Dot 3 --> Dot 4 Brake Fluid

Post by **NafemanNathan** » Thu May 31, 2012 1:48 pm

My Aerodeck specifies using "Dot 3 brake fluid only" on the reservoir, but I'm having a hard time finding any. (Neither Halfords or MotorFactors stock it

), but the guy at MotorFactors said I'd be ok to use Dot 4 as you can always go up 1 Dot apparently. Is this the case?

EDIT: Also I imagine I'd need to bleed the whole system rather than just topping up the reservoir, or would I be ok just topping up?

Also, I know I can get Dot 3 off ebay, but I wanted it sooner rather than later. Although I will go the ebay route if I'd have to drain the system to run Dot 4.

Post by **indigolemon** » Thu May 31, 2012 2:06 pm

The go up one DOT thing is bollocks, as DOT 4 and DOT 5 are totally incompatible.

DOT 3, DOT 4 and DOT 5.1 are all polyethylene glycol-based fluid and can be swapped/mixed at will. DOT 5 is silicone based and doesn't play nicely with the others.

[edit] I should really answer the question though I suppose

YES! you can use DOT4 with no problems.

Post by **NafemanNathan** » Thu May 31, 2012 2:19 pm

Cheers bud. Actually he did say "for example you can use Dot 3 for Dot 2 and Dot 4 for Dot 3", so maybe he just should have thought further ahead and also mentioned where that "rule" stops lol.

So cool, I can use Dot 4 and I don't need to bleed the system

Post by **indigolemon** » Thu May 31, 2012 2:25 pm

Yeah man, DOT4 is like a better specced DOT3. You can mix them no problem.

VT3C RUNN3R · Post by **VT3C RUNN3R** » Thu May 31, 2012 3:36 pm

I can get DOT3 brake fluid here on the US Airbase if you like mate? then could post to you? its cheap too something like $3/4 a quart I believe so equivelant to 2/3 pounds. But to be fair I have nothing to compare that price to

Post by **vanzep** » Thu May 31, 2012 3:38 pm

indigolemon wrote:The go up one DOT thing is bollocks, as DOT 4 and DOT 5 are totally incompatible.

DOT 3, DOT 4 and DOT 5.1 are all polyethylene glycol-based fluid and can be swapped/mixed at will. DOT 5 is silicone based and doesn't play nicely with the others.

[edit] I should really answer the question though I suppose YES! you can use DOT4 with no problems.

Thats good info

Ta

Post by **RattyMcClelland** » Thu May 31, 2012 3:42 pm

Yep you can fix dot3 and dot4. Dot5 needs to be completely changed..Dot3 can be found in Halfords but yours must be Clubbing Eddy.

Post by **NafemanNathan** » Thu May 31, 2012 3:51 pm

VT3C RUNN3R wrote:I can get DOT3 brake fluid here on the US Airbase if you like mate? then could post to you? its cheap too something like $3/4 a quart I believe so equivelant to 2/3 pounds. But to be fair I have nothing to compare that price to

Cheers for the offer bud, but if I can simply mix Dot 4 with Dot 3 then I can get that today

You never know, the previous owner may have used Dot 4 anyway!

RattyMcClelland wrote:Yep you can fix dot3 and dot4. Dot5 needs to be completely changed..Dot3 can be found in Halfords but yours must be Clubbing Eddy.

The staff in there are that's for sure. Though what do you expect?

The halfords here is pretty big, but I guess they only really cater for demand... Annoyingly.

skinny · Post by **skinny** » Fri Jun 01, 2012 12:07 am

There's no point in looking for dot3 its just a worse performing version of dot4, hence why it's pretty much been phased out now.

Post by **NafemanNathan** » Fri Jun 01, 2012 8:23 am

Yeah, I bought some Dot 4 the other day and on the back it pretty much said that Dot 4 superceeds Dot 3.