Type Of Brake Fluid

The only material difference is their boiling point so unless you are racing you and your bike could never tell the difference. Your wallet might.

 

Really don't think you should use dot5, as its silicone based. And should not be used with abs systems.

 

I didn't read your first message properly, didn't notice you said dot 5.1
Which isn't the same as dot 5
Personally I would use what the manufacturer recommends.

 

You could have a look here, for what it might be worth:
https://www.caroutfitter.com/best-brake-fluid-reviews/

Personally I haven't given it much thought, except that on my cars, I prefer to alternate between yellow and blue just to make sure I have got all of the old fluid out.

 

I believe you shouldn't put DOT 5 in a system that has previously had DOT 4 in it, even if you think you have flushed it, as it goes gloopy. When I restored my MK3 Cortina 10 years ago I completely replaced the braking system and put DOT 5 in it. I have bleed the system twice since then and what came out was exactly the same purple colour that went in. DOT 5 is also paint friendly unlike 4.
Top tip time, use DOT 4 for striping paint from plastic parts as it wont damage the plastic.

 

1. Do not use 5.0

2. unless you are taking the bike off to track/race/always slamming the brake like mad, you will not see the benefit of 5.1 since the real benefit of 5.1 is higher boiling point.

 

Hello Timmy, and welcome in

You say "Do not use 5.0" but with no evidence or explanation as to why not. It's kind of like me putting on the What are you Drinking Tonight thread "Do not drink white wine" but without explaining that it is a fruit based cocktail designed specifically for the ladies

 

Okay okay, i guess I can see that lol.

you shouldn't use 5.0 as it is silicon based while 3/4/5.1 are glycol base therefore are not compatible with 5.0.

From my understanding, 5.0 also does not play well with ABS system.

 

From my understanding DOT 5 is not hygroscopic where the previous numbers are (which also effects the boiling point)

The two do not mix, obviously if you add 4 to 5 then you allow it to absorb water as well, and it sludge. If you wanted to use DOT 5 then you would need to start with a new system, with zero traces of 4.

Main advantages of 5 over 4 are the higher boil point, not hygroscopic, and there is generally less corrosion of brake cylinders and damage to seals.

I have heard the same about Abs, I think it's to do with abs systems being calibrated to work with non silicon fluids, I think dot 5 compresses differently.

DOT 3 is standard, DOT 4 is heavy duty, both are glycol based, so strip paint where DOT 5 is silicon, and won't strip paint.

Bit of a yawnworthy post... I did a fair bit of research when I rebuilt the Land Rover brake system, was going to use DOT 5, but in the end there weren't enough advantages to justify three times the price of DOT 4.

 

I have gone from dot4 to 5 (silicone based) there is no problem with interaction and goop as one is different SG to the other and will sit on top/below cant remember which right now no significant difference in feel though.