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Front brake system


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Morning all. 

Embarrassing confession on this one...for some reason I used mineral clutch fluid when I was bleeding my brake systems a couple of weeks ago. 

Life has since got in the way and I only got back in the garage yesterday to put dot4 through. However now there is absolutely no pressure in my front system. 


Do I just need to persist/get a syringe on it, or will the mineral fluid have damaged any of the components? 




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Sadly all the seals will need changing as they will have swollen and eventually split, might be ok with the pipe but it will need to be flushed.

lots have people have made the mistake the other way by putting Dot 4 in mineral clutches.That generally works for a week before the seals swell up and split. BMW motorcycle forums are full of tales with bikes from about 2010.

This mistake is less common because not so many people have mineral oil in their garage to make the mistake. 

I have first hand experience because my Nephew was sold Mineral oil to go into a Peugeot braking/Clutch system that should  use DOT 4. First the clutch went light then stopped lifting fortunately it made it undriveable before it stopped the brakes working. The cost was enough to scrap the car.





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  • 2 weeks later...

The front calliper pistons seals aren't immersed in fluid but it may be wise to change them... you can’t buy just the seals... it’s a new piston and seal set...the seals are ‘square’ in form but I have in the past used ‘O’ rings that work fine with new pads but as the pads wear the o rings don’t allow the pistons to creep out to take up wear in the pads.  

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