losing breaks in Reverse
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Cargo Master
Joined: Jul 2015
Posts: 3,076
Likes: 21
From: Aransas Pass, Tx
losing breaks in Reverse
Hey guys, I've had kind of a strange issue for the last 6 months or so, off and on. When I'm slowly backing into a parking spot usually with the steering wheel cranked because I drive a truck the size of a school yard, I suddenly lose power breaks and the pedal goes all the way to the floor before engaging. This only happens when at idle and when I'm using power steering.
Also if I am coming to a stop and the engine speed is up, I can feel a difference in the pedal once the engine returns to idle but it only drops a little, not all the way to the floor like backing up situations.
Obvious culprit would be the vacuum system, from pump to manifold to break booster and all the lines in between. I guess my question would be, if the lines and manifold check out ok, would those symptoms be an indication of the booster or pump? I replaced the pump about three years ago but we all know how reliable those things are.
Also if I am coming to a stop and the engine speed is up, I can feel a difference in the pedal once the engine returns to idle but it only drops a little, not all the way to the floor like backing up situations.
Obvious culprit would be the vacuum system, from pump to manifold to break booster and all the lines in between. I guess my question would be, if the lines and manifold check out ok, would those symptoms be an indication of the booster or pump? I replaced the pump about three years ago but we all know how reliable those things are.
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Cargo Master
Joined: Jul 2015
Posts: 3,076
Likes: 21
From: Aransas Pass, Tx
Dangit the only spare of those I have is from the manual truck I parted out in Williston.
I still need to check for leaks anyway... How would I determine what part is defective? I haven't ever had to deal with breaks other than change out calipers and pads.
I still need to check for leaks anyway... How would I determine what part is defective? I haven't ever had to deal with breaks other than change out calipers and pads.
Cargo Master
Joined: Nov 2009
Posts: 2,558
Likes: 19
Start with a vacuum gauge. If the booster is bad it seems like the pedal would go hard. If the master is bad it seems the fluid pressure would be lost.
As a side note. I had a weird brake issue for a while. Some times the pedal would go mushy and I would lose braking power. This was accompanied with a rapid clicking noise, which I never noticed in the panic of trying to stop without incident. I have since bypassed the RABS module under the truck as I thought it was bad. Turns out what ever controls that still freaks put occasionally and clicks like crazy when stopping. It doesn't happen all the time so I am unsure how it decides to pulse the rear brakes.
As a side note. I had a weird brake issue for a while. Some times the pedal would go mushy and I would lose braking power. This was accompanied with a rapid clicking noise, which I never noticed in the panic of trying to stop without incident. I have since bypassed the RABS module under the truck as I thought it was bad. Turns out what ever controls that still freaks put occasionally and clicks like crazy when stopping. It doesn't happen all the time so I am unsure how it decides to pulse the rear brakes.
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Cargo Master
Joined: Jul 2015
Posts: 3,076
Likes: 21
From: Aransas Pass, Tx
It's definitely a loss in fluid pressure not a hard pedal. I'll look into master cylinder symptoms and see if that lines up with what I was feeling.
Anyone have an idea of why I'm only losing brakes when I'm turning the wheel and at idle if it was the master cylinder?
Anyone have an idea of why I'm only losing brakes when I'm turning the wheel and at idle if it was the master cylinder?
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
Jarrett, I was trolling up on the 99 - 03 forum after reading this post. Here is the last post which may or may not be your issue. I did find it interesting though.
Originally Posted by growler 300 power
Before you buy anything, make sure you check your sway bar - especially if the alignment shop replaced the bushings on the axle. If they did, it is possible that the sway bar is contacting one of the calipers when you crank the wheel in reverse. This will upset the caliper on that side and unload the pressure to the pads and make the pedal go to the floor. This same thing happened to me on my old 97 crew cab after I replaced the sway bar to axle bushings. There is just enough free play for the sway bar to hit the caliper in reverse if the sway bar is not centered before tightening the bushing clamps at the axle. This causes great 'pucker' factor to your backside when it happens! Its simple to check, just have someone crank the wheel to the lock position and see if it hits the caliper on either side. Hope this helps you out. Ron
Here is a link to the actual thread ... https://www.ford-trucks.com/forums/1...-radius-4.html
Originally Posted by growler 300 power
Before you buy anything, make sure you check your sway bar - especially if the alignment shop replaced the bushings on the axle. If they did, it is possible that the sway bar is contacting one of the calipers when you crank the wheel in reverse. This will upset the caliper on that side and unload the pressure to the pads and make the pedal go to the floor. This same thing happened to me on my old 97 crew cab after I replaced the sway bar to axle bushings. There is just enough free play for the sway bar to hit the caliper in reverse if the sway bar is not centered before tightening the bushing clamps at the axle. This causes great 'pucker' factor to your backside when it happens! Its simple to check, just have someone crank the wheel to the lock position and see if it hits the caliper on either side. Hope this helps you out. Ron
Here is a link to the actual thread ... https://www.ford-trucks.com/forums/1...-radius-4.html
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Cargo Master
Joined: Jul 2015
Posts: 3,076
Likes: 21
From: Aransas Pass, Tx
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Cargo Master
Joined: Jul 2015
Posts: 3,076
Likes: 21
From: Aransas Pass, Tx
I figured it out... when I installed my sway bar, I accidentally put it a little too far toward the driver's side. This caused it to contact the brake caliper at full lock and do exactly what Jim suggested. Thank you everyone for the help!
Edit: reps attempted and denied.
Edit: reps attempted and denied.
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