Clutch Biting Point Moved

Hey all, I'm creating this thread to share the symptoms, diagnoses and solutions I found when my clutch pedal feel and clutch biting point started to change this winter for my 2010 Mazdaspeed3 with 140,000kms.

The Original Symptoms:
After some regular highway driving, I started to notice the biting point for my clutch was off. It started biting way closer to the floor, any movement from the bottom and it would be ready to go into gear. I also noticed this while parked, going into first gear was much less graceful. The problem then got worse as I would come out to my car in the morning and need to pump the clutch 5-10 times in order to get it to go into gear at all.

The 1st Diagnosis:
I checked the fluid level first, no change, still at the max line. No obvious leaks either at master or slave cylinder. Following advice from the other posts on this issue, I had my mechanic bleed the clutch system from the slave cylinder. Upon bleeding the system, the master cylinder died, the seal went and fluid would not stay in the chamber. I had a new master and slave cylinder ordered to mitigate having the slave cylinder failing in the future.

The 1st Solution:
I had my mechanic install master and slave cylinders, bleed the fluid from the clutch system and new fluid went in. All air bubbles and old fluid were bled out of system via the slave cylinder. I test drove the car and no initial pumping of the clutch was required to get it into gear, but the biting point on the clutch was still near the bottom of the floor again. I deemed this acceptable and took my car home.

The New Symptoms:
After a week of driving the clutch biting point started to move again. While driving I could have it bite near the floor, near the top or have the pedal go to the floor with little pressure and lock me in/out of gear. The pedal could be lifted up from underneath with my foot and then would require pumping to build pressure again.

The 2nd Diagnosis:
I did another inspection of the fluid level, newly installed master and slave cylinders, brake lines, and calipers but found no leaks. I had my mechanic bleed the brakes to see what fluid looked like since the brakes share the same system as the clutch (it's baffled but old fluid can make it's way into the new fluid). Upon bleeding one of the brake calipers the fluid came out brown and far less viscous than the new fluid that was installed last week. We had also experienced -25C weather recently, so it is very likely that ice crystals were forming in the brake lines, getting sucked back into the clutch system, thawing in my heated garage and creating water/air pockets in the clutch's part of system.

The Final Solution:
A full 4 wheel brake bleed was preformed to evacuate the entire system and new fluid went in. Upon test driving for the last 2 days, the clutch and brake pedal feel has improved dramatically and the biting point for the clutch has remained where it should be. For me that's about half way through releasing the clutch.

Hopefully this post is helpful for others. So far I haven't seen anyone else with clutch issues like this report bleeding the ENTIRE brake fluid system. Remember to service all of the fluids in your car. I've owned the car for 2 years now, put just over 40,000kms on it but didn't have all the fluids changed when I bought it (just oil and coolant), so it was very much past due. Had I told my mechanic this in the first place he probably would've recommended doing the full flush the first time around. Live and learn.

 

Glad you got it sorted, I find myself changing out my fluid brake / clutch every 2-3 years or 25-30k km.

My thought when you said it was cold in the morning and worse was fluid in the lines, speaking of which it's time for me to do it again in the spring it's been 2 years.

 

Since the clutch and brakes share a reservoir you always want to bleed both at the same time.

You should also inspect your clutch pedal and the mounting bracket to make sure they aren't cracked and failing