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Discussion Starter #1
I recently purchased a Silver Spur and am working my way through the necessary maintenance as the last time it was serviced was four years ago. Unfortunately it looks like the steering pump is leaking (the fluid is low but not empty) and Bentley have informed me it's because the last person who changed the pipes replaced the fluid in there with mineral oil instead of suitable steering fluid. They reckon a complete steering pump and rack rebuild is necessary.

The car seems to be running fine, and clearly has for a while; nothing else is leaking out. Question - Would I be safe to simply flush the mineral oil out of the steering system and simply replace it with suitable Dex, or does the system need a complete decontaimination and rebuild as Bentley reckon?

One reason I'm a little hesitant to take their very expensive advice, is that the car came with the service history invoices which show that it was the very same Bentley location that in fact changed these pipes and refilled it. Unless someone deliberately went out of their way to repeat the work and fill it with the wrong stuff for no reason, there's a little itch telling me that maybe they just might have had something to do with this little misdemeanor in the first place. I'm sure a rebuild would be great, but I'm not convinced it might be the best route for my wallet, or the simplest solution. I may be wrong, but it sounds like a far simpler solution if I can get away with it.

Would love to hear any opinions on whether they're on the money, or if I might get away with just doing a flush and refill.

Thanks all.
 

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There are stop-leak products that you can add to power steering fluid, they work by swelling the seals. They are available at most auto factor stores. I had a minor leak in a Mercedes power steering box approx. 9 months ago and I used a stop-leak product and the leak hasn't returned to date. Ideally the leak/s should be traced and resealed or components replaced and resealed but a stop-leak may work if the fluid loss isn't excessive. Try it at your own risk.
 

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I've read that pas will run fine with lhm it has better lubrication than atf, but I think in your case the seals have shrunk in the less penetrating lhm.
Just drain and refill, I would.
Mike
 

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Drain and refill.
The worst that can happen is that they are right and you need a new rack.
But you could end up either postponing or avoiding a costly repair.
 

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I've read that pas will run fine with lhm it has better lubrication than atf, but I think in your case the seals have shrunk in the less penetrating lhm.
Just drain and refill, I would.
Mike
Yes thats the route I would take nothing to lose if it doesn't work
 

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Discussion Starter #6
Thanks so much for the responses. Nothing's leaking out anymore anyway so a drain and refill looks like the way I'm going to go. Will keep you all posted!
 

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Check indeed that it not just a hose which is leaking, not tight enough
Will do Jean. There's not actually anything coming out that I can see, and the level hasn't chnaged since I purchased it last month (it's very low and below minimum, but not empty), so I think the hoses maybe okay. Will do a full test while its heated up as well just to be sure.
 

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I experienced a leak with my 1980 Sw II with fluid over the business end of the steering rack, enough to make a 4" pool on the shop floor. The hi-pressure hose was wet also so I figured it may be from the pump or hose. I used a P/S fluid that was clearer than ATF so I was a bit mystified and mirrors and inspection of the area when on my lift did not yield any conclusions.

It turns out to be the gasket between the oil fill and head known as the triangle seal. I removed the alternator and fill assembly and replaced it with a custom gasket rather than the original paper thin OEM. Now dry as a bone.
 

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Windyweekend, how do you do the level please ?
Engine hot or cold ?


Your dipstick has 2 graduations hot é cold or just one ?



Which year is your Silver SPur. ?
 

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Discussion Starter #11
Windyweekend, how do you do the level please ?
Engine hot or cold ?


Your dipstick has 2 graduations hot é cold or just one ?



Which year is your Silver SPur. ?
Checking Cold - its well below the minimum mark, but I can see the top of the fluid (which is mineral oil) in the reservoir, so nothing is leaking out anywhere. I do need to do a check once its hot and had a chance to circulate. It's possible that with extra fluid it will just foam up/out anywhere it can which is what Bentley are saying is the cause because it's mineral oil.

It has one graduation with just a min and max mark, but the liquid is about half an inch below the min mark at the moment. It's a 1988 Silver Spur.
 

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Discussion Starter #12
I experienced a leak with my 1980 Sw II with fluid over the business end of the steering rack, enough to make a 4" pool on the shop floor. The hi-pressure hose was wet also so I figured it may be from the pump or hose. I used a P/S fluid that was clearer than ATF so I was a bit mystified and mirrors and inspection of the area when on my lift did not yield any conclusions.

