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turkey50
New User
Jul 13, 2008, 10:51 AM
Post #1 of 8
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I am having problems with my brakes on a 2004 ford ranger edge. The brakes go from hard to soft. The fluid levels are fine, and the brake pads are fine. Could it be the brake booster or the master cylinger? And if you replace one should you replace both? Need some advice on this one.
Thank you
George
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jayeffel
User
Jul 13, 2008, 10:57 AM
Post #2 of 8
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Re: brake problems
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Were the brakes worked on recently? There could be air in the lines that needs bled off.
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turkey50
New User
Jul 13, 2008, 3:43 PM
Post #3 of 8
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Re: brake problems
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No, they are the original brakes
George
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jayeffel
User
Jul 13, 2008, 6:14 PM
Post #4 of 8
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Re: brake problems
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might check the brake pads and disks if original, check brake lines for cracks/leaks; though the level would drop in the master cylinder if a leak was there. Other than that I can't guess.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 13, 2008, 7:49 PM
Post #5 of 8
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Re: brake problems
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Hmmm? This is probably vacuum boosted - right? Kind of new for a failed booster but there could be a problem with vacuum supply to it or a check valve commonly used on the booster.
Master cylinder could have a problem also but I don't think it would be as likely to be intermittent as the vacuum boost could be,
T
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turkey50
New User
Jul 14, 2008, 2:59 AM
Post #6 of 8
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Re: brake problems
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is the check valve on the brake booster the plastic peice on top of the booster canister ?
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 14, 2008, 5:52 AM
Post #7 of 8
(1500 views)
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Possible Vacuum Power Assisted Brake Problem
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That's just a generic pic of a typical check valve. This shown is right angled from hose to plastic light or dark color possible with a VERY sticky barbed spout into grommet in the metal housing. They could easily break just removing one for whatever reason and I think I've replaced them when broken physically rather than when the "check" valve operation was faulty. The deal with this style is the engine or some use a pump for source of vacuum thru that hose which must be without leaks AND to a good source usually intake manifold vacuum which is not it highest at all times. High at idle times with low engine load and about no available vacuum during accelleration to the check valve saves the best it had since your last braking when it uses it and tha vacuum needs to be replenished for next use of brakes.
They are designed to give you a couple assisted stops when the source of vacuum ceases as in a stalled engine, repated pumping has a little extra time for you till it recharges too.
There is a diaphragm in there that can leak, the valve might not be "checking" (flow should be ONE way only) so could have the feel of power brakes intermitently as well as if source is weak or leaking it could be painfully slow.
Test: When engine is off just press brake pedal. It should be assisted and you feel that it's softer. Just rehit brakes a few times and it'll feel like it's just a brick on the floor - that would be normal with engine off. You still have braking action but without assist.
Many can hold assist in reserve overnite or indefinately but all should hold for minutes at a bare minimum.
Pump a pedal lightly till it feels stuck hard with engine off and while maintaining pressure start engine and you should feel the assist and pedal will sink a bit more -- that would be normal and a test also.
______________
Sorry for the book - Another scenario is the habit of "left" foot use dragging on brake which if you were under load with engine such as pulling a trailer or driving a long incline the reserve would be lost as engine vacuum is minimmal under load and then if you requested brakes it might not have much or any assist waiting.
There could be other mechanical or hydraulic problems but it's more likely an assist problem IMO,
T
(This post was edited by Tom Greenleaf on Jul 14, 2008, 5:59 AM)
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turkey50
New User
Jul 14, 2008, 5:45 PM
Post #8 of 8
(1492 views)
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Re: Possible Vacuum Power Assisted Brake Problem
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Tom,
Thank you for all your help it was the master cylinder, we replaced it and bleed the brakes really well, now all is working just fine.
Thank you for all your help once again. 
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