More brake problems
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Junior User
Joined: Apr 2004
Posts: 61
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More brake problems
OK, here's the low down:
86 F250 4x4 6.9. Brakes were questionable when I bought the truck a few months ago. Finally had the time to dig into them and found that the rear brakes weren't working right. Both auto-adjuster cables were snapped and one of the wheel cylinders was leaking. Replaced both wheel cylinders and bled the system. (Actually, I only bled the rears as the book said that if I only allowed air into the rear, then I shouldn't need to bleed the whole system. OK, so I'm lazy...)
I got the auto adjuster kits and replaced the cables, adjusters, spring and ratchet-thingy. Everything appears to work as it should. I allowed the self-adjusters to do their thing by backing up and stopping hard. They seem to work OK and have stopping power, sometimes enough to lock up at full speed if I stop hard enough.
However, the pedal has an intermittent soft feel to it, even though it seems to work, but, even when the pedal feels firm, it always goes to the floor.
Last night I was digging back into it again and found that when I disconnected the brake booster that the pedal always felt firm like it should, but, of course, takes a bit of effort to stop. I replaced the vacuum line, hoping that might be the cure, but there was no change.
So, I guess I could bleed the front brakes to see if there is any trapped air. I've been reluctant because one of the bleeders are snapped off, so I have to fix that too.
Is there any way to test the booster to see if that is the problem? Could a bad vacuum pump cause the issue? How much vacuum should be at the booster?
Thanks.
86 F250 4x4 6.9. Brakes were questionable when I bought the truck a few months ago. Finally had the time to dig into them and found that the rear brakes weren't working right. Both auto-adjuster cables were snapped and one of the wheel cylinders was leaking. Replaced both wheel cylinders and bled the system. (Actually, I only bled the rears as the book said that if I only allowed air into the rear, then I shouldn't need to bleed the whole system. OK, so I'm lazy...)
I got the auto adjuster kits and replaced the cables, adjusters, spring and ratchet-thingy. Everything appears to work as it should. I allowed the self-adjusters to do their thing by backing up and stopping hard. They seem to work OK and have stopping power, sometimes enough to lock up at full speed if I stop hard enough.
However, the pedal has an intermittent soft feel to it, even though it seems to work, but, even when the pedal feels firm, it always goes to the floor.
Last night I was digging back into it again and found that when I disconnected the brake booster that the pedal always felt firm like it should, but, of course, takes a bit of effort to stop. I replaced the vacuum line, hoping that might be the cure, but there was no change.
So, I guess I could bleed the front brakes to see if there is any trapped air. I've been reluctant because one of the bleeders are snapped off, so I have to fix that too.
Is there any way to test the booster to see if that is the problem? Could a bad vacuum pump cause the issue? How much vacuum should be at the booster?
Thanks.
Senior User
Joined: Feb 2006
Posts: 111
Likes: 0
can you here a swoshing noise when you pump the pedal with the truck off it maybe the brake booster might want to try and blead the fronts at the banjo fitting on the caliper if you cant open the bleeders i have had a similar problem and replaced the booster
Fleet Owner
Joined: Sep 2005
Posts: 28,609
Likes: 18
From: Lake Tahoe, Nevada
[QUOTE=briansrapier]
However, the pedal has an intermittent soft feel to it, even though it seems to work, but, even when the pedal feels firm, it always goes to the floor.
ALWAYS GOES TO THE FLOOR? I'b be changing the master cyl/ booster assembly, pronto.
However, the pedal has an intermittent soft feel to it, even though it seems to work, but, even when the pedal feels firm, it always goes to the floor.
ALWAYS GOES TO THE FLOOR? I'b be changing the master cyl/ booster assembly, pronto.
