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EVguru wrote:Seal kits for 41mm Grimeca calipers are available from several sources. There is a version used to replace the AP Lockheed caliper on Triumphs and Nortons and the seals are the same as the 1010 and 1025s.

Try https://www.rgmnorton.co.uk/dept/caliper_d01147.htm

I bought mine from NLM, so Mdina should have them...

Bought a caliper piston seal kit from Mdina and they seem to be correct for my caliper, along with the 'O' ring that is a different shape to the original but I think is correct - the original has been flatted over time due to the compression, with the concomitant result that the id is smaller than the new one.
The dust boot however is still to be identified - could it be that the caliper housing is Grimeca but the inner components are Brembo? Does the standard Grimeca 38mm piston have a groove machined in to locate the dust cover, as this is what I have on mine?

The master cylinder though is another matter - I now think that it probably a Brembo item rather than a Grimeca item. Hopefully Andrew at Mdina will help resolve the matter as I have sent him my mastercylinder to help him identify the components.

Thanks for all your comments and I shall report back once the matter has been resolved. In the meantime if anyone has any other helpful/insightful comments to make, they would be gratefully received.

Thanks,
Charles

Just to bring you all up to date - the mastercylinder casting is apparently a Grimeca part (Stuart from NLM confirmed this to Andrew at Mdina) but the piston manufacturer cannot be verified but is thought to be Grimeca. The seals that Andrew had at Mdina were not for this piston however. Well, to cut a long story short, I refitted the seals that were on it, reassembled the mastercylinder, fitted new caliper seals and O ring and put the items back on the bike; new brake fluid, bled easily, and now brake works well with no binding - pads probably due for renewal soon but as I am not using it at all at the moment, they can wait.
All in all a lengthy and somewhat unsatisfactory exercise - I know that the brake seems to be working well now but I really would like to know what mastercylinder it is so that I can get the correct parts as and when I need to - assuming they are available and that we get out of this covid-19 pandemic!!!
Thanks for all your comments and advice,
Adios,
Charles

Charles,

https://www.ariete.com/sites/default/fi ... nico_0.pdf

If you look at the very top it says Morini 500 - is it the same code on the parts kit you bought from Mdina?

'Protect the NHS' - you might need it!

Hi Mickey,

Thanks for the link. I am not sure that it is the same number that I bought from Mdina - I do not remember the item number so will have to trawl through some of my old paperwork. I think that form the picture it looks similar and therefore not correct but then the image could just be a generic one - the dust boot looks like it is for a system that uses a pull rod to move the piston rather than the cam type tha pushes the piston up from underneath.

Thanks again,
Charles

I've just removed my Grimeca calipers- is it OK to split the calipers to aid rebuild? I recall reading somewhere that generally, splitting should be avoided, however it would very much simplify the task of getting the corroded pistons out, cleaning etc if I were to split them. Thanks for any guidance!

JonnyP wrote:I've just removed my Grimeca calipers- is it OK to split the calipers to aid rebuild? I recall reading somewhere that generally, splitting should be avoided, however it would very much simplify the task of getting the corroded pistons out, cleaning etc if I were to split them. Thanks for any guidance!

Yes, in fact it's the only way to clean them properly. Once you get the seals out you need access to the seal grooves to get any corrosion or dirt out. An ultrasound cleaner is good here too, but the square-ish section of the seal groove collects the muck in the little corners you can't see. A good stiff toothbrush may help too. There is also a seal that covers the fluid hole between the two halves.

Thanks Steve, much appreciated.