Brake Pedal soft after several parts replaced - RESOLVED!

[Zorin]

Hi, everyone! Long time, no real excitement with the Explorer. It's just soldiered on and on for the last 62K miles of my ownership.

So, recently, we had a right front brake caliper freeze up and cause a pull. So, we replaced it, and at the same time, warrantied the brake pads, as that side was thinner than the driver's side. This was in November. It stopped pretty decent, but it's worth noting that this thing has always had a so-so brake pedal. Stops good, feels a little soft.

Last week, the same caliper froze again. (Cheap parts, man!) So, we replaced it, and once again, warrantied the pads. Upon reassembly, it had a pretty piss poor brake pedal. So I bled and bled, and never got the pedal back. It would sink to about 1 inch off the floor. The car now has 177,000 miles on it, and it felt about like a bad master cylinder, so I bought a replacement at AutoZone. (By the way, this is where the pads and calipers are from as well.) It sucked badly, and would not pump up either. Pretty good flow on the primary side (front brakes), not real great on the secondary (rear brakes). So I warrantied it. I installed another. Upon bench bleeding and installing, I found that when you crack the lines loose at the master to bleed, the primary port sprayed nicely, the secondary port just kind of drooled. That told me that we had another bad one, so I ordered a Motorcraft master cylinder from the dealer. Installing that, we found the HCU was completely full of air from two bad master cylinders. After multiple ABS service bleeds, and 3 bottles of brake fluid, we have enough brakes to drive it (we are getting fluid to the back brakes now, but it still has quite a bit of air) but predictably, the pedal is still somewhat unpleasant. One thing we find interesting, when you crack the rear bleed screw, the HCU makes a hissing noise as the pressure is let off. Not all the time, but if you crack it open fast, it does hiss.

I'm a pretty well versed mechanic, but my question is are these THAT hard to get all the air out of? I have spent several hours reading the historical threads, and YES, my rear calipers are correctly installed. I'm aware of the brake pedal TSB, but after studying the brake pedal assembly, I just don't see how this is contributing to my problem......that thing is pretty well made!

Looking for any ideas I can try out. I suppose it's possible the caliper is bad, but I am not sure how. Nothing is leaking, at least visibly anyways. I understand this generation of Explorer doesn't have the best reputation for bad ass brake pedal feel, but I just don't remember it being QUITE this bad.

Thanks for any ideas you can throw up, and I'm happy to get it back in the shop, get you pics, and try suggestions!

Tim

 

[07EddyB]

You are correct that this gen of Explorer has less than ideal brakes.
I don't have an answer to your problem. I will say this though - you have gone through two calipers and two master cylinders with no success. I understand that Autozone can be hit or miss - but you are missing above the statistical average. It would be very odd that you keep getting bad parts.
So it's time to step back and reassess the situation and look past the parts you have already swapped.
It's easy to get myopic in these situations - it could be something as simple as a defective flex line at one of the calipers.

 

[Zorin]

You are correct that this gen of Explorer has less than ideal brakes.
I don't have an answer to your problem. I will say this though - you have gone through two calipers and two master cylinders with no success. I understand that Autozone can be hit or miss - but you are missing above the statistical average. It would be very odd that you keep getting bad parts.
So it's time to step back and reassess the situation and look past the parts you have already swapped.
It's easy to get myopic in these situations - it could be something as simple as a defective flex line at one of the calipers.

I agree that it does seem preposterous. The calipers were a couple of months apart - so I kinda see that....

I did check the flex lines, although all I could really do was visually inspect them, and feel them while someone else pressed on the brake pedal. I didn't feel any swelling or ballooning, so I am assuming (definitely not the safest thing) that they are OK.

List of parts replaced:
Master Cylinder
Right Front Brake Caliper
Front Pads
Rear Pads (done when a rear wheel bearing was changed last week as well)

I'm reasonably certain the master cylinder is good, as it is a dealer part, and not remanufactured.

Moving on, has anyone achieved a good pedal out of one of these? I mean, there's a ton of threads with this concern. I'm the kind of that really wants to know why, LOL!

EddyB, thanks for the thoughts, I'm going to continue hunting.

Tim

 

[Bazz270]

Are the brake hose banjo flat washers changed to the new fresh oem ones?

P.S.

Try the workshop manual first,nor the forum threads.
No any problems with brake pedal on well maintained GEN4 at all LOL

I mean MOT here will never allow running such a bad maintaned vehicles with soft pedals

I guess there is a tonns of threads because usually people are stupid and greedy with aftermarket replacements and wrong repair procedures

 

[Zorin]

Are the brake hose banjo flat washers changed to the new fresh oem ones?

Yes, new crush washers used each time the caliper was replaced. I didn't use OEM crush washers, but I did use the new ones included with the brake caliper.

Tim

 

[Zorin]

I should clarify something......the brake pedal feels REALLY decent with the engine off.

Start the engine, and it's like stepping on a cow patty.

