Zoom hydraulic brakes: use baby oil?

[mohammed]

My brakes have gone squidgy so need to add some oil and remove air. I’ve got a bleed kit but no ‘mineral oil’.

I’m not going to do a proper bleed rather just top up the oil in the system.

I don’t have official hydraulic brake mineral oil so I was thinking to substitute this with baby oil (which I have plenty of lol).

Do you think this will be ok mixing the oil which is already in the system with Johnson’s and Johnson’s baby oil?

 

[m@Robertson]

The people who have tested this have all said its fine, while at the same time throwing in all kinds of disclaimers about not killing yourself by doing unapproved things with something scary like brakes.

If you know what you are doing with hydraulic brakes in the first place (i.e. how to do a top-up as you describe) you should be ok. The real risks come from dumb mechanical errors like letting air into the system or not resealing it right and so on.

For the peanut gallery, here's a top-up for Shimanos. I do the same thing with Maguras and an open bleed syringe.

 

[fooferdoggie]

the fluids are different then straight mineral oil as they have different boiling temps. the manufactures dial their brakes and fluids in together.

 

[PedalUma]

Just go to the auto parts store and spend $5.00 for brake fluid. Baby oil will expand the seals by 30%. Don't ask how I know this.

 

[fooferdoggie]

Just go to the auto parts store and spend $5.00 for brake fluid. Baby oil will expand the seals by 30%. Don't ask how I know this.

sorry but thats really bad advice only brakes designed for dot 5 fluid should use them. that fluid would destroy the seals on brakes made for mineral oil.

 

[retiredNH]

Heck, it's only your brakes! Especially if you live in a hilly area like I do, why not experiment? Maybe you'll find that baby oil doesn't work so well for that sudden stop and save the rest of us from a mis-adventure...if you're still around to tell us.

Obviously I'm being sarcastic, but be aware that not everything you read online is true, or safe. It's one thing to cut corners on your chain or tires. It's much worse to "save" on brakes or batteries.

 

[PedalUma]

Okay, then go to a bike shop and buy the right stuff. I agree. Cutting corners on brakes, when it is material, matters.

 

[mohammed]

Thanks all, ordered some bike mineral oil from Amazon.

 

[m@Robertson]

Just go to the auto parts store and spend $5.00 for brake fluid. Baby oil will expand the seals by 30%. Don't ask how I know this.

Bear in mind his brakes use mineral oil, not DOT fluid.

Like I said... this is not a new idea. You will find it bandied about and tested on many MTB web sites. In a pinch, baby oil will do. Bear in mind for those saying don't do it, the alternative is to ground the bike and walk. Or keep using it with a squishy lever. Compare that to a theoretical concern on reduced effectiveness and, again, its not like this is a new idea. If I needed to take a fun ride, I'd wait for Amazon to deliver the right fluid. If I needed to get to work or buy groceries, I'd use the baby oil and do a full flush when I had the chance afterwards.

Here's just one example that is smart about explaining the possibilities for problems, used a control and a tear-down inspection.

 

[fooferdoggie]

Bear in mind his brakes use mineral oil, not DOT fluid.

Like I said... this is not a new idea. You will find it bandied about and tested on many MTB web sites. In a pinch, baby oil will do. Bear in mind for those saying don't do it, the alternative is to ground the bike and walk. Or keep using it with a squishy lever. Compare that to a theoretical concern on reduced effectiveness and, again, its not like this is a new idea. If I needed to take a fun ride, I'd wait for Amazon to deliver the right fluid. If I needed to get to work or buy groceries, I'd use the baby oil and do a full flush when I had the chance afterwards.

Here's just one example that is smart about explaining the possibilities for problems, used a control and a tear-down inspection.

short term I would not worry about it but long term who knows? it may depend on how hard you use your brakes. on our tandem no way. even with the ice-tech rotors and finned pads overheating can be an issue.

 

[retiredNH]

Heck, even water would work, kinda, in a pinch. Any poorly compressing fluid would.

But the OP isn't in a pinch.