Dear All, off my newly acquired Le Mans Mk II, I’ve stripped the rear brake master cylinder with a firm tap with a thin punch, the knock-out type, no circlip involved. The rebuild instructions are for the circlip type, so are not much use (in 17 languages!)
The anti extrusion ring fits over the top hat seal, lip facing inwards. I assume that the whole lot is held in with a brisk tap to the flat washer, which somehow locks the assemble in place but no luck so far.
I’ve checked on youtube, but all the videos work on the circlip type, so any ideas of how the assembly is fixed into the master cylinder guys please ??
I managed to push mine in carefully with a very fine screwdriver, working around a bit at a time. As for which way round it is supposed to go, I have no idea. First time I tried the whole piston kept popping out so I tried it another way round and it bit the second time.
It is not an easy job trying to hold the piston down whilst trying to push the ring into place. I have heard you can use a short piece of 15mm copper pipe to push it into place. Not tried that one myself.
Whilst you have everything apart, make sure the 2 holes in the bottom of the reservoir are clear or you will have a nightmare bleeding the brakes.
Also make sure there is a tiny bit of free play between the pivot arm and the end of the piston. That will also prevent the brakes bleeding as it holds the seal over the hole that supplies fluid from the reservoir into the main chamber.
I remember tapping in the (new!) retaining washer using a tube and hammer, which I think you have to do against the spring as well. Wasn’t difficult, provided you got a suitable size bit of tube.