Repairing a steel brake pipe with kunifer?

[T i m]

On daughters new to her 2010 Meriva checkover the local garage mentioned
a couple of instances of brake pipe surface corrosion but only minor and
that would likely only be 'advises' on the MOT in Feb.

Q. Given that from the ABS unit, all though the engine bay and all the
way under the car and nearly up to the rear wheel looks like new, would
it be a viable solution to cut the steel just before the rusty bit,
flare and then continue in cupro nickel to the flexies? *Can* you flare
the factory steel pipe with the std d-i-y type tools?

I replaced the n/s/f pipe from ABS to inner arch in cupro on my Meriva a
while back and that wasn't too bad because it was only short and mostly
in the engine bay but I understand steel is better from a anti
crush-ability POV so might be a better solution under the car?

Obviously it would be 'better' in one continuous length but I believe
I've previously worked on cars with in-line couplers here and there
(probably to ease manufacturing).

Cheers, T i m

[Roger Mills]

Post by T i m
On daughters new to her 2010 Meriva checkover the local garage mentioned
a couple of instances of brake pipe surface corrosion but only minor and
that would likely only be 'advises' on the MOT in Feb.
Q. Given that from the ABS unit, all though the engine bay and all the
way under the car and nearly up to the rear wheel looks like new, would
it be a viable solution to cut the steel just before the rusty bit,
flare and then continue in cupro nickel to the flexies? *Can* you flare
the factory steel pipe with the std d-i-y type tools?
I replaced the n/s/f pipe from ABS to inner arch in cupro on my Meriva a
while back and that wasn't too bad because it was only short and mostly
in the engine bay but I understand steel is better from a anti
crush-ability POV so might be a better solution under the car?
Obviously it would be 'better' in one continuous length but I believe
I've previously worked on cars with in-line couplers here and there
(probably to ease manufacturing).
Cheers, T i m

If it's only surface rust, I'd be inclined to clean it up with wire wool
and then smear some grease over it.

[T i m]

On 06/09/2023 22:06, Roger Mills wrote:

<snip>

Post by Roger Mills
If it's only surface rust, I'd be inclined to clean it up with wire wool
and then smear some grease over it.

Where the pipe crosses over from the n/s/r (after running down the
length of the car) to the o/s/r brake, it looks like there is a 30mm
long section that was held in a clip that now has some rust on it.

I think the bits on the front are where it curls under the front wheel
inner arch and onto the bracket to the flexy.

I assume if I was to go wire wool > grease the "Brake pipes corroded,
covered in grease or other material" are just an advisory and wouldn't
constitute a fail.

Cheers, T i m

[Roger Mills]

Post by T i m
<snip>

Post by Roger Mills
If it's only surface rust, I'd be inclined to clean it up with wire
wool and then smear some grease over it.

Where the pipe crosses over from the n/s/r (after running down the
length of the car) to the o/s/r brake, it looks like there is a 30mm
long section that was held in a clip that now has some rust on it.
I think the bits on the front are where it curls under the front wheel
inner arch and onto the bracket to the flexy.
I assume if I was to go wire wool > grease the "Brake pipes corroded,
covered in grease or other material" are just an advisory and wouldn't
constitute a fail.
Cheers, T i m

I'm not sure that it's even an advisory if you have removed the obvious
signs of rust and if there's no visible pitting.

[Fredxx]

Post by Roger Mills

Post by T i m
<snip>

Post by Roger Mills
If it's only surface rust, I'd be inclined to clean it up with wire
wool and then smear some grease over it.

Where the pipe crosses over from the n/s/r (after running down the
length of the car) to the o/s/r brake, it looks like there is a 30mm
long section that was held in a clip that now has some rust on it.
I think the bits on the front are where it curls under the front wheel
inner arch and onto the bracket to the flexy.
I assume if I was to go wire wool > grease the "Brake pipes corroded,
covered in grease or other material" are just an advisory and wouldn't
constitute a fail.
Cheers, T i m

I'm not sure that it's even an advisory if you have removed the obvious
signs of rust and if there's no visible pitting.

https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/1-brakes#section-1-1-11

Says:

1.1.11. Rigid brake pipes

If the metal brake pipes have surface dirt that needs to be removed
before it’s possible to assess their condition, you can lightly scrape
the pipe with a specialist brake pipe corrosion tool or the corrosion
assessment tool ‘spade end’. It must be done with care so that any
protective coating does not get damaged.

Chafing, corrosion or damage to a rigid brake pipe so that its wall
thickness is reduced by 1/3 (approximately 0.25mm for typical hydraulic
brake pipe) justifies rejection, although it’s accepted that this is not
easy to determine. If you are not sure whether the pipe is sufficiently
deteriorated to justify rejection, you should give the benefit of the doubt.

____________________________________________________

Tricky one, minor pitting is ok.

[T i m]

Post by Roger Mills

Post by T i m
<snip>

Post by Roger Mills
If it's only surface rust, I'd be inclined to clean it up with wire
wool and then smear some grease over it.

Where the pipe crosses over from the n/s/r (after running down the
length of the car) to the o/s/r brake, it looks like there is a 30mm
long section that was held in a clip that now has some rust on it.
I think the bits on the front are where it curls under the front wheel
inner arch and onto the bracket to the flexy.
I assume if I was to go wire wool > grease the "Brake pipes corroded,
covered in grease or other material" are just an advisory and wouldn't
constitute a fail.
Cheers, T i m

I'm not sure that it's even an advisory if you have removed the obvious
signs of rust and if there's no visible pitting.

If we assume it is sufficiently badly pitted that someone looking to be
'better safe than sorry', what about the idea of chopping off the pipe
just before the rusty part (in the case of the o/s/r in this case) and
replacing from there to the brake area in Kunifer type stuff (on the
grounds it's easier to form than steel)?

The idea is that ... if it's 'perfectly feasible' to apply an
appropriate flare using the std flaring tools used for the copper based
pipes, could leaving the 'stronger' steel pipe in place though the
majority of the car but having a joint, be better than replacing it from
end to end?

Given it's something quite important, my 'do it right, do it once' ethic
says replace it end to end but that might mean that you end up with a
more crushable pipe being exposed over a greater length?

I'm guessing you can't buy OEM brake pipes pre-formed for something that
old (or anything)?

Cheers, T i m