Sorry for all these stupid topics guys..

I put Dot 3 brake fluid in my car today before seeing the filler cap that says 'Use Only Dot 4'

Should I be worried?

I could be wrong mate but I always thought that DOT 4 is just an upgraded version. If you ve only used it to top up then Id guess you ll be ok. Did you buy the fluid recently or was it some old stuff that was just knockin about?

I bought it especially today, just to top it up to stop that bloody warning light flashing (it was only half empty)!

Cheers for your reply !

DOT4 and DOT3 will mix but DOT 3 has a lower boiling point than the DOT4. If you`ve just put a bit in, I`d be surprised if you notice any difference.

If you are worried, why not change the fluid in the system with new fluid (DOT4!)? This should be done every few years in any case as the fluid absorbs water which leads to a gradual lowering of the BP over time.

One of those jobbies that uses a bottle of fluid and pressure from your spare tyre makes it an easy one man job.

Will

Ah, that's a relief. I only really used it to top it up so I hope there'll be little difference as you say. Wasted £2.50 on a bottle which I can't use the rest of though - drat!

Cheers for all your replies, lads!