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I'm looking for a bleed kit compatible with Tektro HD-R210 brakes.

I believe this is an OEM part - it doesn't look like there's a lot of information available for them. The levers are labelled to indicate use of Mineral Oil.

Would Tektro HD-R210 be compatible with Shimano bleed kits, or would I need a Tektro specific kit?

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    A quick point of information: I believe that mineral oil is generic umbrella term, and oils can vary significantly in their chemical and physical properties. Without explicit documentation, I'd err on the side of assuming incompatibility. If I can substantiate this comment, I'll turn it into an answer.
    – Weiwen Ng
    Apr 10, 2020 at 14:28
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    Please put up a picture of both the caliper and levers that shows the bleed ports. I can't seem to find one for this brake. Apr 13, 2020 at 2:52

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This is a good question. As detailed below, there is reason to think that mineral oils are unlikely to be compatible between brands. I can't unequivocally show that Shimano oil will damage Tektro brakes. However, if the tradeoff is possible damage to the seals in the Tektro brake, then it would seem better to use Tektro oil.

First, mineral oil is, per Wikipedia:

Mineral oil is any of various colorless, odorless, light mixtures of higher alkanes from a mineral source, particularly a distillate of petroleum...

Higher alkanes are molecules with 9 or more carbon atoms. Per the table in the link, their boiling points range from 150.8 (C9H20) to 286.8 (C16H34) degrees Celsius. Their density varies less, their viscosity varies more.

We don't know the mix of alkanes in Shimano and Tektro oil. Their compositions and resulting physical properties may be close enough for them to be mutually exchangeable. Some posters on bike forums have reported interchanging oils for Shimano and Tektro, e.g. this poster, this poster who said their LBS said the oils are interchangeable, and one poster here who put Shimano oil into Tektro Hy/Rd cable-actuated disc brakes. This article on Juiced Bikes seems to imply that either oil is fine.

Bikerumor interviewed several brake manufacturers, and one of the questions was interchangeability. Some brakes (e.g. SRAM, Hayes, and Hope), use DOT brake fluid (of which there are several types). We can categorically say that DOT fluid should never, ever go into brakes designed for mineral oil. DOT fluid is corrosive to things like paint. If the seals are specifically designed to resist it, this is fine. If they are not, you'll corrode the seals and then your brake will fail.

Shimano said that their brakes could only take Shimano oil:

I can tell you with absolute certainty that Magura fluid will destroy Shimano brakes in a very short amount of time. I’ve seen it happen several times. The rubber seals in the system have to be specifically designed to interact with a specific brake fluid. If you use a different fluid, the seals will interact differently. Specifically, when you put Magura fluid in Shimano brake, the lever feels spongy and the pad contact point changes because the square edge seal at the caliper is breaking free from the piston at a different time.

There are third party companies that make mineral oil brake fluid and it says right on the bottle that it is compatible with all mineral brakes. Shimano has never approved a third party brake fluid to be compatible with our brakes and we never will. How is it possible that one fluid can work in both Magura and Shimano brakes if Magura fluid destroys Shimano brakes?

Magura simply said to only use Magura oil in their brakes. However, both manufacturers have a commercial incentive to say that, and Tektro didn't respond to the interview. This leaves open the possibility that Tektro's oil is similar in composition, chemical, and physical properties to Shimano's oil.

Nevertheless, even considering that issue and the forum posts, I don't consider the tradeoff to be worth experimenting. Brakes, after all, stop your bike.

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  • What an amazing and thorough answer that deserves far more upvotes than the one I gave it.
    – jungledev
    Feb 18, 2021 at 12:07

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