Board logo

few drops of brake fluid in transmission.
bikecarbfred - 15/6/20 at 07:25 AM

I used a empty brake fluid bottle to drain some gear box oil into.

The gearbox oil is new.

The brake fluid bottle I emptied properly but obviously there is residue on the walls.

Would it harm the transmission?

Only talking 1 litre. Gearbox takes about 2.5

SJ - 15/6/20 at 07:41 AM

Personally I would bin it and buy some more. Just not worth the risk.

nick205 - 15/6/20 at 07:58 AM

quote:
Originally posted by SJ
Personally I would bin it and buy some more. Just not worth the risk.



Ditto.

Transmission oil isn't expensive and if you've gone to the effort of draining what was in there then replace it with new. Just not worth the risk or worry of anything else in my mind.

JAG - 15/6/20 at 08:08 AM

Agree with the previous replies.

Basically the tiny bit of brake fluid residue will attack all of the seals inside the transmission.

Over time the rubber will slowly distort and the seals will fail.

The same thing happens if you get a small amount (<1% by volume) of Mineral oil in the brake fluid of your brake system.

bikecarbfred - 15/6/20 at 09:56 AM

mmm interesting, its like alien blood