Brakes, or lack there of.

OK, I just bought a 69 Chrysler 300 last week and the brakes are terrible. I changed out the worn front shoes, but that didn't help. The pedal may move a total of a half inch, and it is rock hard. I,m thinking the booster is bad. What do you guys think? The only other booster I have had to replace leaked air, but I can't hear anything from this one. The car has been sitting for quite a while.

Booster could be rusted. Master cylinder could be rusted. What does the fluid look like?

It sounds like you have 4 wheel power drums. In my experience, these should feel strong in moderate speed stops. Maybe not completely even L/R but should stop you pretty fast and easy from speeds of 30-50 MPH or a bit more.

This is not what you are seeing so something is not right. Suggest visual inspection of all 4 corners and bleed the brakes first. If you don't find anything wrong then consider booster or master problem.

If you want to stop from higher speeds well or repeated stops time to upgrade to front discs. If your system needs major work... especially the front, suggest you consider disc upgrade.

IIRC...with the engine off, pump the brakes a few times to use up whatever reserve vacuum there is. Holding the pedal down FIRMLY, start the engine. If the pedal sinks appreciably, the booster is bad.Again this is if I recall the NAPA days correctly. Hope this helps.

The pedal is hard as a rock with or without the engine running. And it just barely is able to stop. I don,t think bleeding the brakes is the issue, if it was they would be spongy. The fluid color is typical brown like all old fluid.

Bad booster.

I'm going to say that you might want to pull all 4 drums and be sure the brake shoes and wheel cylinders are not stuck in place from sitting.

I'd also pull the master cylinder away from the booster and see if the pedal will travel the full stroke. I've seen the push rod get stuck inside the booster, as well as between the brake pedal and the booster. If you move the master cylinder out of the way, the brake pedal should freely travel the full stroke the pedal will allow. A fully bled and properly adjusted drum brake system usually doesn't have a lot of pedal movement, but they usually grab pretty good.

Lots of stuff gets stuck from sitting around a while without being used. Gene

There is a check valve in the hose fitting on the booster that can refuse to pass air. You should be able to suck thru it but not blow thru it from the hose end. Have you verified that you have vacuum at the booster?

Sometimes its simple stuff like a cracked/broken hose or that check valve.

Kevin

I'll check on the booster by unbolting it and checking rod movement. Definitely have vacume, and the wheel cylinders all look fine.

just because the wheel cylinders "look" fine, and have no leaks, they can still be locked up from rust. the only way to confirm this is a disassembly of at least the springs to see if the cylinder push pins move in both directions. just be careful if they do move, you don't blow them apart, throwing internal cups and springs into shop "never-to-be-found-land".

I pulled the master away from the booster today. Pedal easily travels to the floor. Started the car and it pulled the pedal back up with the vacume. I would find it hard to believe that all four wheel cylinders would have frozen up. So, I am still without brakes.

Ahhh, but they can all rust up. If one is rusted from moisture, then the moisture is there in the fluid for all cylinders to rust.

Bleed some fluid from the other cylinders and see how rusty the fluid is.

Obviously you took the drums from the wheels. Did they come off easily? If they fell off easily the brakes aren't adjusted properly. I would go ahead and take the springs and shoes off and clean everything then grease the flat spots on the backing plates where the shoes ride. Almost all of your pedal feel is the rear brakes. You should be able to have a helper gently work the pedal and see movement with the assembly. If everything checks out, you need to adjust the brakes. After assembly, turn the wheel and tire by hand and adjust the brakes until you feel resistance. It's ok if the wheel is slightly hard to turn when you have it right, the brakes will wear in. Take it to Midas or a similar shop and have them pressure bleed the system with new fluid.

As someone who drove '69 C bodies when they were new, that power drum setup should be able to throw you into the windshield on a hard stop.

amen to that ! B-body the same !

my bet

Ok, I pulled a couple of wheels yesterday and had my wife depress the brake pedal slowly. Much to my surprise, the wheel cylinders are frozen up. I have never seen a wheel cylinder stuck like that. Always worked or leaked. Learned something new. To my disbelief, none of the three major parts stores in town even list wheel cylinders. Might have to buy them from Summit.

If the bleeders aren't frozen rusted then bleed the brakes while waiting for the new cylinders, and before installing the new wheel cylinders. Get ALL the old fluid out as there is probably lots of moisture in the fluid and it could rust up the new cylinders. And double check the master cylinder.

i have run into frozen wheel cylinders so many times i lost count. and to make matters even more interesting, this also happens on daily drivers as well. when the fluid gets moisture in it [the fliud is "hydroscopic", which means it absorbs water] and turns that nasty brown/black color, problems can, and do, occur. this applies to DOT 3, 4, and 5.1 fluids only. DOT 5 doesn't absorb water because of it's synthetic nature, but i have also experienced frozen cylinders [although rare] using that because the cylinders had collected water at the bottom of the cylinders, leading to rust in that area only, just enough to make it stick. after taking the cylinder apart, the area could "usually" be polished out without making the bore out of round, then using a kit, put back in service.

A lot of parts get stuck or froze together on vehicles that sit unused for long periods of time (In areas that are damp, this stuff can happen in less then a year), brakes are among the worst offenders, but I've seen cases of nearly everything automotive stuck together with other parts that sit against them.

Most old cars found that have been sitting for years have locked up drum brakes. I've seen brake shoe stick to the drums, and brake shoes stick to the backing plates. Often wheel cylinders and e brake cables are stuck/frozen tight. I've even had removable brake drums stuck on rear axle flanges bad enough the drum had to be cut off the axle. Gene

Alright, it turns out that a couple of wheel cylinders were stuck, plus the rear rubber line and the right front rubber line were completely stopped up. Maybe I'll have brakes on all 4 wheels again tomorrow afternoon. In all my years of working on cars, I have never seen this much stuff stopped up on an old car. I must have been lucky in the past. I get this finished, it will be time to tackle those door panels.

Glad you're making headway! I would go ahead and replace all four rubber lines while you are at it. The old lines will sponge in and out like bellows. This is a problem that is common but sometimes hard to identify.

glad you found the problem ! if replacing a couple of cylinders, replace them all. if the return springs are several [many ?] years old, you might consider those as well, and they aren't that much, cost wise. when you have the brakes apart, look closely at the backing plates for grooves, or worn depressions in the shoe contact pads. if any are found, a spot or two of weld, then ground down will fix that. small [tiny] depressions can be filed flat. upon reassembly, a dab of high temperature grease on these pads helps a lot.

I always replace everything from pedal to pads on anything questionable, or has been sitting for an unknown length of time.
Still finding everything over the counter.
That's the part that surprised me.
These systems are so easy I can do it in an afternoon or two.
I am no pro by a long shot.
No fancy lines and only a bender and flare kit for "special" tools.

These systems have lasted 40 years once and will do it again.
By then I will be long gone.

Brakes are fixed, even stops pretty straight from speed. Now to figure out a way of repairing the door panels because no one makes C body panels.