Brake bleeding help (long post)

[Matt Harwood]

I'm stumped and hope you guys can help me.

I just put all-new brakes on my '98 Dodge 3/4 ton pickup: calipers, rotors, drums, shoes and rear wheel cylinders. I also replaced one hard line on the rear axle to replace a rusty one that snapped when I tried to remove it. I bled the brakes thoroughly with a friend pumping the brakes the way I always have. He pumps gently 3 times, then holds it. I crack open the bleeder screw until he tells me the pedal is on the floor. He keeps his foot on the floor until I tell him the screw is closed. Repeat until fluid runs clear of bubbles. This has <span style="font-style: italic"><span style="font-weight: bold">always</span></span> worked for me in the past, and was the preferred way to bleed our race car brakes.

The truck, however, continues to demonstrate an incredibly soft pedal. It stops fairly well, but you need to mash the pedal to the floor, and I can't lock up the brakes (not that I want to, but it suggests that there's still some braking power I'm not able to use). I have adjusted the rear drums so that the shoes are just slightly touching the drums. I can hear it and feel slight resistance when I turn the wheels. The parking brake is high and firm and grabs better than it ever has. Brakes are hot after a drive so I know they're working, just not as well as they should and the pedal is mush.

I have been over every inch of brake line and every union looking for a leak. You would think that under pressure, it would show fluid leaking out where the hole was, correct? No signs of leakage anywhere. Am I wrong that a leak would drip when pressure was on the system?

I tried wrapping the bleed screw threads with teflon tape, thinking that they were introducing air to the system when I cracked them open. No change.

I bought a vacuum bleeder today and at 20-25 inches of vacuum, I just slightly crack the bleed screw maybe 1/16 of a turn or less--<span style="font-style: italic">just barely</span>. The fluid in the reservoir bottle of the vacuum bleeder percolates and bubbles, but no fluid comes out. There's clearly air in there somewhere, but with the amount of fluid I've moved through it, I can't imagine where. Opening it further, some fluid comes out, but the bubbles are bigger and more rapid.

I have been through about 8 pints of fluid, and still have the soft pedal. Fluid is obviously being pulled through, but there is still air somewhere in the system. I tried the vacuum bleeder at all 4 corners with the same result. Air is not leaking past the vacuum hose at the fitting because it holds 20+ inches of vacuum pretty well.

The pedal is pretty solid without the engine running, but with boost it goes to the floor. I should note that before I did any work, the pedal was high and solid with no problems. I just wanted new, un-warped rotors.

So what the heck am I doing wrong? What am I missing? This shouldn't be this hard, right? Any advice? Someone want to come over and do this for me because I'm a retard? I'm already 7 days and $1000 into this project--I'll pay you just to get it done! That's money and time I could have spent earning a living and finishing the Buick's engine!

Jeez, I hate this $*ing truck.

[Guest Hal Davis (MODEL A HAL)]

Chalk your drums and see if your shoes are getting full contact or just hitting in one high spot (on the shoe, not the drum) and flexing the rest of the way without contacting. On a vehicle this new, I'd be surprised if that's the problem, but since you've just about exhausted your efforts......

I've also seen brand new drums and rotors that were not true. When you adjust the shoes out, do you get a constant drag or intermittent indicating a drum out of round?

I'm not familiar with a vacuum bleeder except the little hand held deal you put on the bleeder screw and can supposedly bleed them by yourself. I've never had much luck with them. I've seen the same thing as you. All kinds of bubbles. I assume they come in from around the threads of the bleeder screw. I've had much better success bleeding with pressure from the pedal. As long as you don't let off the pedal while the bleeder screw is open, no air can get back into the system from there.

I have emptied the master cylinder with one of those vacuum pumps trying to do it by myself. Sinking feeling knowing you were just about done and now you just sucked air into the sytem up top and have it all to do again. <img src="http://forums.aaca.org/images/graemlins/confused.gif" alt="" />

[Ron Green]

Push and hold the brake pedal down for a minute and see if it slowly creeps down indicating a leak or air. Obviously this is not a ABS system, right? As typically they need to be dealer bled.

