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Discussion Starter · #1 ·
Hi,
Is there any known reason to not upgrade the brake fluid from the OEM Dot4 to the Dot5.1?

I know a lot of people on here have upgraded the fluid, including me when I had the brakes replaced with GTT's Spiroslots, but noticed on top of the brake fluid reservoir cap it says to only use Dot4.

Reason I ask is the brake fluid is due a change and I want to get the service book stamped but would also like to continue using the Dot5.1 fluid and wondered if the MINI dealership would be willing to carry this out?
 

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cristo
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They might. I supplied them with ATE Super Blue, and they used it instead of their own fluid.
At first they balked and said a non-OEM brake fluid might cause warranty problems with the brakes, but when I told them I had already replaced the pads and rotors with aftermarket ones, they said OK.
 

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THE STICK
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Thwe main reason not to upgrade to 5.1 is because its still crap for heavy use IMO. Unless your getting it free as part of a brake upgrade and the car is just for fast road I'd not bother using 5.1.

Use RBF600 its a million times better than most normal 5.1s. I run it and I think it was cheaper to buy than the 5.1 I was initially looking at.
 
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Discussion Starter · #4 ·
Thanks for the replies chaps.

Just spoken to Roland @ GTT (should have rung him first really :hmph:) and it's OK to replace the Dot 4 with Dot 5.1 as they are alright to mix. Thanks Roland.

But do not replace with Dot 5 as apparently thats altogether different, Dot 4 and Dot 5 don't get on :D.

I only use the car for road driving so I'm not that heavy on the anchors anyway so would have thought the Dot 5.1 would be ample for my use, but thanks Richard I will have a look at RBF600. Would that be compatible with Dot 4?
 

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THE STICK
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I know that I boiled my 5.1 (and my car has JCW brakes and had not been on the track!) ... after doing this several times the fluid started to deteriorate and I ended up with a spongey feel. I have cooked the brakes several times now since RBF600 went in and its never boiled and the feel is still spot on.

I don't believe the RBF600 can be mixed with dot 4 ... not sure on dot 5 ... I was due a fluiod change so I had the system bled completely by ThinkMINI and flushed. They then refilled with RBF600. I think they were charging about £10 a bottle.
 

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PowerSteeringPumpActivist
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High-Performance Brake Fluid Options

Thwe main reason not to upgrade to 5.1 is because its still crap for heavy use IMO. Unless your getting it free as part of a brake upgrade and the car is just for fast road I'd not bother using 5.1.

Use RBF600 its a million times better than most normal 5.1s. I run it and I think it was cheaper to buy than the 5.1 I was initially looking at.
I know that I boiled my 5.1 (and my car has JCW brakes and had not been on the track!) ... after doing this several times the fluid started to deteriorate and I ended up with a spongey feel. I have cooked the brakes several times now since RBF600 went in and its never boiled and the feel is still spot on.

I don't believe the RBF600 can be mixed with dot 4 ... not sure on dot 5 ... I was due a fluiod change so I had the system bled completely by ThinkMINI and flushed. They then refilled with RBF600. I think they were charging about £10 a bottle.
Thanks for the tip Richard! :D

I'm currently looking into higher-rated options for brake fluid beyond the standard dot 5.1 after I too boiled my dot 5.1 fluid last weekend. :eek: I guess I was being a bit hard on on the braking zones. :p

I was able to find information on high-performance alternatives with the following boiling points:
  • Motul RBF-600: 312°C/593°F dry and 216°C/420°F wet.
  • Castrol SRF: 310°C/590°F dry and 270°C/518°F wet.
  • Endless RF-650: 323°C/613°F dry and 218°C/424°F wet.
  • ATE Super Blue / ATE Super Gold (identical except for the colour): 280°C/536°F dry and 198°C/388°F wet.

So it seems as though Endless RF-650 is the best from new, but the Castrol SRF has the best staying power over time (as moisture creeps in). Motul RBF-600 seems like it could be a good option if the other two are disproportionately expensive (I've not yet come across prices for a UK supplier). :cool:

I'd be glad to hear some thoughts if anyone has tried any of these brands personally. ;)

All the best,
Andrew.
 

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THE STICK
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Lucky Dave at ThinkMINI can probably get hold of it for a good price as he now stocks RBF600 since Alex and I started using it, so I guess he can get 650. If he can't i'm sure he could point you in the direction of a supplier
 
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