No brake pedal feel after changing front/rear pads

Hello. I just found this forum as I was searching an issue I am having with my step-daughter’s 2016 CX5. She let the brakes go far too long (65k miles) to where the right front rotor was getting chewed up and there was some noise coming out of the rear. I replaced the one rotor and did the pads on all four corners. The rears were down to the backing plates. Ugh. I wish I had found this site sooner. Here is what I did (old school):
Front: used a C-clamp to compress pistons and swapped pads.
Rear: A friend of mine told me that I had to turn in the rear pistons (using vise grips) and then compress the piston slowly with a C-clamp. He never mentioned anything about going into maintenance mode. I did what he said and was able to get the pistons compressed and the pads on (I figured out that I had to align the grooves in the piston with the nub on the pad. I did crack the plastic EPB cover on rear pass.

I put it all back together and I had little or no brake pedal. I tried pumping it a bit, but that didn’t work. I thought I might have some air in the line and tried bleeding each caliper but that didn’t help. Now I have very little friction at each pad. I am able to rotate each rotor while someone holds down brake (which goes all the way to the floor now). The same friend told me that the master cylinder is either air bound or needs replacement.

Does this sound right? In reading some posts on this site, I realize that when doing the rear brakes I should’ve put it in ‘maintenance mode’ and got the correct tool, but even if I did the rears incorrectly, shouldn’t the front brakes still work? How could a master cylinder just fail like that?

There is no brake warning light on the dash and the EPB engages and releases.

I’m happy to replace the master cylinder if I have to, but I’m not 100% confident that is going to fix the issue.

Sorry for the long (first) post. I’d appreciate any feedback.

thanks
Frank
 
I did a bunch more reading this morning and it seems the advice given to me (rotate the pistons while compressing them little by little) is NOT the correct thing to do, but I just went out and checked and the EPB is functioning properly. I'm hoping that I didn't ruin the rear calipers, but even if I did, I still have no front brakes either. I was going to start pulling the master cylinder but figured I'd wait to see if any of the experts here had better advice. Is it possible that there is a ton of air in the system? I have a power bleeder that hooks up to my compressor. I was wondering if maybe I should give that a shot before pulling the master cylinder.
 
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2013 Mazda CX-5 Sport FWD Auto
It might be time for a tow to a mechanic. As you’ve probably found out by now, maintenance mode on the rear brakes had to be enabled first. The pistons should not have been rotated either. I’m guessing something is broken now on the rear brakes. If pressure can’t build back there when the brake pedal is pushed, you’re not going to get pressure to build at the front either.
 
Ok. Thanks. Strange that the EPB works, though, isn’t it? I just went in and did the whole Maintenance Mode procedure and everything worked as it should. If all a mechanic is going to do is change the rear calipers, isn’t that something I can do myself? In Maintenance Mode this time 🙄
 
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2013 Mazda CX-5 Sport FWD Auto
Can you see the piston moving when the EPB is engaged? Just wanted to double check that vs hearing the whir of the motor. I’m hoping somebody else might be able to chime in with more advice. I’m not sure if the caliper got messed up when that piston was pushed in or if something else in the system was damaged by the pressure there.
 
:
Ottawa, Ontario
:
17 Mazda 6 GT
Don't take anymore advice from your friend. He has no idea.
You might have to bite the bullet and take it to a Mazda dealer.
I wouldn't trust my local independent shop if I were you either. They are not Mazda trained, and probably don't know about the maintenance mode requirement either.
Most guys just do what your friend does: go by past experience and turn/jam the piston.
I've watched a few youtube videos even, and those so called experts doing brake tutorials on there didn't mention maintenance mode either.
Good luck.
 
:
2020 CX-5 AWD
... If all a mechanic is going to do is change the rear calipers, isn’t that something I can do myself? ...
As mentioned in earlier posts, I believe area of concern resulting from your mistakes is with the EPB. A disclaimer that I've never had issues with this and don't have hands-on experience. However I've read multiple accounts of issues with the EPB, in cases where others made the same mistakes that you did.

So if you're thinking about continuing to DIY, then I recommend removing and examining the EPB. Or you can take it to someone who knows what they're doing, as others have already mentioned as well.
 
:
Southwest Ohio
:
'19 CX-5 diesel
Step-daughter's car (vs your own car) = take it to Mazda to be sure their done right at this point. You don't want to take a chance on brakes not working properly for her. Period.

If it was your car that you drive, I'd say do what you want.

Just IMHO ... That and a bag 'o chips will getchya a bag of chips ;) . Chalk that one up in the "lessons learned" column .
 
:
Pueblo county CO
:
CX-5 Sport 16.5 6M
The '16 has issues with the rear calipers on vehicles produced in a certain date range. Those needed new calipers anyway, but it's out of warranty now.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Hello. I just found this forum as I was searching an issue I am having with my step-daughter’s 2016 CX5. She let the brakes go far too long (65k miles) to where the right front rotor was getting chewed up and there was some noise coming out of the rear. I replaced the one rotor and did the pads on all four corners. The rears were down to the backing plates. Ugh. I wish I had found this site sooner. Here is what I did (old school):
Front: used a C-clamp to compress pistons and swapped pads.
Rear: A friend of mine told me that I had to turn in the rear pistons (using vise grips) and then compress the piston slowly with a C-clamp. He never mentioned anything about going into maintenance mode. I did what he said and was able to get the pistons compressed and the pads on (I figured out that I had to align the grooves in the piston with the nub on the pad. I did crack the plastic EPB cover on rear pass.

I put it all back together and I had little or no brake pedal. I tried pumping it a bit, but that didn’t work. I thought I might have some air in the line and tried bleeding each caliper but that didn’t help. Now I have very little friction at each pad. I am able to rotate each rotor while someone holds down brake (which goes all the way to the floor now). The same friend told me that the master cylinder is either air bound or needs replacement.

Does this sound right? In reading some posts on this site, I realize that when doing the rear brakes I should’ve put it in ‘maintenance mode’ and got the correct tool, but even if I did the rears incorrectly, shouldn’t the front brakes still work? How could a master cylinder just fail like that?

There is no brake warning light on the dash and the EPB engages and releases.

I’m happy to replace the master cylinder if I have to, but I’m not 100% confident that is going to fix the issue.

Sorry for the long (first) post. I’d appreciate any feedback.

thanks
Frank
With the mistakes you’ve done to the rear brakes with EPB, and there’s no brake warning lights of any (3) that’s is very strange, especially you now have the brake pedal goes to the floor.

I’d suggest you to redo the rear brakes all over again according to the proper procedure with maintenance mode. Make sure to read this excellent thread first by tomcat1446:

Maintenance Mode for 2016/2017 CX-5 electronic brakes

Before you do the caliper piston push-down, check the piston’s grooves which are lined up in perfect North South orientation from your previous job. If not, you caliper could have been damaged. Here’s a picture with explanation from blackcx5:
658C2FF0-290E-4A50-82FE-1228AB920EEF.jpeg


Remember Mazda has revised the rear brake calipers for 2016 CX-5 as the factory calipers would cause EPB dragging even the lock-up. I personally would suggest getting the revised calipers for safety reason. The date code on the caliper will tell you the difference between the old version and revised version. See the attachment of the TSB by Anchorman for details:

TSB R052/16C - Noise from REAR BRAKE/Trace of Rear Brake Dragging

I simply don’t believe your master cylinder is failing.
 
Last edited:

madar

Contributor
:
2016.5 CX 5 Touring AWD, 2015 SCION XB
You might want to put a new rotor on the other side in the front, they should be replaced in pairs, new pads don't mate well with old rotors unless they get resurfaced.