rear disc master cylinder INLET GROMMET available pn 110312710

[gtgt_bangbang]

Brembo Rebuild kit for the rear brake master cylinder does not include the inlet grommet ( grommet on top , where spigot for the hose in from reservoir attaches.)
Seems slacker of them; how to do a complete rebuild without the exposed rubber , loose & cracked seeping up there ?

No PN for this grommet in bmw bike fiches as far as I could find.

Bremo offer a replacement grommet + spigot as a Ducati part , apparently for reservoir relocations;
'78 uses the 0deg / straight spigot (PN 110312710) , but there are 45 & 90 angled spigots too , if you're into the kinky stuff.

A quick gander on duckduck finds the kit from $4 to $20 ,

Ought to get to that install soon, the new grommet sure looks & measures similar to the mushy mass that came off mine, but will update thread if there is some issue inserting it.



related ;
There is a 5/8" dia ball hone , close enough / suitable for both F & R on my model.
I broke-in a new hone in with a couple scrap-pipe passes before unleashing it on the soft aluminum cylinder at rear.

The iron master cyl, up front/undertank, was still pitted after honing , so got the Appleton Hydraulics "brass insert" treatment.
They took their time ( almost miraculously , the " adhesive drying this very moment) when I finally got through to them after ~3 weeks of no news.) but the repair looks fine


I saw a couple of Duc rear masters (available new) that look similar to the airhead part ( NLA new) , might be workable replacement
Most have different levers , but recall that one had the lever coming off same direction as airhead's , might be a swap

 

[oldcamper]

It fits pretty tight. A very light film of the Brembo silicone grease may help with the install.

As for availability, Brembo’s OEM contract with BMW may be different from that with Moto Guzzi or Ducati. Brembo might not be allowed to sell BMW specific repair parts to anyone other than BMW, and that could well become an issue if BMW decides not to handle the replacement/repair parts anymore. Hopefully China or India will soon step up. Similar but not exact replacement cylinders sell for less than $30 new and complete on Ebay

 

[20774]

What bike is this for?? Helps those that are trying to follow along.

 

[gtgt_bangbang]

What bike is this for?? .

... Mine !

actually while I mention a '78 up ^^ there ( briefly, as I try not brag too too much!), I figure any REAR DISC - BREMBO may? be a candidate ,
but I'm not really In The Know to find all applicable models, so rather not make wooly claims.

best of my knowledge, similar vintage REAR DISC used that same master cylinder body.

The biggest left down while looking for a rear master , was searching the numbers on my casting, finding a NEW and very cheap Duc master having the same casting numbers,
but seeing the lever pivot design was incompatible. ( why the same PN ? dunno. never been an Italian engineer ..

agree that model/MY is a good fact for a lot of posts but this one just included hopefully adequate key words to be a steppin stone to s/one's search and leave it at that

 

[20774]

I still think it's beneficial for people to know what you're working so they can judge how it might affect them...give them something to look for in their own wrenching.

From your past posts, when asking for under tank photos for a '78 R100, that strongly suggests that's the bike you're working on!!