Rear master cylinder replacement

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boompse
Posts: 2
Joined: 30 May 2021 03:59
Location: Melbourne

Rear master cylinder replacement

Post by boompse »

Hi there,
My rear master cylinder keeps seizing. I've pulled it apart. The piston and bore look good but the spring looks mangled. Mdina Italia offers the seal kit (M12868) but that doesn't include the spring. I would prefer to replace the whole master cylinder - does anyone have suggestions as to where I could get a new master cylinder or a new piston with seals and spring?
morini_tom
Posts: 920
Joined: 05 May 2006 13:47
Location: Northampton

Re: Rear master cylinder replacement

Post by morini_tom »

I have no clue if this would be a direct replacement or if they are any good. But I did read somewhere that classic karts used grimeca master cylinders similar to ours, and found this copy of one online.

Worth investigating possibly?

https://www.ebay.co.uk/itm/Motorcycle- ... 2196571847

Alternatively, previous owner of my triple disc 350 fitted a new brembo master cylinder on the rear. It works well and doesn’t look out of place, although he did have to cut and weld the actuating arm to get the angles right, which is not ideal on a brake component. Part number 10.29(or maybe 28).34.02
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'It must be a .....'
Posts: 365
Joined: 12 Sep 2010 12:25

Re: Rear master cylinder replacement

Post by 'It must be a .....' »

Hi, the rear master cylinder from the 501 Camel (small tank pre electric start) is a direct fit on the road 500

It also makes the brake much more progressive than the original (different piston diameter?)
boompse
Posts: 2
Joined: 30 May 2021 03:59
Location: Melbourne

Re: Rear master cylinder replacement

Post by boompse »

Thanks for the reply. The 500 Camel does indeed have the same rear master cylinder but my problem is, where do I get one? Mdina Italia have been not helpful - partly I think because whatever parts book they have is not the same as the parts book I have. I was sent a 'rebuild kit' which is hilariously useless. There appears to be no 'Grimeca.com' and whatever Grimeca bits I can find are all for Piaggio and Malaguti scooters, etc. I'd get a Brembo master cylinder - some of those look similar - but I don't want to pay a fortune, wait two months to have it delivered and then find it doesn't work. Surely someone has a 500 with an aftermarket rear master cylinder and if so, what is it?
MickeyMoto
Posts: 2415
Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Rear master cylinder replacement

Post by MickeyMoto »

boompse wrote: 12 Oct 2021 01:12 Thanks for the reply. The 500 Camel does indeed have the same rear master cylinder but my problem is, where do I get one? Mdina Italia have been not helpful - partly I think because whatever parts book they have is not the same as the parts book I have. I was sent a 'rebuild kit' which is hilariously useless. There appears to be no 'Grimeca.com' and whatever Grimeca bits I can find are all for Piaggio and Malaguti scooters, etc. I'd get a Brembo master cylinder - some of those look similar - but I don't want to pay a fortune, wait two months to have it delivered and then find it doesn't work. Surely someone has a 500 with an aftermarket rear master cylinder and if so, what is it?
Or maybe nobody who reads the forum has an aftermarket rear master cylinder on a 500. In which case when you find one that fits you can share it with us.

Have a chat with Ducati Paddy. He is very helpful, but as he does Brembo may not be able to help.
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Daddy Dom
Posts: 512
Joined: 16 Nov 2006 19:48
Location: Auckland, New Zealand

Re: Rear master cylinder replacement

Post by Daddy Dom »

Storz Perfomance list this Grimeca one (1118) although it's pretty different from the one on my 1983 triple-disc 3½.
Also I'm not sure how current their catalogue is.

https://www.storzperf.com/catalog/page34.html
MRC 3082½
morini_tom
Posts: 920
Joined: 05 May 2006 13:47
Location: Northampton

Re: Rear master cylinder replacement

Post by morini_tom »

Read my post from 10th September above!! I’ve given the details of the brembo on my bike which can be modified quite easily to fit.

Late 350 with a disc (k1 and k2) have the same master cylinder as the 500
huub
Posts: 194
Joined: 24 Jul 2006 15:11

Re: Rear master cylinder replacement

Post by huub »

you might have a look on aliexpress ,
they list pretty similar master cylinders for a couple of euro...
could be worth checking the dimensions
(ex, look for zx7 brake cylinder)
i have good experiences with these chinese brake cylinders
https://nl.aliexpress.com/item/32826060 ... 0035%22%7D
Last edited by huub on 15 Oct 2021 11:13, edited 1 time in total.
3potjohn
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Joined: 02 Jun 2007 13:58
Location: Devon

Re: Rear master cylinder replacement

Post by 3potjohn »

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