V70 power steering advice

[hitandhope]

I've got a nice V70 with a problem which is driving me mad - advice please.
2008 2.4D, manual, 130 000 miles.
Power steering whine - it's had several flushes, a new pump and a new rack - plus one pipe section which was leaking. It threw a belt a little while ago too.
Garage confirmed the noise was at the pump, and that it was pulsing/irregular.
A power steering specialist said that the pipes degrade and swell causing the internal diameter to shrink and cause excess pressure...which could explain the pulsing behaviour. But the pipes are expensive bits, I've been told Sweden only parts.

Has anyone been here/any advice please? Is this the likely cause, are there any good sources of cheap pipes?

The whine is annoying, I'm putting up with it for now but do worry a little about being stranded.

[ferg55]

If you can take the hoses off, you could take them to a generic hydraulic hose supplier, typically serving the HGV / construction vehicle / agriculture industry. They usually can make up any spec of hose with the correct fittings, or at least an equivalent.

[hitandhope]

List of this saga - now completed.
Squeaking and weak steering, 6 months after it threw a belt. No leaks/fluid loss.
System flush helped for a while....but
Problem came back, so pump replaced. Reservoir churns when running.
Hoses flushed, and gently pressure checked with no issue found.
Again, better for a while but issue came back. Rack replaced.
Damaged hose found, not off shelf, so had to hire a van for a holiday.
Squeaking remained. Priced up replacement of all hoses.
After swearing, we thought it through. When switched off, you could see bubbles rising. When running, reservoir churned badly, needed cap on. Mechanic experimented with air introduction on a healthy system - put a bit of washer hose in the reservoir when running. It went beserk. So we concluded an air leak was the real problem, one slight enough to let air in but not bad enough to leak fluid. Air wouldn't be getting in on the pump output side because it's high pressure, but it could be getting in as the pump sucked in fluid. The pipe could even be air porus with age, or have a pinhole leak.
Reservoir replaced, along with the pipe feeding the pump.
No noise, no bubbles, and runs flat calm with the cap off. Lovely.

PROBLEM SOLVED.

I'm putting this on, partly as therapy but also as reference in case anyone else has a problem, the reservoir and hose replacement was the easiest and cheapest bit. That said, a pump replacement on a 130k car was logical...but I wish we'd thought through sooner to avoid a new rack.