2013 100k Clutch Pedal Soft Overnight - Clutch Gone?

Problem solved but first let me clarify what exactly was feeling like after my muscle memory was adjusted - the top of the pedal was very soft; the clutch grabbing point wasn't really that low to the floor as I stated first. It was actually somewhat inconsistent - sometimes low but sometimes very high; the effective travel of the clutch action was very short, meaning I had to go really slow otherwise the shifting was jerky and I could sense it in the engine noise and vibration.

What was done:
I flushed the brake fluid, replaced master and slave (service manual calls it release) cylinders and pedal is now better than it was before the failure. Smooth shifting. It wasn't as hard as I thought - 3.5 hrs total, with a few delays. If I have to do it again - probably 1 hr.
Some tips:
- The main hiccup I got was a o-ring that normally sits at the end of the slave cylinder hose was stuck inside the old slave cylinder when I pulled it out. I did not notice it, installed, started bleeding and brake fluid leaked all over the place sending me in panic mode that the new part is defective. I carefully pulled out the tiny o-ring, installed on the the hose end and back in business. If you are doing this job, it may be wise to order these o-rings - I think there is one at the master attach point as well.
- I did not have to remove air handler - just the battery box. But I do have small hands. The slave is very easy to remove from the bottom but if you do have small hands removing it from top is possible
- The slave bleeder is not a bolt style but a plastic twist lock - as you are on top of it installed, turn counter clockwise to open (it turns 180 degrees) and clockwise to close. It makes a nice click at the ends.
- I kind of like how Mazda did these parts. It's all plastics so I don't think the concern about the slave cylinder rusting was valid (it has a nice boot too). Very easy to replace - just snap together. Lasting 100k miles is decent.
- I think it was the master that was bad as the old one clearly had more play than the new one. I did replace the slave as it was only $45 and it was making squeaky noisy since 20k miles. On top of that, I accidentally squirted fluid from the old all over my wife who was at least 10ft away. So watch out for that too.
- The brake fluid at 100k miles and 8.5 years of Midwest climate wasn't looking terrible. Whoever says replace it every 2-3 years/30000 miles is either up selling you or it is climate/care dependent. I will be replacing every 5 years on my future cars as it is a easy and cheap job.
- I couldn't find these parts from 3rd party stores and no dealer had them in stock. I first ordered from one of the many 'mazda-parts-something' online stores but the lead times was like 2-3 weeks (they said Mazda warehouse ships to them first, then they ship to me). Don't waste your time with them. Got it thru the local dealer in 5 days and it was only $12 more than what the online prices were (after 15% coupon).
 
Problem solved but first let me clarify what exactly was feeling like after my muscle memory was adjusted - the top of the pedal was very soft; the clutch grabbing point wasn't really that low to the floor as I stated first. It was actually somewhat inconsistent - sometimes low but sometimes very high; the effective travel of the clutch action was very short, meaning I had to go really slow otherwise the shifting was jerky and I could sense it in the engine noise and vibration.

What was done:
I flushed the brake fluid, replaced master and slave (service manual calls it release) cylinders and pedal is now better than it was before the failure. Smooth shifting. It wasn't as hard as I thought - 3.5 hrs total, with a few delays. If I have to do it again - probably 1 hr.
Some tips:
- The main hiccup I got was a o-ring that normally sits at the end of the slave cylinder hose was stuck inside the old slave cylinder when I pulled it out. I did not notice it, installed, started bleeding and brake fluid leaked all over the place sending me in panic mode that the new part is defective. I carefully pulled out the tiny o-ring, installed on the the hose end and back in business. If you are doing this job, it may be wise to order these o-rings - I think there is one at the master attach point as well.
- I did not have to remove air handler - just the battery box. But I do have small hands. The slave is very easy to remove from the bottom but if you do have small hands removing it from top is possible
- The slave bleeder is not a bolt style but a plastic twist lock - as you are on top of it installed, turn counter clockwise to open (it turns 180 degrees) and clockwise to close. It makes a nice click at the ends.
- I kind of like how Mazda did these parts. It's all plastics so I don't think the concern about the slave cylinder rusting was valid (it has a nice boot too). Very easy to replace - just snap together. Lasting 100k miles is decent.
- I think it was the master that was bad as the old one clearly had more play than the new one. I did replace the slave as it was only $45 and it was making squeaky noisy since 20k miles. On top of that, I accidentally squirted fluid from the old all over my wife who was at least 10ft away. So watch out for that too.
- The brake fluid at 100k miles and 8.5 years of Midwest climate wasn't looking terrible. Whoever says replace it every 2-3 years/30000 miles is either up selling you or it is climate/care dependent. I will be replacing every 5 years on my future cars as it is a easy and cheap job.
- I couldn't find these parts from 3rd party stores and no dealer had them in stock. I first ordered from one of the many 'mazda-parts-something' online stores but the lead times was like 2-3 weeks (they said Mazda warehouse ships to them first, then they ship to me). Don't waste your time with them. Got it thru the local dealer in 5 days and it was only $12 more than what the online prices were (after 15% coupon).
Thanks for the update with more tips on replacing clutch master cylinder and salave / release cylinder.

