Originally I had intended to run bog standard rubber hydraulic hose front to rear for my rear steer. However, it needs 24 feet of pipe which apart from anything else is rather expensive.

Obviously, steel pipe is used on commercial power steering, but when I look at the max burst pressure of most metal pipes used for this kind of thing, Eg tube to BS 2871 , they only go up to about 100 bar in 10mm OD.

Obviously there are tubes which will carry just about any pressure, but is there a spec of soft copper tube (ideally) with a decent bore (8 to 10mm) that will take the 130 bar the pump spits out?

Alternatively, you know you get the goodrich hose that can be terminated using an olive and a compression fitting? Is there a similar system available for rubber braided hose? At least with something i can make up in situ I've got a fighting chance of getting the length and orientation of terminations right.

OK, I could get Pirtek to make the hoses on site, but that costs even more of an arm and a leg.

It just strikes me that regular Hydraulic stuff is rated to 250 Bar or more. Is there something with a lower (but still safe) rating that is easier to work with?

Si

Si,

Your local hydraulics place should have steel pipe in stoc that'll laugh at that pressure, it's pretty cheap as well.

As for self fitting hydraulic hoses, the only thing that i've ever seen that'd do that job are a range of screw on fittings from gates but they are quite horribly expensive.

I'd stick to buying a reel of hose and some fittings and mock the entire system up, using a white pen to number and mark the orientation of the fittings.

What DD said, they do steel hydro pipe to spec for not much. For the rubber bits Hyphose will send you home with some hose and some fittings to stick them in a required then bring them back and they'll swage them for not much. Two PAS pipes for mine cost £20 and that was with weirdo connectors on the end to join to the D2 PAS box.

Alternatively, if you can get the vehicle to them Hyphose will measure up & make in-situ. Seen them do it several times in their car park with various wounded plant equipment.

Steel pipe rots fast on a car, see if you can get Cupro Nickel pipe instead. Used in most aircraft hydraulics it lasts for ever and comes in a huge range of sizes. Its also very bendy by hand and doesnt crush. It's a pretty common thing to see it being used for brake pipes, but you can get it much bigger wall and bore sizes.

Thanks chaps,

Today I went to talk to my local brake specialist and the figures quoted for soft copper tube in the manufacturers book gave a max working pressure of 137Bar - so OK for a 130Bar pump. I've ordered 25' of that along with some BSP flare fittings which should sort out the trickiest bits.

They quoted me £47 for the tube, fittings and flaring - which doesn't seem too spiteful.

DD - Good idea about mocking it up and marking the orientation. That never occurred to me! Stupid really!

Si

not being picky here, i might have read something wrong, but for some challenge events dont the require that any pressureised liquid that travels out the engine bay be transfered via hydraulic hose, asin rubber hose?

oh, and if you go down to your local agricultural dealer, they should be able to make pipes up for you, with all the fittings you need.

I've never heard of that. Would it apply to brake lines as well?

I suspect that they would accept the interface between moving bits like the engine on rubber mounts and the chassis being flexible, but runs of pipe fixed to the chassis being rigid.

It's the kind of rule that I can see having been added to stop people using rigid pipe to connect moving parts together?


Yup - they are who I use (Oakes Bros, used to be Sussex Tractors)

Si

All that is required to have solid pipes traveling through the cab, is that they are colour coded, i think it used to be red for coolent yelow for hydraulics and blue for fuel (don't quote me on that, have a look in the blue book for further info)

If you have non metalic pipes in the cab they have to be lagged

personally i would not run any pipes through the cab, but would run them via the tranmission tunnel or down the sides of the chassis. That way if anything ruptures at least there is a bit of metal between you and the nasty stuff.

Thanks DD.

I'm not having anything going through the cab - so should not be a problem.

Si