Bike out of commission

[Smokin]

Please forgive me for being a plonker, But what exactly does oil in brake lines do? I know it's quite thick compared to brake fluid but that's the end of my knowledge on the matter.

[xwhatsit]

Well, I don't know much about hydraulics too, but the useful thing about normal hydraulic brake fluid is that it doesn't compress very well. Normal oil does compress. So you would grab a handful of brakes, the lever would squeeze, the oil in the line would compress and nothing would happen at the caliper end.

[FROSTY:Me]

brake fluid is (for the sake of this argument) water. Oil is oil--
oil causes massive issues with at the minimum all the seals in the system possibly the brake lines too
By issues in a nutshell I mean --it destroys em

[Smokin]

Ahhh, Thanks for clearing that up. I can see how it can cause problems now.

[Mikkel]

Well, I don't know much about hydraulics too, but the useful thing about normal hydraulic brake fluid is that it doesn't compress very well. Normal oil does compress. So you would grab a handful of brakes, the lever would squeeze, the oil in the line would compress and nothing would happen at the caliper end.

No, Oil does NOT compress! That's why you can use it for hydraulics. Liquids as a general rule does not compress - that's why the pressure increase when diving in the ocean increases linearly, not potentially, with depth.

brake fluid is (for the sake of this argument) water. Oil is oil--
oil causes massive issues with at the minimum all the seals in the system possibly the brake lines too
By issues in a nutshell I mean --it destroys em

Yeah, it'll fuck the seals I guess.



But Jeff, if someone with enough brains to dick around with your bike wanted you dead they would have done one of two things:

1. Cut the brakeline 85% through - it will then only fail when you REALLY need your brakes.

2. Put water in your brake fluid - when the brakes heat up (let's say a trip over the hill to Akaroa) it will evaporate... And trust me - you can compress steam, that's what they call brake fading. Just that's a small fraction of water to brakefluid - if you put in a whole lot it would get rather nasty very very quickly.

Hope you get it sorted out - but don't go paranoid already.

[xwhatsit]

No, Oil does NOT compress! That's why you can use it for hydraulics. Liquids as a general rule does not compress - that's why the pressure increase when diving in the ocean increases linearly, not potentially, with depth.

Hey, you're right! Look who's a dumbarse. Apparently it does compress -- a little -- but it's a tiny amount.

S'why I stick to fiddling with drum brakes

[MVnut]

Usually not a lot of extra room inside a reservoir so I presume some brake fluid must have been removed before any oil could have been added. Has anyone done any servicing recently, mistakes happen you know (although this is a biggie)

[jade]

I dont think anyone sabotaged your brakes,
I reckon the apprentice where you got your pads done put oil in your lines instead of brake fluid

[Motig]

Yes, if they've just been done recently I would suspect a cock up re the fluids.

[Paulus]

Many years ago a friend bought a bottle of PJ1 premix oil from Tommys Yamaha and when he poured it into his mixing container it was like water. Took it back to Tommys and it turned out it was brake fluid incorrectly packaged in a premix oil bottle! Mistakes can happen - even at a factory.

[Mikkel]

Hey, you're right! Look who's a dumbarse. Apparently it does compress -- a little -- but it's a tiny amount.

S'why I stick to fiddling with drum brakes

Nah mate, didn't mean to imply you were a dumbarse

And yeah, most liquids will compress - as you say - a little... very very little.
But it's not like it's obvious or common knowledge...

Drum brakes? you're a brave man!

[JWALKER]

yes, one of the bike shops recently serviced the bike and did the brake pads and stuff.
but, i spoke to them and they said they know the difference between fluids and there is no way they could have done it, they are not that stupid, but at the moment im thinking the opposite.
also, i think they are going to make me pay, to fix up trhis incident, which im not very impressed about

[FROSTY:Me]

dude what kinda master cylinder you got--4 screws or just screw lid?

[JWALKER]

its the back one and im pretty sure its only two screws

[jonbuoy]

Does sound like it could be a fuck up - if you wanted to tamper/sabotage you'd do the fronts for sure. More likely someone would just tip the bike over rather than undo screws siphon out brake fluid and top up with oil. I think your shit out of luck proving it if they did them a while ago and only you only just noticed.