3R - Soft Brakes?
Discussion
Recently got my 3R back from my friendly dealership having taken it in concerned about an 'abnormally soft' brake pedal. They have performed a fluid change and bled the brakes and returned the car with a clean bill of health. However, I still don't like the pedal feel at all - pedal must move a good couple of centimetres before any bite and will quite easily depress 3-4 cm or all the way to the pedal stop under spirited use. Should the pedal be any harder than that or is it a case of TADTS and fork out for the necessary brake upgrades? Heel and toe in my car is impossible due to the fact that the brake pedal sits about 4-5 cm below the normal position of the throttle pedal.
Any advice or comments gratefully received!
Any advice or comments gratefully received!
Does the pedal remain constantly soft and have the same amount of "free play" in it no matter how many times you press it, or does only the first press feel soft, and each subsiquent press feel good until about a mile down the road?
If the latter of the two is true, then it's probably a loose wheel bearing as Phil said.
Basically what happens is the brake disc wobbles due to the loose bearing during corners, as it follows what the hub does (where your wheel bearing is situated). The lateral movement of the disc actually pushes the pistons in the caliper back away from the disc when it is in its normal position.
What this means is that the first time you press the brake pedal after a corner, the pistons will have to take up the slack between where they are, and where the disc is. That is why you feel the pedal drop much further than normal. Of course, after this initial press of the pedal, the pistons are back where they should be and everything feels fine again - until the next corner that is.
It's called pad knockback. Lots more info here:
www.stoptech.com/tech_info/wp_knockback.shtml
If the pedal feels squishy the whole time then please ignore all of the above post.
If the latter of the two is true, then it's probably a loose wheel bearing as Phil said.
Basically what happens is the brake disc wobbles due to the loose bearing during corners, as it follows what the hub does (where your wheel bearing is situated). The lateral movement of the disc actually pushes the pistons in the caliper back away from the disc when it is in its normal position.
What this means is that the first time you press the brake pedal after a corner, the pistons will have to take up the slack between where they are, and where the disc is. That is why you feel the pedal drop much further than normal. Of course, after this initial press of the pedal, the pistons are back where they should be and everything feels fine again - until the next corner that is.
It's called pad knockback. Lots more info here:
www.stoptech.com/tech_info/wp_knockback.shtml
If the pedal feels squishy the whole time then please ignore all of the above post.
Thank you for the replies. Pedal feel is soft all of the time and cannot be firmed up with just a couple of applications. Pads are new, fluid just changed and brakes bled within last 2 weeks. I am concerned that perhaps a small leak is allowing air back into the system at either the master cyclinder or at a calliper; to avoid simply re-bleeding the whole system, is there any better way to pressure check brakes?
Al D said:
Thank you for the replies. Pedal feel is soft all of the time and cannot be firmed up with just a couple of applications. Pads are new, fluid just changed and brakes bled within last 2 weeks. I am concerned that perhaps a small leak is allowing air back into the system at either the master cyclinder or at a calliper; to avoid simply re-bleeding the whole system, is there any better way to pressure check brakes?
Could this be a duff master cylinder? internal bypass?
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