Right, got away from work early today but still on-call so can't get down and dirty with Peggy in case I have to rush back in. So I went to the lock-up to see if I could find the spare m/c. 5 mins later it was in my hands. It was supplied by Speedys a couple of years ago (three and a half!) for Madge, my '67 Singer Vogue. When it arrived the piston would not move a mm, even when I pushed the push-rod against a wall and put all my body weight on it. It's a pattern part with a plastic reservoir made for, amongst others, the Peykan! Anyway, I called Speedy and told them about it. They sent a 'normal' metal bodied one which worked fine. I asked about sending the faulty one back and they said not to bother, "Just put it in the bin".
Well, not one for throwing stuff away I just put it in the lock-up and forgot about it, which brings us back to today. Got it home and the piston was still stuck. I removed the push-rod assembly then dowsed the top of the piston and the other end with some silicon lubricant.
I left it for 30 mins then holding the push-rod against the top of the piston, started to tap lightly on the push-rod. I slowly increased the 'weight' and after about a minute the piston moved. I could then push it down and look at the bore. There was slight surface rust at the very top which must have 'fused' the piston in place. I was able to get some scotch pad in there and clean it up. Liberal doses of the silicon lube and cleaning out has removed all traces of the rust leaving a smooth bore.
I'm going to use some compressed air to remove the piston (it won't come out with tapping) and give the seals the once over and also give the bore a final check. If all is well I'll re-assemble and fit it to Peggy. I'm making the huge assumption here that the m/c for the 1725 Vogue is the same as for the 1725 Commer!
Peggy can do 78mph!
If I told you I was a pathological liar, would you believe me?