Technical Dot 5.1 Brake Fluid in Cinq Question

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Technical Dot 5.1 Brake Fluid in Cinq Question

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Right, I have bought some Dot 5.1 brake fluid to change the old **** in the Cinq for whilst fitting new lines and rear pistons. Now I know some people use it with no worries, but I've heard a few people have had leaks from caliper seals using it because it is "too thin". What do you lot reckon, use it or not?
 
Although it may be overlooked and probably there would be no problems with it, I would always stick to Fiat Lubricants if poss, so thats a DOT 4 fluid, these are designed for the car.

Its very much like putting performance oil in of a weight such as 0W-40, which may seem a good idea, but is also too thin and not really benficial.

I would stick with original - just because it says performance on the tin, wont necessarily make it better for your car, only probably very modern cars with the latest braking systems.
 
I used it in mine and its just done an intensive track day without problem. Make sure you flush it through the system fully to remove any old fluid. This took over a litre when I did it.

John
 
Ah nice one, no trip to 'frauds on the bus for me (y).
JR I acknowledge what you are saying, but I had boiled brake fluid in the past so went for a higher b.p..
 
Dot 5 is simply better than Dot 4. The price difference is so little that I would always use Dot 5.

Dot 5 has a higher boiling point. All brake fluids (other than silcone) absorb water, and this reduces the boiling point. The higher the boiling point to start with, the higher it will be after any amount of water has been absorbed.

As John said, you need to put a lot of fluid through to clear the old out. It is also a good idea to syphon as much fluid out of the reservoir as possible before you start. Dot 5 is denser than dot 4, and so if you add Dot5 to a reservoir full of dot 4, the dot 5 will sink to the bottom and get flushed out through the master cylinder first. If you empty the reservoir as much as possible, the you remove the majority of the dot 4 without diluting any of the new fluid.
 
I know this should go without saying but when you syphon brake fluid use a mechanical syphon priming pump.
 
It's practically empty anyway folks, has had lines off for 24 hours ;). Seems I'll be alright with this I have, i'm not going out and buying more when this wil be ok.
 
Well can't find any leaks, have used up pretty much a whole 1 litre and they are still spongy :rolleyes: but my assistant has gone away until tomorrow so have to leave it at ~3/4 pedal travel and not drive it. Found the wheel bearing is shagged, so looks like a new one, but have freshened and tightened it up a bit. And THE only place I trust with fitting tyre's is closed for the weekend so have to wait to get tyre revalved :bang:
 
rallycinq said:
I prefer silicone, but only in a new braking system.

Cheers

D

I was thinking of going with the silicone stuff...

You think it would be ok just to flush the sytem with some then re-fill?

Would work out expensive to do at first but then obviously can just use Silicone... :confused:
 
Not sure why you want to use silicon, but unless it's for serious competition or track day use its a waste of money IMHO. If its fast road use then i'd suggest that 5.1 is more than adequate (y)

John
 
nitrane.co.uk said:
Not sure why you want to use silicon, but unless it's for serious competition or track day use its a waste of money IMHO. If its fast road use then i'd suggest that 5.1 is more than adequate (y)

John

The brake fluid did get very hot on a track day I did a few months ago might well just try the Casrol response Aaron suggested first and go from there
 
nitrane.co.uk said:
Not sure why you want to use silicon, but unless it's for serious competition or track day use its a waste of money IMHO. If its fast road use then i'd suggest that 5.1 is more than adequate (y)

John


Yup, sums it up nicely.

The bit I really like about silicone is that its not flammable. Normal brake fluid doesn't even need a spark to set it off.

Cheers

D
 
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