Tim

 

[Bazz270]

Yes, new crush washers used each time the caliper was replaced. I didn't use OEM crush washers, but I did use the new ones included with the brake caliper.

Tim

Rule number #1 dont use aftermarket or aftermarket reman parts on your brake system

 

[Zorin]

Rule number #1 dont use aftermarket parts on your brake system

I typically agree, however the brake calipers are no longer available new from Ford.

Tim

 

[Bazz270]

And what about Motorcraft remans?

 

[Zorin]

And what about Motorcraft remans?

I didn't see any available, and neither did the dealership I use for parts.

Tim

 

[Bazz270]

There is no magic and no special brake system problems on GEN4 .try another replacement caliper (possibly any more reliable brand or the factory remans -you really can find one in other dealerships,ebay,summit or rockauto).

As a skilled mechanic,you cant just start your diagnostics procedures from the junk cheap parts assuming that they are all good.

I am wondering what cheap brand to you have for such a frequent caliper replacements?

 

[Zorin]

There is no magic and no special brake system problems on GEN4 .try another replacement caliper (possibly any more reliable brand or the factory remans -you really can find one in other dealerships,ebay,summit or rockauto).

As a skilled mechanic,you cant just start your diagnostics procedures from the junk cheap parts assuming that they are all good.

I am wondering what cheap brand to you have for such a frequent caliper replacements?

As mentioned, I bought everything at AutoZone, a prominent parts store here in the US. It's a little strange, as I normally get pretty good parts from AutoZone with little fuss.

I HAVE been seeing their quality slip lately, so I may begin by re-checking the brake caliper I installed. I kinda had this thought last night after EddyB's post.

Both of you are right, sometimes it is better to start by rechecking what changed in the system before what did NOT.

Tim

 

[94Eddie]

The flexible brake lines can act as a check valve when they go bad. Basically they hold pressure against the caliper side even when the brakes are applied. This keeps the brakes applied on that wheel which very well could be your situation since you have had issues with locked up calipers. It would also explain why you have had to replace the same caliper in a short period of time. Some people use vice grips and pinch the flexible hose to keep the system from bleeding out when it is disconnected with the caliper. This should not be done as it can damage the hose and cause issues. A bad hose can also cause a soft pedal because it can expand under pressure. The flexible hoses are inexpensive to replace and they probably should be if they are original at 177k miles.

Here is a short video on the topic.

 

[Exploder321]

Hi, everyone! Long time, no real excitement with the Explorer. It's just soldiered on and on for the last 62K miles of my ownership.

So, recently, we had a right front brake caliper freeze up and cause a pull. So, we replaced it, and at the same time, warrantied the brake pads, as that side was thinner than the driver's side. This was in November. It stopped pretty decent, but it's worth noting that this thing has always had a so-so brake pedal. Stops good, feels a little soft.

Last week, the same caliper froze again. (Cheap parts, man!) So, we replaced it, and once again, warrantied the pads. Upon reassembly, it had a pretty piss poor brake pedal. So I bled and bled, and never got the pedal back. It would sink to about 1 inch off the floor. The car now has 177,000 miles on it, and it felt about like a bad master cylinder, so I bought a replacement at AutoZone. (By the way, this is where the pads and calipers are from as well.) It sucked badly, and would not pump up either. Pretty good flow on the primary side (front brakes), not real great on the secondary (rear brakes). So I warrantied it. I installed another. Upon bench bleeding and installing, I found that when you crack the lines loose at the master to bleed, the primary port sprayed nicely, the secondary port just kind of drooled. That told me that we had another bad one, so I ordered a Motorcraft master cylinder from the dealer. Installing that, we found the HCU was completely full of air from two bad master cylinders. After multiple ABS service bleeds, and 3 bottles of brake fluid, we have enough brakes to drive it (we are getting fluid to the back brakes now, but it still has quite a bit of air) but predictably, the pedal is still somewhat unpleasant. One thing we find interesting, when you crack the rear bleed screw, the HCU makes a hissing noise as the pressure is let off. Not all the time, but if you crack it open fast, it does hiss.

I'm a pretty well versed mechanic, but my question is are these THAT hard to get all the air out of? I have spent several hours reading the historical threads, and YES, my rear calipers are correctly installed. I'm aware of the brake pedal TSB, but after studying the brake pedal assembly, I just don't see how this is contributing to my problem......that thing is pretty well made!

Looking for any ideas I can try out. I suppose it's possible the caliper is bad, but I am not sure how. Nothing is leaking, at least visibly anyways. I understand this generation of Explorer doesn't have the best reputation for bad ass brake pedal feel, but I just don't remember it being QUITE this bad.

Thanks for any ideas you can throw up, and I'm happy to get it back in the shop, get you pics, and try suggestions!

Tim

I went to look up 'HCU' online as I was drawing a blank on the abbreviation and found this: Diagnosing ABS/ESC Hydraulic Control Units | Know Your Parts
The HCU seems a likely culprit. I haven't had to run down issues like you describe, but they sound similar to the issues discussed at the link.

