Fishing for ideas about brake pedal going to floor

[Bill Pressler]

quote:Originally posted by Milaca

If you pump the pedal 2 or 3 times, does the pedal get a better feel or does it still go to the floor?


Brent's rootbeer racer.
MN iron ore...it does your body good.

Yes, after two or three pumps, good pedal height is restored.

Bill Pressler
Kent, OH
'63 Lark Daytona Skytop R1
'64 Daytona Hardtop

[Milaca]

Then it sounds like you have air trapped in the system.


Brent's rootbeer racer.
MN iron ore...it does your body good.

[Dick Steinkamp]

quote:Originally posted by Milaca

Then it sounds like you have air trapped in the system.

...or the brakes are adjusted too slack, or the M/C is leaking internally.


Dick Steinkamp
Bellingham, WA

[63t-cab]

I'm leaning towards what Dick said, "internal leak"

Joseph R. Zeiger

[jclary]

I went back and read (quickly) the replies to the original post. Unless I missed it...no one addressed the possibility of the tiny "breather" hole in the master cylinder cap. If it is stopped up...it can also cause the pedal to go to the floor under certain circumstances. However, the symptoms are usually a bit different. What happens is that if the system can't breathe...the master cylinder can develop a negative pressure...(vaccum)...not allowing the brakes to build pressure. In this scenario...normal pedal will resume as soon as you unscrew the cap to check for fluid. Then it will perform OK for a time until you "pump" it into an additional vacuum. It has confused many mechanics and owners who have overlooked this tiny but important design feature of the braking system.

John Clary
Greer, SC

Life... is what happens as you are making plans.
SDC member since 1975

[studebakerkid]

I put new brakes on a mustang one time for a customer. The master cylinder seemed fine when I drove the car. The vehicles owner did not do the double pump on the brakes that those of us with single stage mastercylinders are accustomed to. When she depressed the pedal it went to the floor she just jave the pedal a gentle press and when I did that the pedal went to the floor too. The cups were no longer flexible enough to hold a seal so I replaced the master cylinder. That ended the problem.

If you car is ugly then it better be fast.....

65 2dr sedan
64 2dr sedan (Pinkie)
61 V8 Tcab
61 Tcab 20R powered
55 Commander Wagon
54 Champion Wagon
46 Gibson Model A
50 JD MC

[hotrodstude]

is the master cylinder new or rebuilt????

2006,f-150,2x4,v-6,5-speed manual,8ft bed, will post stude info when i get it on the road.

[stan zoerner]

I had heard about the breather hole in the M/C, amazing the old tips that folks remember...I had a similar pedal and it was one of the front brake drums was WAY OUT OF SPEC...I was lucky I didn't blow out a wheel cyl.going down a hill..lol

[edpjr]

I had a similar problem with my '66 Commander. A new master cylinder resolved the problem. [^]

edp/NC
'63 Avanti
'66 Commander

[G T Joe]

There is a simple test to determine if you need a master clylinder, this is with a car that has a dual master clyinder you pump up the brake pedal and and see if it fades or goes to the floor you press as hard as you can on the brake pedal for one minute, if you lose the pedal and there are no other leaks in the brake system its is the master clyinder , learned this many years ago from a Delco- Moranne engineer at the GM school of product service.

Joseph Kastellec

[Bill Pressler]

Joe bled again with a mechanic buddy of his when I was out of town, and the pedal is staying up. I then drove the car about eight miles to its winter storage place. Seemed to pull on hard braking, but could be the front end at 103K miles (new wheel cylinders and hoses at each wheel have been installed).

Thanks to all who contributed ideas here and Joe for implementing the fix.

Bill Pressler
Kent, OH
'63 Lark Daytona Skytop R1
'64 Daytona Hardtop

[1962larksedan]

Another quick 'n' dirty test would be to clamp off all three rubber brake hoses then stand on the pedal (NO pumping) with the car sitting still, needless to say. If it no longer bleeds down then you have a wheel cylinder problem. If the pedal [u]does</u> bleed down-----------I would replace the master cylinder if any doubt to its condition.

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[rjohnston79]

Hi, I have a similar problem, so was not sure if I should jump in here or start a new thread. My 1963 Daytona brakes started to act up this fall before I put her away. The brakes worked fine during light braking, but during harder stops (like down a hill - good story to tell there) the braking action suddenly vanishes and the pedal drops right to the floor and does not come back unless pulled up with my foot. It is not a gradual loss of braking, it almost like something "pops" but its fine again after reseting the pedal. Since the car was on its way to seasonal storage when it happened, I have not looked at anything yet, except to say there appears to be no fluid loss anywhere and there have been no new brake parts for 2 years. It's also my first Stude, and my first non-engine related problem. Now for the story: I was heading down a steep hill with a traffic light at the bottom in a 60kph zone. The light turned yellow and I started slowing down when at maybe 50kph the pedal went "pop" to the floor, and I was rapidly closing on the vehicle stopped in front. A quick grab at the handbrake and a hard right into a convienently placed ice cream shop entrance resulted in a safe but dramatic 180 degree stop that Im sure was entertaining for the folks at the shop. My wife was following in the other car, and seemed to think the situation rather comical... hmmm, maybe after a change of underwear =P Any thoughts? When I get a chance I'll try the quick n dirty test above.

Ron Johnston
1963 Studebaker Daytona

[ozarkman]

I would say you probably have a bad master cylinder. When was it last replaced or rebuilt?

You could also have a bad hose that's ballooning under pressure.

From deep in the Ozarks...

Fred

[Milaca]

Ron, do you have power (vacuum assisted) brakes?


Brent's rootbeer racer.
MN iron ore...it does your body good.