Peugeot 205 power steering mystery?

[jerrytug]

Hi chaps I have had plenty of cars with hydraulic steering, driven from a belt drive pump. On full lock, there is an arrangement which avoids hydraulic lock and belt slipping at full lock, eg manouvering in a car park. But it has never been an issue before.
However on this 205, when you put the wheel hard over, the engine slows a bit, and there is a screeching from the (new, correctly adjusted) pump drive belt.
Normally in other cars this has not happened. There must be an arrangement, and it must be either a simple pressure relief valve, or bypass valves which are opened, by the rack position presumably, at full lock.
Such an arrangement seems to be lacking, and it is surprisingly annoying because I like parking in tight spaces, and the momentary mechanical shriek of pain when touching full lock makes me wary. The belt is new, but the previous one was burned and ragged, which figures..
The steering and engine are both non-standard for the reg. number, so googling for under-bonnet parts is not really much use, 2 belts got sent back before the correct one was found.
(The Haynes book is no help either)
That is why I want to learn, from first principles, how this hydraulic situation is dealt with on simple 80's and 90's frog cars.
On the bright side,someone has shoehorned in a later Citroen 1.9 turbo diesel, and it goes like a scalded cat

Thanks in advance

 

[Bullet2012]

No advice or help but, if it goes like a scalded feline then it deserves to yell like one .

 

[Edward Teach]

Perhaps it needs the pump to suit the rack (old pump), as opposed to the pump that comes with the donor engine.

 

[jerrytug]

Perhaps it needs the pump to suit the rack (old pump), as opposed to the pump that comes with the donor engine.

Good idea!

 

[Misterg]

That is why I want to learn, from first principles, how this hydraulic situation is dealt with on simple 80's and 90's frog cars.

Our old 'D' reg 205 GTI didn't have any problems like that.

(****e clutch mechanism, crappy electrical insulation, flimsy body & occasional bursting into flames, yes... But it was a blast to drive.)

Crank a few more flats on the belt tension and see if it still does it?

 

[jerrytug]

@Misterg ha ha, yes I have noticed that the (original) battery wires are barely thicker than the ones in my kettle lead..
Yes maybe I should tighten the belt and see what happens..if there is no plumbing solution....

 

[hotponyshoes]

There has to be some sort of bypass arrangement on it.
I think the citroen has a pressure relief valve in the pump.
Take that out and see if it's moving freely.
It might well have some crud blocking it shut (especially if the engine was changed in less than clinical conditions)
Or, if the engine had come from a scrapper and been sitting around for a while drained of fluids it might just be rusted closed.
Get the factory parts catalogue and there might be seal kits for the pump and a nice picture showing you were everything is.
If not try looking at the high pressure hose as often the valve is integrated within the outlet port

 

[zzr1200]

Once the steering is at full lock just release the pressure on the steering wheel a little, you dont have to hold the pump on squeak pressure to maintain full lock.
Problem sorted, sort of.

 

[frank horton]

My T4 has been doing all years I've had it......just the same as u......
ZZR1200 has the correct answer BUT try getting the wife to learn.....
everyday outta the drive screech screech.....
I just give up.....

 

[jerrytug]

Thanks folk, very helpful. The old steering fluid was contaminated with black stuff which might have jammed a valve, I never thought of that.

 

[Robotstar5]

I like the way Land Rover covered themselves when they first started fitting power steering to the Range Rover (classic) a note in the drivers handbook "do not hold the steering on full lock for more than 30 seconds"

 

[hotponyshoes]

Thanks folk, very helpful. The old steering fluid was contaminated with black stuff which might have jammed a valve, I never thought of that.

Pipe might be breaking down internally.
Especially if its been left drained of fluid for any length of time.

 

[Rkweld]

As has been said your black stuff may be the pipe breaking down. You say about a relief valve in the rack and others say in the pump so you may have 2 items with no relief valve?? Search the system for a relief in all the places recommended and check it. If there is not one match the pump to the rack and see if that has one. Is it definately belt squeal? Not a valve squealing from fluid bypassing it?

 

[anto44]

The bypass valve will be in the pump, very rare to see a problem with one.
Was it screeching before the new belt was fitted?

 

[qwakers]

If it has the wrong pump for the rack it is possible the bypass valve is set to too high a pressure for the rack so it never bypasses....

 

[hotponyshoes]

If the valve is in the pump (and the pump still has the correct belt/pully on) then i would think it should still bypass before slipping the belt regardless of what rack its attached to?

 

[m_c]

If the valve is in the pump (and the pump still has the correct belt/pully on) then i would think it should still bypass before slipping the belt regardless of what rack its attached to?

It should do.

My query is what does the OP class as correctly adjusted?
If you're not used to adjusting Polyrib belts, then you'll likely think it's tight enough, but it'll be slack.
On narrower polyrib belts (4rib), you should only be able to twist it on it's longest run by about an eighth. If you can twist it to a full 90deg, or deflect it more than a couple mm by hand, then it's not tight enough.

 

[Onoff]

SWMBO's 2001, 1.4i, 206 had a long running screeching noise. Every amateur mechanic, dad at the school gates, the BiL, the bloke at the MOT station reckoned it was to do with the power steering.

It wasn't. It was the AC clutch bearing.

Still, leading up to finding that it has had a new pump, fluid, belt and various tensioners!

 

[Turbo]

A popular pas upgrade on a 205 is to ditch the belt drive pump & fit an electric one from a 106 or saxo. It fits neatly behind the battery & is a lot more efficient.

 

[jerrytug]

As has been said your black stuff may be the pipe breaking down. You say about a relief valve in the rack and others say in the pump so you may have 2 items with no relief valve?? Search the system for a relief in all the places recommended and check it. If there is not one match the pump to the rack and see if that has one. Is it definately belt squeal? Not a valve squealing from fluid bypassing it?

Good question I will verify.