story of a 1957 drum brake

[chevyunger]

Hi community,
we purchased a 1957 Cadillac Series 62 sedan in April.
The car seemed to be good and we had hope for a nice season.
Only the brakes were bad, so we changed the wheel cylinders (wet) and brake shoes (worn).
On our first trip (look at that: http://www.thejukin50s.de/) we managed 30 miles and were towed home with a hot, smoking left rear drum.
After that we tried new brake hoses and changing the brake shoes (shop mixed primary and secondary brake shoe), nothing works.
Than we had a test drive with cancalled rear left brake and got a hot rear right drum.
So, story is not over. Next step will be a new master brake cylinder, because we think that there is a constant pressure on the system after the first few brakes, maybe coming from a flabby spring in the master cylinder.
If you have other suggestions, pleas feel free to post.

thanks and kind regards

Matthias

[Walter Youshock]

Been there.  My right front locked up and the car and I almost burned up!  Really, you have to go over the entire system--wheel and master cylinders; hoses; and have the booster rebuilt.  Have the drums checked as well. 

I got in the habit of bleeding the system every year now.  The wheel cylinders started to seize on mine.  The system is basically open to the atmosphere and it will attract moisture.  The booster is where fluid and air work together to give the boost.  The slightest failure on either side can expose the fluid to even more atmosphere.

Drum to shoe adjustment is critical as well. 

Good luck!

[chevyunger]

Hi Walter,
do you found a specific failure finally?

regards
Matthias

[Dave Shepherd]

In my shop we would open bleeders starting at the master/booster and work back til the brake released, this should help pinpoint the cause.

[gary griffin]

Brake systems are vented to the atmosphere.  Every time fluid is pumped out of the master cylinder to activate brakes a little bit of air comes into the system. The air has moisture in it and over time the moisture mixes with the fluid and the brake fluid-water mixture travels through the system.  Most of  of us do not change our brake systems fluids regularly and we are pumping the water enhanced mixture through our brake systems.  I just had to replace two rear wheel cylinders on  a Triumph Stag because the were designed to be on a slant and water collected at the lowest spot and during storage the wheel cylinders failed. If I had changed the fluid often enough I would not have had that problem.  In our old cars, many of which sat idle for many  years and the old fluids were not as good as modern fluids I am surprised that we do not have more failures due to internal corrosion in the systems.  Stainless steel brake lines are a good start if you are doing a restoration but if not, a thorough flushing is a good  alternative.  Do not just bleed them, run enough fluid through them to flush out all of the old fluid as it is contaminated and damaging your system.

[Coupe Deville]

Not sure if other 57s have this but when I got my 57 the previous owner said the brakes dragged sometimes. I have since replaced wheel cylinders shoes and hardware. But when you released the brake pedal you could see it was not returning all the way. There was a spring attached to the pedal to pull it up. Mine was badly attached so I attached it to a new mounting point on the brake pedal and the brake pedal returns fully by its self now. Just a though. Im not positive the spring is original, but it does work fine.

-Gavin   

[Walter Youshock]

If your's had a return spring on the pedal, something was wrong.  When my brakes started to act up, the pedal wouldn't fully return and the lights stayed on.  That should have been my first clue something was wrong.

What returns the pedal to "off" position are the brake shoe springs and the large one in the master.  If they can't push rusty, cruddy fluid back, then there's bigger trouble coming.

[Jon S]

There should be no brake pedal return spring, but many people added them when the brake pedal would not return to fully released position as opposed to analyzing the problem.  Most times it was an incorrectly adjusted brake pedal push rod which is easily adjusted behind the brake pedal in the passenger compartment.  I used Castrol LMA (Low Moisture Absorption) brake fluid years ago and have been very happy with it.  It's DOT 3 and has kept moisture out of my system.

