Packard Forum Index » V-8 (1955-56)

Hey guys
Hope someone can help me. While driving my '56 Clipper a couple of weeks ago I had to slam on the brakes (anyone that has ever driven in Dearborn, Mi will understand). The next time I drove the car the brake pedal went almost to the floor. Now the pedal is all the way to the floor and there seems to be no pressure in the system at all. The car has Power brakes. I checked under the car and didn't see any signs of fluid leakage around the master cylinder or at any of the wheel cylinders. Also the brake lights stopped working at the same time. Any idea of what my be wrong? BTW, the brake lights quit working at the same time.

Check your fluid level, chances are it was sucked into the engine. I've said it time and time before, these things are dangerous!

If the fluid is still in the master cylinder I suspect that the master cylinder piston is defective. Kits are available.

Every once in a while someone comes up with the "sucked into the engine" quote. I don't see how that can happen unless you have over a quart of brake fluid in the lower end of the canister. Look at where the suction is and look at where the fluid is. A simple test will illustrate my point. Fill an eight oz. glass half full of water. Then stick a straw down in the glass one quarter of the way. This will leave an air gap of about an inch and a quarter. Holding the straw steady so it won't slip into the water or touch it at all, suck up the water in the bottom half of the glass. You can't do it? Get someone with leather lungs or a good vacuum pump. They can't do it either? Unless the straw is immersed in the water it isn't going to be able to suck it up no matter how much your cheeks are caved in! Some Caddy units are different in that they suck from the bottom of the canister and quite naturally get any amount of fluid in the canister. The Packard TV pulls the vacuum from a much higher position.

The fluid has to go some where, if it's not in the master cylinder, and it isn't leaking, it either has to be in the vacuum chamber, or was sucked into the engine as vapor.

I'd take a good look at the compensator valve because your symptoms describe what happens if it doesn't seal tight immediately when pedal pushed-- a known issue with details on another thread in the forum. There might be a slim possibility the rear hose failed and dumped the fluid where you made the panic stop but you'd have known that immediately with the lack of a next stop. If the reservoir is full and no signs of leakage anywhere else, that valve is about all that's left.

I suspect that the fluid is in the vacuum side of the unit. I have rebuilt a few of these and found fluid in the canister several times. I also drive my Packard around Dearborn Mi all the time and can't say I have had to slam on the brakes because of other drivers. It was a great blue sky fall day here yesterday and the Packard enjoyed the exercise.

Joel, glad you're having good weather to tool around in your 400. The one saving grace in the T/V unit is that it is easy to remove, given a bit of patience and the hydraulic kit is readily available.
Frederickr - pay close attention to that poppet valve and spring as everyone has recommended. Remove the reservoir
cap to see if it is still full of fluid. If not, you are going to have to pull the T/V unit and rebuild it. Let us know your progress.

At the BACK WALL of the RESERVOIR there is approx a 1/16 inch dia. VERTICLE passage that opens from the reservoir and into the rear seal area of the master cylinder OUTSIDE of the the pressure chamber. Brake fluid can travel down thru the hole and then be sucked into the vacuum can.

I too have found brake fluid in the vacuum can of 2 different tradle-vac power units.

Randy: your explanation of the glass with the straw is correct. BUT does NOT model the issues with the treadle vac. If u CAPPED the top of the glass and perhaps allowed only a SMALL vent hole then YES ABSOLUTLEY the vacuum in the straw would remove the water from the glass even tho the straw never touched the water. It is called EVAPORATION! A strong vacuum pump and certainly the vacuum of a gasoline engine would empty a beer glass half full of water in about 30 minutes. The top of the glass would need to be significantly (tho not necessarily completely) sealed from the atmospher to do it.

I never had any treadle vac failures with my 56 Exec. However, it did suck brake fluid that was found in the power can. That is why i did the conversion to a modern unit.

During my Treadle-Vac driving there were probably at least 3 occasions where i had to make hard emergency stops and one pedal slammer at about 60 MPH down to nearly stop. NO failure. GOOD BRAKES!! HOWEVER, i can not afford to chance the possibility of no recourse for recovery if the compensator valve does fail. It's the compensator valve that is a very bad design and allows for no recovery whatsoever under failure.

Just out of curiosity, what model brake unit did you use for your conversion and did it fit pretty much in stock location without major surgery. Any info appreciated.