DOT 3 or 4

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DOT 3 or 4

Post by frederick » Sat Sep 21, 2019 12:45 am

My clutch m/c reservoir (from 08 donor) is stamped DOT 4 as is the brake and clutch reservoir caps as specc’d (4 or 5.1) in the guzzi manual. So my front calipers have known DOT4 all their life. However the T4 kit m/c caps are stamped DOT 3. Since I know not to switch unless components are pristine, any problem with me running DOT4 in the new brake M/Cs?

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Re: DOT 3 or 4

Post by westendguzzi » Sat Sep 21, 2019 7:28 pm

Dot 3, 4 & 5.1 are all glycol based and are compatible. The higher the number, the higher the boiling point.
They all take in water over time (years) which reduces the boiling point, hence they should be changed.
Dot 5 is silicone based so will not mix with the glycol base.
The answer is you will be fine with the Dot 4, just make sure there is no Dot 5 in the system.

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