Brembo rectangular reservoir pedantry

[the lodger]

My Brembo front brake master cylinder, which is rectangular ( M900 from 1995 ) , has a lid which is weeping a bit so I thought I would replace the gasket . There was a cap and gasket for sale on ebay for a reasonable price so I bought the set. It looks like a proper Brembo one , but compared to my original there is a difference in the "warning" script on the top of the cap. My original cap says .......ONLY USE DOT 3+5.......whereas my new one says ......ONLY USE DOT 4...... . The vendor says that Brembo changed their cap part number and hence the warning to exclude a reference to using DOT 5 as it damaged the seals .

Any thoughts anyone ( I warned you it was pedantic ! ) ?

[Nickj]

I've got a pair of surplus coffin tops which are off of my S2R, should fit.
See how you get on with the lettering (don't stare at it too hard whilst in motion!) if it bugs you that much let me know

[slob]

DOT 3
DOT 4
DOT 5.1 (note the ‘point one’)
are all ok, they’re all Glycol based (and mixable). The main difference is the boiling point.

DOT 5 is Silicon based and can’t be mixed with Glycol based types, it will also cause problems with seals in systems not designed for it. AFAIK Harley-Davidson are the only bike manufacturer that specify DOT 5

[the lodger]

Thank you for the replies.

Does anyone know if I can buy just the gasket for the reservoir ?

[slob]

Give your nearest Ducati dealer (or Moto Rapido) a call.

[Darkness]

Originally Posted by the lodger

Does anyone know if I can buy just the gasket for the reservoir ?

Not from Ducati. The part number is for the lid, diaphragm and screws.

By the way, check which size master cylinder lid you need. Early 900 and 600s have the same size as the clutch reservoir. Later ones are larger.

[the lodger]

Mine seem to be the same size visually . When you say larger , do you mean obviously larger or is it fractions of a millimeter ?

Can you tell me the part number for the correct set ?

Many thanks

[Luddite]

If you absolutely, positively have to have the original wording, then Stein-Dinse appear to have them.




https://www.stein-dinse.biz/product_...roducts_id=294

Edit: The full Brembo part number is 110430860 (another example here) https://www.ebay.co.uk/itm/BREMBO-PS...-/351990583876

[Darkness]

Originally Posted by the lodger

Mine seem to be the same size visually . When you say larger , do you mean obviously larger or is it fractions of a millimeter ?

Can you tell me the part number for the correct set ?

Many thanks

The bigger ones are significantly bigger.

[Mr Gazza]

I think there are some crossed wires here?
I think all the lids are the same size and not even handed from what I remember. (Although there is a front and back.)
However the actual pots do come in different sizes (heights). The early brake reservoir was the same size as the clutch, but this was enlarged fairly early on. I am fairly sure that there are two different piston sizes for the brake master too. (not that it's an issue here).
Certainly the single disc models use a 12.7 or 13mm piston and the twin disc version is bigger but I can't remember the size atm! I believe the single disc reservoirs stayed the small size for a while but were later increased to the same size as the twin disc one, with just the piston sizes differing.

Watch out for Scrambler brake masters (They use a cable clutch) as they use "coffin" reservoirs with a 13mm piston, but I think the design is different to the Monster era Coffins and I don't think they interchange.

Strange that the lids with DOT 3+5 seem to be saying use Glycol OR Silicone based fluids... That can't be right??

Some useful contacts.. http://www.ducatipaddy.com/
https://www.powerhouse.uk/content/mo...-seal-kits.php

[Darkness]

Originally Posted by Mr Gazza

I think there are some crossed wires here?
I think all the lids are the same size and not even handed from what I remember. (Although there is a front and back.)
However the actual pots do come in different sizes (heights). The early brake reservoir was the same size as the clutch, but this was enlarged fairly early on. I am fairly sure that there are two different piston sizes for the brake master too. (not that it's an issue here).
Certainly the single disc models use a 12.7 or 13mm piston and the twin disc version is bigger but I can't remember the size atm! I believe the single disc reservoirs stayed the small size for a while but were later increased to the same size as the twin disc one, with just the piston sizes differing.

Watch out for Scrambler brake masters (They use a cable clutch) as they use "coffin" reservoirs with a 13mm piston, but I think the design is different to the Monster era Coffins and I don't think they interchange.

Strange that the lids with DOT 3+5 seem to be saying use Glycol OR Silicone based fluids... That can't be right??

Some useful contacts.. http://www.ducatipaddy.com/
https://www.powerhouse.uk/content/mo...-seal-kits.php

Nope. I’ve had both and the lids aren’t interchangeable.
Early coffins are the same size lid as the clutch, whereas later 90s coffins are bigger.

If you take your lid off, make a note of the Brembo seriel no. Cast into the underside.

[Mr Gazza]

Fair Dinkum Darkness.
I have a box of all sorts and I thought that I had mixed lids and masters with no problems, but I will have another little play when I get a chance and see if I have two sizes of lid.
I've only ever seen DOT4 lids though.