rear brakes not working

[jrbarrie83]

The last item before I can get it inspected ... the rear brakes.  My dad and I bled the lines and we are getting fluid all the way to the rear.  Figured to start with the cylinders so I replaced both of those this morning.  I bled the lines and took it out for a test drive.  I did the whole "back up with the e-brake on to adjust the shoes".  It did seem to stop better, however later on I jacked it up and spun the wheel, then put on the brakes ... nothing.  Where should we go from here?  Could it be that I didn't bleed the lines properly?  Shouldn't I still get some sort of reaction?  I mean I stood on the brake pedal and got nothing.  I can't understand why if I am getting fluid all the way to the cylinders why they still aren't working.

Thanks!!
Jim

[blazing816]

Do you front brakes work?? cause if they are bad too, could be master cylinder.

My mechanic buddy has told me with some of the older and long trucks that he has had to put the rear brake lines underwater to get all the air pockets out when bleeding them. He has been doing it for 20 years and has only had to do it 6 times (my truck being one). I have never heard of this before (sure someone else here may know more), but I would trust the man with my life and anytime I get stuck I give it to him. Anyways I do not remember his explanation to me, but it fixed my brakes, so I did not really care.

[jrbarrie83]

Thanks.  Yes, the front work very well.  My dad said to gravity bleed them, which I did not try, so maybe that will be the next step.  How long should I let fluid run out until they are bled properly?

[blazing816]

I always use the "two man" setup (not a fan of the power bleeders), I usually stay by the bleeder and have the Mrs. pump the brake pedal as I tell her. I just watch for if there is any air bubbles in the line, once the air bubbles stopped and I am seeing new clean fluid there usually good to go.

[howlinwolf]

just wanted to throw in, my proportioning valve had stuck, and while i was getting fluid at the rear for bleeding, i was NOT getting pressure. after disassembling the valve, and cleaning it, it works way better.

[jrbarrie83]

Good tips ... thanks!  We're gonna work on it Thursday morning, so if having help bleeding them correctly doesn't fix the problem, we'll take apart the master and go from there.

[zieg85]

In the past to unstick the proportioning valve I've opened up both front bleeders on the calipers and did a "panic stop". Mash on the pedal as hard as you can, then keep it to the floor and tighten up the bleeders.  Try that a couple of times and tap on the valve lightly with a hammer.  As long as you don't let the pedal up you shouldn't get air into the lines.  My $.02  I've never had to replace or take a part a proportioning valve...  Brake fluid is gonna fly and make a mess.  If your paint job is nice you may want to place coffee cans over the calipers when you do this..

[diphthong]

This could all be in the adjustment.   Pardon me but, I've never trusted auto adjuster, they suck.

When you say you 'stayed by the blender' what kind of blender are you using.  Are you using a clear container filled with water and a piece of vacuum or fuel line connecting the wheel cylinder to the water and pumping out all the bubbles?

Your description of your bleeding method sounds like this is the method of bleeding you're using.  Which is the best for home work, I don't think bleeding is the issue.

Reading your bleeding method from your post I can tell this Isn't totally your first rodeo. Taking this into consideration, there seems to be a dichotomy with your description.

1) Fluid is getting  to the rear cylinders in the bleeding process without raising any flags.

2) But the rear brakes don't work.

Don't get me wrong,  this certainly could be a bad proportioning valve, but whenever I see a dichotomy like this, you have to ensure the basics are covered.

And that's what we're going to do:

Jack this sucker up (Safely ) remove the rear tires and drums.  If you can pull the drums off without any resistance from the friction material, the brakes were incorrectly adjusted. 

Now look real close at the inside braking surface of the drums, can see a lip/edge that would indicate the drums have been turned? If these drums have been turned too much this can compound your problem.

                                     *******************
The following is the correct way to adjust your rear brakes on your rig.

Reinstall a drum only and spin it, if there Isn't any drag, remove the drum and spin the adjuster wheel the correct way that expands the the brake linings, do this until the drums goes on needing a slight amount of force. If this takes more the one rotation of the adjuster wheel to accomplish this, we're on the correct path.

Now that the drums are back on with just a little force needed to push them on, reinstall the tire and wheel. At this time the tire and wheel will probably spin freely, Give it a whirl.

Get under your truck, because you just spin the adjuster wheel the correct way that tightens the brakes, you now know the correct direction to rotate it to tighten them more, do it now WHILE spinning the wheel and drum assembly and rotate that adjuster until it almost stops the wheel, then back it up maybe 1/8 - 1/4 turn. If your have new adjuster you may need a skinny screwdriver to pull back adjuster arm to reverse direction of the adjuster star.


After completing this process on both sides. Have another person pump up your brakes, if I was correct you'll now have rear brakes.



I once had a shop owner tell me "it's possible to have just one plug wire crossed"   :-)

[454Man]

X2 on the adjuster. Mine had the same prob. To test out the theory push the parking break little more than half the way down. Now do you have breaks?