Seems like you have tried about everything. Some vehicles as per the manual like you to start with the furthest brake and work to the master cylinder and others the opposite. Try starting with the nearest brake front and work to the longest.

Hopefully your bad luck won't come my way as tonight I am bleeding a brake system.

[Dave@Moon]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Obviously this is not a ABS system, right? As typically they need to be dealer bled. </div></div>

I believe that this truck <span style="text-decoration: underline">at least</span> has rear wheel ABS. My 1996 Ranger has rear wheel ABS standard, with 4 wheel ABS optional. Even Mopar would've progressed to that point by 1998! <img src="http://forums.aaca.org/images/graemlins/smirk.gif" alt="" /> <img src="http://forums.aaca.org/images/graemlins/tongue.gif" alt="" />

It appears that the brakes can be bled with ABS without using special equipment. I found this 1994 procedure on dodgeram.org for bleeding ABS brakes. It may have changed by 1998, however. Note that there are three additional valves that need to be bled <span style="text-decoration: underline"><span style="font-weight: bold">before</span></span> bleeding the wheel cylinders and calipers. Also note that the <span style="text-decoration: underline">rear</span> brakes are bled first.

The dodgeram.org web site has much more in terms of techcinal information and procedures for this truck. You may want to peruse it a while! <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" />

Good luck!

[Pontiac59]

My 1989 Chevy Suburban has a proportioning valve that basically cuts off the rear system if it detects that there's no pressure due to a leak - it's just about impossible to bleed it using the pedal and not kick that switch over. To reset it you have to equalize the pressure on the other side of the system.

It could be your brakes have a similar type of problem, it feels like your bleeding is working but if the valve kicks over and cuts off the rear brakes, you won't get all the air out of it. The vaccuum pump however should take care of it. Must be the ABS requires some other proceedures to go with it.

Monro Muffler will bleed brakes for like $20 - well worth not having the headache if you ask me - I would have done same on this Dodge had I had this problem with it.

[Ron Green]

Dave,

From what I've read regarding bleeding ABS brakes and from speaking to several friends who own service stations, they sometimes require special methods, equipment, computer reprogramming, etc. They won't touch them.

I'm happy to report my brake bleeding went well last evening and the wife (pumper) and I are still on speaking terms. She is actually getting really good at this. Pump, pump, pump, holding, floor...................... <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[Matt Harwood]

Well, I just got back from AutoZone where I've been purchasing all these parts to buy a new brake line. I had put a small loop in the one I bent myself to make it shorter rather than cutting and flaring it, and thought perhaps air was trapped in the loop. While I was there, they called up my name in the computer and it listed a 1996 Chevy 3500 pickup on my list of vehicles. I don't have a Chevy (though I'm seriously considering getting one to replace the Dodge), so I had them look at what I'd bought for it. You guessed it:<span style="font-weight: bold"><span style="font-style: italic"> wheel cylinders.</span></span> The Dodge wheel cylinders are 15/16" and the Chevy are 1-3/16" a difference of 1/4"--about 25% too big! So I'm going to put them on and that SHOULD solve the problem. That just <span style="font-style: italic"><span style="font-weight: bold">has</span></span> to be it.

I'll let you know, and I appreciate all the helpful tips. I always know I can rely on you guys here to help me out. I thought I was going insane, and the Dodge came dangerously close to getting a wrench in its windshield.

Thanks!

[joe_padavano]

Larger wheel cylinders won't cause a soft pedal, but they will require additional fluid which will make the pedal travel further. Of course, at some point it should still be rock hard. I'm almost certain your truck has ABS, which does require a special bleeding process.

