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The mkiv Supra Owners Club

Brake fluid change


Mgrene

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Good day.

 

Well this might be a stupid question, but I am still new to some of this stuff :imsorry:

 

I will soon get my brake fluid changed at a car shop but earlier today when I looked at the engine bay, I discovered that there were two places where the brake fluid could be filled? What's up with that?

 

Which one is the correct one and is there something that I need to inform (precautions to be taken) the carshop before they start changing the brake fluid?

 

attachment.php?attachmentid=181990&stc=1&d=1394557792

Brake fluid.jpg

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Guest Budz86

Yes, I believe it's to show how high the level is. Use dot 5.1 too, it probably says to use dot 4 but this was all they had around at the time

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Yes, I believe it's to show how high the level is. Use dot 5.1 too, it probably says to use dot 4 but this was all they had around at the time

 

Actually it says that I should use dot 3. I have bought Motul RBF600. Its "only" dot 4 but as far as I can read on various sites, this oil is top dollar.

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Dot 4 is perfectly fine on a road car. 5.1 has a higher boiling point, and is primarily for track use.

 

Brake fluid should be drained and replaced every few years anyway, as it's hygroscopic and deteriorates with age and moisture.

 

Also, I think I'm right in saying that you can't mix 5.1 with any other grades?

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Dot 4 is perfectly fine on a road car. 5.1 has a higher boiling point, and is primarily for track use.

 

Brake fluid should be drained and replaced every few years anyway, as it's hygroscopic and deteriorates with age and moisture.

 

Also, I think I'm right in saying that you can't mix 5.1 with any other grades?

 

I do not know the brand of the present oil and that is why I am going to drain the whole system and fill in brand new oil.

 

The car will primarily be used for road and not track.

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Don't drain it but bleed the system, keep topping up the reservoir until you draw the new fluid

through all four calipers.

 

A vacuum bleeder makes the job very easy and removes the need

to pump the brake pedal.

 

Motul RBF600 is perfect and has a higher wet and dry boiling point than Dot 3, 4 or 5.1

 

You can't mix DOT 5 with DOT 3, 4 or 5.1, DOT 5 is Silicon based and it wont mix

with the others which are Poly Glycol based

Edited by Dnk (see edit history)
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No problem, it can be a tad confusing and most would think it was 5.1 that didn't mix. Pretty

stupid numbering if you ask me.

 

DOT 5 has a few other differences, it doesn't absorb moisture and it wont

damage your paintwork, it's not a very good lubricant so not ideal in a car with

abs

 

RBF600 -- 312 C dry boiling point and 205 wet boiling point

RBF660 -- 325 C dry " " 205 wet " "

 

DOT 3 --- 205 C dry and 140 C wet

DOT 4 --- 230 C dry and 155 C wet

DOT 5.1 - 260 C dry and 185 C wet

 

DOT 5 Silicon - 260 C dry and 185 C wet

 

Super DOT 4 - 300 C dry and 195 C wet

Edited by Dnk (see edit history)
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Don't drain it but bleed the system, keep topping up the reservoir until you draw the new fluid

through all four calipers.

 

A vacuum bleeder makes the job very easy and removes the need

to pump the brake pedal.

 

Motul RBF600 is perfect and has a higher wet and dry boiling point than Dot 3, 4 or 5.1

 

You can't mix DOT 5 with DOT 3, 4 or 5.1, DOT 5 is Silicon based and it wont mix

with the others which are Poly Glycol based

 

Maybe I should do the bleeding myself instead. Doesn't sound that complicated. Any particular strategy to be used (start in the front and end with rear caliper or)?

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When we did mine we did the passenger front, passenger rear, drivers side rear then drivers

side front using this vacuum bleeder.

 

Brakes were spot on doing this, the brakes had been replaced with new UK spec calipers all round

07300.jpg

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