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MG Midget and Sprite Technical - Steel braided brake hoses UK Legal Confusion

I have been looking into fitting 2 lengths of approx 1m braided brake hose (to connect a servo). I see "diy" kits are available using an olive and screw-up fittings. While this is an advantage in that the length can be adjusted during fitting, there seems to be great confusion over UK road legality.

Despite hitting Google repeatedly I can't get the definitive answer although at the moment the consensus of the searches seems to be that only swaged fittings are acceptable, although other suggestions are that a fitting with a centre core is ok.

Even the reseller's own brochure for the self assembly units says "....uses olive compression fittings which are not necessarily road legal in some aspects of kit car construction"
What difference do kit cars make?
Would that be better or worse compared to a Sprite?
Why "not nesessarily"?

I'm not sure that MOT inspections take a lot of notice, but in the event of an accident caused by brake failure....??

Does anyone have any more information? This is for UK, which I'm sure will be wildly different from USA and Australia



Graeme Williams

Is this relevant?

"Repairs to the pressure lines of hydraulic brake
systems are unacceptable unless suitable
connectors are used. Compression joints of a type
using separate ferrules are not suitable"

http://www.motuk.co.uk/manual_360.htm

Geoff Ev

Graeme,

I did mine in copper - local motor accessory shop did the flaring as well - 1.4 metres for both.

It is quite easy to bend - just go at it slowly and keep checking as you do each bend.

R.

richard boobier

And another pic.

I now have a HIF6 so a bit more room.

R.

richard boobier

kit cars are built to IVA regs, see here for more details - https://www.gov.uk/vehicle-approval/individual-vehicle-approval
Nigel Atkins

Graeme. Is this a pressure line (i.e. one carrying significant fluid pressure) or a vacuum line? The loss of pressure, from the master cylinder to caliper/wheel cylinder, means you have lost braking function to either part or all of the system. Loss of vacuum pressure to a servo means you have to push harder on the brake pedal. Easy to see why best quality fittings are required on lines carrying pressure. Less easy to see why such are needed on a vacuum line. That line of inquiry might be worth exploring.

Les
Les Bengtson

Geoff: I think that refers to repairs using sections of pipe with ferrules. The reason I say this is that further down, on the right, it talks about "reasons for rejection" as "flexible hoses with corroded ferrules". The implication I would draw here is that flexible hoses with uncorroded ferrules are acceptable.

However I think ferrule in this context refers to an outer ring (sleeve) around the joint. My concern is with the system which uses olives and compression fittings rather like plumbing fittings. You can't actually see the olive of course, only deduce that the system uses olives by looking at the form of construction.

I think the worry is that incorrectly assembled the olive could pull off and the system fail. Swaged pipework is purchased from a manufacturer and made (hopefully!) to more rigorous standards and meets some form of quality control like D.O.T.

Aguably there are lots of things we do on our cars wich could be done incorrectly and fail with disasterous results. Fitting olives to make up pipework is no different to replacing seals in master cylinders in terms of incorrect assembly impications.

Richard: did you plumb in the servo after all other engine bay gubbins was there? I found trying to work around everything quite challenging, particularly trying to "lose" excessive lenth of pipe run. Hence liking the idea of flexibles.
Graeme Williams

Les: it's the brake fluid line! But are self-assembly components lower quality?
Graeme Williams

Graeme,

Yes it was fitted when the car was fully built up.

You can work out the lengths required by using a fairly stiff piece of electrical wire, you bend it to mimic the pipework.
Allow fairly generous bends to avoid kinking and secure it with clips to ensure it does not vibrate in use.
Both of mine were 1.4metres long - just checked the invoice.

R.
richard boobier

I can't think of a good reason to use a flexible line, whether or not stainless steel braided brake hose to plumb in a servo. If I was forced to use a flexible line I'd have a proper line made up with threaded fittings and that would have been pressure tested after manufacture. The correct way to plumb in a servo is with rigid hose (eg: cupro nickle).

Daniel Stapleton

This thread was discussed between 12/09/2013 and 13/09/2013

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