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Discussion Starter · #1 ·
As the title suggests my 2007 Mazda3 has brakes that have recently gone squishy. Obviously this is a huge safety problem so I'm not driving it until I can get it sorted out. When applying the brakes the pedal feels squishy and travels further than normal, but does slow the car down. If I pump the pedal a couple of times it firms up and feels normal until after it's released. I checked the brake fluid reservoir and looks like it might be very low. Hard to tell for sure until I try adding more fluid up to the max line. This is the 5 speed MT and there are no issues with the hydraulics for the clutch as far as I can tell. I also took a quick look at the rear bleeder valves since I can get to them pretty easily without jacking the car up. I removed the cap for the rear driver's side bleeder valve and it was wet, apparently with orange looking brake fluid. Is that expected, or could this be where I'm losing pressure/brake fluid? Also I noticed this bleeder was nice and shiny looking. Not sure if that's because of the cap that's been protecting it, or because it's been soaking in brake fluid for who knows how long. The bleeder on the other side unfortunately has the cap missing and is rusty (and dry). Any ideas on how to diagnose this?
 

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First thing is inspect the entire system for signs of leaks, including the hard lines and soft lines. That being said, it sounds like you already found your leak, as the bleed valves should be dry. How about see if it is loose? Could be it was never tightened properly the last time the brakes were bled. You also will need to thoroughly bleed/flush your brake fluid and top off with fresh new fluid. You likely not only have low a low fluid level, I would bet air has seeped into your lines if indeed that bleeder was loose. Other possibilities include a worn out master cylinder, but from your description and low fluid levels, you likely have been seeping fluid for awhile.
 

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Discussion Starter · #3 ·
Thanks, that's super helpful feedback. Bleeder valves haven't been touched recently AFAIK. I remember the brake fluid was checked at an oil change shop a couple of years ago and they said it was fine. I'm not sure if they would have touched the bleeders for that and if anything happened then I would think I would have started having problems sooner than now. Is it possible for bleeder valves to come open or start leaking on their own? Buddy of mine is saying brake fluid under the bleeder cap is not uncommon and may not necessarily be the problem. I did also take a look around the MC but didn't see any obvious signs of leaking around the booster or firewall. Not exactly what a problem there would look like but didn't see any signs of residual fluid that might have leaked there. Either way a brake bleeding is in order. I read that the brakes are on separate diagonal lines on this car. Does it matter which side I start on? I'd like to start on the side with the potentially leaky valve (rd/fp) first to see if the pedal improves.
 

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Discussion Starter · #4 ·
Just an update on this - initially I had a hard time reading the brake fluid level since the outside of the reservoir is pretty dirty and not very clear to begin with. I picked up some DOT 3 and tried topping opt the reservoir but discovered it was already pretty much completely full. So it would seem I haven't lost any significant amount of fluid. Or could there still be pockets of air further down in the system? One other thing worth mentioning is that I remember having an anomaly with the ABS a couple of years ago. After having the ABS activate while braking on gravel the pedal went soft afterwards. It remained soft until ABS kicked in again when braking on gravel and remained firm since (until recently). I'm wondering if there could have been another ABS event that caused the pedal to go soft again. Could the problem be a fault in the ABS module? Stuck valve or air in it? Any ideas on how to diagnose this? Hoping it doesn't need to be replaced since they are $$$ but also don't want to go chasing after problems elsewhere if that really is the problem. Let me know if there are any ideas on anything else to try/check.
 

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Has happened to my 2006 Hatch a few times.
I find an area to brake that re engages the abs.
Might take a few times.

Another way is to pump the brake pedal without
the key on or engine running till it feels really hard.

I thing it boils down to valves in the ABS control that don't
fully close after an ABS event.

Good luck.
 

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Discussion Starter · #6 ·
Yeah. I tried this went for a quick test drive after re-hanging my tailpipe that had a hanger I recently discovered had completely rusted through. I got the ABS to activate when was pulling into my gravel driveway but didn't seem to fix the softness of the brake pedal. Maybe I can try again and try pumping with the engine off. The last time I had this happen I remember hearing a very characteristic whining sound when I released the brake pedal but I don't think I'm hearing that this time. I don't think the car is super unsafe but it does make braking more sluggish which could definitely be dangerous if I had to brake suddenly. I love having ABS as a safety feature and it's definitely saved me a couple of times on snow/ice, but it's just really frustrating how this "safety" feature might be what's making the car unsafe. Going to try to get it to my buddy's house to go up on his lift and try/check some things and then off to the shop if we can't get it fixed. Need it fixed so it can pass state inspection. I'm suddenly realizing this car is really starting to get old coming up on 15 years soon. Just hoping after taking care of this stuff I can hopefully get a couple more years out of it.
 

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Again, no matter what is wrong you need to bleed the system. If fluid leaked out, then air probably leaked in. No the bleeders should never loosen on their own, and no fluid leakage at the bleeders is never normal. When I bleed my brakes, the bleeders always crisply crack free the first time I open them, I don't see any possible way that they would do this by themselves if they were properly tightened in the first place.

Can't help you if it is ABS related, that's beyond my experience level.

The good news is a bleed should cost you one bottle of brake fluid, very inexpensive.

I don't know if it is proper procedure, but on mine I start with the rear passenger side, then rear driver's side, then front passenger side, then finally front driver's side. I bleed more cycles on the ones furthest from the master cylinder, reasoning there is more fluid in the longer line that needs purging. Make sure to continuously monitor the fluid level in the reservoir, because it it gets low and sucks air into the lines you have to start all over.

With a helper the entire procedure should take no more than 30 minutes.
 

