Beware of bad advice – Hydraulic Brake Maintenance

posted in: Maintenance, Two Wheels | 0

A word of advice to any bike maintenance novice out there like me, do not accept what someone behind a counter tells you as being gospel. Double check on the internet. There is a whole host of information out there from text to videos.

Here’s my story…

Okay, so I have been cycling for a good number of years and I have never really made the decision to learn how to maintain my bike, until now. Better late than never! Armed with my Haynes Mountain Bike manual, I set about what seemed like a simple task of bleeding my back brake.

My first task to overcome were the questions:

  1. Why have I now got no braking at all?
  2. Why is it not working, even though there doesn’t appear to be any more air coming out of the nipple bleed

Having checked the reservoir for the umpteenth time, I have come to the conclusion that I need to top it up, even though it looks like it is at its limit.

Now onto my reason for writing this article in the first place. Not understanding the complexities of oils, I went to my local Halfords and to the “Bikehut” to seek some expert advice. I mentioned that I had Shimano brakes and that I need to top up the oil. I was sent to the car department to purchase Clutch and Brake fluid. £6.49 lighter, I took it home.

Something kept nagging at me though. Why does it say Mineral Oil on brake lever reservoir casing if I am okay to use clutch and brake fluid that is used in cars. After some investigation, I found to my horror, that I had been given really bad advice.

Yes, you can use car brake and clutch fluid, however, it is not of the right viscosity for a mountain bike and therefore, the braking can be very sluggish. Adding the wrong oil can (although not totally proven) damage your braking system.

After more investigation, I found that I do indeed need to use Mineral Oil. So, armed with a mouse and a telephone, I set about sourcing some mineral oil for my bike.

Mineral Oil – Usually a reddish colour.

I hit yet another learning curve. Apparently there is more than one type of Mineral oil. [sigh]. Lucky for me however, I managed to talk to the right people and I ended up on the phone to a Mountain Bike enthusiast expert that works a who advised me of the correct oil to use and they do indeed stock it.

So now having purchased my mineral oil, which comes complete with a pipe and waste packet, I can now happily refill my brake oil reservoir and continue to bleed my brakes.

Update: Tuesday 29th November.

I would like to make a very important point to anyone reading this article; do not, under any circumstances, over tighten the reservoir bolts as the heads are very fragile and if like me, you have, you end up in a situation where you cannot top up your brake fluid as you cannot get the reservoir cap off because the Allen key just goes round and round! Looks like I might have to buy new brakes! Marvellous!

Update: Wednesday 30th November

After a conversation with the people at, they are confident they can remove the screw and replace it with a new one, which is fantastic news. I have asked them to sort my brakes out whilst they are at it too. 🙂

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