rocketdownunder

Hello all
A couple of days ago i decided to take the 55 for a spin with my 15yo son, cruising along then i gave the old girl a stab on the gas pedal , went to brake and nothing there , brake pedal was hard but i had to really push hard to pull up , it was like the power assist was gone , like trying to brake with motor off, now i know it sounds like the power booster is gone but is there anything else i should be looking for that could be wrong, when brakes were working i could here a hissing noise coming from the booster when i applied the brakes but stopped when i lifted, is this normal , when the brakes failed i can no longer hear the hissing noise, i tried pumping the brakes but no go,any help would be appreciated.
cheers chris.

svnt442

It's the booster. I'll bet it's running a bit rough at idle as well. Pull the line from the booster and cap it and it should smooth out.
I just did the one on my 442 a few months ago.

rocketdownunder

But thats what has me puzzled , the idle hasn't changed , the idle is as smooth as before , the wipers have been converted to electric so i can't use them to see if there is a vacum drop , the weather here has been awfull so i havn't had a chance to take it to my mechanic to check for vacum leaks , just thought i would post on here for other peoples opinions
cheers chris.

AndyBee

Speak of the devil.... i drove my ´56 to my work today, it felt like the pedal was hard and when i drove it during lunch break, the power breaks did not work. I also noticed that the wipers suddenly stopped in the center of the window when i accelerate. Is there maybe a vacuum leak somewhere in the hose that connects vacuum to both the viper and the power brakes? If not, is it the master cylinder thats faulty? How do i know which parts that´s broken? Thanks for your help!

Bluevista

That stopping when you accelerate/low vac is why they got rid of vacuum wipers. I hate them on the freeway, practically fly off the windshield when you decelerate though.
If there's enough vacuum for them to work I doubt low vac is your problem.
Sounds like the booster, check valve or vac line.

Check this out, it tells you how to test the booster and all that.

http://www.classicperform.com/TechBo...oubleshoot.htm

hialeah56

has anyone ever tried one of these? these are for high performance engines so that you could still have brakes.
http://www.summitracing.com/parts/SSB-28146/

rocketdownunder

Got the 55 back today , new shocks , engine mounts, rebuilt master/booster , drives and brakes like new

Lady72nRob71

Great!!!
Go enjoy now!

55miketn

My brakes do the same but I just bought the car and haven't had a chance to explore the problem. I am thinking that , like yours, my vacuum assist is gone.(I replaced all the vacuum lines and clamps and repaired the vacuum tank. Have 15 inches of vacuum at carb. Next step is to tear down the vac. booster and see what problems are there.
I would like to know what wiper motor you used to replace the vac. wipers??
Thanks

rocketdownunder

I bought the car with the electric wiper motor fitted but i do have the reciept it says the item is a W55 description 1955-56 olds 88-98 electric wiper conversion with **** adapter, price was $224 plus shipping this was in sept 2008, the place is Tanson Enterprises, 2508 j street sacramento, CA 95816-4815, phone (916)448-2950 hope this helps, i'll just add the wipers work great and have 2 speeds and return to the normal position regardless when you turn off.
cheers chris.

USAragtops

can't bleed drum brakes on '72 cutlass. pedal goes to floor. there is a hissing sound from booster when pedal applied. bled closest 1st following seq. still nothing. does bad booster have an affect on bleeding ?

droldsmorland

USA... sounds like you have a couple of problems...
The booster is out of the picture with the engine off as far as bleeding goes. However with the car on you shouldn't hear hissing. The boosters shot or the line feeding it is shot or the boot between the master and booster is shot.
You could/likely have air trapped in the master and possibly a leaking wheel cylinder. Check all 4 cylinders. Trapped air will always prevent a good manual (no power bleeder) bleed.

Inspect the soft lines going to each wheel. Replace if older than 20 years old. Its a safety thing.

Invest in a power bleeder. Life is much easier with one. Then you can change fluid bi-yearly as you should. $70 dollar tool for a inexpensive unit. Available as Jegs, Summit.

As for the rest of this post always check the boot seal between the master and assist booster. They fail and give the symptoms of a broken bladder in the booster. $10 part vs $200 part.

USAragtops

Droldsmorland, Thanks for info will do as suggested

Tedd Thompson

15 lbs is on the low side of what is needed. Do you have the second vacuum line coming off the fuel pump attached or a leaky cracked vacuum line there? If not attached your vacuum will run about 15 lbs and can cause the brakes to be rather intermittent on start up and slow to recover if used often like going down a twisty hill.

A quick test of the vacuum booster and check valve can be accomplished by taking the large vacuum hose off the tank end and listen for a sucking sound as you release it. If you have a sucking sound it's not the vacuum tank or booster but probably the check valve. If no sound check farther down the line for leaks or a bad vac booster. Let us know how it works out before you dump a bunch of money into it , vac boosters are not cheap to have rebuilt...Good or bad results let us know this is a common problem with the tredal vac system that is almost 60 years old...Tedd

twintracks

Sometimes a bad master cylinder will leak back into the booster, and ruin the seals in the power brake booster. You might need to replace both.

rustyroger

I think you have a bad master cylinder.

Roger.

Rocketowner

Master cylinder and booster are all in one unit on a '55. You will probably end up rebuilding the whole unit ,but there's a small chance that you might fix it by adding 2 Tablespoons of "100% Neatsfoot oil" through the vent on the top of the unit..Pull the drivers side carpet back, remove the panel in floor board to access the unit, and remove the 2 small screws ,lift the vent and screen.this will give you a straight shot to the leather seal that usually gives the problem. You can buy Neatsfoot oil where horse supplies are sold. Good luck, Larry. Sorry, didn't know this post was 5 years old

twintracks

No worries. My response was to the guy with the '72 Cutlass.