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You need to figure out whether that brake fluid at the bleeder was a leak, as in loose bleed screw, or not. If a leak, then bleeding the system as Davids3 suggest is the first thing to do.

If there is no leak, then the ABS pump pistons may be sticking and causing the low pedal. These things are why periodic brake bleeding is essential, keeps things clean so the pistons can work without hanging up. If it is the ABS pump, then eventually it will need to be replaced or maybe rebuilt. I've seen places online that do this work, way cheaper than buying a new pump, but of course, you must be able to remove, reinstall and properly bleed system.
 

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Again, no matter what is wrong you need to bleed the system. If fluid leaked out, then air probably leaked in. No the bleeders should never loosen on their own, and no fluid leakage at the bleeders is never normal. When I bleed my brakes, the bleeders always crisply crack free the first time I open them, I don't see any possible way that they would do this by themselves if they were properly tightened in the first place.

Can't help you if it is ABS related, that's beyond my experience level.

The good news is a bleed should cost you one bottle of brake fluid, very inexpensive.

I don't know if it is proper procedure, but on mine I start with the rear passenger side, then rear driver's side, then front passenger side, then finally front driver's side. I bleed more cycles on the ones furthest from the master cylinder, reasoning there is more fluid in the longer line that needs purging. Make sure to continuously monitor the fluid level in the reservoir, because it it gets low and sucks air into the lines you have to start all over.

With a helper the entire procedure should take no more than 30 minutes.
You need to figure out whether that brake fluid at the bleeder was a leak, as in loose bleed screw, or not. If a leak, then bleeding the system as Davids3 suggest is the first thing to do.

If there is no leak, then the ABS pump pistons may be sticking and causing the low pedal. These things are why periodic brake bleeding is essential, keeps things clean so the pistons can work without hanging up. If it is the ABS pump, then eventually it will need to be replaced or maybe rebuilt. I've seen places online that do this work, way cheaper than buying a new pump, but of course, you must be able to remove, reinstall and properly bleed system.

Pretty sure you need to cycle the ABS while bleeding to put clean fluid in the ABS pump.
Dealer equipment ?
 

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Discussion Starter · #13 ·
Finally have an update on my Mazda after being in the shop for ~2 weeks. Long story short it was the ABS module that had failed, as I suspected but was hoping against. Replaced. Fixed. Passed state inspection. I have one bit of advice I can offer on the ABS module problem that hopefully can help others diagnosing this in the future: The symptom I was experiencing was a soft brake pedal when initially hitting the brakes, but becomes solid after a second pump. It was also apparent when bleeding the brakes. A single push on the brake pedal wouldn't let out much fluid at all, but pressing the pedal first and bleeding on the second press would produce plenty of fluid at the bleeder valve. Hopefully that will be of some help to anyone else trying to troubleshoot their MC/ABS in the future.

Within a couple hours of dropping it off at the shop I got a call back that they were fairly confident it was the MC since they found a bit of fluid between MC and the booster. So they replaced MC and 2 calipers with broken/stuck bleeder screws (don't ask :mad:). The shop was real busy so I wasn't expecting it to be done for a day or two so I gave it another day before giving them a call to see what was going on. They basically said it wasn't ready yet because they couldn't get a real solid brake pedal so they were going to try using the computer to bleed the ABS. From their description it sounded like it was the same brake pedal I had to begin with - soft at first, solid after a second pump. Another day or two and they replaced the MC and calipers again, thinking it must have been bad parts. Finally I get a call back saying they don't really know what else they can try and I should check with a dealer if they could diagnose the ABS. This was after I gave them the OK to go ahead with a few other repairs (2 new tires and ball joint) which combined with the MC were going to be over $1200. I was already hesitant about going forward with the repairs since the car is only worth around $4k on paper so I was already starting to think about ditching the Mazda and putting the money towards my next car. I did my best to check with the dealer and the only real answer they could give me was that a diagnostic would "start" at $112. So basically they can charge as much as they want just for the diagnostic and that doesn't cover anything related to fixing the problem, which is likely going to include a $700+ ABS module. So I called the local shop back and got them to see if they could get me a price for putting in a used ABS module. Little while later they tell me they found one nearby it's ~$500, installed. That brings us to last Friday when I called again to see how things were going after another period of silence. Wrong part - they sent him the ABS module that has DSC which my Mazda doesn't have. New one wouldn't be in until Tuesday (today). I got the call around 10AM this morning which was surprisingly early, so I wasn't so sure that it could be good news. But surprisingly the news was that they FINALLY had brakes in the Mazda. Final cost ended up being less than I was expecting after all that - $1580 which included 2 new tires, 2 calipers, 1 ball joint, a new MC, and installing the used ABS module. I'm not super happy about having to pay that much to keep a $4k car on the road but I think it was at least pretty good bang for the buck in terms of what I got done for the money. I'm pretty sure the shop ended up eating the cost for a HUGE amount of labor (basically doing the whole MC job 2 extra times beyond it being part of getting to the ABS module). I checked the receipt and they billed a total of 6 hours labor - the rest was parts. They even offered to put the old MC back in since that apparently wasn't the main source of the problem but I kept the new one on their word that the old one may have been leaking a bit and I know those things aren't going to last forever. And they kept their word and "made it worth my while" with an extra $50 discount for the inconvenience with how long things took. And the brakes felt great on the way home and everything passed state inspection.

At this point I'm relieved that the new ABS module did the trick since it was a bit of a gamble without going through a real diagnostic first. But they agreed there wasn't really anything else left that could be the problem so it was pretty much the only thing left to try.
 
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