Spongy brakes, bleeding doesn't work (2013 Mazda5)

2013 Mazda 5 Sport 110,000 miles. No warning lights no codes thrown.

Wife let the brakes get pretty low on fluid, barely any (but a little) visible in the reservoir. Brakes got spongey, lots of travel, loud brake booster. I topped it off and the situation got about 50% better.

Front pads were low, just about 2 MM left so I replaced them. I've done them once before without complications. Did the same steps, and did not bleed at this time.

Took the car out, brakes were really nice and firm and responsive, almost like when new. Gave a couple firm stops from 40 to 0 (not panic stops, just firm, no ABS shudder felt) and the brake instantly became very spongey and unresponsive. They still kinda-work and bottom after 2.5-3 inches travel.

Brought it home and up on the stands, bled from back to front and then bled zig-zag some people on a few forums suggested. At right rear I got a bit of foamy bubbles the first bleed, but that's all I ever got. Bleeding gave maybe a 20% improvement.

I am stumped. Air in the ABS module or a valve stuck open in there? Maybe I just need a power bleed? I know many mechanics would be glad to sell me all the relevant parts, needed or not.
 
Dirt road, 45 mph, hard brake. Don't know what it did but the brakes are about 50% better. They still sink a bit more than I would like under sustained pressure but they're functional.
 

There are a few past threads on this. All resolved with replacement ABS module.

Been a while since I've seen the video and it seems Ford has issued a recall. Why hasn't Mazda?!?!
Forzda 5 uses the same part.
 
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Dirt road, 45 mph, hard brake. Don't know what it did but the brakes are about 50% better. They still sink a bit more than I would like under sustained pressure but they're functional.

Having some of the same issue myself. Pads have a bit more life than the 2mm you described on yours. I noted the brakes worked but felt weak. Bled all four and lubed the slider pins…… then apparently didn’t get one of the bleeder valves all the way tight because it pissed away most of the new fluid in that line and the reservoir (luckily a rear bleeder). Refilled and rebled. After some driving and hard stops they are better than before than before I started, but the pedal has a lot of travel.

Driving fast on the dirt road and braking hard probably engaged the ABS and may have moved any air out of the ABS module when it engaged.

I talked to one of my mechanics at work who suggested it’s possible one of my calipers is binding up and not sliding. Told him I’d removed and greased all of the pins, but he suggested I still go wheel by wheel and make sure the calipers are moving vs. just the piston trying to do all of the travel itself. Haven’t had time to do that yet.
 
Have a mechanic bleed the ABS module. OR you can buy find an Autel unit that works on the Mazda on Amazon that has free returns ;)
I actually just pulled the trigger on Autel AP200C tool that is capable of performing ABS auto bleed. However, I could not make it work on my 2013 Mazda 5 Sport. I contacted Autel and they informed me that my car does not support ABS auto bleed in the first place.
 
I actually just pulled the trigger on Autel AP200C tool that is capable of performing ABS auto bleed. However, I could not make it work on my 2013 Mazda 5 Sport. I contacted Autel and they informed me that my car does not support ABS auto bleed in the first place.
Very surprised none of their products support Mazda5 (perhaps limit on Mazda's end?). Call a local Mazda dealer, describe your situation, and ask if they offer ABS bleeding and cost. If they do, this confirms the limit is on Autel (would not be surprised b/c Mazdas, in general, has very poor aftermarket support). You can try a local mom-and-pop shop to see if they do the service for cheaper (pro Snap-on units are very expensive but can do more) or keep searching Google for alternatives. If the dealer confirms they can't bleed ABS, then you're SOL -or makes the decision easier to go pull a used unit from a more recent wrecker b/c apparently you cannot interface with it.

You can investigate more into Mazda IDS but it'll be expensive (*BitTorrent*). This is the software dealer uses so you'll need a laptop and interface hardware. You can also reach out to a YT owner demoing IDS and ask them to confirm if this supports ABS bleeding for Mz5.

Mazda IDS Compatible Hardware:
VXDIAG VCX NANO Ford/Mazda
VCM II
wiScan T6
FVDI J2534

Good luck.
 
