Brake Fluid

[BTCC_ Racer]

Hi,

Even my local Lexus dealer isn't giving my a straight answer and searching the forum i'm getting mixed answers.

What brake fluid does the ISF run? Or can I use Dot 4 or Dot 5.1?

Dot 5.1 is a higher spec so will be better.

Thanks

 

[BillNick]

I traced back the part number on my 6yr service receipt and it came up Toyota 5.1

That's for RCF, but I imagine they would use the same for all F's and prob LC500 too.

[BTCC_ Racer]

I'll get some Motul Dot 5.1

[hockeyedwards]

I asked my local dealer after my lil mishap, 5.1 was their answer.

[ColinBarber]

IS-F factory spec is DOT 3

RC F / GS F is DOT 3 or DOT 4

[BTCC_ Racer]

I’ve ordered some dot 5.1. Is this incorrect then?

I’ve been heard of dot 3 being used 

[BillNick]

3. 4 and 5.1 are all cross compatible

4 has higher boiling temp than 3 and 5.1  has higher boiling temp than 4 therefore a “better” fluid choice but that’s not to say the lower ones are not ok.

DOT 5 is the one that’s NOT compatible.

Factory spec is indeed 3/4 but like I said, Lexus Sidcup put 5.1 in mine at my last service in August without me asking 

[Rob RCF]

DOT 4 seems to be the standard and what practically every modern car uses. Should be fine even for F cars. In fact the manual states to use either DOT 3 or DOT 4 (for my RCF at least).

DOT 5.1 has a higher boiling point and is better for high performance applications (ie, track use), however it has some downsides as well (more hygroscopic/water absorbing, needs changing more regularly, more corrosive on paint, manufacturers don't seem to recommend it in some cases etc).

I think more important than which you use is how often you change it, tbh. Notice that DOT 5.1 wet has a lower boiling point than DOT 4 and even DOT 3 dry.

[hockeyedwards]

Sooo I probs have DOT 4.55 then? 😆 combination of 4 and 5.1... only did a top up and quick bleed, might do a full change at some point then, car stops when I press the pedal, that's good right? 😉