Master Cylinder Piston (FB)

[jjwaller]

Hi Folks:
Been lurking for a while, first post.

Fantastic site, learn alot.
Have 78' E model.
Trying to clean all the spooge out of the front master cylinder.
Thought I had done it last time, but front brakes still slowly
begin dragging after a while.

Question. How does the piston come out of the master
cylinder? I dont see a lock ring or anything. Need to get it
out to clean and probably install a new rebuild kit due to the
amount of corrosion and water found in there.

Thanks much
John

78' XS1100
81' CB900C

[dragxs11]

retaining ring is located behind the rubber boot. It's buried in there, and not too easy to get to. I, and many others have opted for the partsnmore.com master cyl instead of messing with the old one. There are two different master cyl's on xs's.... either with a slanted reservor for long bars, or a straight one for short bars. The partsnmore replacement best accomodates the latter.
Matt

[prometheus578]

If the master cylinder looks like that, may want to disassemble the calipers and give them a good cleaning, too.

[jjwaller]

Good idea about the calibers. Next on list.
Ordered new master cylinder form Partsnmore.

Thanks much for help.

John



'78 XS1100
'81 CB900C
And looking

[andreashweiss]

Afyer you install new master cylinder if your brakes still drag check the caliper slider that has the rubber seal. This caused me endless frustration until I found out why calipers still dragged. Just take apart and clean polish etc. lube it up so it slides better.

[Ken Talbot]

Aw, c'mon now, don't be afraid of a little spooge. Get the rubber boot with its spring retainer out of the way and do a bit of digging. In this shot, you can just make out the two small holes in the circlip that holds the plunger in the master cylinder. You'll need a fairly slender, long nose pair of circlip pliers, but it can be done. It also helps to depress the plunger a bit so the tips of the pliers can get well seated into the holes rather than being limited by the washer just under the circlip.


With a bit of care, you may find you don't have to buy anything at all, if you just get it all clean. Just for reference, this is a rear master cylinder which usually tends to be in worse shape than the front, and you can't get these from Parts'n'More.