Packard Forum Index » Post-War (1946-54)

Hey guys,

I've been having problems getting my brakes to work properly. Un-kinked the rear brake hose and inspected the rear brakes themselves, and bled the whole system till there were no bubbles in the fluid. The pedal is soft, and at 15-20 mph the car gently comes to a stop with me standing on the pedal, when it should come to a screeching halt.

Something I noticed when looking at the rear brakes was the presence of fluid in the rubber dust boots of the rear wheel cylinders. I'm not sure if that's the cause, but the brakes were working okay before I tried making them work better. Any ideas?

Thanks,

-Garrett

It may or may be your only issue but fluid behind the dust cups means the cylinders are leaking.

Thanks O_D,

I really don't know why they are leaking. Could the kinked hose have had some influence on that? The wheel cylinders are only about 2.5 years old and I haven't driven the car very much. I guess that's the next step; replacing those cylinders.

-Garrett

If one is leaking and you do need to replace or rebuild it, I would look at all cylinders to verify status. To have them leak in such a short time, I would also suggest making sure there was not some kind of contamination of the fluid with something other than brake fluid. A cleaning solvent residue, petroleum product or even poor quality fluid might have ruined the rubber.

Another possibility for the cylinders leaking after only 2.5 years is abrasive grit in the system. You don't necessarily have to replace the cylinders, assuming the bores are in good shape which they certainly should be after only that short time, you could hone the bores and just install new cups available as wheel cylinder kits but before I did that, or replaced them, I'd very thoroughly flush the entire system. I've use simple rubbing alcohol (isopropyl alcohol) for system flushing, followed by a long blast with dry air to insure complete evaporation of the alcohol. Then just to be sure, one flush with fresh brake fluid.

When I was working as a parts counterman, we had a lot of problems with some replacement, aftermarket, wheel cylinders leaking after about a year of daily use. I found out that the parts manager had been specifying the cheapest house-brand cylinders on estimates to make sure we didn't lose the job to some tarpaper shack down the road. I started quoting jobs with cylinders from a more reputable/recognizable supplier and the problem went away. Yes, we did lose some business to the tarpaper shack, but we no longer had to eat the labor on any comebacks.

When doing brake work myself, I always flush all metal parts - wether new or reused - thoroughly with a good quality aerosol brake cleaner, but let them air dry for a good long time.

Garret, when you worked on those brakes, did you replace the steel lines? Even if you flushed existing lines that looked fine from all outward appearances, there could still be internal corrosion. In that case, you could be pushing some of that rust downstream with each braking application, which would slowly chew up the cups.

The brakes in my '54 are pretty darn good for being all drums, and non-powered brakes. Even Jim remarked how well it stops when he drove it decently.

On my brakes, all the linings are the NAPA brand "Professional" grade shoes.

I also replaced all the wheel cylinders and lines because my old fluid was gelled in the lines.

Basically everything except for the drums and backing plates on my brake system was replaced with Napa equivalent direct replacement parts based on the original wagner part numbers.

Are you sure your brakes are adjusted correctly? Remember they are not self adjusting brakes, so you almost need a slight drag when adjusted corrected, and they have to be readjusted as part of regular maintenance to take up the wear in the shoes.

There is a major and minor adjustment, I did both since the system was fully apart and replaced.

Also a soft/spongy brake hose could cause problems as well and should be replaced ASAP.

If everything checks out, and they are still soft, then you still have air in the system somewhere.

Like you Kev, my brake system is completely new with the exception of the drums and backing plates. The front brakes were slightly out of adjustment and I fixed that yesterday. The wheel cylinders and hardware I have are from Kanter. IIRC the cylinders are Raybestos brand.

What I find so confusing is the fact that these brakes were working pretty well before I started messing with them. The reason for messing with them was the fact that I could never properly adjust my rear brakes to where the parking brake would catch. If I tried to adjust them properly the rear brakes would spark and lock up.

-Garrett

I know that Ross always recommends to adjust the rear brakes with the parking cables completely slacked, and even push the cable a bit into the drums so there is no residual tension on the shoe. So basically, you get the normal brakes adjusted first, and then do the parking brake by adjusting the equalizer only, without touching the adjustment on the drums at all.

You may want to check the cable isn't getting hung up anywhere and it is sliding on the equalizer is correctly. You could have rust causing one of the cables to bind where it enters armored cable near the drum.

I fully agree that Ross' method as given by Big Kev is the ONLY correct way to adjust rear brakes. Anything other is just wasting your time.