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Power Steering.

Posted: Tue Feb 07, 2017 12:25 pm
by mike-b
Anyone know what the "Where abouts" pressure should be in a power steering system.?
The manual (Fords own) tells me everything I need to know except the pressure produced by the pump, so yes I have RTFM.

The problem I have here seems to be over pressure at the outlet of the pump. The system uses A.T.F.. Is it possible to have the pump giving out more pressure than it should?

Many thanks, Mike

Posted: Tue Feb 07, 2017 8:23 pm
by ChrisJC
According to my Range Rover Classic manual, it should be 100psi at idle with no load on the steering to 1000psi on full lock, pulling hard on the steering wheel and running the engine at 1000rpm.

Chris.

Posted: Wed Feb 08, 2017 2:01 pm
by mike-b
Chris, Thanks for that, though not a range rover Its a lot higher than I expected and a decent guideline.
I have had two pressure hoses made by `Earls` at Silverstone and both of them leak though I am not prepared to blame Earls something somewhere is wrong.
I am using the original Ford pump and rack, the new hoses were needed due to relocating the pump.

Posted: Wed Feb 08, 2017 11:36 pm
by stevieturbo
Exactly what were made ?

Earls do very specific hoses for PAS and I would be amazed if they leaked. They're very sturdy and easily DIY'd anyway


And as mentioned, pressure is largely only created when the rack is moving and there is load against it, but they do run very high pressures.

Posted: Thu Feb 09, 2017 9:17 pm
by mike-b
Stevie, I agree with all you have stated about Earl`s, they have made other hoses for me in the past and they have been spot on.
This time they have made two PAS hoses, size -6, both have leaked between the olive and the part that compress it. None of the parts that were threaded leaked at the thread.
Due to their excellent work in the past I had to assume something else was wrong, hence my question regarding the working pressure. There was no leak at tick over speed only when the steering operated - therefore under pressure.
I have another identical (Granada) pump that I can change but that wouldn`t stop a leak from a hose fitting, my only alternative is another hose from elsewhere.. As I had the hoses made up for me I have to question their part or material used to make the hoses.
So again this led me to question the pressure used in a PAS system.

Posted: Thu Feb 09, 2017 10:54 pm
by stevieturbo
Olive ?

Earls PAS pipes dont use an olive. They're a re-usable compression type fitting where the hose is clamped onto a tapered sleeve inside the pipe via the outer bit.

A bit like some of the other rubber type hoses, although all their PAS stuff is steel with a heavy hydraulic type hose.

Image

The only hoses that use compression type olives usually are teflon hoses.

Posted: Fri Feb 10, 2017 9:07 pm
by mike-b
Stevie, You are correct about the fitting - my explanation was rubbish, "A tapered sleeve" is exactly the wording required, not an olive.
Before you read further lets be clear here, I am not putting Earls down, I have had no cause to moan about their work or products in the past, this could all be a simple mistake, we all make them so why not Earls.

Though I used a straight type fitting the method is exactly the same and it leaked at the compression point, not the thread Tightening it further made no difference. Today I disconnected the other end at the rack, upon inspection this end used the same system but was beefier than the pump connection and they both used the same threaded ends. Why that would be I have no idea. however there can be no doubt whatsoever both fitting use a different tapered sleeve - for the same size hose(?). Laid side by side they are different sizes.
At the second visit to Earls I did ask if a hose without the s/steel braiding could be used, I was told the braiding was required to aid the compression system - that meant (to me anyway) they could not make a hydraulic hose of the size I required without the use of braiding.
I have gone to the industrial makers of hydraulic hoses. and I am having a 6mm I.D. hose with swagged ends as per the industrial norm. I will have a PAS system that does not leak - one way or (in this case) another.

Posted: Fri Feb 10, 2017 9:29 pm
by stevieturbo
Not sure how the fittings can be different ? They're all the same design and use the same hose etc ?

And lots of people do use regular teflon hose for PAS, pressure wise it is rated ok. Although clearly Earls hose would be far more robust and less likely to ever burn/chafe through

ATF/PAS fluid is rather flammable...so not really one to mess with given the potential pressures involved.

Have you unscrewed the fitting to see why it is leaking ? Maybe they somehow didnt push the hose in fully before tightening ?

Posted: Sat Feb 11, 2017 1:33 pm
by mike-b
The actual fittings are the same size with just one exception. That is the part that fits inside the hose and over the very end of the hose ( not the braid ) is smaller at the pump end compared to the rack end. The rack end is larger and more robust, the pump end is flimsy compared to the rack end and that is where the leak is at the flimsy pump end.
Everything is fine until pressure is applied i.e. moving the steering wheel..
The hose its self is fine.
Like you, I cant get my head round it either but that is how it is both the internal fitting are different. Why? Your guess is as good as mine. If a robust fitting is Ok for one end of the hose should it not be good enough for the other end? Apparently not.
Anyway it is not a problem any more as its in the bin - its rightful home.

Confusing is it not, now I have stopped banging my head on the wall I feel a lot better.
By the way ..... thanks for the input, Mike

Posted: Sat Feb 11, 2017 5:16 pm
by stevieturbo
And the offending part is a steel fitting ?

Same sort of design as the other PAS bits ?

pics ?

Posted: Sun Feb 12, 2017 5:24 am
by unstable load
mike-b wrote: Anyway it is not a problem any more as its in the bin - its rightful home.
Is it the crimped fitting or the screw together type?
Why not whip it apart and see what the difference is?
Some spanners or a hacksaw, depending on type of fittings used.

Posted: Sun Feb 12, 2017 11:15 am
by stevieturbo
Earls PAS are screw fit, all DIY stuff

Posted: Sun Feb 12, 2017 9:42 pm
by mike-b
John,
The hose was taken apart, it was then that I noticed the internal fitting on one end was beefier than the other even though they used the same external fittings and thread.

Stevie,
Earls PAS kit probaly is DIY stuff .... but they built it - all I had to do was bolt it to my adapters then clean the mess after I moved the steering wheel. Before that there was no leak.

That hose is now out of sight, the dustmen took it away on Friday.

Posted: Mon Feb 13, 2017 4:43 am
by unstable load
It sounds like the bloke that built your hose used an incorrect dash number fitting at one end.
The fittings come in a big number of permutations for the combinations of pipe diameter and end fitting type/size and isn't difficult to get wrong at all.

Posted: Mon Feb 13, 2017 10:48 am
by stevieturbo
unstable load wrote:It sounds like the bloke that built your hose used an incorrect dash number fitting at one end.
The fittings come in a big number of permutations for the combinations of pipe diameter and end fitting type/size and isn't difficult to get wrong at all.
With the PAS hoses though there arent really any variations and they only offer then in -6
Their PAS stuff should not work with any other type of hose and visa versa

A picture would have been very helpful, but we're guessing blind here.