Pre-bent brake lines

[TommyBuoy]

Hello!

Just had my car on the ramps and noticed some corrosion around the brake line inside the front wheel arches (both sides), the black coating isn't broke , but bubbled underneath. Knowing this could be an mot issue depending on the severity - I didn't want to start scratching at it yet - does anyone know anywhere that would supply pre formed brake lines?

Car is a 640i (F12 2012). If not, any ideas of cost estimate from experience?

[d_a_n1979]

Try your local BMW dealer; or BMW Cotswolds. Otherwise it'll more than likely be straight piping that needs to be bent/made to fit

I'd be very surprised if your pipes are that badly corroded though, on such a young'ish car too!

I'd personally give them a very gentle wire brushing and then if they're ok after that (ie. it's just surface corrosion); give them a good spraying with waxoyl or stonechip etc

Wondering if it's an undercoat that's perished and nothing to do with the pipe etc... Start cheap/free and work from there

[TommyBuoy]

Thanks for the reply.

I did wonder after typing whether it's corrosion of the actual pipe or a protective covering issue. It's only travelled 1 inch up from the connection on both sides and the rears don't look like they have aged at all (unless done previously I suppose!)

Good advice, I'll look at doing a bit of investigation.

[d_a_n1979]

TommyBuoy said:

Thanks for the reply.

I did wonder after typing whether it's corrosion of the actual pipe or a protective covering issue. It's only travelled 1 inch up from the connection on both sides and the rears don't look like they have aged at all (unless done previously I suppose!)

Good advice, I'll look at doing a bit of investigation.

No worries

You need: https://www.amazon.co.uk/Roughneck-ROU52005-Mini-W...

And:

https://www.amazon.co.uk/Hammerite-5092832-Stone-S...

Gently brush the cack and weathered/corroded covering off, spray lightly with stonechip and carry on driving

[TommyBuoy]

Fortunately I have both those - the perils of rebuilding old bikes for track work, they don't have to be pretty!

[Mr Tidy]

I had some deterioration of the coating on the rear pipes on my E46 3 Series.

I just wire-brushed them, then sanded them with Carborundum paper and painted them with Hammerite - job done!

If the issue is with the rear pipes and they need replacing it's probably cheaper to get them replaced with pipes that aren't pre-bent - that way you may not have to have the fuel tank dropped to fit the driver's side rear pipe.

Edited by Mr Tidy on Wednesday 9th October 23:25

[Sardonicus]

Dont fk about with brake pipes they are thin walled construction as it is and corrosion is a No No especially sanding them and painting them FFS bubbling under a coating means the coating as breached and corrosion is almost certainly within also a common VAG issue on older models

[d_a_n1979]

Sardonicus said:

Dont fk about with brake pipes they are thin walled construction as it is and corrosion is a No No especially sanding them and painting them FFS bubbling under a coating means the coating as breached and corrosion is almost certainly within also a common VAG issue on older models

By the sounds of it, the corrosion is the OEM coating, not the piping itself.

And I can tell you now, there are thousands of cars on the UK roads that have badly corroded brake pipes that the owners don’t know about. Those that do and gently clean them and then coat them for protection are not being dangerous. If done right, they’re fine

[Sardonicus]

d_a_n1979 said:

By the sounds of it, the corrosion is the OEM coating, not the piping itself.

And I can tell you now, there are thousands of cars on the UK roads that have badly corroded brake pipes that the owners don’t know about. Those that do and gently clean them and then coat them for protection are not being dangerous. If done right, they’re fine

My point is by the time you've arsed about sanding and painting them you do just as well to change them I know they are an issue on E46 rears I own one just something I would not gamble with TBH no telling how far the wall as corroded or how deep the pits are

Edited by Sardonicus on Thursday 10th October 17:15

[d_a_n1979]

Sardonicus said:

My point is by the time you've arsed about sanding and painting them you do just as well to change them I know they are an issue on E46 rears I own one just something I would not gamble with TBH no telling how far the wall as corroded or how deep the pits are

Edited by Sardonicus on Thursday 10th October 17:15

The OP was talking about his F12 6x car, not a nigh on 18 year old E46.

I get what you’re saying, but completely different circumstances and, iirc, the brake lines on later BMW models don't corrode like the E46s or E39s did

[helix402]

E90 brake pipes rust like E46s now.

[brman]

and so do F12s apparently. If the OP has bubbling he has corrosion

[Pica-Pica]

helix402 said:

E90 brake pipes rust like E46s now.

I had some changed on my E36 after an MOT failure. The indy found them a pig to change as they ran across between the dash panel and the back of the I6 engine. He was good as his word on the quote he gave though! As for the rears, they would pop on and off the advisories, but were never changed.

In production they are robotically bent, then supplied to the factory. I used to keep some spare samples, as they were good for reaching all sort of things, and I kept a full-size house ladder stored hanging by a pair of brake tubes.