Hydraulic Oil (Split from "Greasing Bearings - Wow")

[thedatastream]

Split from https://www.cyclechat.net/

Okay lets chuck the cat in with the pigeons then...........

On that basis , you could put baby oil (mineral based) into your hydraulic brakes. Assuming of course they don't require DOT fluids.
Personally though I wouldn't want to test them out going down the Ben Nevis Red route!

I found this http://cr4.globalspec.com/thread/17517/hydraulic-oil in which many different hydraulic oils are discussed. Post #12 suggests that there may be corrosion issues using baby oil in hydraulic brake systems. I haven't looked into this any further though.

J

 

[spandex]

I Have met a couple on the road when I was touring in Canada that had Hydraulic disk brakes on both of there bikes. But one of the bikes got snagged and leaving the hose spit!!! But the bloke did a grate job in fixing the hose he then topped up the oil with cooking oil! He told me it was working grate and had been that way for just over a week as they had not got to a bike shop to get it fixed. That was the last I had seen of them but it did leave me thinking how long could you leave the brakes like that? but it did show it works...

 

[rusty bearing]

It probably would!

The reason for using proper hydraulic oil is in the additives , However in theory any fluid could be used in a brake, even the cup of tea you might be drinking right now. The important property of a fluid from our point of view is that essentially it cannot be compressed. So any pressure applied to a fluid in a closed container is transmitted equally throughout....Pascals law.
Anyway that is putting it very simply. Trouble with the cup of tea theory is the heat generated by disc brakes, boils the tea, tea turns to gas, gas compresses = failed brakes. If I remember, the boiling point of say Dot4 when new is @240C.

Enough with the science bit....worth reading up about though. At least when you lie in a crumpled heap calling for strong drink you'll know why your brakes went AWOL

 

[snailracer]

Now I don't know how similar hydraulic disk "oil" is to car brake fluid, but in cars it is important to use the right type otherwise the seals get destroyed.

 

[rusty bearing]

Most cars use predominently Dot 4 whereas bikes use Dot 4, 5.1 or LHM mineral oil and yes its important to use the correct one regarding the seals, although I've never determined which of the chemicals in a brake fluid actually does the damage. As the Dots are Glycol based and LHM is , well, mineral based therin lies the clue.
Fortunately bike brakes are usually marked on the reservoir cap as to which fluid they use. This doesn't stop people using all sorts, we've had them in the workshop with 3 in 1 oil, and worst of all old Dot3 which I haven't seen for years!

As spandex has said cooking oil will do , it just doesn't have the additives for anti corrosion and all the other stuff. However in times of great hardship you can make chips with it, just try that with Dot4!