Vehicle: 2014 Mz5 Sport with 100,500 miles. Similar brake pedal issue here. A week ago for no clear reason brake pedal travel decreased substantially according to the primary driver of the car. Brakes still work but really gotta push that pedal to the floor. No brake, ABS system or any other light on the dash. Drove it for another 400 miles since it was first reported. No change one way or the other so not intermittent.

New front and rear brake pads didn't do it. (Front pads were really worn so had to go anyway but the rears were not too bad.) One of the rear calipers was sticking. Replacing it didn't fix. The brake system (not the ABS system) was bled at the shop when calipers were replaced. No leaks were detected at the wheels/hoses. But no difference to the pedal feel/travel still. So I wonder if there is something going on with the ABS. I have not felt it kick in yet. Need to find a dirt road probably.
 
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Vehicle: 2014 Mz5 Sport with 100,500 miles. Similar brake pedal issue here. A week ago for no clear reason brake pedal travel decreased substantially according to the primary driver of the car. Brakes still work but really gotta push that pedal to the floor. No brake, ABS system or any other light on the dash. Drove it for another 400 miles since it was first reported. No change one way or the other so not intermittent.

New front and rear brake pads didn't do it. (Front pads were really worn so had to go anyway but the rears were not too bad.) One of the rear calipers was sticking. Replacing it didn't fix. The brake system (not the ABS system) was bled at the shop when calipers were replaced. No leaks were detected at the wheels/hoses. But no difference to the pedal feel/travel still. So I wonder if there is something going on with the ABS. I have not felt it kick in yet. Need to find a dirt road probably.
Watch the video in post #3, it will explain everything.
A common theme I’m seeing is that this occurs to folks who’ve never change or bleed their brakes (old fluid, made worst if overheated due to aggressive driving/stuck caliper that generate too much heat on old fluid).


@turbonium959 - check out FORscan.org! Can use free version (I highly suggest buying a short license to support developers) and you need to buy ODB2 adapter. Note that it seems the higher quality adapters enable more functions so don’t cheap out. You now have dealer level full protocol access (Mazda IDS) to the car for cheap.
 
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Watch the video in post #3, it will explain everything.
A common theme I’m seeing is that this occurs to folks who’ve never change or bleed their brakes (old fluid, made worst if overheated due to aggressive driving/stuck caliper that generate too much heat on old fluid).
Good point. I've never bled calipers on this vehicle in the 70k or so miles I've had it around. Might have led to this.

And yes, watched the vid - thanks. Very helpful. Questions:
1) There is likely no way out then other than via replacement of the HCU including the electronic "brains" of it?
2) If #1 is true, does it also have to be properly programmed immediately after installation?
3) If #2 is true... can only a Mazda/Ford dealer can handle the programming or do most shops have proper tools for that? (I've never had any ABS issues with any of my other vehicles so have little clue.)
 
One thing you might consider is replacing the short rubber brake line at the caliper with a steel braided one.
As that short rubber section gets older, it becomes less "stiff" and has a tendency to expand (like a balloon) when applying the brakes. This will result in that spongy feel. I have read many anecdotal stories that steel braided brake lines result in much better brake feel and application. Might be worth a shot.
Another possible issue: I had an old Ford Escort that actually had the opposite problem where the rubber line collapsed internally. When applying the brakes the fluid pressure would be forced through the line and the brakes would apply. However, once the pressure was released (getting off the brake pedal), the line would collapse and prevent the fluid from reversing. Result was that the affected brake caliper was always pushing on the pads and resulted in overheating the brake and ruining the pad and rotor. Took a while to figure that one out.
 
Good point. I've never bled calipers on this vehicle in the 70k or so miles I've had it around. Might have led to this.

And yes, watched the vid - thanks. Very helpful. Questions:
1) There is likely no way out then other than via replacement of the HCU including the electronic "brains" of it?
2) If #1 is true, does it also have to be properly programmed immediately after installation?
3) If #2 is true... can only a Mazda/Ford dealer can handle the programming or do most shops have proper tools for that? (I've never had any ABS issues with any of my other vehicles so have little clue.)
I should clarify racking up mileage alone is not the problem as hwy miles have no impact on brakes generating excessive heat, which degrades fluid. The main culprit is the nature of Dot 3 brake fluid, which is hygroscopic (pulls moisture from air) and degrades over time; the added heat transfer from aggressive braking/stuck calipers further compounds the problem. It is "recommended" (insert air quote ) to change (not just bleed) brake fluid every 2 years, personally 3-4 yrs is fine but your '14 is quite old if still on original brake fluid.

