Topic: cb550 master cylinder disassembly issue - not the circlip

[xruss]

I'm having trouble figuring out how to remove the old piston from the master cylinder on my 76 cb550.  I've pulled off the lever, removed the rubber sleeve, and managed to pry out the circlip with a pick.  Now what?  I don't see any other piece that needs to be removed, but that old piston isn't coming out.  It has spring action to it as well, so I don't think its simply frozen up.  What am I missing?  I have the rebuild kit ready to go. 

[Bob Wessner]

Are you sure you 'ge removed the 'real' circlip? It usually requires something more substantial than just a single pick to remove.

[xruss]

Unless there's more than one, yes, I got it.  You got me though, I used two picks.

[Bob Wessner]

OK, two would work. Perhaps there's some corrosion??

[aperry]

I think the rubber boot has a little circular clip that holds it in place.  Is it possible that you remove that (and not the "real" circlip)?  Sometimes the circlip is kind of hard to see because all that is visible is the two little tabs that you use to remove it.  And they're often covered in crud.

After the circlip is removed, I think the piston comes out quite easily.  I think you can poke at it (with a rod or something) from the opposite side to push it.

[xsmooth69x]

try soaking it in some PB penetrant or some seafoam.

this is everything inside ur mater cylinder. if you got out the evil atrocious c clip (in green) that is all that is holding things in place.

if you take a small screw driver and wedge it where the red circle is u might be able to pry it out. if not give it a quick soak and try again

 

[xruss]

There's the little round retainer for the rubber, then the full on circlip.  It was covered in crud, but I was able to scrape it out.  I actually broke a tab off of side of it yanking it out of there, but it came. 

Not sure what exactly comes out though.  There is the piston itself in the middle, but it seems the circlip holds in place a larger diameter piece that surrounds the circlip.

[aperry]

The thing is spring loaded.  I think it should noticeably "pop" outward once that dreaded circlip is removed. 

I honestly think you'd be swearing more right now if you removed the real circlip.  In the photo of the parts above, notice the small secondary clip that holds the boot on.  Did you end up removing both clips, or just one? 

[xruss]

I'll hit it with some PB, but it still seems like with as free as the piston itself is in terms of spring action, it should come out. 

[xruss]

I definitely got the circlip with the two holes out.  I'll give it another look to see if there's something else there, but I'm 99 percent sure I got both out. 

[aperry]

Ok, I'm convinced, I guess you did remove it!  Well done!!

Yeah, there's a washer under the circlip.  It should not prevent the piston from coming out though.  Maybe it's locked up with rust/crud?  If you push on it from the other side (through the bore), just be careful not to scratch the bore.

[xruss]

Well, I have it another look and confirmed both rings are out.  I can see the groove that the circlip sat it and it is clean all the way around.  It appears that the washer is stuck.  I couldn't tell before that it was in there, but from the parts diagram above as well as my refurb kit, that's my problem.  I've hit it with some PB, so we'll see.  I tried pulling on the piston with pliers and tried tapping it out from the other end, so it must really be gummed up somehow in there.

[Tugboat]

40-year-old brake fluid really does a number on these things!

[CoachDoc]

In the past I've read that since the brake fluid  is
water soluble, boiling the MC in water might dissolve some of the crud and free up that washer to get the piston out. Never tried it myself, but it makes some sense. I had the the same problem with the circlip and the other bogus clip. One of the toughest parts of my restoration was getting that MC apart. Good luck.

[xruss]

To close the loop on this, I hit it with some PB Blaster, let it sit for a couple of hours, then used a punch and hammer to drive it out from the other side.  After seeing the gunk, I can understand why it didn't want to break free.  I just needed some reassurance that there wasn't something else that needed to be removed before I used a little good ol' fashion persuasion in the form of a five pound hammer.  Thanks all.

[goldarrow]

Good that you got them all out. Now make sure that you clean the two holes in the reservoir real good.

May be let it soak in hot dish soapy water over night and use air compressor to blow the crud out. But clean it real good though.