Air in braking system
Discussion
Morning Gents,
Any ideas again regarding the ongoing saga of Princess caliper upgrades and master cylinder replacement.
At the moment I have replaced mc and carried out the princess caliper upgrade.
I am still getting a pedal which isnt constant and firms up when pumped.
Further really weired is when reversing and applyinhg brake pedal sinks further down then returns once moving in a forward direction ?
I have pressure bled, carried out two people bleeding and gone round and round and still feels like air.
I did not however "pressure bleed " the master cylinder before I fitted it and am now wondering if this could be the issue.
I have opened the outlets under pressure and still no difference.
Help do I seriously need to remove the master and start again ? or could this be a dud master cylinder ?
Any ideas would be appreciated.
Regards
Braveheart
Any ideas again regarding the ongoing saga of Princess caliper upgrades and master cylinder replacement.
At the moment I have replaced mc and carried out the princess caliper upgrade.
I am still getting a pedal which isnt constant and firms up when pumped.
Further really weired is when reversing and applyinhg brake pedal sinks further down then returns once moving in a forward direction ?
I have pressure bled, carried out two people bleeding and gone round and round and still feels like air.
I did not however "pressure bleed " the master cylinder before I fitted it and am now wondering if this could be the issue.
I have opened the outlets under pressure and still no difference.
Help do I seriously need to remove the master and start again ? or could this be a dud master cylinder ?
Any ideas would be appreciated.
Regards
Braveheart
When I put a new m/c on I make sure to fill it with fluid before connecting to the car pipes to minimise air going into the system.
Anyhow yours is on now and must be full.
If you bleed out of one of the calipers do you still see any air bubbles in the bleed pipe?
How far is the pedal traveling - engine off/no vacuum?
Anyhow yours is on now and must be full.
If you bleed out of one of the calipers do you still see any air bubbles in the bleed pipe?
How far is the pedal traveling - engine off/no vacuum?
Thanks for all your replies.
Hoses are braided and were all ok before the " upgrade "
Adam thanks for reply pedal firm and 80% ok but every now and again it drops slightly and comes back up when pumped slightly = No confidence on the road !
Have put nearly 200 miles on them now and dont feel like they are biting enough.
I have " cracked open " the ports on the mc while pressurising the mc with no change also.
As said really weird bit is reversing produces a sinking pedal which comes back up after moving forward.
Jack Valiant was saying took four attempts to get air out so may just have to resign my self to a whole day with the pressure bleeder of going round and round and round to see if this may do it !
All the best
Braveheart
Hoses are braided and were all ok before the " upgrade "
Adam thanks for reply pedal firm and 80% ok but every now and again it drops slightly and comes back up when pumped slightly = No confidence on the road !
Have put nearly 200 miles on them now and dont feel like they are biting enough.
I have " cracked open " the ports on the mc while pressurising the mc with no change also.
As said really weird bit is reversing produces a sinking pedal which comes back up after moving forward.
Jack Valiant was saying took four attempts to get air out so may just have to resign my self to a whole day with the pressure bleeder of going round and round and round to see if this may do it !
All the best
Braveheart
Sinking pedal...I would say leaking master or Slave cylinder..Air definitely is the culprit..Are you losing fluid?..If it were me i would take it to someone to sort..I don't personally touch brakes or clutches but never drive if either are dodgy..Brakes especially as thats what stops you hitting things like...Other cars...Trees...Buildings...Animals & People.
If you have facilities and are confident in what you are doing then check all the brake lines for leaks..Banjos for leaks...Servo for leaks...
You shouldn't be having this much grief bleeding 4-pot calipers...
If you have facilities and are confident in what you are doing then check all the brake lines for leaks..Banjos for leaks...Servo for leaks...
You shouldn't be having this much grief bleeding 4-pot calipers...
Reversing causes the pedal to sink? Curious...
I wonder if what you're feeling is not an air lock but simply the piston moving back without any resistance; and something is pushing your pistons back into the calipers to cause this.
It could be that one or more of your discs is not running true and the rotation of the wheel/disc is pushing the piston(s) back into the caliper.
It could also be something odd with the pads or anti squeal/rattle shims/springs. I've seen some pads with a dense foam/rubber backing which could cause this effect; and some spring designs have weird fitting arrangements that are not intuitive and if used incorrectly might cause some weird things with how the pads sit in the calipers.
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