cold weather-brake pedal sticks to floor
#1
01-07-2004, 03:56 PM
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cold weather-brake pedal sticks to floor
We have a '94 F150, manual transmission. About a month ago, it got really cold outside, & the truck had been sitting for a few days. I go to drive it, & the brakes are "stuck" (like the parking brake was stuck). I quickly realize that the brake pedal never returned to its normal position, so I lift it with my foot. After driving it 15 miles to the mechanic, the problem disappeared & the mechanic could find nothing wrong.
Today, it is very cold again (Michigan), and the problem is back. The dealership thinks its a brake booster problem, but all of my online research implies that a brake booster problem would result in a brake pedal that is hard to push, not a sloppy pedal that stays on the floor. I should add that the brakes otherwise engage just fine. Any ideas before we go to another mechanic only to be told nothing is wrong? Thanks!
Today, it is very cold again (Michigan), and the problem is back. The dealership thinks its a brake booster problem, but all of my online research implies that a brake booster problem would result in a brake pedal that is hard to push, not a sloppy pedal that stays on the floor. I should add that the brakes otherwise engage just fine. Any ideas before we go to another mechanic only to be told nothing is wrong? Thanks!
#3
01-16-2004, 12:35 PM
Could be a few things.... A stuck valve in the booster could in fact prevent it from returning. If it hasn't doen it since, it could have been a fluke thing... Condensation may have gotten in there somehow... warming it up melted it and viola!
Maybe a piece of grit (or a itty bitty icicle) got lodged in the compensator port on the master cylinder and got caught up on the seal in the bore? ummm... I'm stumped here.... The only other thing I could think of is a weak or broken return spring in the master cylinder (although that should cause it to be bad most, if not all of the time)
-Joe
Maybe a piece of grit (or a itty bitty icicle) got lodged in the compensator port on the master cylinder and got caught up on the seal in the bore? ummm... I'm stumped here.... The only other thing I could think of is a weak or broken return spring in the master cylinder (although that should cause it to be bad most, if not all of the time)
-Joe
#4
02-09-2008, 02:39 AM
94 F150 4x4 Brake Pedal Sticking
I have had the same problem. Two of my children have had the pedal go to the floor and stick resulting in brakes stopping abruptly. They then have to pull it up with their foot. Truck has automatic transmission with about 198K miles and both times this happened just after starting (i.e. still cold). It gets driven nearly every day, so it isn't from sitting. Most recently, it occurred during wet and cold conditions. After driving for a short time, the problem goes away. I have driven it many times and never had any problems myself. Seems very random and brakes otherwise work fine. All parts are in good condition and fluid is topped off. I have worked on and driven many cars and the only other time anything like this occurred was on an old Bronco but was caused by a blown brake line.
Last edited by jriley; 02-09-2008 at 02:41 AM.
#5
02-11-2008, 12:04 PM
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Originally Posted by estimac
We have a '94 F150, manual transmission. About a month ago, it got really cold outside, & the truck had been sitting for a few days. I go to drive it, & the brakes are "stuck" (like the parking brake was stuck). I quickly realize that the brake pedal never returned to its normal position, so I lift it with my foot.
When you got in the truck, was the brake pedal already down and the brakes applied? Or not until you pushed on it? How far down was the pedal? If you push on the brake pedal when this happens, does it return part way but not all the way? Or does it just sit right at the position you push it to?
Something in the system must be adding higher amounts of friction in the cold temperature. The culprits are either the MC, Booster, or Pedal.
The master cylinder is probably fine... all the sliding parts are in the brake fluid so they are lubricated. The booster could be the culprit as it has some seals and other parts that slide and are open to the air. But the boosters are tested at -40 in development so something must have changed to cause the problem. The pedal could also be the issue if it is sticking in the cold temps. That might be the easiest thing to try first... spray the pedal joints with some silicone and see if it fixes it.
DO NOT spray lubricant into the booster (meaning the hole where the pedal rod goes in, or anywhere else). The boosters use EPDM rubber since it is compatible with brake fluid, but it does not play nice with other types of oil and spraying the wrong thing in there could cause major issues.
