AX Brake Fluid: Choices and Recommendations...

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

User avatar
CitroJim
A very naughty boy
Posts: 43132
Joined: 30 Apr 2005, 23:33
x 1503

AX Brake Fluid: Choices and Recommendations...

Post by CitroJim »

Today I find Daffodil's brake fluid is looking very manky and needs to be changed. It's dark brown and looks more like well-worn LHM rather than standard brake fluid :shock:

Being an LHM man at heart I'm finding the whole (new to me) subject of brake fluid types a bit confusing and muddled..

Should I use DOT3, DOT4 or go for DOT5?

I understand DOT5 is a silicone based fluid and will not mix with the other DOTs although there is variety of DOT5 that will :?

I believe DOT5 cannot be used with ABS systems but that's not an issue because Daffodil does not have ABS ;)

Question is, for a lightly used car should I go for DOT5 with the advantage of it being non-hygroscopic and if so, how do I flush all the old fluid out before filling with DOT5 to ensure there will be no adverse reactions?

Or should I stick to using DOT4 or even look for DOT3?

Grateful your thoughts :D Thanks!

User avatar
white exec
Moderating Team
Posts: 6434
Joined: 21 Dec 2015, 13:46
x 1090

Re: AX Brake Fluid: Choices and Recommendations...

Post by white exec »

Be careful about actual silicone brake fluid, Jim, as its lubricating qualities are very limited.
The stuff was enthusiastically marketed a good while ago (by Namrick, Brighton, alongside their stainless steel nuts and bolts), as the ideal solution for classic cars. Unfortunately, many owners had to remove it when some types of master, slave and servo cylinders started to judder and creak.

I think DOT4 is what you should use, but check. The AX mechanic's booklet will have the spec.

User avatar
Paul-R
Donor 2020
Posts: 5067
Joined: 07 May 2009, 16:24
x 687

Re: AX Brake Fluid: Choices and Recommendations...

Post by Paul-R »

IIRC Dot 5.1 is the next progression in DOT non-silicone fluids. Having said that, DOT 4 is probably sufficient.

User avatar
xantia_v6
Forum Admin Team
Posts: 7630
Joined: 09 Nov 2005, 23:03
x 434

Re: AX Brake Fluid: Choices and Recommendations...

Post by xantia_v6 »

Stick with DOT4. But keep it off of your hands and paintwork, it is not nearly as user-friendly as LHM.

User avatar
white exec
Moderating Team
Posts: 6434
Joined: 21 Dec 2015, 13:46
x 1090

Re: AX Brake Fluid: Choices and Recommendations...

Post by white exec »

Thanks, Paul. That got me reading up on the DOT categories (Wikipedia, Brake Fluid).

User avatar
CitroJim
A very naughty boy
Posts: 43132
Joined: 30 Apr 2005, 23:33
x 1503

Re: AX Brake Fluid: Choices and Recommendations...

Post by CitroJim »

Thanks all :D DOT4 it will be ;)