 

[Zorin]

PROGRESS!

So I decided to start back, and check over what we already DID. What's changed?

I noticed that the right front caliper would move a LOT even with the brakes depressed. I'm pretty good about tightening things, so I pulled it apart.

Found a missing bushing for the caliper slide pin in the bracket. This caliper came with the bracket, so we'll try yet another one......from someone else. We'll get that rectified, and go from there.

Tim

 

[Littleant]

Did auto repairs for many years and the only way I would bleed brakes was using a pressure bleeder. Was nessery for a one man shop.

 

[Zorin]

I went to look up 'HCU' online as I was drawing a blank on the abbreviation and found this: Diagnosing ABS/ESC Hydraulic Control Units | Know Your Parts
The HCU seems a likely culprit. I haven't had to run down issues like you describe, but they sound similar to the issues discussed at the link.

This was a good read! That tool isn't badly priced, actually.

Tim

 

[ocnsguinn1]

Hi, everyone! Long time, no real excitement with the Explorer. It's just soldiered on and on for the last 62K miles of my ownership.

So, recently, we had a right front brake caliper freeze up and cause a pull. So, we replaced it, and at the same time, warrantied the brake pads, as that side was thinner than the driver's side. This was in November. It stopped pretty decent, but it's worth noting that this thing has always had a so-so brake pedal. Stops good, feels a little soft.

Last week, the same caliper froze again. (Cheap parts, man!) So, we replaced it, and once again, warrantied the pads. Upon reassembly, it had a pretty piss poor brake pedal. So I bled and bled, and never got the pedal back. It would sink to about 1 inch off the floor. The car now has 177,000 miles on it, and it felt about like a bad master cylinder, so I bought a replacement at AutoZone. (By the way, this is where the pads and calipers are from as well.) It sucked badly, and would not pump up either. Pretty good flow on the primary side (front brakes), not real great on the secondary (rear brakes). So I warrantied it. I installed another. Upon bench bleeding and installing, I found that when you crack the lines loose at the master to bleed, the primary port sprayed nicely, the secondary port just kind of drooled. That told me that we had another bad one, so I ordered a Motorcraft master cylinder from the dealer. Installing that, we found the HCU was completely full of air from two bad master cylinders. After multiple ABS service bleeds, and 3 bottles of brake fluid, we have enough brakes to drive it (we are getting fluid to the back brakes now, but it still has quite a bit of air) but predictably, the pedal is still somewhat unpleasant. One thing we find interesting, when you crack the rear bleed screw, the HCU makes a hissing noise as the pressure is let off. Not all the time, but if you crack it open fast, it does hiss.

I'm a pretty well versed mechanic, but my question is are these THAT hard to get all the air out of? I have spent several hours reading the historical threads, and YES, my rear calipers are correctly installed. I'm aware of the brake pedal TSB, but after studying the brake pedal assembly, I just don't see how this is contributing to my problem......that thing is pretty well made!

Looking for any ideas I can try out. I suppose it's possible the caliper is bad, but I am not sure how. Nothing is leaking, at least visibly anyways. I understand this generation of Explorer doesn't have the best reputation for bad ass brake pedal feel, but I just don't remember it being QUITE this bad.

Thanks for any ideas you can throw up, and I'm happy to get it back in the shop, get you pics, and try suggestions!

Tim

Hey I don't know if this helps but I once had the same problem , except a different car , I had a friend pumping while I was bleeding in between the pumps and I was calling the pumps as he released the brake pedal I heard the wheel cylinder suck air , and that was it . One wheel cylinder sucked air but did not leak , I replaced the one wheel cylinder and problem fixed , That is the only time I have seen any part suck air and not leak .So maybe something to look for .Good Luck

 

[Zorin]

Hey I don't know if this helps but I once had the same problem , except a different car , I had a friend pumping while I was bleeding in between the pumps and I was calling the pumps as he released the brake pedal I heard the wheel cylinder suck air , and that was it . One wheel cylinder sucked air but did not leak , I replaced the one wheel cylinder and problem fixed , That is the only time I have seen any part suck air and not leak .So maybe something to look for .Good Luck

I think we MAY be getting a little of that action on the funky front caliper as well. I'm not entirely sure how well the caliper pistons seat when the caliper is allowed to pivot on the pins due to no bushing in the bracket.

I'm trying to finish up some other stuff, then I will go buy another caliper from another vendor to try out. We also found that the new brake pads we installed (that now only have 18 miles on them) are chunking out at the center slot. So, we'll be getting a different set of pads as well.

AutoZone and I will be having one of those unpleasant discussions, you know?

Tim

 

[410Fortune]

Let us know if that resolves the soft pedal otherwise I have some advice that might help
Dealt with soft pedal on my wifes 07 FJ after getting some air into the ABS pump because the front calipers were off the truck for a few days
Also I have dealt with air in ABS systems on explorers a few times in the past