1) Past Mz5 post were ultimately solved with replacement HCU. From my understanding, the HCU is a mechanical device with electric servos, there is no circuit board/chip to program.
2) There unit itself does not need any programming, just plug and play. What you need to do is prime unit if you are buying new. I recall all previous owners pulled a used united from a wrecker, which would have fluid in it. You should cycle the old fluid by triggering an ABS event (empty parking lot on a heavy rainy day).
3) This is what @turbonium959 is trying to confirm for DIY. Dealers should(?) be able to trigger an ABS flush and most decent shops with better equipment (say Snap-on, which is a premium) should be able to do it but I'm not 100% sure and haven't seen anyone confirmed. FORscan.org is the greatest thing for Ford/Lincoln/Mercury/Mazda (Ford partnership ear cars only, newer Mazda vehicles are not supported).
 
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I should clarify racking up mileage alone is not the problem as hwy miles have no impact on brakes generating excessive heat, which degrades fluid. The main culprit is the nature of Dot 3 brake fluid, which is hygroscopic (pulls moisture from air) and degrades over time; the added heat transfer from aggressive braking/stuck calipers further compounds the problem. It is "recommended" (insert air quote ) to change (not just bleed) brake fluid every 2 years, personally 3-4 yrs is fine but your '14 is quite old if still on original brake fluid.

1) Past Mz5 post were ultimately solved with replacement HCU. From my understanding, the HCU is a mechanical device with electric servos, there is no circuit board/chip to program.
2) There unit itself does not need any programming, just plug and play. What you need to do is prime unit if you are buying new. I recall all previous owners pulled a used united from a wrecker, which would have fluid in it. You should cycle the old fluid by triggering an ABS event (empty parking lot on a heavy rainy day).
3) This is what @turbonium959 is trying to confirm for DIY. Dealers should(?) be able to trigger an ABS flush and most decent shops with better equipment (say Snap-on, which is a premium) should be able to do it but I'm not 100% sure and haven't seen anyone confirmed. FORscan.org is the greatest thing for Ford/Lincoln/Mercury/Mazda (Ford partnership ear cars only, newer Mazda vehicles are not supported).
Yes, it was 70k miles over 6 years or so. The system was probably bled when the vehicle was purchased but not since.

OK, so as long the right part is installed, should be ok to install without dealer support hopefully. I've just reread this thread and saw the post about FORscan.org. I've never heard of it - great tip. So if you have a PC, proper cable and their software installed, a proper ABS flush can occur? I'm not sure if I understand the connection between FORscan software and the ABS bleeding correctly so thought I'd confirm.

I saw online that part number C5Y3-43-7AZB is the right fit for a 2014MY vehicle. The actual part on my car is C513-437AZ-B - looked under the hood the other day. They are probably one and the same, right? My concern about getting a used part from a wrecked car is that it may not last very long or have some other issues. I would hope that a new unit should give me another 100k miles... although paying $1k for it is not something I'm able to do. I think the MSRP plus tax will put it at $1100 if not more. Nuts.

One more thing. In doing some test driving on a dirt road the other day, I noticed that the ABS kicked in once. I'll need to find a road with higher speed limit and fewer residents to test it further. :) I also notice that while driving, after one or two quick pumps, the break pedal gets firm again like it used to be. I wonder if there is hope for the valves in my existing HCU to open up eventually? Or that's not how that works?

Thanks for the help!
 
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Yes, it was 70k miles over 6 years or so. The system was probably bled when the vehicle was purchased but not since.

OK, so as long the right part is installed, should be ok to install without dealer support hopefully. I've just reread this thread and saw the post about FORscan.org. I've never heard of it - great tip. So if you have a PC, proper cable and their software installed, a proper ABS flush can occur? I'm not sure if I understand the connection between FORscan software and the ABS bleeding correctly so thought I'd confirm.

