Horrible little square master cylinder

[kfz]

Hate these little square MC that half an eggcup of fluid and have the press in ring instead of a proper circlip.

What am I doing wrong here? Trying to rebuild a tinting square brembo MC. How is the piston retained? and what is stopping the piston pushing the dust cover off. And yes I am rebuilding it because when I took the lever off for a clean it fired the piston across the garage.

Kev

[Darren Williams]

What bike?

I'm getting a new master cylinder for the clutch on my 2016 Griso. It bleeds off pressure after about 20 seconds. Makes riding in heavy traffic a bit "interesting" when the gear box loads up in first gear so you can't put the bike in neutral, you can't go forward so you can't pump it back up, so in and out of neutral constantly is only option.

Guzzi had the new dealer try to flush it, which helped for a couple hundred miles, and said if that didn't solve it they would have him put a new one on. Now waiting on the part. Don at Motiv Cycle in OKC, the new dealer, has been very helpful and accommodating. Gonna have to spend some $$$ with him hoping he can make it as a Guzzi dealer.

[kfz]

What bike?

I'm getting a new master cylinder for the clutch on my 2016 Griso. It bleeds off pressure after about 20 seconds. Makes riding in heavy traffic a bit "interesting" when the gear box loads up in first gear so you can't put the bike in neutral, you can't go forward so you can't pump it back up, so in and out of neutral constantly is only option.

Guzzi had the new dealer try to flush it, which helped for a couple hundred miles, and said if that didn't solve it they would have him put a new one on. Now waiting on the part. Don at Motiv Cycle in OKC, the new dealer, has been very helpful and accommodating. Gonna have to spend some $$$ with him hoping he can make it as a Guzzi dealer.

No not this.

Sounds like your return hole in the MC is blocked. not releasing pressure.

[Perazzimx14]

Pardon my but-in here but what you are describing sounds like a classic "air" in the system. It can happen and due to your deer caper you may have a pesky air bubble gremlin.
They need maybe to try and pump the system from the bottom (slave cylinder bleed....up....

:-)

Yes reverse bleeding brakes is a great way go about this task. Inject the fluid in at the bleed nipple and push the air up and out the master cylinder the way it naturally wants to go. Perfectly bled brakes in minutes.

[Darren Williams]

The system was fully flushed and pressure filled. Worked OK for a few rides, and then started bleeding off again.

After getting it back together after the deer mishap, it was fine for several rides before showing up post setting for a couple bad weather weeks. Anyways, it's warranty so I'm good with the new master Cylinder.

[Darren Williams]

No not this.

Sounds like your return hole in the MC is blocked. not releasing pressure.

Sorry about hijacking your post.  What bike do you have?

[kfz]

Sorry about hijacking your post.  What bike do you have?

Thats fine Darren, no worries.  Its a mille GT but the MC is fitted to most of the later 80's Tonti's. 

Kev

[guzzisteve]

So, did you get the plunger locked in? The outer edge of the washer thing goes in a slight groove in the body. Cupped side out w/rubber behind it. I use a deepwell socket and hammer.

[kfz]

So, did you get the plunger locked in? The outer edge of the washer thing goes in a slight groove in the body. Cupped side out w/rubber behind it. I use a deepwell socket and hammer.

It doesnt lock it. the pison is mall enough to fit through the ring and jusr pushes the dust cover off.

Stumped really.  This is what it was like before and now I can see why.  What a wretched little design.  I'll stick the delinked brakes and Japanese MC on the other bikes.

Kev

[Chuck in Indiana]

It doesnt lock it. the pison is mall enough to fit through the ring and jusr pushes the dust cover off.

Stumped really.  This is what it was like before and now I can see why.  What a wretched little design.  I'll stick the delinked brakes and Japanese MC on the other bikes.

Kev

Uhh, when Guzzisteve talks, I listen. Now, *I have no experience* with this master cylinder, but on the rear, you assemble everything, put a 14mm deep socket in the bore, whack it and it's magically done.

[kfz]

Uhh, when Guzzisteve talks, I listen. Now, *I have no experience* with this master cylinder, but on the rear, you assemble everything, put a 14mm deep socket in the bore, whack it and it's magically done.

Yep done that. The ring is in tight but this doesnt prevent the MC comlete with dust seal and hopefully not the spring passing straight out. The ring in effect does nothing. Something is not right.

Kev

[jacksonracingcomau]

Yep done that. The ring is in tight but this doesnt prevent the MC comlete with dust seal and hopefully not the spring passing straight out. The ring in effect does nothing. Something is not right.

Kev

shim missing  ?
think I have same mc off nevada
used it on my sb to delink, perfect feel for two 05. brembos
stops like linked could never as it was

[kfz]

shim missing  ?
think I have same mc off nevada
used it on my sb to delink, perfect feel for two 05. brembos
stops like linked could never as it was

Possibly, what shim?