Hydraulic brake fluid.

[Pale Rider]

I doubt the wrong fluid will have done any damage in the hour or two it was in there.

Bear in mind MTB downhillers used to use water in early disc brakes because the proper stuff was too dear.

The seals are not made of paper, they will easily withstand a short period of contact with the wrong fluid.

Brakes are safety critical, but if there is a failure it will be gradual, so @Brandane is not taking much of a risk by seeing how things go with the correct fluid.

 

[Drago]

The material in of which the seals are made is molecularly quite mobile, hence them being flexible and retaining that flexibility for years if cared for. Thus I would contend it is likely that they'll be compromised within minutes of contact with DOT fluid.

 

[Pale Rider]

The material in of which the seals are made is molecularly quite mobile, hence them being flexible and retaining that flexibility for years if cared for. Thus I would contend it is likely that they'll be compromised within minutes of contact with DOT fluid.

I find that unlikely, but it's certainly possible.

The gold maintenance standard would be to bin the brakes and fit new ones.

Not so daft because budget Shimano disc callipers are not expensive.

The life of the seals may be reduced, but I doubt they will fail catastrophically.

I wouldn't want to suggest anything that might compromise a rider's safety, but I believe a careful 'see how they go' or rather 'see how they stop' approach is a safe way to proceed.

 

[Brandane]

I wouldn't want to suggest anything that might compromise a rider's safety, but I believe a careful 'see how they go' or rather 'see how they stop' approach is a safe way to proceed.

That is the plan ...... The seals will swell and cause stiffness of operation rather than total failure, if my understanding is correct. If they eventually need replaced, then so be it. Lesson learnt (errm - another one).

 

[Pale Rider]

That is the plan ...... The seals will swell and cause stiffness of operation rather than total failure, if my understanding is correct. If they eventually need replaced, then so be it. Lesson learnt (errm - another one).

Makes sense to me.

You will obviously keep a closer eye on brake operation, and I think you will get some advance warning of any problems.

Performance may decline, or perhaps more likely the feel of the lever will change, it might become soft or 'dead' and wooden.

Literally keeping an eye out for seeping will also be worthwhile, which I'm sure you plan to do.

 

[Cubist]

I seem to remember that Halfords sell a litre bottle of hydraulic transmission fluid suitable for the likes of Citroen for about the same price of a 50cl bottle of Shimano oil.

Edit: or a litre of the real thing fromTweeks for twenty quid. (eBay).

We could form a cooperative and share litre between ten of us.... Best part of a lifetime supply.