I saw online that part number C5Y3-43-7AZB is the right fit for a 2014MY vehicle. The actual part on my car is C513-437AZ-B - looked under the hood the other day. They are probably one and the same, right? My concern about getting a used part from a wrecked car is that it may not last very long or have some other issues. I would hope that a new unit should give me another 100k miles... although paying $1k for it is not something I'm able to do. I think the MSRP plus tax will put it at $11000 if not more. Nuts.

One more thing. In doing some test driving on a dirt road the other day, I noticed that the ABS kicked in once. I'll need to find a road with higher speed limit and fewer residents to test it further. :) I also notice that while driving, after one or two quick pumps, the break pedal gets firm again like it used to be. I wonder if there is hope for the valves in my existing HCU to open up eventually? Or that's not how that works?

Thanks for the help!
Call your local Mazda dealer’s service department and ask if they can perform an ABS flush. Make sure to confirm it is an ABS flush (regular brake fluid flush does not activate/cycle the HCU’s valves). If yes, have the dealer do it and be done with it. However, before performing the ABS flush (dealer service or DIY), make sure to change all of old brake fluid first; bleeding is the last step and there’s no point to bleed the system with old fluid.

I also learned about FORscan a few weeks back only b/c I was looking at the Maverick and Bronco (buy base trim and turn on all terrain modes, turn on cruise, lane keep, etc +add hardware, if not avail). Seems not many Mazda owners (of the Ford partnership era) is aware of this software. You can turn on/off OEM functions, just like a dealer turn features off to force you to buy a higher trim or made avail in international markets. I’m tempted to set it up to turn off the seat belt reminder and turn on the low washer fluid light (need to add sensor on the reservoir). I’ll leave the onus on you to read up on FORscan before you proceed any further as you can mess things up. They have a forum/community where Dev team is still adding/enhancing features. I saw an old thread where a late 2000s Taurus(?) owner asked to add ABS flushing for their model year, which the Dev did add at a later time. That said, I cannot guarantee FORscan can perform ABS flush for your Mazda 5 out the box. It seems the higher end automated hi/lo switching adapters enable more features, and the Windows version has more feature than the Android/iOS app.

I cannot say what part number is needed as I’ve never looked into it. But wow, didn’t think this thing cost $1100 – crazy… This might explain why all previous owners went with u-pull. I would suggest looking at Mazda 5’s (wiki) chassis cousins to open-up the potential list of donor cars. Since Ford issued a recall for the HCU, I’d do some research for compatible newer Fords in the junkyard.

You are on track. This comes back to the discussion with @turbonium959. It worth a try to DIY bleed the HCU before just dropping in a replacement. Bleeding it may get the values to move or get any air out. Check with the dealer first. If they say yes, you can have them do it or look into FORscan (can also ask/post in their forum) to DIY.
 
Call your local Mazda dealer’s service department and ask if they can perform an ABS flush. Make sure to confirm it is an ABS flush (regular brake fluid flush does not activate/cycle the HCU’s valves). If yes, have the dealer do it and be done with it. However, before performing the ABS flush (dealer service or DIY), make sure to change all of old brake fluid first; bleeding is the last step and there’s no point to bleed the system with old fluid.

I also learned about FORscan a few weeks back only b/c I was looking at the Maverick and Bronco (buy base trim and turn on all terrain modes, turn on cruise, lane keep, etc +add hardware, if not avail). Seems not many Mazda owners (of the Ford partnership era) is aware of this software. You can turn on/off OEM functions, just like a dealer turn features off to force you to buy a higher trim or made avail in international markets. I’m tempted to set it up to turn off the seat belt reminder and turn on the low washer fluid light (need to add sensor on the reservoir). I’ll leave the onus on you to read up on FORscan before you proceed any further as you can mess things up. They have a forum/community where Dev team is still adding/enhancing features. I saw an old thread where a late 2000s Taurus(?) owner asked to add ABS flushing for their model year, which the Dev did add at a later time. That said, I cannot guarantee FORscan can perform ABS flush for your Mazda 5 out the box. It seems the higher end automated hi/lo switching adapters enable more features, and the Windows version has more feature than the Android/iOS app.

