Brake fluid - what type are you using, and where to get it??

MrNorm · Post by **MrNorm** » Fri Jan 21, 05 8:47 pm

Can't decide what type of brake fluid to use.

If it wasn't for the thought of system leaks damaging the paint, I'd go for conventional polyglycol fluid as a no-brainer (DOT 3, 4, or 5.1).
Silicone fluid (DOT 5) is appealing for that reason alone to me. But it's pricey, don't know how easy it is to get over here, and there are a number of other disadvantages.

I've been through all the pros and cons, so I thought I'd ask you guys what you use. And where is the best place to get it over here??

Anonymous · Post by **Anonymous** » Fri Jan 21, 05 10:14 pm

DOT5.1 - local motor factor. (easy)

I tried DOT5 stuff in one car I had after changine every single brake component in one go, but I never liked the pedal feel after. Few other people have commented it left them with a slightly soft feeling pedal.

Kev · Post by **Kev** » Fri Jan 21, 05 10:26 pm

DOT 4

Holly · Post by **Holly** » Fri Jan 21, 05 10:34 pm

Dot 4, Dot 5 will feel spongy when it soaks up any water that works it's way into the system ... as most of us don't change our brake fluid every year it happens ...

MrNorm · Post by **MrNorm** » Fri Jan 21, 05 10:48 pm

Actually the sponginess with DOT 5 (silicone) is because it traps air very easily. Very difficult to bleed fully and that's why (sometimes) you get the spongy pedal. It won't absorb water at all, it's the polyglycol fluids that do that - all of them DOT 3, 4, and 5.1.

However, some would say that it's better to have the water evenly absorbed rather than sitting in a clump at the lowest point of your system (your calipers) as it could with silicone.

Those are 2 of the disadvantages I mentioned for silicone.
Question is - do they outweigh the advantage of friendliness to paint?

Not having bought any brake fluid for many many years (really!), how much does the 5.1 go for - is it significantly more than the 3&4 (advantage is higher boiling point). And are there any good brands that are known to be good stuff?

Anonymous · Post by **Anonymous** » Fri Jan 21, 05 10:54 pm

TBH I just buy Comma brand. All brake fluids have to meet certain specifications to get the DOT on the label, and Comma stuff has always seemed OK to me. Never had a problem with it.

As for paint friendlyness.... just keep a rag under the M/C when filling or bleeding and wipe off carefully.

I don't trust DOT5 at all anyway.

Blue · Post by **Blue** » Sat Jan 22, 05 12:16 am

Silicone, Carspares stock it, it's flamin' expensive....

Kev · Post by **Kev** » Sat Jan 22, 05 12:35 am

Silicon? We've all heard the scare stories.......DOT 4 every time for me. (Just use a rag under the M/C.) Don't fret on your paint when you are liable not to stop!

Holly · Post by **Holly** » Sat Jan 22, 05 1:31 am

Sorry, I'm having a backwards day (as usual) ... make that a backwards week ...

Anonymous · Post by **Anonymous** » Sat Jan 22, 05 6:47 pm

I'm with Kev. A good DOT4. Had silcone fluid in various vehicles over the years. i seemed to have more seal failures with it, but that would be kinda difficult to quantify.

Never got on with the pedal feel either. Eventually converted all my cars back to normal fluid.

Just don't spill it when putting it in. Then your paint will be fine.

As for cost i think its about ?20 a litre. Easy to get for me cos Automec, the UK suppliers are round the corner.

Did you know you can get bleed nipples with non return valves in to make bleeding easier, (and a one man job). Got them on the triumph.

Anonymous · Post by **Anonymous** » Sat Jan 22, 05 7:00 pm

Gotta be DOT4. The DOT5 gathers water ate the lowest point as you say, which will boil under heavy use - do you want that? As for paint damage, how often have you damaged your paint with fluid eh? Spilt a drop, then wipe it off quick, it`ll be OK.

TrevD · Post by **TrevD** » Sat Jan 22, 05 7:05 pm

Dot 4 , when i ran a motor factors we stocked all types , only complaint was from a biker who used dot 5 in his harley ,a cylinder started leaking , he contacted the manufacturer who told him that the rubber used in older brake components was not compatable with silicon fluids (dot 5) , he flushed the system and put dot 4 in it and cured the problem . i always use dot 4 .

Kev · Post by **Kev** » Sat Jan 22, 05 7:15 pm

When bleeding brakes I use a giant Hypodermic needle that I got in Ibiza full of a jelly cocktail. Hook it up to the nipple with some IV tube I "found" outside a hospital then crack the nipple and suck the fluid through. Works a treat and it's one man operating

MrNorm · Post by **MrNorm** » Sat Jan 22, 05 7:59 pm

Hmmm, I think you are convincing me to stay with conventional fluid.....(which is kind of where I was heading anyway I think

)

One of my concerns was based on the fact my new calipers and master cylinder have been sitting in the house for years and years. They have the plugs in the orifices (good word

), but I'm wondering if the seals will have dried up or something? Don't want to bolt on m'new M/C, bleed everything then find fluid coming out the back of the cylinder or something.
What do you think? Will they likely be OK. And if they aren't will it be immediately apparent once I fill the system?

Hey Roger, I like the one way nipples! where can you get them?

Holly · Post by **Holly** » Sat Jan 22, 05 10:37 pm

I thought mostly the seals went when put through heat cycles, so if they've been in the house they should last yonks ... (also means no condensation either).

I'd like to find out more about the (brake) nipples too! Could do with those on everything