Brake issues
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Senior User
Joined: Aug 2007
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From: Ontario, Canada
Brake issues
My son has a 97 F-150 and we just replaced all the lines,master cylinder, brakes and front calipers now we have a bleeding issue.
Bled the brakes several times but pedal still goes to the floor
it does have rear abs is this the culprit.
Thanks for any advice
Steph
Bled the brakes several times but pedal still goes to the floor
it does have rear abs is this the culprit.
Thanks for any advice
Steph
Elder User
Joined: Mar 2010
Posts: 601
Likes: 0
It really helps, with that much air to remove, to use a vacuum pump. I've used a Mityvac for 30 years. They are pretty inexpensive.
Aside from that, I assume you did bench bleed the master cylinder ? If not undo the lines and do that first. Second, did you remove the old parts before you went shopping, and take the calipers for the core charge ? If so, it's possible that the two front calipers are on the wrong wheels. They can be reversed, as they do look the same. The difference though, is the location of the bleeder screws. When the calipers are in the correct locations, the bleeder screws will be at the top. Installed on the opposite wheels, they will be at the bottom, and you will NEVER get all the air out.
After checking the above, and hopefully using the vac pump, start the truck and let it run for 5 minutes or so, and replenish the vacuum level in the booster. You should have usable brakes. If not, check all line/fittings.
One other thing to check. If you have RABS, and they are drum brakes, adjust the shoes to almost touching the drums. If they are still backed way off from the installation, it can take a lot of pedal to push them out very far, and in some cases, pop a cylinder piston nearly out of the bore (enough to leak fluid.)Dave
Aside from that, I assume you did bench bleed the master cylinder ? If not undo the lines and do that first. Second, did you remove the old parts before you went shopping, and take the calipers for the core charge ? If so, it's possible that the two front calipers are on the wrong wheels. They can be reversed, as they do look the same. The difference though, is the location of the bleeder screws. When the calipers are in the correct locations, the bleeder screws will be at the top. Installed on the opposite wheels, they will be at the bottom, and you will NEVER get all the air out.
After checking the above, and hopefully using the vac pump, start the truck and let it run for 5 minutes or so, and replenish the vacuum level in the booster. You should have usable brakes. If not, check all line/fittings.
One other thing to check. If you have RABS, and they are drum brakes, adjust the shoes to almost touching the drums. If they are still backed way off from the installation, it can take a lot of pedal to push them out very far, and in some cases, pop a cylinder piston nearly out of the bore (enough to leak fluid.)Dave
Thread Starter
|
Senior User
Joined: Aug 2007
Posts: 155
Likes: 0
From: Ontario, Canada
It really helps, with that much air to remove, to use a vacuum pump. I've used a Mityvac for 30 years. They are pretty inexpensive.
Aside from that, I assume you did bench bleed the master cylinder ? If not undo the lines and do that first. Second, did you remove the old parts before you went shopping, and take the calipers for the core charge ? If so, it's possible that the two front calipers are on the wrong wheels. They can be reversed, as they do look the same. The difference though, is the location of the bleeder screws. When the calipers are in the correct locations, the bleeder screws will be at the top. Installed on the opposite wheels, they will be at the bottom, and you will NEVER get all the air out.
After checking the above, and hopefully using the vac pump, start the truck and let it run for 5 minutes or so, and replenish the vacuum level in the booster. You should have usable brakes. If not, check all line/fittings.
One other thing to check. If you have RABS, and they are drum brakes, adjust the shoes to almost touching the drums. If they are still backed way off from the installation, it can take a lot of pedal to push them out very far, and in some cases, pop a cylinder piston nearly out of the bore (enough to leak fluid.)Dave
Aside from that, I assume you did bench bleed the master cylinder ? If not undo the lines and do that first. Second, did you remove the old parts before you went shopping, and take the calipers for the core charge ? If so, it's possible that the two front calipers are on the wrong wheels. They can be reversed, as they do look the same. The difference though, is the location of the bleeder screws. When the calipers are in the correct locations, the bleeder screws will be at the top. Installed on the opposite wheels, they will be at the bottom, and you will NEVER get all the air out.
After checking the above, and hopefully using the vac pump, start the truck and let it run for 5 minutes or so, and replenish the vacuum level in the booster. You should have usable brakes. If not, check all line/fittings.
One other thing to check. If you have RABS, and they are drum brakes, adjust the shoes to almost touching the drums. If they are still backed way off from the installation, it can take a lot of pedal to push them out very far, and in some cases, pop a cylinder piston nearly out of the bore (enough to leak fluid.)Dave
My son had the calipers on the wrong the side bleed the brakes again and (voila) we have solid pedal. I should have notice it myself.
Thank you for making me have a second look.
Elder User
Joined: Mar 2010
Posts: 601
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Good deal, glad it was easy. You might want to bleed the system again after using the truck a few times. Minor amounts of air can be trapped in the RABS unit, and may find their way out eventually. Hard to tell sometimes, because the front brakes do most of the stopping.
Dave
Dave
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