Modern Vespa

Ahhhh! Ok. Thanks!!
I managed to make it work without.
Will use next time.

What had me confused - no other parts fit in E - until I took Dremel and sand paper to it…

Thanks Saf.
Appreciate it.

Little help?

Are use the MMW master cylinder on my scooter.

A little bit of research appears to show that the piston, and the accompanying rubber seals, or right out of the Piagio.

I think so anyway.
Historically, Scooter center has told me they don't carry the seals for rebuild. I now see that they have a rebuild kit that includes the piston, for about $70… Seems unreasonable for a piece of rubber.

I'm wondering if this cup shaped seal, is findable, on the inter-webs. Does anybody know what this type of seal is referred to? I welcome any search tags if you have ideas. Thanks.

-CM

Here you, complete rebuild kit…

https://www.sip-scootershop.com/en/product/gasket-set-grimeca-brake-master-cylinder-grimeca-sip_49474800

is that an 11mm?

Thanks guys.

Safis - I missed that when I searched. Helpful.


OCT - Piston is 12MM. Would love to find the cup in the US...

Piaggio also sells it as an OEM part. Maybe you can get it in the US…

OEM code is: 494748

Here you go…
https://www.scootermercato.com/Scooter-Parts/Disc-Brake-Parts/49474800_2

Jesus Safis.

Hahaha.

Awesome!!

Can you help me find the keys to my tool shed? They've been missing for about three years.

How did your seal get damaged?

Good question.
Just basic use.
Second one - kit came with two - swapped first after a year.
Looks like the brake fluid is attacking it?

I have the most unpleasant challenge of bleeding the brakes tomorrow.
Done a full flush.
For the sake of RnD, bought a new caliper off aliexpress.
Tore it down into halves - and shot some pics.
Will post when complete.


More on the "double bleeder" set up when I have it all working/back together.

that piston looks wore the F out. I didn't think it was that old?

I'd check the bore to make sure you're not doing it all over again in short order.

I have a master cylinder repair kit on my shelf. Been there for many years. Never had cause to use it.

Nice orange caliper…

The back shaped to clear the hub?

I think I bought that kit to repair the MC on my Stella. I tore the seal being too gorilla handed with it and just replaced the whole thing. $80 and done.

This is a bit unnerving for me since i bought the same MMW brake master cylinder for my rusty VB1 project. There's a guy who is located in Greece that resleeves KTM hydro clutch master cylinders (Brembo and Magura) with a 10.5mm stainless steel sleeve. It ain't cheap at around 160 euros, but at least once rebuilt you would know it would last forever (just like the stock Grimeca MC). I wonder if he could sleeve other brands of MC's? Maybe option 1 would be to hard anodize the MMW MC while it's still brand new?

Interesting.
Perhaps there is some kind of burr from one of the two holes machined from the reservoir.
I'll have a look see today.
Thanks!

Question - what does one home a brake master with? Or does one not hone?

Usually hone with a small drill bit with 400-1500 grit strips taped and rolled around.

Spin the roll inside and let the flapping action do it's work.

Usually go in 200 grit steps in fineness.

Aiming for shiny/mirror finish.

Hit it with some emory paper wrapped around a socket

Thanks gents.

One follow up.
I would have thought that a cross hatch pattern was desirable - rather than shiny smooth?

a ball hone will take care of any sharp edges if the bore is smooth. most the MMW parts look to be made with a CNC Chisel on the outside, but I'd hope that the bore is reasonably good.

^^^

what mr. Owens said-- hit it with a ball hone. you can pick one up off flea bay for about $10

I have an ooollllddddd snap on three stone brake cylinder hone but the smallest it goes is about 1/2"

Patric/Greasy - saw these.
Just tied up with other shop stuff - so didn't get a chance to work on scoot yet.

I'm going to order a repair kit from Mercato if they have 'em - and grab a small hone - cause I'll have the time and its only about $15.

Thanks for the other comments as well - I thought it was normal that these things got stiff and nasty after 6 months...
Who knew.

Want to get this back to super smooth.
Might play with a handle design that is progressive as well - where it pushes on the piston - we'll see...

End of the weekend.
Scrolling through YouTube - as one does.
Line of "shorts" shows up - and I'm like: wait. thats me!

https://youtube.com/shorts/zTfHcCmRRZ0?feature=share

¯\_(ツ)_/¯

hahaha.
Hope y'all all have a good week.
Good motivation to get back at the scoot and get rolling again.

What can you say? Folks dig The Unicorn.

Mini Vespa celeb…

rock star

It's better (like everything else) when it's not displayed as a "short."

That is one cool ride.

Thanks!!

It's hard to say if I like tuning/restoring [sic] more.

After some great input from the crowd, I:
- realized my swing arm was worn
- realized my master cylinder had a burr
- realized I needed to get my scoot back on the road!!

Bought a master cylinder off Aliexpress for $25 or something. Maybe $14. IDR.
For those that don't know - the German companies are basically buying the same and rebranding.

Was curious.
Turns out - The quality is superb.

My chewed up master cylinder seals are still sealing.
Will replace with new and hone in future.
Temporarily hit with light sand paper and existing piston seals.
Smooth - for time being.
Thanks for heads up on Abby Normal west.

Got out and rode today.
72 and sunny.
Cali may be whack- as the kids say - but t shirt and jeans felt pretty damn good tday.

Appreciate all the help.
Few pics below documenting the situation.
- CM


Bit of modification required.

Seriously - the machining is excellent, and there was zero swarf. Why shouldn't I like RPM more then BGM at .15 the price?

Installed extra bleeder screw at low point and hung the caliper to fill (with syringe).

All assembled with new caliper in… orange. ¯\_(ツ)_/¯

Good for the sole

72 and sunny.
No crullers, but plenty of coffee and sun.

Oh man, the Orange Unicorn is badass, and clean! Very nice!

Man that thing is a statement.

Love it.

Cool machine and love the wood side stand.

You can do that sort of thing when you have a sidecar to store the block in.

He's showing off his wood.

If you had an 8" 4x4, you'd show it off, too.

Hahaha.

That block has been with me since I prototyped the leaning mechanism.
(I actually HAVE a side stand - but it just never ends up at the top of the project list).

It's versitile!
I can lean it in or out.
Turn it on its side or stand it tall - to change the angle.
You gotta see the beauty of it in action to fully appreciate.

Maybe I will whip up a fold down stand this year.
Tho it might be that block on a hinge.
🙂

Woof!

I came across this and I thought of you. I still have this fantasy about making a precise cut on a rotary pad using common tools. I also have a set of old T4 VW heads that the local machinist said he could not flycut. This looks promising, though slow. There are lots of fools on YouTube putting fly cutters on Harbor Freight drill presses. Looks like a great way to ruin your part and take out an eye.

So how are you liking the LED that you have installed?