Series 3 Flexible brake hose bulging after contact with oil

I recently noticed that the rear over-axle flexi hose on my Series 3 has started to bulge at one end where EP90 oil has got onto it. I am unsure if this is just a coincidence

I replaced all the hoses with new when I rebuilt the vehicle from 2013-15.

I have a current issue with the rear differential drive flange oil seal dripping a bit of oil. Some of this has been sprayed outwards onto the hose by the rotating drive flange.

I only had this oil leak appear last year after a long run (200 mile round trip) in fairly warm weather. I didn't get round to sorting it over the winter as I was working on another vehicle. I have checked the oil level in the differential and it hadn't dropped by much at all.

Has anyone seen this happen with these hoses before? I would have thought that a Hydraulic hose would have been made of something designed to be in contact with oil. However I do know that brake fluid is a different chemical.

Thanks for any replies.

Webley1991 said:

I recently noticed that the rear over-axle flexi hose on my Series 3 has started to bulge at one end where EP90 oil has got onto it. I am unsure if this is just a coincidence

I replaced all the hoses with new when I rebuilt the vehicle from 2013-15.

I have a current issue with the rear differential drive flange oil seal dripping a bit of oil. Some of this has been sprayed outwards onto the hose by the rotating drive flange.

I only had this oil leak appear last year after a long run (200 mile round trip) in fairly warm weather. I didn't get round to sorting it over the winter as I was working on another vehicle. I have checked the oil level in the differential and it hadn't dropped by much at all.

Has anyone seen this happen with these hoses before? I would have thought that a Hydraulic hose would have been made of something designed to be in contact with oil. However I do know that brake fluid is a different chemical.

Thanks for any replies.

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Rubber generally doesn't like oil. Hydraulic hose is lined, and I should think the brake line is too. But the oil is probably attacking the rubber outer.

Replace it. Can't be too careful with brake bits.

Rubins4 said:

Replace it. Can't be too careful with brake bits.

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Definitely. Apart from anything else, it will be an MOT fail.

Get a braided set, they do work slightly better as they expand less and they resist damage better. Not a lot more expensive either.

Thanks for the replies.

I only noticed it on Saturday and am planning to replace it as soon as I can. The vehicle will be parked up until then.