It turns out to be the gasket between the oil fill and head known as the triangle seal. I removed the alternator and fill assembly and replaced it with a custom gasket rather than the original paper thin OEM. Now dry as a bone.
Thanks - I'll check into the other seals. This might well be part of the problem here, regardless of what fluids in there.
 

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Dexron II is a mineral oil. Misfilling your power steering with another mineral oil should not warrant a rebuild as your seals are likely not damaged. The wrong fluid may have simply creeped out because of its thinner viscosity. What mineral oil did you then find in your system? Motor oil?
If your steering pump leaks, this may simply be due to age. Seal kits for all the pumps used over the time at RR are readily available, those pumps were GM units, generally. If hoses leak, then simply try to tighten (not over tighten), drive your car and see what happens.
If your rack leaks then it is in for a rebuild. Those racks are prone to leaks, even if always driven with the correct fluid. They leak internally into the gaiter, and from there onto the street or your garage floor.
 

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I think you should now check the level hot. Hot you should be slightly under MAX.
Yes, it's possible in fact you had too much oil, that's why I was asking how you check.


On your car, the level must be done engine HOT, because the oil volume increases when oil is hot...


You may have no leak....to be checked and confirmed
 

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Discussion Starter #15
I've had to deal with other more pressing maintenance but am now revisiting this. I topped up the steering pump with a little mineral oil (because that's what was put in it by Bentley when they 'fixed' it before I bought it). The level hasn't changed and it's been fine, but I want to rectify this once and for all as the color of the oil, LHM or otherwise, has been a distinctly cloudy mud colo(u)r one way or another , which is bothering me. Can anyone provide some guidance on the best procedure for replacing the steering fluid? I've read about the the turkey baster technique for taking out the old oil and then gradually replacing it, but in this case I'd be extracting LHM and replacing it with fresh Dexron. Is this approach adequate enough, or is there an alternative solution to drain and replace the steering fluid? I'm not finding anything in the workshop manuals on this so am open to options.

Any guidance would be much appreciated.
 

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Many Many years ago BMW released a TSB stating that mineral oil can be substituted for ATF in power steering / hydro-boost system. The reason behind it was to resolve a cold-weather issue that was oil viscosity related.
No crazy high tech flushing or parts changes were required for the fluid "conversion."

I use a Mityvac MVA6851 with the car running; 1000x's better than the turkey baster, and a few bucks more.

Great tool for emptying the mineral oil tank, changing lawn mower engine oil, etc.

If the lazy stick hits you hard, search out a domestic repair shop that has a BG power steering service/flush machine.

Since these cars use a Saginaw pump and reservoir, the BG machine does a great job exchanging the fluid with no hose separation. There are a few youtube videos that demonstrate the procedure.

But, in retrospect, you can just leave the fluid in there and replace it with more "green."

I see no harm in its use besides cost since it is engineered for power steering systems.
The modern Bentleys use it and likely the reason why it was accidentally installed.
 

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Why do you leave the engione on when vacuming ? You might bring air in the system , very difficult to take out and creating noise because of emuslion.

Personnally I vacuum like you, engine off, the most I can in the tank, then refill with fresh oil and drive a little and vacuum again......untill oil gets clean and new in the tank.
First time you may need to do it 3 times or more, then regularly for maintenance.
 

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You might bring air in the system, very difficult to take out, and creating noise because of emulsion.
Hello, I don't vacuum out the entire contents while running... actually it is very difficult to totally empty due to the high volume of oil circulating in the tank.

I lower the level until the oil starts to aerate then add fresh fluid and repeat.
 

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If you aerate oil that means emulsion because you put air in it,. It could be difficult to put the air out if it goes deep in the system as often.
Personnaly, I do not recommend to vacuum engine runing.
The risk to get trouble is huge.
Better do it several time with engine of.

Or you open the return, put it in an old bucket, as k a guy to start the car and fill with fresh oil untill it comes back clean nthen ask the guy to stop the engine.
In that case you renew the complete system, the guy could also turn slowly wheels left and right with front wheels lifted.
 
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