I cannot say what part number is needed as I’ve never looked into it. But wow, didn’t think this thing cost $1100 – crazy… This might explain why all previous owners went with u-pull. I would suggest looking at Mazda 5’s (wiki) chassis cousins to open-up the potential list of donor cars. Since Ford issued a recall for the HCU, I’d do some research for compatible newer Fords in the junkyard.

You are on track. This comes back to the discussion with @turbonium959. It worth a try to DIY bleed the HCU before just dropping in a replacement. Bleeding it may get the values to move or get any air out. Check with the dealer first. If they say yes, you can have them do it or look into FORscan (can also ask/post in their forum) to DIY.
Thanks again- very helpful!

I should be on fresh fluid after recent service. Will see what dealers say. I was told to expect a nice diagnostics charge at the dealer that is usually the less expensive of the two. (I called with a general explanation of the issue a week ago or so.)

I put too many zeros in the new HCU price. Its MSRP is a little over one grand before tax. Discount OEM parts stores sell them for $700-800. Used units, naturally, are much much cheaper but never know what condition they are really in. Obviously if I can just reuse my own part and not have to worry about replacement then great!

I'll research some more and post more later.
 
BIG Thanks to @Maikel , seems FORScan can indeed calibrate and bleed ABS valves/solenoids (individually!). Can't confirm the menu options are the same for both gens but I suspect it should be. This also confirms Autel is not up to date with their software and the avg owner would need to take it to the dealer (or get your own FORScan setup).
 
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Last time I checked, Mazda 5 2012-2018 still wasn't on the list for any ABS services procedures.
A lot of other features to make it useful though. Just too scared to play with AsBuilt programming.
 
Going to add this experience we just had:

Mom's MAZDA 5 2015 got the mushy brakes. Pedal would go near the floor and still stop the car fine and actuate the abs but it was definitely uncomfortable. It just felt like your brakes were almost gone.

Took it to a local tire shop who does lots of work on our cars. Initial diag was the Master Cylinder. MC was replaced. Wasn't better. Their diag "expert" was confident the calipers were to blame. So they replaced calipers. I wasn't a party to that decision...I think we all know that calipers aren't going to cause a weak brake pedal unless they are leaking externally or have air in them. They bled the entire system again including the ABS module...still no dice.

I recounted the info in this thread to them and the fact that Ford had a recall, etc. They were able to locate the recall but were skeptical that it applied because the recall was for the prior generation cars.

Told them that we were willing to to take the risk. The module was the last part of the system left to replace anyways.

They got the HCU (ABS Hydraulic Control Unit) from Mazda ($1100) and it fixed it right away.

To the shop's credit they ate half the repair bill without even us asking.
 
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Thanks for the helpful info in this thread. I have a 2012 Mazda 5 with the soft pedal issue. I took it to the Mazda dealership, they said the brakes were fine, so then they bled the system but it showed no improvement. They said the problem might be due to pinhole leaks in the brake lines or a defective master cylinder. They told me to come back in a couple weeks if the problem gets worse.

Most of the answers I've seen online for this issue on Mazda 5 have been resolved with an ABS control unit replacement. Only one person had his fixed with a master cylinder replacement.

Is there any way to diagnose the existing HCU plus the master cylinder at the dealership to find which one is the culprit, or should I bite the bullet and tell them to get a new HCU installed?? I have a feeling they might even try to sway me away from that idea and exhaust all the other usual options (master cylinder, fuel lines, brake booster, calipers).
 
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Just an update on my situation -- I was able to locate a used ABS module for my 2012 Mazda 5 from a secondhand auto parts store online ($150 Canadian, with express shipping and 90-day warranty included) and got the mechanic to install it. The brake pedal is back to normal now. Mechanic was surprised it actually worked; he had been insisting I should replace the master cylinder.

The part number is listed as C5Y3437AZB, but the replacement and original modules are labelled C513437AZB on the outside - the difference is "1" instead of "Y". Either will work. My original defective part looks the same except it has a Ford label stamped on it. My replacement came from a 2015 Mazda 5.
 
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