Brake pipes corroded MOT fail twice in two years

markhod

Hello,

In 2015 I had a MOT fail due to:

Offside Front Brake pipe excessively corroded (3.6.B.2c)

This was replaced. Then this week my car failed this years MOT for the same thing. I think I am surprised in just two years something can corrode to the point of needing to be replaced. At least googling on this lots of people seem to suggest normal lifetime for such a component is 10 years or so. The car is a 2005 Mini One. I wondered what peoples opinions on here are about this? If its normal is there something I could do to ensure the new pipes fitted do not also corrode? Its not obvious to me how I could clean them to prevent this in future without e.g. jacking the car up and doing it (which I am sure most people do not have any need to do).

Cheers,

Mark

debtdebt

If you're not willing to jack up the car to get under it and either grease or spray a protecting layer onto the brake pipes, I'd suggest storing the car in a dry garage and not driving it in the wet.

Herzlos

Is it definitely the same section of pipe that was replaced?

markhod

Herzlos wrote: »

Is it definitely the same section of pipe that was replaced?

I don't know. Both times it is definitely:

Offside Front Brake pipe excessively corroded

So unless this is fixable by replacing a sub-length of the pipe, it would mean it is the same part?

markhod

debtdebt wrote: »

If you're not willing to jack up the car to get under it and either grease or spray a protecting layer onto the brake pipes, I'd suggest storing the car in a dry garage and not driving it in the wet.

Unfortunately I don't have a garage, so on road storage is the only option.

hmm I suppose I could get a garage to do that once a year, if its significantly cheaper than replacing them every 2 years.

Strider590

Perhaps they actually just covered it in lithium grease, then knowing a customer is likely to get shirty about paying someone £40 to squirt a bit of grease on it, they told you they'd replaced it instead......

System

If it was the same MOT place that repaired it last year I'd point that fact out to them and ask why it needed doing again when they'd only just done it a year earlier.

Joe_Horner

Looking at a random brake layout for the Mini One on realoem it looks like there are at least half a dozen pipes that could be described as "OSF" depending on which end they're corroded at.

Once you've had this one done, cavity wax is good for protecting them. It sticks better than grease, creeps to cover bits you might miss when spraying, "self heals" if the coating's broken, and doesn't trap water like underseal can.

One spray can of Dinitrol or similar would more than cover all the pipes on the car.

Robisere

Metal brake pipes as fitted to cars new, are usually steel and they do corrode easily. Steel pipe can also crack under "work-hardening" caused by vibration over a period of time.

When I worked as a workshop foreman at a large independent garage and MOT station, we always replaced corroded steel pipes with "Kunifer" Cupro-Nickel pipe:
https://www.amazon.co.uk/d/55k/Clarik-Cupro-Nickel-Kunifer-Brake-Pipe-Roll/B00CRGGTX2

The advantages of 'Kunifer' pipe, are that it does not corrode like steel, but oxidises to a hard, corrosion-resistant surface. (Like a Copper roof, or Bronze) It is also easier to work with, being flexible to a greater extent than steel pipe, and easier to cut and join with the correct bending tool and joint fittings.

Make up your own minds as to why manufacturers do not fit such pipes as standard on new cars.

EdGasketTheSecond

Robisere wrote: »

Make up your own minds as to why manufacturers do not fit such pipes as standard on new cars.

Cost, strength of steel compared to Kunifer, and steel is less susceptible to work-hardening. Against that steel pipes corrode and are difficult to fit as a replacement as you can't bend them into shape and make ends easily requiring lots of dismantling in some instances to fit pre-bent pipes.

Kunifer is a good material for a replacement pipe though.

Robisere

EdGasketTheSecond wrote: »

Cost, strength of steel compared to Kunifer, and steel is less susceptible to work-hardening. Against that steel pipes corrode and are difficult to fit as a replacement as you can't bend them into shape and make ends easily requiring lots of dismantling in some instances to fit pre-bent pipes.

Kunifer is a good material for a replacement pipe though.

I should not have use "work-hardening", but "Fretting" instead. That is the action of pipes contacting and rubbing against retaining clips and other areas of the floorpan/bodywork. Cupro-Nickel has a much higher resistance to wear in that instance. Reading this is worthwhile:
http://copperalliance.org.uk/docs/librariesprovider5/resources/is49-copper-nickel-brake-tubing.pdf

Extract:
" Volvo, Lotus, Aston Martin, Porsche and Audi all now fit copper-nickel brake tubing as standard equipment. "

These manufacturers have also discovered that the easier fitting of cupro-nickel, saves assembly time and therfore money per unit build.