Front caliper rebuild questions

[sujitroy]

I'm rebuild some spare calipers.
1) since there is only one hole where the piston sits in the caliper half and fluid goes in there. During brake bleeding where does the air in the caliper cavity where the piston sits go? I can only assume you stop bleeding, close the bleed screw , wait for some time until the air raises to the top and then bleed again. Is my assumption correct?

Also in the first photo, what is this screw for?

Here are some photos of the split caliper with O ring and measurements. The O rings which came out are soft and pliable so I don't believe they can be original. The new O ring from JP in the kit is slightly bigger in diameter than the original, but squeezes in OK.

For those of you who have separated the calipers, was that O ring hard and brittle?

Sujit,

[new to this]

In picture 1 shouldnt that bolt be a bleed screw
when i split my calipers it was a long time a go now, but they were not hard and brittle, i got all my bit from Paddocks,i used 2 O rings,but i did put a spacer between mine, to be able to run vented disc

[trunt]

Just did this.

There are 3 channels and think the way the channels are arranged for both pistons the air is forced out by the Incoming brake fluid. I have never waited, just keep pumping until there is no more air bubbles.

My old seal was not hard, it was in remarkably good shape, the new one was also very slightly oversized but went in the hole nice and snugly.


Terry

[trunt]

On the bolt/ bleed screw mine were different on the two calipers. I chose the highest point (but it’s marginal) for the bleed screw which when installed is the same way as in Sujit’s picture, also if you put the “bolt” in the other position it screws in almost to the head which didn’t look right.

it seemed to me that you could replace the “bolt” with another bleed screw, it’s just a blind bleed screw.

found a picture..thats how I have mine..

1298-Large.jpg

[sujitroy]

in the caliper half where the hose connects there is another hole for air. it was covered in crud. need to investigate the other half