MrReee

DOT3 or DOT4 Brake Fluid

I am not harsh on my brakes - but I see lots of people on here use DOT5

DOT3 is just £2 for 500ml - even if just for flushing through?

Any need to pay for DOT5, overkill?

MrReee

NorthDownsScooby

New Pete = new fluid to rant about

GC8

The advantage Pete, is that DOT5 fluid will be silicone based and as a result it isnt hygroscopic. Wheterh that makes it wortwhile I dont know; Id see what the manufacturers used, DOT4 is probably more than adequate for most cars...

D1CCY

DOT5 is not compatible with other fluids, also the silicone base makes it thicker and can slow brake response unless the system is designed for it.

Confusingly DOT5.1 is compatible and OK to mix with DOT3/4 fluids. The specs of DOT4 and 5.1 reqiire higher boiling points but I don't think the differences are huge. I'd say go for reputable make rather than worry about the DOT no. I think Castrol Response is DOT4 and AP racing do a DOT5.1 if you want to be posh. Probably more important to change at least every 2 years.

MrReee

Cheers all, it's 2 years since the last change - I'm not hard on my braking system so I may flush it through with DOT3.

Any idea anyone how much it will take to flush through with clean fluid?

MrReee