No bolts for new spindle

My son is putting the Avis adjustable beam and disc brakes on his 1970 Beetle.

We hit a problem: there are no bolts to attach the calipers to the new spindle. Does anyone know what size bolts these are? We have tried M10 x 1.50 and M10 x 1.25, neither of which work.

Update: problem solved. They are M10 x 1.50. I couldn't get this size in finger tight before and was scared to strip the threads. But with a little pressure on a spanner it went in and is the right size. Now to install the calipers.

New brake lines (steel)

As could be expected, the steel brake line servicing the back wheels was rotted, so we took it out and replaced it with a new one (blue in the pictures).  We had to bend it into shape first so it would fit over the transaxle.  Then we had to connect it with the brass fixtures which connected it to the main brake line and the rubber lines to the wheels (these other lines aren't shown in the pictures).  After that we had to fit the line into the place the old one had been, and get it onto the bolts that are supposed to hold it in place. Understandably, we hadn't got it bent quite right at first, and so it was a tough job getting it in.

new brake line (blue) from right side

new brake line (blue) from left side

Disc brake conversion

Fuel Tank and Line Check