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Scott Shepherd
06-24-2015, 6:58 PM
I have an older Ford Explorer and it sat for a while. I went to drive it in the snow and the brake pedal went to the floor as I backed out. In looking, it left a line of fluid on the ground. I parked it and it sat for 2-3 more months until I had time to deal with it. The rear metal line was corroded. I bought a new line, replaced it, bled the brakes and had no pedal at all. Worked on it for a while, on and off, bleeding over and over and over. Still no pedal. Figured the calipers were seized up anyway, so bought new hydraulic lines and new calipers and pads. Installed new hydraulic lines, new calipers, new pads, bled the brakes about 5 or more times. No pedal. Well, I say no pedal, but which the truck off, I get pedal, as soon as start it, the pedal goes all the way to the floor and I literally don't have any brakes, other than the friction on the pads themselves.

Figured it was only two real pieces left, the master cylinder and the brake booster, and it's my understanding that the brake booster just makes the pedal easier to push, so I put a new master cylinder on. Bench bled it, installed it, still no brakes.

I have one of those pressurized canisters that you put on the master cylinder and it allows you to bleed the brakes by yourself and really well, and when that's hooked up, I'm not losing any pressure on the top side of things. No air appears to be coming out. I've pushed about 2-3 quarts of fluid through it all and still, no brakes.

I've asked a number of people a lot smarter than me about it and everyone seems to be stumped. I've googled over and over and have yet to find a solution.

Could I just be missing an air pocket somewhere? Wouldn't I at least have some pedal?

Any ideas?

Pat Barry
06-24-2015, 7:20 PM
WHen you say that you pushed fluid through it, do you mean all the way through and out the bleed ports at all the brakes? Because all the brake lines need to be full of fluid

Scott Shepherd
06-24-2015, 7:27 PM
Oh yeah, I've pressurized it with the tank thing, and then bleed the lines until it's nothing but clean, new fluid coming out the lines, no air, starting in the back passenger side, then the back driver, then the front passenger side, finishing with the front driver's side, as per the instructions for this vehicle.

Pat Barry
06-24-2015, 7:59 PM
I'm no mechanic by trade, more of a shadetree mechanic, and what you did all makes sense. I did a quick search and found this video on you tube (https://www.youtube.com/watch?v=GrFEzfDnzqM). Maybe the adjustment to the pushrod will fix ya

Tom M King
06-24-2015, 8:07 PM
You did pump the pedal?

Philip Johnson
06-24-2015, 8:20 PM
I'm not sure how ford brakes work but I had the same problem on a vw after replacing calipers. The rear calipers are adjusted by operating the parking brake. Every time you operate the parking brake it would ratchet the caliper piston in a bit to take up the excess gap. Without the proper adjustment there was too much gap between the pad and rotor for the brake pedal to fully set the brake. I also had gotten a bad rebuilt caliper that the adjuster did not work once I replaced bad caliper and adjusted rear adjusters only took a few pumps to bleed them. Did your rear brake calipers have the Pistons that you have to screw back in?

Scott Shepherd
06-24-2015, 8:41 PM
You did pump the pedal?

You don't have to with the pressurization tank auto bleeder. You take the top off the master cylinder and put this device on it that seals. Then it has a pump up tank that the fluid is in and you pump it up until it has 15 lbs of pressure on it, which mimics pumping the brakes.

Phillip, it's 4 wheel disc brakes, I don't believe there is any adjustment like that.

ken masoumi
06-24-2015, 10:14 PM
You don't have to with the pressurization tank auto bleeder. You take the top off the master cylinder and put this device on it that seals. Then it has a pump up tank that the fluid is in and you pump it up until it has 15 lbs of pressure on it, which mimics pumping the brakes.

Phillip, it's 4 wheel disc brakes, I don't believe there is any adjustment like that.
But it sounds like you couldn't pump the brakes even if you wanted to since the pedal is stock( all the way down) to the floor.

Tom Stenzel
06-24-2015, 10:32 PM
You don't have to with the pressurization tank auto bleeder. You take the top off the master cylinder and put this device on it that seals. Then it has a pump up tank that the fluid is in and you pump it up until it has 15 lbs of pressure on it, which mimics pumping the brakes.

Phillip, it's 4 wheel disc brakes, I don't believe there is any adjustment like that.

The S series Saturns with 4 wheel disk brakes had a parking brake system similar to the VW. Scott, If your Explorer is anything like the one my supervisor had it's not like that at all.

Somehow I have a feeling that the ABS pump/system is messing with you. It does have ABS, right? If not the only thing I can come up with is one of the bleeders isn't in a high point and leaving a pocket of air in the caliper after you've "bled" it.

I saw that happen on a Dodge van once, when a caliper was replaced with the wrong one and that placed the bleeder in a low spot. Take a good look at the caliper pistons and the location of the bleeders, making sure all pass the smell test.

-Tom

Lee Schierer
06-24-2015, 10:33 PM
If the cylinders in the calipers have been pushed back into their housing and are not touching the rotors after you were done bleeding the system, when you step on the pedal, it will go all the way to the floor until you pump enough fluid into the system to push the cylinders out so the pad touches the rotor for all eight cylinders and pads.

