Brakes... WTF? - Ranger-Forums - The Ultimate Ford Ranger Resource

General Technical & Electrical General technical and electrical discussion for the Ford Ranger that does not fit in any other sub-forum.

LinkBack Thread Tools Search this Thread
Old 08-07-2007
Thread Starter
Join Date: Aug 2006
Location: Lakewood, CO
Posts: 22
Brakes... WTF?

The scenario:

A few days ago, I started up in the morning and went to pull out of the parking lot. Hit the brakes for the first time and the pedal was spongy. Pumped and tried again, and they caught just fine. Had no further problems that day. Same thing happened yesterday... truck sat at work all day, went to leave and the pedal was really spongy again. For the first 30-60 seconds of driving, the pedal went back and forth from scary-spongy to normal. Then, after that, they were fine all the way home (1/2 hour).

I changed out the proportioning valve about 3 months ago and bled the whole system at that time. I don't see any leaks and the fluid reservoir is still full.

Any ideas on what could cause temporary loss-of-pressure after sitting for 10-12 hours? And why might it start happening out of the blue? Could it just be a really tiny leak somewhere? Thanks!
Reply With Quote
Old 08-07-2007
wydopnthrtl's Avatar
iTrader: (2)
Join Date: Dec 2005
Location: SE, Mi
Posts: 2,342
A hardened seal within the master cylinder is what I'd guess. Or maybe it's simply wore out.

If you can quickly stab the pedal and it bites.. then I'd be very confident that's what is wrong.

btw, Seals failing a month or two after a fluid change is quite normal. Especially if the fluid was old and had debris in it. When you flush the fluid the larger particals get trapped in the seal areas and then act as an abrasive on the seals over the next few months.. then they fail.

The only way to prevent this is to either flush the fluid every couple years since the car is new.. or to never flush it.

I choose the first method.

Reply With Quote
Old 08-07-2007
Needforspeed3685's Avatar
Join Date: Aug 2005
Location: Lowell, AR
Posts: 1,836
My first assumption was air in the lines, but I must agree with Rich on the seal issue.

I have an entire brake system from the Explorer (4WABS) if you need any parts.
Reply With Quote
Old 08-09-2007
Thread Starter
Join Date: Aug 2006
Location: Lakewood, CO
Posts: 22
Okay, thanks. Don't know the service history before I bought it, but I know most people don't put brake-flushing very high on their priority list.
Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Brakes WTF? Ardy General Technical & Electrical 9 10-22-2011 07:45 PM
9" brakes or 10" brakes Runarenis 4.0L OHV & SOHC V6 Tech 12 08-21-2011 11:55 PM
Need to figure out wtf is wrong with my brakes korey89 Drivetrain Tech 21 10-28-2009 12:54 PM
Drum brakes: wtf bad after 19k? swamper06 Drivetrain Tech 21 08-22-2007 05:53 PM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -6. The time now is 12:35 AM.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.