Front brake master cyclinder

[Guest]

I got the piston in the front brake master cylinder to move, and I can hear air moving through the hole where the brake hose goes. However, when I hooked it to the hose, filled it with fluid and pumped the handle, nothing came out. A few air bubbles come up. I took the screw out and pumped the handle again, but no fluid came out of the hole.

I have not been able to remove the piston.

 

[GSXR7ED]

Oh, man!

That is going to be an adventure for you!

I ended up gouging the piston and just bought a new one. Begins on Post #56:

https://www.thegsresources.com/_forum/showthread.php?216696-82GS750T-Seal-T-M-Gear-Shift-Oil/page2

Got them pretty clean!

Ed

 

[Guest]

Here it is with the circlip, washer, and gasket removed. I haven't been able to get the piston out.

 

[GSXR7ED]

Ohhhhhhh!

That was tough to get out!

I have pic of that too! There's a special tool to pinch the circlip out. And I think I used a needle-nose to pull the piston out. Be careful not to scratch the cylinder walls.

Ed

 

[Guest]

That's the thing... the piston won't come out.

 

[GSXR7ED]

Keep your patience. Gently keep gripping it with pliers...it does loosen up...but the rubber is suctioning it.

It will eventually come out.

Ed

 

[Guest]

Keep your patience. Gently keep gripping it with pliers...it does loosen up...but the rubber is suctioning it.

It will eventually come out.

Ed

It sounds like there's a piece of metal inside stopping it from coming out. Did Suzuki make master cylinders that couldn't be opened?

 

[Guest]

Here's me trying to remove the piston.

https://vimeo.com/383925309

 

[GSXR7ED]

It sounds like there's a piece of metal inside stopping it from coming out. Did Suzuki make master cylinders that couldn't be opened?

That piece of rubber around the Piston is part of the problem...it's suctioning the Piston from being removed.

I kept at it for a couple of days while the other pieces were soaking in solvent. Eventually, it popped out.

I had to learn patience. Just keep gently pulling at it...you are dislodging it gradually.

Ed

 

[cowboyup3371]

Is the circlip removed? Take a dental pick and pull the rubber boot out (you can get a new one)

 

[GSXR7ED]

Is the circlip removed? Take a dental pick and pull the rubber boot out (you can get a new one)

The circlip is removed...he's having issues pulling the Piston out.

It's wedged in there tight because the rubber seal around the Piston must travel upward and out of the chamber.

It takes time because of the suction the rubber is causing because it's been in there (probably) since the bike was built.

Ed

 

[Rich82GS750TZ]

might try removing the the reservoir and getting some penetrating oil (PB blaster?) in at it through the holes in there. Also let some PB sit on top of the plunger for a couple of days.

 

[GSXR7ED]

might try removing the the reservoir and getting some penetrating oil (PB blaster?) in at it through the holes in there. Also let some PB sit on top of the plunger for a couple of days.

I just watched the video OP posted and yes! The reservoir cap/lid needs to come off to let air flow through those tiny vents in the Master Cylinder.

Good call!

Ed

 

[salty_monk]

Is it a concourse build? If not forget it & put one on from an EX650... Actually yours is probably single brake so look at the 250 or the KLR

 

[Guest]

Is it a concourse build? If not forget it & put one on from an EX650... Actually yours is probably single brake so look at the 250 or the KLR

A what? What's a concourse build?

 

[cowboyup3371]

A concourse build is basically making it look EXACTLY how it looked when it came off the showroom floor - ALL parts

 

[Big T]

Slide a chopstick in the hose end, tip the cylinder up and tap the chopstick on the table until the piston pops out

 

[Guest]

Slide a chopstick in the hose end, tip the cylinder up and tap the chopstick on the table until the piston pops out

I tried that, it seemed only a small part of the tip went in. Didn't do anything. I tried with a smaller screwdriver, still nothing. How about a heat gun?

And you know that hole under the reservoir, shouldn't I be able to see the piston moving through that hole?

 

[GSXR7ED]

I tried that, it seemed only a small part of the tip went in. Didn't do anything. I tried with a smaller screwdriver, still nothing. How about a heat gun?

And you know that hole under the reservoir, shouldn't I be able to see the piston moving through that hole?

I know that it seems like it won’t come out...lord knows I had nothing but time when I was working on the road at Holloman AFB, NM...but it will pop out.

It takes “unexpected patience” and you’ll know what I’m talking about.

Ed

 

[Rijko]

It sounds like there's a piece of metal inside stopping it from coming out.

From the video you posted, yes it does sound like that.
Metal hitting metal, that's not just a rubber stopping the piston from coming out.

Some rebuild kits use a metal washer behind the circlip, and this washer
could've gotten stuck in the groove the circlip was in.