Vintage BMW Motorcycle Owners

Couple of questions:

1) The rebuild kit instructions state that the "easily damaged" seal (on the piston) should be guided into the cylinder bore with an "assembly awl." I don't have an assembly awl and I don't want to damage the seal. Do I really need an assembly awl? If not not, does anyone have suggestions about how to safely insert the piston??

2) When I took off the circlip, the spring and washers popped out onto the table and I didn't get a chance to see what order they were in . . . . Is the order of the spring and washers in my photo correct? I think it is, but I don't want to mess it up.

I don't remember having much of a problem when I rebuilt the M/C on my /7 a number of years ago...I didn't have an awl but was able to get the rubber seals in place.

As for general how-to, check out Brook Reams site on rebuild of an R75/6 master cylinder:

https://brook.reams.me/bmw-motorcycle-r ... k-caliper/

I rebuilt the master cylinder on my 100S. All the new parts fit easily except for the front seal on the piston. Somewhere on the web I found that this could be installed without damaging the seal by using the plastic tip of a tube of caulk, the kind designed for caulking guns. You have to cut the tip off the tube at a diameter equal to or slightly larger than the diameter of that part of the piston, call it a ring, that the seal fits behind. Fit the large end of the tip over the end of the piston so that it fits over the ring and then, using a little brake fluid as a lube, or not, slide the seal over the small end of the tip and then back over the ring until it fits where it should on the piston. Worked a charm.