can you use dot4 or synthetic brake fluid in older P6 Rover

[Rovernuts]

just trying to see if anyone has upgraded their brake fluid to a more modern fluid and if they have had any problems...........my brakes are all rebuilt so there is no worry of lines blowing etc

Thanks

[ian.stewart]

Dot4, Dot5, are only higher boiling point brake fluid, still mineral oil, and still capable of stripping your paintwork, still Hydroscopic. totally compatable with Dot3
Dot5.1 Synthetic, Expensive, has a High boiling point, Does not attack paint, the stuff I have come accross is TOTALLY INCOMPATABLE with mineral oil, mix the two and it can turn to a jelly like substance totally ruining the brake system, I still think it has a absorbancy problem, either air or water, but has to be changed on a regular basis,
IMO unless you are Circuit Racing, and have a system that was designed to run syn, dont do it, I have a few mates who build HotRods, and at one time have used the stuff, but I think nearly all have gone back to mineral oil,

[Paul B]

Dot4, Dot5, are only higher boiling point brake fluid, still mineral oil, and still capable of stripping your paintwork, still Hydroscopic. totally compatable with Dot3
Dot5.1 Synthetic, Expensive, has a High boiling point, Does not attack paint, the stuff I have come accross is TOTALLY INCOMPATABLE with mineral oil,

Wrong, I'm afraid!

Dot 5 is synthetic silicone based, totally different to Dot 2, 3, 4 or 5.1.

Do a Google on it.

Halfords told me Dot 5.1 is nearly the same as Dot 5, but it is totally different and more than a few motoring organisations had demanded to know why Dot 5.1 is so closely named as Dot 5.

http://en.wikipedia.org/wiki/DOT_5

[sidecar]

I think that dot 5 is silicone based, it's ment for car's that hardly do any miles like the one's in muesums etc. It is compressable to a small degree and it therefore not ideal in anything that is "high performance" It does not damage paint or absorb water which is why it is good for cars that sit around for months or years.

Dot 5.1 has the high boling point of dot 5 but is less compressable. (Might not be silicone based, I'm not too sure on that one)

The best stuff by far is Castrol SRF but it costs a bomb!

http://www.merlinmotorsport.co.uk/m17/C ... _info.html

[14500rpm]

Theres an article on StopTech's website about brake fluids, and some interesting thoughts on those pressurised bleeder things too:

http://www.stoptech.com/tech_info/wp_br ... d_1a.shtml

[bodger]

just trying to see if anyone has upgraded their brake fluid to a more modern fluid and if they have had any problems...........my brakes are all rebuilt so there is no worry of lines blowing etc

Thanks

go with DOT 4 , you won't have any problems and unless you race to hard you won't nee anything extra

[Paul B]

I think that dot 5 is silicone based, it's ment for car's that hardly do any miles like the one's in muesums etc. It is compressable to a small degree and it therefore not ideal in anything that is "high performance" It does not damage paint or absorb water which is why it is good for cars that it around for months or years.

Dot 5.1 has the high boling point of dot 5 but is less compressable. (Might not be silicone based, I'm not too sure on that one)

The best stuff by far is Castrol SRF but it costs a bomb!

http://www.merlinmotorsport.co.uk/m17/C ... _info.html

Harley have used Dot 5 for a couple of decades now. Dot 5.1 is totally different than 5, as I found when researching it, AFTER I added it to my Sportster front brake.....

I have been told some tales on the Harley forums, of seals rotting, flexi hoses bursting, fluid gelling, brakes failing, pads seizing on and setting fire to bikes etc etc.

So, to recap, Dot 5 is NOT compatible with any of the other Dot grades.

[r2d2hp]

Ian is correct. 5.1 is synthetic (not silicon) or can be.

I use Comma 5.1 Synthetic and have no problems at all, it also compatiable with dot 4 and dot 3 etc and ok in ABS systems

[Paul B]

Ian is correct. 5.1 is synthetic (not silicon) or can be.

I use Comma 5.1 Synthetic and have no problems at all, it also compatiable with dot 4 and dot 3 etc and ok in ABS systems

You can mix Dot 3, Dot 4 and Dot 5.1 together, but not with Dot 5. Dot 5 is a different animal altogether. It is synthetic, does not damage paint, but mixed with any of the others it can cause all sorts of problems.

[r2d2hp]

5.0 is Silicone and can not be mixed.

Good Article here >>
http://www.stoptech.com/tech_info/wp_br ... d_1a.shtml

[minorv8]

I have used silicone DOT 5 brake fluid for over 10 years in my turbo Mini. It´s fitted with Metro vented 4-pots, EBC pads, late model SPi master cylinder etc etc. Well, if someone understands what I am saying (at least Stevieturbo knows Minis) the brakes are rather effective. It´s a road car that sees occasional track days. I have not had ANY problems with silicone fluid, the car has very solid pedal etc. When I had the car resprayed I removed just about everything apart from subframes. During assembly, I had to use "normal" DOT4 brake fluid since none of the shops around had any silicone fluid. Well, I now have a direct comparison and the brakes feel exactly the same.

OTOH, my Minor has big 4-pot Brembos in front and VW calibers in the rear. It also has DOT 5 fluid. The master+servo are from an ancient Metro which I believe may be a bit tired. I will swap them this winter and for above reason I will use DOT 4 brake fluid. I am hoping to see some improvements in pedal feel. The performance is superb but the car does not simply have the fell of my Mini.

Reason for using silicone initially was the resistance to absorb water. I have had the pleasure to store my cars in cold garage over the winter time and I don´t want to do any brake relared repair before I car drive the car out ot the garage in the spring.