If you have a leaking cylinder it will do the same thing as a ruptured break line.

Mike Lassiter
06-24-2015, 11:41 PM
pressure bleeding works great especially for only one person, however you can still have an air pocket in the master cylinder that cannot be pushed through the lines and out a bleeder. Air can get trapped where it cannot be worked out with just the pressure bleeder. Work the pedal slowly down with the pressure bleeder connected. Fully down to the floor maybe a couple of times with a bleeder screw cracked open slightly. This will let the master cylinder push any trapped air into the lines so it can be pushed on out. Even better if you might have one is the master cylinder bleeder that has a vinyl hose on a plastic threaded fitting to bleed the master cylinder. Typically get these with a replacement master cylinder to bleed it before hooking the metal lines back to it. I have saved most over the years because they are sometimes handy for stuff like this. Disc brakes are unforgiving of any air in the system.

Scott Shepherd
06-25-2015, 8:10 AM
Thanks for the suggestions. I'll look into those. What I can't understand is why, with the truck off, I have good, solid pedal, but once I start it, then the pedal goes to the floor. It was have ABS, but it appears that most advice says if the ABS light isn't on, or throwing a code (which it isn't), then the ABS part is fine and you should just bleed it. We suspect that it's still air trapped in there somewhere, and I've heard a number of stories like this where people have really fought hard to get the air out and some times, they can really be difficult to get out.

I'll take a couple more passes at it and see what we can do, but I still don't understand why I have pedal without it on, but no pedal with it on.

Mike Lassiter
06-25-2015, 8:45 AM
I know what you are talking about, and you get a similar result from most vehicles that use vacuum booster for the power assist. Once the vacuum reserve gets depeleted the pedal will become harder to push and not push down as far. Starting the engine while holding the pedal down and vacuum gets restored the pedal will again go down further.
I don't know what magnitude the vacuum booster increases the applied pressure versus without, but consider several rubber hoses that can swell slightly from the much increased pressure when booster is working. Any air will compress and create a spongey feeling pedal. If I remember right it is common for the rear most section of the master cylinder to be a problem if any air is still in it.
If it works right brake fluid in that section will push the piston forward for the front section. Should there be a leak in the back section (or air) then that piston will move forward when the pedal is pressed until it actually contacts the front piston and mechanically push the front piston rather than hydraulicly pushing it. That causes a much lower pedal than normal, but is apart of the design of the split system as opposed to the older systems that had only one line on the master cylinder. In them if a hose ruptured ANYWHERE or fluid loss you lost ALL braking. The dual system splits the system into two seperate systems so if you loss fluid on one half the other will still provide some brakes.

Mike Lassiter
06-25-2015, 9:02 AM
this will help explain my post and shows a cross sectional view of a master cylinder and also points out another possible problem - but I'm not sure if it would apply since you are using a pressure bleeder it would push the rear piston back I would think.

From Federal Mogul: http://www.federalmogulmp.com/en-US/Technical/Documents/Installation%20-%20No%20Pedal%20After%20New%20Master%20Cylinder%20 Installation.pdf

Curt Harms
06-25-2015, 9:03 AM
I'm with Tom re the ABS system. If the pedal doesn't bottom with the power off but does bottom with the power on, what changed re the brake system? Electric and vacuum. Is there a fuse you could pull on the ABS and see if that helps?

Scott Shepherd
06-25-2015, 9:12 AM
Yes Tom, all new calipers are on the right wheels, so the bleeder screws are all at the tops of their respective calipers.

Mike, I have verified that the piston isn't sticking, the piston was against the snap ring as shown in the document you posted, when I took it off to double check it the other day. I think it's just air trapped in there somewhere and it's being a pain. I'll keep working at it and see if I can get it out.

Mike Lassiter
06-25-2015, 9:23 AM
Scott the cross section view sort of illustrates what I was trying to say about having 2 pistons inside. Air in the rear section will cause a low pedal because it prevents the fluid from pushing the front section forward as normally. I have literally pulled my hair out trying to work air out of hydraulic clutch systems on diesel pickups in days past. Often would have to reverse bleed them to push the air up from the slave cylinder back toward the clutch master cylinder. Sometimes you struggle for hours then suddenly it works the air out and everything is good.

I think you're pretty sharp, and will get it sorted out. It seems some times things just refuse to do right. Perseverance will pay off - eventually.;)

Bill Orbine
06-26-2015, 8:00 AM
It does sound like you have an air pocket. Little pedal with engine off, no pedal running. Breaks are very weak. You've left the vehicle sitting for months without repair. Dripping away. You should bleed at all wheels. And in some cases, actually with two things in mind, bleeders may not be at the highest point of calipers AND there are more than one bleeder per caliper. With bleeders not at the highest point, you might need to remove calipers to orient the bleeder to "highest point" to remove trapped air. In the case of more than one bleeder per caliper, there may be another on other side of rotor... generally tends to be true sometimes in sporty vehicles.

