reroute for some reason.

Tom