[Matt Harwood]

Well, with the new cylinders in place, the situation has definitely improved. The smaller brake cylinders have made about an 80% improvement in pedal feel, and it engages much higher now. I cheated when bleeding them this time since I was alone, and simply stuck the hose in a bottle of brake fluid and pumped the pedal several times with the valve open. A real bleed should improve it more.

Joe, I hear what you're saying. I agree--the larger cylinders merely need more fluid, but when the master cylinder isn't capable of delivering sufficient volume under pressure, you get a mushy pedal. I guess it stopped pretty well, but with the pedal on the floor with no more travel. That felt wrong and probably wasn't safe.

As far as bleeding it with ABS (it has rear wheel ABS, though I've never felt it working), I shouldn't have needed any special procedures. The system was never open sufficiently to let any air into the ABS apparatus. A majority of the system always had fluid in it. I also think some of that special procedure for ABS brakes is hogwash--we bled the brakes on C5 Corvettes all the time, and they had complex ABS and traction control systems located in the back of the car by the rear axle. Never had a problem bleeding them using the pedal method. I honestly don't think that was the problem.

Anyway, the pedal is much better. Stopping power hasn't improved and I still can't even spike the brakes into lock-up (not even the unloaded rears), but I'm going to let the pads and shoes bed in for a few days, bleed the brakes again, then evaluate. Also, I should probably remember that it has pretty big tires, the pavement is dry and it is a 6500 pound truck and not my little Mazda Protege5--of course the brakes won't be as sharp.

Thanks for all the help, guys. Looks like my problem was a simple part number mix-up at the parts store. To think I wasted 3 days chasing my tail when it was right there in front of me. Feh.

[Guest Skyking]

Matt, for what it's worth, try putting a 2X4 on the pedal overnight wedged under the dash. This will keep pressure on the system overnight and will help pull all the air out. I learned this trick owning Metropolitans with the British Girling brake system. It's the only thing that gets the stubborn air out.

[Ron Green]

Quote; "came dangerously close to getting a wrench in its windshield."

Did that many years ago with my Corvette when I was extremely frustrated with something not going right for the 5th time.

Bounced a wrench off the hood of a fairly fresh paint job which required a repaint. Not one of my better ideas! Definitely costly, but sort of felt good at the time.

[Matt Harwood]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Bounced a wrench off the hood of a fairly fresh paint job which required a repaint. Not one of my better ideas! Definitely costly, but sort of felt good at the time. </div></div>

Every so often I make an example of one of my tools/cars/machines. Publicly destroying one in anger demonstrates to the others that they ought to behave. I find this is especially necessary with weed whackers. <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[MCHinson]

Sorry, but your quote of "Every so often I make an example of one of my tools/cars/machines. Publicly destroying one in anger demonstrates to the others that they ought to behave. I find this is especially necessary with weed whackers."

reminds me of this joke............ I can't help myself..... <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

David received a parrot for his birthday. This parrot was fully grown with a bad attitude and worse vocabulary. Every other word was an expletive. Those that weren't expletives were, to say the least, rude.

David tried to change the bird's attitude and was constantly saying polite words, playing soft music, anything he could think of to try and set a good example. Nothing worked. He yelled at the bird and the bird got worse. He shook the bird and the bird got more angry and more rude.

Finally in a moment of desperation, David put the parrot in the freezer. For a few moments he heard the bird squawking and kicking and screaming then suddenly there was quiet. David was frightened that he might have actually hurt the bird and quickly opened the freezer door. The parrot calmly stepped out onto David's extended arm and said: I'm sorry that I might have offended you with my language and actions and ask for your forgiveness. I will endeavor to correct my behavior.

David was astounded at the bird's change in attitude, and was just about to ask what had made such a drastic change, when the parrot continued:

"Now, if I may ask, what did the chicken do?"

[Guest imported_DaveZZZ]

There's an old Chinese saying:

Sometimes you have to kill one of the chickens to keep the monkeys in line.