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What Brake Fluid

Jam911

Well-known member
Joined
31 Oct 2010
Messages
1,720
Hi Guys
I have to do a brake fluid switch soon.

What brake fluid do I need or do you use?

And how much do i need?

Thanks
 
Dot 4 mobil and at work we drain 1 ltr .. start with n/s/r and drain out just over 1/4 of a ltr .. then o/s/r and about 1/4 then fronts .. less is needed at the fronts due to the shorter pipes .

A ltr or just over in all but get more out of the rear due to longer pipes .

I have changed fluid from raceing blue to standard and i can say starting at the n/s/r then its just under half a ltr to run clear .. from blue to normall fluid basically ... a bit over kill but thats what i saw .

Interestingly .. i then undid the inner nipple and no blue fluid came out .. makes one wonder .. do you actually need to undo both nipples ?

Im sure that will draw a comment or 2 :D
 
Thank you sir
 
Iain - to your question, there is of course a need to periodically loosen to prevent them seizing.
That aside, I'd be surprised if there is more than perhaps 5ml in the line between the nipples on each caliper.
So a max. of 20-25ml overall = maybe less than 5% of the total in the system, and you've got to assume it gets pretty well mixed with use, so any water content will be well mixed in.

I'm also interested to understand about clutch bleeding for cooking models V turbo, turbo s and GT models.
Don't the former share the brake fluid with the clutch?
How much fluid is in that system and can you drain it? Is it worth the extra effort?
Cheers chaps!
 
I use either Motul RBF660 or the ATE Racing stuff (Blue is no longer available).

TBH, if you're not doing any track days etc, pretty much any DOT4 stuff will do.

The clutch reservoir is separate on the Turbo, shared on the Carrera's. On the Turbo, it's under the cover just behind the brake servo IIRC. Mine's never been changed in the 10 years I've owned it, it's not a service item other than checking the level, pretty sure it's Pentosin of some description.
 
jonno_ said:
Iain - to your question, there is of course a need to periodically loosen to prevent them seizing.
That aside, I'd be surprised if there is more than perhaps 5ml in the line between the nipples on each caliper.
So a max. of 20-25ml overall = maybe less than 5% of the total in the system, and you've got to assume it gets pretty well mixed with use, so any water content will be well mixed in.

I'm also interested to understand about clutch bleeding for cooking models V turbo, turbo s and GT models.
Don't the former share the brake fluid with the clutch?
How much fluid is in that system and can you drain it? Is it worth the extra effort?
Cheers chaps!

i was told to do all nipples when i started so its kinda habbit .. but i did find it interesting that no Blue fluid came out .. so whats left in ther caliper from a one side only bleed to me must be miniscule .

As you say .. the fluid will mix anyways on a bleed and all you are trying to do is remove as much moisture as possible .. which lets face it ... you could go 6 years without much of a problem .. but as these are sports cars ..

Turbo etc use the fluid thats in the Power steering .. pentosin .. a seperate small resevoir for the clutch at the front and the power assist coming from the power steering pump ... not mixed though .. a seperate resevoir for each .

Im not sure if there is a service interval to actually change pentosin .. i think not as there isnt one for a PAS fluid change .

Ive never done it anyways unless after replaceing the clutch slave cyl and i was bleeding it out .
 
...interesting Iain...

When my engine was rebuilt they also replaced the brake pipes running over the gearbox and bled the system...on the rear passenger side, the inner nipple snapped flush...

I was considering removing the caliper to have a new nipple installed but given that being unable to release both bleed nipples on this caliper probably makes little to no difference I might just leave it...

Helpful to know...Thanks :thumb:
 
Be aware it only takes a tiny air bubble to give spongy brakes .. you may get away with it , you could remove the caliper and tilt the good side up to help as another possible way .

My comments were more based on changeing the brake fluid .. its such a tiny amount that might get left in a caliper that only bleeding from one nipple ihmo will make almost no difference .
 
...Thanks Iain,

In that case I will use my ezybleed and bleed it through again opening up the 7 out of eight nipples..easy and cheap to do..
 
...and I might remove that caliper and bleed it as you say with the good nipple higher than the seized one..
 
Thanks gents.

GMG - procalipers if the OCD gets too much :D
 

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