brake pedal soft

[mustnt-grumble]

in the middle of overhauling front caliper brakes.
bleeding the front calipers, got a good action and good pedal.... until engine starts, and now the pedal will go all the way to the floor.
Never really understood the vacuum power brake assist system.

I guess it just means that there is still air or a leak in there somewhere does it? or is there some possible malfunction in the vacuum thingy that could let the pedal go all the way down yet hydro still ok?

I accidentlay let the reservoir go rather low the other day so it is possible that air got into the rear circuit which i hitherto havent touched.

[joinerman]

Check the flexi pipes are not ballooning up when you press the peddle.

[mustnt-grumble]

flexis look ok but very old so think will replace.
got the calipers back on the disc and pedal seems to have settled down hard at mid stroke. so I guess that is fine.

the wheel is spinning free when the brake gear is off. I mean really free. bearings are about 4000 miles old, so theyve bedded in, and the wheel itself feels A1 perfect on the spin.
When I put the caliper back on, with the pistons "reset", right back, the wheel is still fine and free.

I then press the brake pedal, and the brakes apply: they're working fine - as brakes.

however, from this point forward, the wheels are no longer fully free. they are free enough to turn with one hand, but it's a slight effort, and no longer do they continue to spin free when you give them a shove.

this is clearly because the brake pads are not backing off fully clear of the disc when the brake pedal springs up.

should the wheels spin fully freewhen the brake pedal is released? or is it reasonable to expect a slight bit of touch from the pad? the pads are I think remaining just in contact with the disc, there is zero squeeze there (otherwise I wouldnt be able to move the wheel at all)

whilst Im on about it, what, WHAT, are the leaf springs actually for? I have always wondered that. (I mean the springs that you always get with new pads that clip on to the caliper)

NB I should say, in all of the above waffle, this is spinning the hub with the studs only: the roadwheel is removed.

[Chug]

The hub should turn freely with the wheel fitted, it will be hard to turn without the wheel on.
The spring clips are anti rattle plates, to stop the pads rattling.