Russ Ellis
06-26-2015, 10:10 PM
Some ABS systems require the system to be cycled by a diagnostic computer or other service tool. I would guess anything made in the last decade falls into this category.

Mike Lassiter
06-30-2015, 6:23 PM
So Scott, do we have brakes yet? You have sort of left us hanging.;)

Scott Shepherd
06-30-2015, 6:30 PM
Why yes, yes I do! I took it to a shop and after 2 hours, they said they had no idea either. They called later on and said that the front calipers were on the wrong wheels and air was trapped in one of them. I know that's not true because I was well aware of making sure they were on correct, they even had different part numbers, and I bought the entire assembly. I removed and replaced one, then removed and replaced the other. I know where the bleed valves were because I even commented to someone helping me that I had to watch out because it was going to shoot right at my eye when I cracked it loose, and I was kneeling at the side of the truck when I said that.

I suspect they found something really simple and didn't want to admit to it, but that's just my guess. I have no way to prove I had them on there right, but I know with 100% certainty that they were on there correct. Whatever they found, it fixed it, so I'm good to go now.

Thanks for the input. I guess we'll never know what the issue was, other than air in the system somewhere.

Mike Lassiter
06-30-2015, 6:46 PM
there would be no shame in my book if it was something simple and they found it. As you stated, it WAS air causing it! The thing of it all that bothers me, (and it's happened to me over the years too) is KNOWING you did what you did right, then have someone basically imply you are an idiot and put something on totally wrong and didn't have enough sense to know any better.

Some years ago (decades) I worked with a GM FACTORY TRAINED mechanic. He did a front brake job on a car. Pulled rotors and machined them, then new set of brake pads. We all test drove EVERY job when finished. He returned from his test drive and told me every time he pushed the brake pedal down to stop, he heard GRINDING noise. Like metal to metal he said. Couldn't guess what it might be. Then he pulled BOTH front wheels back off to find he had installed BOTH SIDES of the brake pads backwards. Metal backing plate against the rotor and friction lining against the caliper. He was more than a little embarassed.
I think had they really "found" you installed the caliper wrong, they would have called you and told you they found the problem. Come down and see for yourself, before we correct it. That they told you and didn't report it before they supposedly corrected it makes me think that wasn't what happened.
But regardless, "we've" got brakes.

Scott Shepherd
06-30-2015, 7:02 PM
Yeah, I thought a call would have happened too, considering the place is about 100 ft from here. I can see it from our front door, and I drove it there with no brakes, it's literally that close to us. If I had a rock, I could hit their window from here, yet, no call. When I walked over at lunch to check on it, they said it wasn't ready and they were stumped. Then they told me they thought it was a bad master cylinder. I said "It's brand new. Not even a remanufactured, it's brand new, I just put it on there". They said "Well, we think that might be bad". I said "If that new one is bad, then the old one was bad too, because it did the same thing with the old one as it's doing with the new one, and that's got a lifetime warranty on it, so if it's bad, I'll drive 3 blocks and get a new one and be back in 30 minutes". Then they said "Well, if it did the same thing, then that's probably not it, we'll find it".

Needless to say I wasn't too happy when I rolled into a $261 bill for it. Oh well, it's done, I have brakes, and I got all the calipers and pads from Rock Auto for about $140 for all 4 wheels, so all in all, I'm still money ahead if I had taken it to have it done from the beginning.

Phil Thien
06-30-2015, 7:04 PM
I don't know anything about brake calipers but I'm surprised that if they're specific to a side, that they can be installed on the wrong side. I'd have figured the auto manufacturers would have made it impossible to install them on the wrong side by changing a bolt hole pattern or something like that.

Interesting story thought and I'm glad you got it fixed.

Bill Orbine
06-30-2015, 9:22 PM
I don't know anything about brake calipers but I'm surprised that if they're specific to a side, that they can be installed on the wrong side. I'd have figured the auto manufacturers would have made it impossible to install them on the wrong side by changing a bolt hole pattern or something like that.

Interesting story thought and I'm glad you got it fixed.

It's why auto mechanics makes the big bucks!

Tom Stenzel
07-01-2015, 12:10 PM
I don't know anything about brake calipers but I'm surprised that if they're specific to a side, that they can be installed on the wrong side. I'd have figured the auto manufacturers would have made it impossible to install them on the wrong side by changing a bolt hole pattern or something like that.

Interesting story thought and I'm glad you got it fixed.

On the '70 Dodge vans (and being Chrysler probably everything else they made) the location of the air bleed WAS the difference between the left and right caliper. So if you drilled and tapped two bleeders on one caliper it would be, um, ambidextrous.

My Mr. Goodwrench story? I helped my brother install an engine that he had gotten from a mechanic that worked at the dealership my brother was at. It started fine, then started making a tapping. Then a loud tapping. The the guy in the motor with the hammer started to work. The problem? When Mr. Goodwrench installed the rod bearings he turned the nuts down finger tight. Then forgot to torque one rod cap entirely.

We made him help pull and reinstall the engine for that one! After that the car ran until the floorboards rotted out.

-Tom