Need some help. Rear caliper

[Rocketron]

Hey guys

Really needing some advice here, had a buggered piston on my off side rear caliper so I stripped it, managed to remove the clip and remove the piston internals and replace the piston etc. The problem that has arisen is not being able to bleed the caliper properly.

I'm using a pressure bleeder, flushed plenty fluid through no air but I do have a spongy pedal, defo air in behind the piston, no air got up to the master cylinder, now I'm thinking I should have filled the piston with a little fluid prior to putting it back into the caliper?

Seeing as I never done this if I removed the caliper from the carrier and tilted it up and pressurised the system again would this help remove the trapped air?

 

[Rocketron]

Pressurised and re bled obviously lol

 

[Rocketron]

Anyone? Your help would be appreciated

 

[Stephenvenning]

Air is probably leaking through the threads of the bleed valve hence making the pressurised bleeder useless. Get another person to pump the pedal while you operate the bleed valve. This should get rid of the trapped air.

also did you make sure the clip was in properly? They can look like there in properly, only to pop out after a while causing you to loose the handbrake.

 

[Rocketron]

Air is probably leaking through the threads of the bleed valve hence making the pressurised bleeder useless. Get another person to pump the pedal while you operate the bleed valve. This should get rid of the trapped air.

also did you make sure the clip was in properly? They can look like there in properly, only to pop out after a while causing you to loose the handbrake.

Thanks for getting back to me.

Yeah I'm certain the clip was seated properly, I had the car jakes up and repeated checked the handbrake was working.

Have you had issue with this before after rebuilding rear calipers? Should I have put some fluid into the mechanism prior to refitting?

I'll do it old school and get someone to pump the pedal and see how I get on.

 

[Rocketron]

Just to add I'm not vacuuming the air out im pressurising the system from the resivoir

 

[Womble]

You need to have the piston fully wound in. An air bubble forms behind the piston and you can't shift it, so you need the piston fully home. Also if you just open the bleed nipple and manually pump the fluid through, until it runs out under gravity. Then bleed it.

 

[Rocketron]

You need to have the piston fully wound in. An air bubble forms behind the piston and you can't shift it, so you need the piston fully home. Also if you just open the bleed nipple and manually pump the fluid through, until it runs out under gravity. Then bleed it.

Thanks womble, so take the caliper off the carrier and lower it towards the deck, tilt it nipple up and wind it back in with the nipple opened?

Then bleed it as normal?

 

[Rocketron]

Gravity bled prior to normal bleeding as you said

 

[Womble]

Fluid should run out with gravity with caliper still on the car. Yes wind the piston all the way in.

 

[Rocketron]

Fluid should run out with gravity with caliper still on the car. Yes wind the piston all the way in.

Got it done last night, what a difference, done exactly as you said and worked a treat, I bled the whole system.

Thanks again