Removing the brass cover plate and then the cover plate beneath I discovered the mechanism was sat in water and had probably been that way for years.
I decided the only way forward was to drill the box from the floor which took over 5 hours of continuous drilling, eventually I removed the box to see the protrusions underneath the box and understood why it had been so difficult to remove from the floor. I then quickly removed two later Yannedis supplied 400's that had their pins cut off, packed my tools away and grabbed a bag I was handed earlier which I found out contained two versions of more modern model Gibbons.
Leaving site at around 5.30pm I ran into the notorious London rush hour traffic, arriving home at 9.30pm, dirty and tired.
Today I started work on the Gibbons at 8.30am, getting it back together at around 5.30pm after fabricating a new leather seal, changing the broken springs, drilling out a few snapped screws and re-tapping the holes.
I benched tested the Gibbons and discovered the piston was only working for the last 20% of the swing, I will now strip the Gibbons on Wednesday to find the reason/s for the poor performance of the piston/Gibbons floor spring.
Work continues on with the Gibbons pneumatic floor springs and the more modern hydraulic type from the Star & Garter.
Last week I managed to take out 4 newer hydraulic Gibbons, these are far easier to remove because they are housed in a box that is separate from the floor spring itself. This therefore requires no drilling of the concrete to remove them from the floor to work on them.
I have also removed the component parts only from 8 of the much older Gibbons, in an attempt to speed up the repair process to save time and money. I also returned the two repaired/serviced single action 'modern' Gibbons and temporarily re-fitted the Gibbons I had to drill from the floor the previous week, only to find out that the shoe on the door is rusted/seized up solid, meaning there will be a problem in the centering of the doors when eventually rehung permanently if not attended to.
Below of some shots from the front/street side of the site.