Like most of us guessed, the culprit is the internal leak in your clutch master cylinder. Honestly it seems a bit too early with clutch master cylinder failure before you need the new clutch. How much does it cost for the clutch master cylinder? How did you bleed the clutch cylinders? By gravity、pressure、or manual pumping the clutch pedal?

Mazda has always designed a gasket or seal between brake fluid line and brake calipers. I wouldn’t be surprised if there’s an o-ring seal for fluid line connection to both clutch master cylinder and release cylinder. I believe the shop manual calls new gasket / seal / o-ring all the time once they get disconnected. Yes, always get new gasket / seal / o-ring for similar work.

As for how often should we replace the brake (and clutch in your case) fluid, IMO it’s weather and environment related. Most Euro car makers have 2-year replacement interval, but American and Japanese car makers suggest none. I’d get a brake fluid tester testing the moisture level. If it’s 2% or higher, replace the brake fluid.

I wonder if you’re going to DIY replacing the clutch when the time is come (and shouldn’t be too far away from now in your city driving environment at 100K miles)? ;)
 
,
Mazda has always designed a gasket or seal between brake fluid line and brake calipers.

Not having paid attention before while doing brakes, looking at the gen1 shop manual it looks like the usual 2 crush washers and banjo fitting on the brake line connecting to the caliper.
 
,


Not having paid attention before while doing brakes, looking at the gen1 shop manual it looks like the usual 2 crush washers and banjo fitting on the brake line connecting to the caliper.
In this rear brake dragging by EPB TSB, the gaskets on caliper hose, part no.: 9956-21-000, need to be replaced indicated by a “R”.

47276349-0022-4271-873B-F806B2D4E4A0.jpeg

197FC158-B8BE-408B-90DB-456984357740.jpeg
 
Thanks for the update with more tips on replacing clutch master cylinder and salave / release cylinder.

Like most of us guessed, the culprit is the internal leak in your clutch master cylinder. Honestly it seems a bit too early with clutch master cylinder failure before you need the new clutch. How much does it cost for the clutch master cylinder? How did you bleed the clutch cylinders? By gravity、pressure、or manual pumping the clutch pedal?

Mazda has always designed a gasket or seal between brake fluid line and brake calipers. I wouldn’t be surprised if there’s an o-ring seal for fluid line connection to both clutch master cylinder and release cylinder. I believe the shop manual calls new gasket / seal / o-ring all the time once they get disconnected. Yes, always get new gasket / seal / o-ring for similar work.

As for how often should we replace the brake (and clutch in your case) fluid, IMO it’s weather and environment related. Most Euro car makers have 2-year replacement interval, but American and Japanese car makers suggest none. I’d get a brake fluid tester testing the moisture level. If it’s 2% or higher, replace the brake fluid.

I wonder if you’re going to DIY replacing the clutch when the time is come (and shouldn’t be too far away from now in your city driving environment at 100K miles)? ;)
Master ~ $65, Slave ~$50 + Tax.

Bleeding for both brakes and clutch was done with my wife pumping the pedals while I open/close the bleeders. No issues there.

I doubt that I will be doing the clutch swap my self and the "cheap" shop quoted $1300-1400. I am hoping it will last me 3 more years with 10 miles suburban commute and then I am due for...wait for it... Miata :).
This CX-5 though, being the very first model, turned out to be super reliable car. This clutch job was the very first issue I had with it and that is with minimal to none maintenance. I did notice one of the rear shocks started leaking so 100k miles is finally showing it's toll.
 
Master ~ $65, Slave ~$50 + Tax.

Bleeding for both brakes and clutch was done with my wife pumping the pedals while I open/close the bleeders. No issues there.

I doubt that I will be doing the clutch swap my self and the "cheap" shop quoted $1300-1400. I am hoping it will last me 3 more years with 10 miles suburban commute and then I am due for...wait for it... Miata :).
This CX-5 though, being the very first model, turned out to be super reliable car. This clutch job was the very first issue I had with it and that is with minimal to none maintenance. I did notice one of the rear shocks started leaking so 100k miles is finally showing it's toll.
The clutch master cylinder is much cheaper than I thought.

It seems your wife is very helpful! I usually have to wait until my wife is having a good mood and do the 2-man brake fluid flush ⋯ ;)

Do you intend to change the gear lube for your manual transmission? And check your belt tensioner if you haven’t replaced it yet ⋯
 
The clutch master cylinder is much cheaper than I thought.

It seems your wife is very helpful! I usually have to wait until my wife is having a good mood and do the 2-man brake fluid flush ⋯ ;)

Do you intend to change the gear lube for your manual transmission? And check your belt tensioner if you haven’t replaced it yet ⋯
I already replaced the trans oil. Are the belt tensioners common failures?
 
Back