If the silicone on the pedal joints doesn't do it, you should probably have the booster changed out.
#6
02-11-2008, 07:10 PM
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Originally Posted by mkosu04
Can you provide more details???
When you got in the truck, was the brake pedal already down and the brakes applied? Or not until you pushed on it? How far down was the pedal? If you push on the brake pedal when this happens, does it return part way but not all the way? Or does it just sit right at the position you push it to?
Something in the system must be adding higher amounts of friction in the cold temperature. The culprits are either the MC, Booster, or Pedal.
The master cylinder is probably fine... all the sliding parts are in the brake fluid so they are lubricated. The booster could be the culprit as it has some seals and other parts that slide and are open to the air. But the boosters are tested at -40 in development so something must have changed to cause the problem. The pedal could also be the issue if it is sticking in the cold temps. That might be the easiest thing to try first... spray the pedal joints with some silicone and see if it fixes it.
DO NOT spray lubricant into the booster (meaning the hole where the pedal rod goes in, or anywhere else). The boosters use EPDM rubber since it is compatible with brake fluid, but it does not play nice with other types of oil and spraying the wrong thing in there could cause major issues.
If the silicone on the pedal joints doesn't do it, you should probably have the booster changed out.
When you got in the truck, was the brake pedal already down and the brakes applied? Or not until you pushed on it? How far down was the pedal? If you push on the brake pedal when this happens, does it return part way but not all the way? Or does it just sit right at the position you push it to?
Something in the system must be adding higher amounts of friction in the cold temperature. The culprits are either the MC, Booster, or Pedal.
The master cylinder is probably fine... all the sliding parts are in the brake fluid so they are lubricated. The booster could be the culprit as it has some seals and other parts that slide and are open to the air. But the boosters are tested at -40 in development so something must have changed to cause the problem. The pedal could also be the issue if it is sticking in the cold temps. That might be the easiest thing to try first... spray the pedal joints with some silicone and see if it fixes it.
DO NOT spray lubricant into the booster (meaning the hole where the pedal rod goes in, or anywhere else). The boosters use EPDM rubber since it is compatible with brake fluid, but it does not play nice with other types of oil and spraying the wrong thing in there could cause major issues.
If the silicone on the pedal joints doesn't do it, you should probably have the booster changed out.
#7
02-20-2008, 10:42 AM
Originally Posted by jriley
I have had the same problem. Two of my children have had the pedal go to the floor and stick resulting in brakes stopping abruptly. They then have to pull it up with their foot. Truck has automatic transmission with about 198K miles and both times this happened just after starting (i.e. still cold). It gets driven nearly every day, so it isn't from sitting. Most recently, it occurred during wet and cold conditions. After driving for a short time, the problem goes away. I have driven it many times and never had any problems myself. Seems very random and brakes otherwise work fine. All parts are in good condition and fluid is topped off. I have worked on and driven many cars and the only other time anything like this occurred was on an old Bronco but was caused by a blown brake line.
I had the same thing happen to me the last two cold mornings. When you apply the brakes the pedal seems to "suck" down the floor. I have to control the pedal with both feet to prevent stopping abruptly. Seems like after it warms up some, the problem starts to go away. To me it seems like the valve in the power booster is sticking open. Has anyone changed out a power booster...are they hard to change, is adjusting the pushrod hard? BTW my F150 is a 95 6 cyl with bi-fuel.
Any comments would be appreciated.
Thanks!
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#8
02-29-2008, 07:52 AM
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Originally Posted by njlamber
I had the same thing happen to me the last two cold mornings. When you apply the brakes the pedal seems to "suck" down the floor. I have to control the pedal with both feet to prevent stopping abruptly. Seems like after it warms up some, the problem starts to go away. To me it seems like the valve in the power booster is sticking open. Has anyone changed out a power booster...are they hard to change, is adjusting the pushrod hard? BTW my F150 is a 95 6 cyl with bi-fuel.
Any comments would be appreciated.
Thanks!
Any comments would be appreciated.
Thanks!