[gary griffin]

The pedal should return by pressure in the master cylinder created by the springs on each wheel which open the shoes.  If the pedal does not return it could be the fluid as Jon mentioned or corrosion in the mechanical parts prevent the shoes and opening back up.   No fluid can actually keep moisture from the system because every time you pump the pedal you are introducing a little moisture containing air into the system. The average humidity in your area will have an effect on how much moisture you will be taking in.  Low moisture Absorption fluid could reduce the problem and if you use that and live in a location with low humidity you would not have to replace  your brake fluid as often depending on driving habits and amount of driving you do. If you drive your car a lot and have a habit of pumping your brakes and live in a location that has high humidity you will need to change fluid more often.  There is probably a test you can perform to determine fluid absorption but it is probably easier to just change it every few years.

[chevyunger]

Thanks for your replies,
I think the shop added a return spring to the brake paddle.
I will let them change the fluid and brake pad return springs.
What effect has the return spring in the brake master?
How I have to adjust the brake paddle push rod? Is there an explanation in the shop manual?

Thanks
Matthias

[TJ Hopland]

I once saw a car where the anchor pin was slightly loose.  During normal driving it would shift enough to let a shoe drag on the drum.   To get in the guys shop you had to back up and backing up and hitting the brakes would shift it back so it would not drag.  It was always fine when he got it jacked up and checked things.   Took a long time to figure that one out.     

[Dave Burke]

I have found that few things have been a better purchase than a power bleeder!  I drive my '57 a lot and that fluid goes from clear to yellow in a hurry!  Regular bleeding also helps remove some of that crud that builds up in the system as well.  You might also make sure that the brake pistons are rebuilt - it is pretty easy to do yourself with a specially-made kit.  Same goes for the master cylinder.  I noticed that upon rebuilding my two rear pistons, there was a bit of corrosion in there, so I replaced them.  At present, my braking issue concerns the right front grabbing before the rest - something that is not cool on a panic stop!  I figure that I need to take a look at the rears too to make sure that the piston connecting rods are correctly aligned as some wheels seem to generate more brake dust than the others.

Good luck, and remember: being able to stop when you want greatly enhances the driving experience!

Dave Burke

[chevyunger]

Today we tested the car after changing the brake pad return springs and voila .....
We got low temperatures after an half hour test drive. Only the left front wheel is a little hot with about 172 F.
But it's squeaking and only this wheel.
Do you have a suggestion for squeaking drum brake?

Regards
Matthias

[Barry M Wheeler #2189]

You may need to look on your firewall, Years ago, I had a '57 convertible, and had trouble with getting the brake pedal to "return". The leather inside the drum on the firewall had dried out. Application of neats foot oil squirted inside the drum though the inspection hole solved the problem.

[Coupe Deville]

Where is this inspection hole on the booster? I need to add this oil to my 57.

[Jon S]

My '58 has a small removable rubber plug on the top right side of the booster.  Don't know if '57 is the same.  I use an eye dropper to add the oil and then replace the plug.

[Walter Youshock]

They're not.  '57 is a HYDROVAC.  '58 is a TREADLEVAC.

"57 has more in common as far as brakes to a '55.  "56 and '58 had Treadlevacs.  No idea why they tried the Delco design for '56 and went back to the tried and true Bendix for '57.  Also, ALL '57 and '58 Eldorado Broughams have the Bendix Hydrovac.

[chevyunger]

Car is back from the shop. They make a full brake booster overhaul and new brake pads on the hot wheel, but .......

bad braking when car is cold, and heavy pulling to the right whil breaking.

Car goes now into winter sleep and shop get it back in march for the next try :-(

[chevyunger]

Winter is over and the car is back from the shops second try.
They get the booster work and make all brakepads fit to there drums.
Yesterday we had the first trip with 75 mls in one direction and everthing works. The car brakes a little "digital", which means that the rod travel of the brake is short and pedal is relativly hard. And after low brake power you got the full boost.
But the drums dont get hot.

So, season is open.

[walt chomosh #23510]

Bettina,
  Not sure if you replaced the flexable hoses in your system(4ea),but should they deteriorate internally,you can have brakes dragging. This is VERY common on vintage cars.