- Joined
- Jul 26, 2010
- Messages
- 461
- Reaction score
- 1
- Location
- Morris County, NJ
- My Car
- 1971 Conv; 1 of 17; 351C, 2V, Auto
This weekend went to a show 50 miles away, mostly highway driving.
When I got off the highway, the brake pedal went almost all the way to the floor, had to pump it in order to stop.
After the show, about 6 hours later, the brakes were fine and drove home.
Again, when I got off the highway I had to pump the pedal to stop.
Took it to the mechanic and he saw no leaks, bled the system and saw no air!
He said the only thing the he said it could be is that the brake fluid might be heating up since one of the tail pipes is close to the rear driver side brake line.
Anyone else experience this type of problem?
Could this be possible? Hot brake fluid causing spongy pedal feel?
the only brake line that would be close to the tail pipe is the rubber line going from the hard line on the drivers side in front of the quarter panel to the axle top brake junction block. if that hose is getting that hot it would be melting and show obvious signs of touching the hot tail pipe.
however behind the mufflers the exhaust temp is much much lower and an air gap between the tail pipe and hose is more then enough to keep the brake fluid from boiling from exhaust heat.
additionally if the rubber hose was expanding that much to allow for a spongy pedal then that rubber line would be showing obvious signs of decay possible weeping of brake fluid and cracking.
no loss of fluid or obvious air would indicate that isn't the problem and you have to go back to the master cylinder failing.
there might be O ring failure inside the bore and some times when you push the pedal it hangs up and allows a leak to occur which doesn't allow pressure build up. you would be able to bleed the brakes still because it would be pushing some fluid still and you can pump up pressure but i would replace the master first.
you could try this,,, with the car parked, push the pedal to the floor and hold it,, if it is leaking internally the pressure on your foot will slowly decrease and you will feel your foot sinking slowly into the floor board that would tell you the master is leaking pressure.
When I got off the highway, the brake pedal went almost all the way to the floor, had to pump it in order to stop.
After the show, about 6 hours later, the brakes were fine and drove home.
Again, when I got off the highway I had to pump the pedal to stop.
Took it to the mechanic and he saw no leaks, bled the system and saw no air!
He said the only thing the he said it could be is that the brake fluid might be heating up since one of the tail pipes is close to the rear driver side brake line.
Anyone else experience this type of problem?
Could this be possible? Hot brake fluid causing spongy pedal feel?
the only brake line that would be close to the tail pipe is the rubber line going from the hard line on the drivers side in front of the quarter panel to the axle top brake junction block. if that hose is getting that hot it would be melting and show obvious signs of touching the hot tail pipe.
however behind the mufflers the exhaust temp is much much lower and an air gap between the tail pipe and hose is more then enough to keep the brake fluid from boiling from exhaust heat.
additionally if the rubber hose was expanding that much to allow for a spongy pedal then that rubber line would be showing obvious signs of decay possible weeping of brake fluid and cracking.
no loss of fluid or obvious air would indicate that isn't the problem and you have to go back to the master cylinder failing.
there might be O ring failure inside the bore and some times when you push the pedal it hangs up and allows a leak to occur which doesn't allow pressure build up. you would be able to bleed the brakes still because it would be pushing some fluid still and you can pump up pressure but i would replace the master first.
you could try this,,, with the car parked, push the pedal to the floor and hold it,, if it is leaking internally the pressure on your foot will slowly decrease and you will feel your foot sinking slowly into the floor board that would tell you the master is leaking pressure.
