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Kai2k

N18 MCS Dot 5.1 brake fluid?

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Following a recent spirited drive down from Hartside I've noticed my brakes aren't what they should be. At the time the brakes stank and when I safely pulled over the hammerite I'd applied to the hub part of the disc (obviously not the braking surface :-) ) was bubbling, so I think a lot of heat was generated. As the brakes are rather inconsistent now I presume I've boiled the brake fluid. I'd like to try putting 5.1 in but as always there are mixed views of whether you should, you could damage seals and so on. Has anyone done this and if so, can you please recommend a brand? Thanks.

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I’ve no idea about different brake fluids but during your drive could you not have been suffering from “brake fade” ? Possibly uprating pads may be a good idea to price up ??

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I think @Bornared is on upgrading his disks and pads. Might be worth asking him about what he's chosen and why

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2 hours ago, LCWElvin said:

I think @Bornared is on upgrading his disks and pads. Might be worth asking him about what he's chosen and why

 

I’ve got Pagid uprated discs to go on my Mini (should be fitted by the weekend). I had been looking at EBC but was’nt sure on which pads. Decided to try Pagid uprated discs and see what they are like. Had EBC discs on one of my Subaru’s and never had brake fade. EuroCarParts had a 50% code for discs and pads so thought why not 😉 

I will give feedback on my build page 👍🏻

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6 hours ago, Kettlepot said:

I’ve no idea about different brake fluids but during your drive could you not have been suffering from “brake fade” ? Possibly uprating pads may be a good idea to price up ??

Thanks. I may indeed upgrade discs and pads although many moons ago I had M1144 pads on (a previous car) and they were terrible unless you were racing. At town speeds they were almost dangerous - presume a hard compound. I'd probably go for drilled and grooved discs too but perhaps standard pads. I feel like there may be air in the system as they are inconsistent. For example, I once left a car park with cold car, pulled out and had to stop immediately for the lights. I was doing like 15 mph. They were terrible, like a spongy pedal. Then for the rest of the trip they were back to normal. Given the bubbling paint I mentioned I presume the fluid will have gotten hot. But then again I'm no mechanic!

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I wish I’d bookmarked a website I found a while ago, it gave specs of brake pads for operating temps- min to max and it was an interesting read. If I get a tick I’ll try and find it again.

most racing pads don’t work until HOT most road pads fade when they get reasonably warm. There were a couple that worked from really low to quite high (high enough for most road use)

 

@Kai2k try getting them warm enough to crack a disc. @Mr Watton any ideas who could have done this ? 🤔

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It all depends on what kind of life the pads have had, and how much material is left on the pad. The thinner the pad the harder it can loose the heat. I'm sure when we checked the outer pads they seemed not too bad, but again many factors could be at play here.

 

Black stuff below is slightly better than OEM. I would deffo change the brake fluid anyway, for peace of mind, but it could do with testing to see if the boiling point has been effected, or of there is any water content because its Hygroscopic it can pick up moisture over time, usually recommended to be replaced every two years. Just depends on driving styles and all that jazz.

 

ebc_brake_temp.jpg

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12 hours ago, Kettlepot said:

I wish I’d bookmarked a website I found a while ago, it gave specs of brake pads for operating temps- min to max and it was an interesting read. If I get a tick I’ll try and find it again.

most racing pads don’t work until HOT most road pads fade when they get reasonably warm. There were a couple that worked from really low to quite high (high enough for most road use)

 

@Kai2k try getting them warm enough to crack a disc. @Mr Watton any ideas who could have done this ? 🤔

 

Cracked a disc! Wow. My fluid was changed by MINI last year actually. Yeah my issue is quite a puzzle. It might just be as simple as the fact that mine need to be warm to work better but I just don't know. @Mr Watton I think actually when we looked you said whilst they weren't knackered they were significantly worn meaning the pedal would need to travel more to operate them. Last year MINI said discs and pads needed changing then independent said they did not. It's all a big puzzle but I'm reluctant to put in a 5.1 unless I can be sure I can get one that won't damage seals etc. I thought a JCW would have 5.1 in as standard but I was wrong. I'm half tempted now to just buy a small bottle of dot 4 and bleed mine to see if there is any air in there. 

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I wonder if it’s possible to glaze the pads similar to how you’d glaze a clutch ??

 

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2 hours ago, Kettlepot said:

I wonder if it’s possible to glaze the pads similar to how you’d glaze a clutch ??

 

The face of the disc can be skimmed with a lathe to clean it up

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