Quick Take Review

Spongy. And with too long a pull. That’s what I started to experience recently with the hydraulic disk brakes on my Marin. Time for a bleed perhaps? Or maybe there’s a less involved option? I went searching the interweb for something that might shortcut a full bleed while still providing a fix. What I found was a potential solution called “burping” along with a handful of short videos illustrating the exact procedure.

As you can see, it’s not complicated. You simply remove the brake reservoir cover and pump the lever to release any bubbles that might be in the line. Once that’s complete, overfill the reservoir. Reseat the gasket and cover, and call it done. Love this kind of quick fix. And it worked perfectly for me. After a few minutes, my brakes returned to normal with the perfect amount of pull.

But here’s the rub. What type of brake fluid should you use when topping off the reservoir? Mine take mineral oil, like all Shimano, Tektro, Giant and Magura brakes. Strangely enough, none of my local bike shops stock kits for sale. Hard to believe, but true.

Size: 16 oz
Materials: 100% mineral oil

Another cruise of the interweb turned up a few options, but the cost in many instances was outrageous. From what I can tell, name brand (and color dyed) mineral oil brake fluids cost somewhere between 16 to 20 times that of the drug store variety. For that, some brands come with cool names like Venom and Royal Blood. Others even have sweet logos. But really, 20 times the price? How much better could the name brand stuff perform when it’s just mineral oil?

The answer – I found – was it’s no different. At least in my application. I topped off the reservoir as prescribed with mineral oil purchased at a local drug store ($5 for 16 ounces or roughly 1 cent per ml). By the way, I did not buy scented baby oil which is also mineral oil based. I purchased straight up USP 100 percent mineral oil, no coloring or fragrance added.

Granted, I just topped off the reservoir and didn’t bleed the whole system. But performance is solid and holding without any issues. Okay, there was one issue. I can’t have something hanging around the shop with a label that says “laxative.” As much as I appreciate that mineral oil has multiple uses, that label had to go. It needed replacing with something more fitting for hydraulic fluid. Enter Dragon Piss brand. You probably won’t find it on the shelves of your local bike shop anytime soon. But heck, if you’d like me to sell you some for 20 times what I paid (plus shipping and handling, of course), shoot me an email.

Alternatively, you might want to check out the guys at Epic Brake Bleeding Solutions based in the UK. They have a comprehensive line of fluids and bleed kits and ship worldwide. Not as cheap as the drug store, but much more reasonable than the name brands.

Thanks for reading another outdoor gear review from GearGuide.