New rear brakes

[Gaz mr-s]

I'm installing new rear brakes with refurbed calipers. 

I bled the calipers yesterday evening. I made the mistake today of having the handbrake cables connected, & I wasn't getting a 'good pedal'.

Read a 'how to' again & released tension on the cables & the clevis pins came out as they should.
I re-did the 20 pumps & the pedal is softer still. Perhaps it needs bled more?

But before fitting the calipers I tried the piston wind-back.  I've never had new calipers before, so wasn't quite sure what to expect. I turned & turned. I thought the piston seal became 'scrunched-up', but not certain, but the pistons did not seem to turn back into the caliper body.

Is the above paragraph  what should be expected? If so, what's the next step.?

[Bossworld]

I'm installing new rear brakes with refurbed calipers. 

I bled the calipers yesterday evening. I made the mistake today of having the handbrake cables connected, & I wasn't getting a 'good pedal'.

Read a 'how to' again & released tension on the cables & the clevis pins came out as they should.
I re-did the 20 pumps & the pedal is softer still. Perhaps it needs bled more?

But before fitting the calipers I tried the piston wind-back.  I've never had new calipers before, so wasn't quite sure what to expect. I turned & turned. I thought the piston seal became 'scrunched-up', but not certain, but the pistons did not seem to turn back into the caliper body.

Is the above paragraph  what should be expected? If so, what's the next step.?

There comes a point where you are no longer compressing the piston and are just rotating it.  Particularly useful if, when trying to wind it half a turn out to engage the mechanism, you're not fully aligned with the nipple on the back of the pads.  That's the point at which the boot would start to look crumpled.

I replaced the rear nearside caliper on my mum's car a few months ago and I think I had to bleed the system through three times, I just wasn't happy with the pedal action.  My own car is shockingly sharp/good on the brakes, but then again everything's been renewed.

Having the handbrake cables connected in itself, shouldn't impact the hydraulic action, I don't think it would be standard practice to disconnect them or slacken them for a fluid change?  Unless you've got them too tight?  They're meant to be practically resting on the stops with the handbrake off.

[thetyrant]

Soft pedal could just be the pads and discs not bedded/shaped together, are they new discs ?  if they are used discs with new pads it makes problem worse as discs dont tend to wear down and remain flat/parallel to caliper but get a slight taper, so when fitting new pads its having to tip the pad slightly which gives the soft pedal.

You still get this to adegree even with new pads and discs together but generally not as bad, ive lost count of the amount of people that have complained about soft pedal feel after fitting new pads but not completed a good bedding in session to get pads/discs worn to shape for full contact etc.

Of course you need to be sure everything else is good but if you are then just drive it and do some braking to bed pads/discs together as there is no other way.

HTH

[Gaz mr-s]

Ok chaps thanks. Good to know about the piston rotating.
I'll try bleeding again just to check.

[Gaz mr-s]

2nd bleeding attempt did get more air out.  But still the pedal is too long before feeling anything, perhaps moving an inch, maybe more when the engine's started bringing in the servo.

Only the rear brakes have been worked on. When the lines were disconnected at the calipers can the air travel far enough up the pipes to require the front needing bled NOW.?

I would like to use the car tomorrow, but dodging the rain, so time-limited.

[Joesson]

2nd bleeding attempt did get more air out.  But still the pedal is too long before feeling anything, perhaps moving an inch, maybe more when the engine's started bringing in the servo.

Only the rear brakes have been worked on. When the lines were disconnected at the calipers can the air travel far enough up the pipes to require the front needing bled NOW.?

I would like to use the car tomorrow, but dodging the rain, so time-limited.

Yes. I've only ever bled all four corners, starting with the furthest from the reservoir and finishing with the nearest.
PS . Make sure you keep the reservoir topped up while you are bleeding, otherwise you will reintroduce air and have to start again. Check after each corner at least.

[105e]

I have heard a piece of cling film over the master cylinder when disconnecting the brake lines helps with fluid loss..

[thetyrant]

Bleeding all 4 corners is best just to be sure but i still think  a drive to bed/shape discs and pads together is probably all thats needed, just go easy at first in case it is something else.

Were they new discs or used ?

[Gaz mr-s]

New, Ian. 
I'll get more fluid today & do the fronts tomorrow.

[thetyrant]

OK i would just get out and drive it then, im pretty confident once you get pads and discs squared to each other the pedal travel will be gone, providing of course you done everything else correct which it sounds like you have.

It needs very little extra movement at the caliper to take up pad slack/out of square etc to make a noticable difference at the pedal, if there is no leaks and youve give it a good bleed then should be safe to drive and bed discs/pads together, just take it easy initially to be sure it doesnt get worse.

[Gaz mr-s]

I've got more brake fluid, so I'll see if there's air in the front tomorrow.