Back brakes will not bleed?!
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Freshman User
Joined: Jan 2005
Posts: 31
Likes: 0
Back brakes will not bleed?!
I just changed my master cylinder on my '92 Ranger. I bench bled the MC and installed. I then tried to bleed the back right brake as indicated in the service manual. I couldn't get anything to come out the tube I connected to the tiny bleed valve. Some brake fluid leaked out around the valve, but it wouldn't bleed using the 2 person method. I tried the left back brake and same thing. I then tried the front calipers and they bled okay, although a bit slower than I expected. The truck is stopping fine and the parking brake works. To be honest the truck has 113K and I don't think the brakes have ever been bled. The fluid was quite dark looking. Is there a way to tell if I have a blockage and to clear it out? I guess I could jack the rear and try to spin the wheels to see if the brakes are working.
Elder User
Joined: Jan 2006
Posts: 527
Likes: 1
From: Streamwood,IL
You could do that, or jack it up, and take off the wheel, remove the drum, and use a helper to push GENTLY on the brake pedal to see if you have braking action, particularly the wheel cylinder-that the two little pistons on each side are coming out to work the shoes-if these don't function properly, no brakes..That would be a fairly cheap part to replace if you think your system is clogged up..If your fluid is a dark color, its time to replace it now.....
Laughing Gas
Joined: Aug 2003
Posts: 1,175
Likes: 9
From: So. Cal.
I've had problems bleeding the rear brakes when dirt/rust got into the hole in the bleeder and plugged it. Try removing the bleeder and cleaning the hole out. When you're all finished, be sure to cap it off to prevent future contamination..
Laughing Gas
Joined: Apr 2004
Posts: 819
Likes: 2
From: Northern Maine
What happens when you push on the brake pedal with the bleeder screw removed? Plugged bleeder screws are common, especially if you do a lot of off road driving and/or if road salt is used in your area. I would be very careful about pushing the brake with the drum removed. The wheel cylinder can come apart when there is no drum there to stop the shoes. If your rear brakes don't work, (or if only one works) I would suspect bad wheel cylinders. I have replaced mine twice in 199,250 miles. The front brakes do 80% of the work which could explain why your truck still stops OK.
Senior User
Joined: Jan 2009
Posts: 328
Likes: 1
From: Top Of The World, TN
I'm not sure about the '92's, It sounds like a dirty or defective pressure differential valve. I had one go bad many years ago, due to contaminated fluid, essentially locked up the rear hydraulics.
Laughing Gas
Joined: Apr 2004
Posts: 819
Likes: 2
From: Northern Maine
I very easily could be wrong, but I thought that a proportioning valve was only on front wheel drive vehicles. An old Tempo really gave me a hard time. I had to open the bleeder in the front, opposite to the one in the rear that wouldn't bleed and then have a helper push the peddle half way down (real slow) and hold it there while I closed the bleeder. After that, I was able to bleed the rear brake.
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