clutch slave

[docc]

Here's my thinking: With these V11 getting some years on them, and the clutch slave NLA from Moto Guzzi, it is going to be a real benefit to have a source for seal replacement. Most likely, a seal replacement will keep the cylinder in service for a long, long time.

 

I have also not found a Grimeca rebuild kit for this specific application, although there are 30mm brake kits out there. I may have to score one of those and inspect the seals for applicability.

 

BTW, McMaster-Carr also refunded my money. For now, everyone involved is moving toward a reliable solution. Thanks, everyone, for the assistance and education!

 

I have emailed an EPDM seal supplier for a quote on the square section 3mm x 30mm seal. The round section outer seal looks to be 2mm x 30mm.

[gstallons]

Good deal ....

[docc]

Since this slave cylinder functions just like a brake caliper piston, how likely is it  that the "flat" seal is actually square section?

[docc]

"EPDM", "Grimeca" and "30mm" . . .

That's three of the main food groups right there!

http://www.ebay.com/itm/Aprilia-Grimeca-30mm-diameter-two-piston-brake-caliper-seal-kit-12871-PI-/361835872988?_trksid=p2385738.m2548.l4275

 

Although, both seals are "square" section. Maybe one of them is right for the "flat" seal . . .

[docc]

I have emailed Ariete in Varese, Italy, with the details of the application. 

 

I'm starting to come unglued with the Sport being down this long . . . [does it show? ]

[68C]

That square seal is interesting in that it allows our disc brakes to work.

 

On applying the brake the square seal distorts allowing the slave piston to move far enough to press the pad onto the disc, when you release the brake the distorted square seal pulls the piston back a little to free the brake. The piston only slides through the square seal on initial assembly or to automatically take up pad wear.

 

The clutch slave cylinder travel is greater the piston does slide through the square seal and consequently the seal wears quicker. It does not need to be square seal, although usually is, as the spring inside the clutch slave cylinder does the returning action of the piston.

 

I remember talking to the Norton team at the '91 IOM TT, they said they did not like using silicon brake fluid on their race bikes as it was too slippery and compromised the returning action of the square seal which caused a slight dragging of the brakes. They suggested silicon fluid was only used to stop owners damaging their paintwork with spillage and to help when owners did not change the normal fluid regularly.

 

Http://Www.ucx.com/documents/squareseal.pdf.

[docc]

That certainly explains the square seal distortion I can see and would further explain why the piston wouldn't retract and the clutch doesn't re-engage reliably. Now, to find that seal:

 

 30mm ID x 3mm square section O-ring EPDM

 

Anybody?

 

[edit 13 July 2017: I don't believe these measurements are reliable.)

[swooshdave]

You need a second V11. Do we need to find one for you?

[docc]

Tomorrow, I'm riding my *Amazingly Reliable* back-up bike with 49,500 miles on it.

 

[docc]

I'm struggling with the startling statistic that this single solitary seal has stranded my Sport . . .

I suppose, if this has happened to two of the three *most used* V11 we know of , it is worth finding a solution for those to follow.

[swooshdave]

I say put it back together and see if it leaks.

[MartyNZ]

Seriously, y'all?

 

No one in the entire world can source an EPDM 3mm square section O-ring seal (30mm ID)?

I googled "square section seal EPDM" and found these guys:

http://www.alliedseals.com/square.htm

They don't have exactly the right size, but come close. It may be worth asking them if they will make a custom order for you. If there is a minimum buy quantity, then I'd buy a couple from you.

[Chuck]

I'll put up a blurb on WG and see if anyone knows of something.

[docc]

I say put it back together and see if it leaks.

It's not that it leaks, the clutch won't always re-engage; feels like the piston is sticking.

[Chuck]

I'm struggling with the startling statistic that this single solitary seal has stranded my Sport . . .

I suppose, if this has happened to two of the three *most used* V11 we know of , it is worth finding a solution for those to follow.

Definitely. Is there a part number on the slave?