Steering Box, Steering Pump replaced, still not right

[Mamod17]

Hi all, I'm hoping someone can help. I recently had my steering box replaced after a failed rebuild (to fix a leak). Once reinstalled it still didn't work properly. Then I had the power steering pump replaced which seemed to make the system work for a while. But now at parking speeds the system completely loses power and steering becomes incredibly heavy. I had it fixed once where apparently the hoses were installed around the wrong way. Worked for a while now back to heavy steering generally and no power at parking speeds.

HAs anyone else had these symptoms and found a solution? Thanks in advance!

Mamod

[635911]

Hi Mamod,

No experience of the symptoms you have, but can highly recommend Active Steering at Marrackville.

nice work and really keen to help.

No association except as a customer.

Toby

[miklilmag]

Hello,
-low on fluid,
Check that first,

Franke

[Da_Hose]

Hmmm .....

I believe the pressure bypass is built into the pump. If so, you would want to check the output on the pump to be sure it is sending out full pressure. Rebuilt parts sometimes come DOA.

Jose

[Mamod17]

Thanks for your replies! I will check all the options.

[dwcains]

Maybe a bit too basic, but have you checked the belt? Is it slipping at low revs?

[Mamod17]

I suspect/hoping it might be something like that. I only had steering box pulled out to fix an oil leak and it hasn't been the same since despite 2 x steering boxes and ps pump. Will be able to look at it properly next week...

[Mamod17]

Well, changed the power steering fluid which was looking a little thin and didn't make too much difference. The power steering pump still whines away when it starts getting warm. Looks like I'll have to try another rebuilder to go through the system again.

[tschultz]

Whining means it is low or air in the system.

I suspect you have an oring that isn't sealing properly that is caused air to enter the system. It purges once you drive around for a while...

[Brucey]

there is a filter in the base of the reservoir. You should check that this isn't clogged. IIRC it is sintered metal, so can be cleaned and re-used if you can't find a replacement.

If this filter gets even slightly blocked, the pump tends to draw air in on the feed hose or the feed hose connections (were these replaced?). Air causes whining and if there is enough of it you could lose pressure too.

cheers

[Mamod17]

Thanks guys - will check out air in the system...

[sansouci]

there is a filter in the base of the reservoir. You should check that this isn't clogged. IIRC it is sintered metal, so can be cleaned and re-used if you can't find a replacement.

If this filter gets even slightly blocked, the pump tends to draw air in on the feed hose or the feed hose connections (were these replaced?). Air causes whining and if there is enough of it you could lose pressure too.

cheers

I think it is actually cavitation and not outside air. Even so, the pump needs to fully draw from the reservoir.

[Brucey]

cavitation or air? I dunno, but the connections on the feed hose can leak air for sure even if there is no appreciable fluid leak (they normally see only a small pressure, and oil is so much more viscous than air...) .

I have heard of clogged filters causing in the inlet hose to collapse BTW, although I don't know if there was definitely cavitation also when this happened. It might be that if the inlet hose suction isn't enough to cause the hose to collapse, there is unlikely to be true cavitation per se.

BTW I think you can tell if there is an air leak fairly easily; if you run the engine for a few minutes, and then inspect the oil in the reservoir, you will see if it is full of tiny bubbles or not. Small bubbles don't settle out of cold ATF at any speed, plus any air leak is probably worst when the system is cold (biggest pressure drop across the filter) so once there is air in the oil, it will persist for a fair while even if the air leak diminishes after a period of running, or stops altogether.

cheers

[Mamod17]

Thanks Brucey, I'll check it out - probably Thursday

[slofut]

Mamod, I'm really sorry to see you're still struggling with this problem, I figured you had it solved by now. Even though it ain't rocket science, sometimes these gremlins can be a real bear to solve, defying logic along the way. There is a reasonable explanation however, and I'd love to know what it is. Please keep us updated on your progress.

[Brucey]

mad thought; rebuilt pumps usually come with blanking plugs fitted. Is there any chance that these were not all removed?

Also; IIRC another failure mode is that the high pressure hoses can fail internally such that they present a blockage to the pump; this causes whining!

cheers

[Mamod17]

So my mechanic found a bunch of flakes in the filter so he' removed the lot, plus the hoses, cleaned everything out, has a new filter on order plus a reconditioned pump on the way. I'm hoping this will end well...here's what's happened so far....

Leaking steering box - reconditioned and replaced - didn't work as promised - replaced with E28 steering box - heavy steering - replaced power steering pump - steering still stiff and heavy - fiddled with, slightly better - then heavy again - and now we're here - 2 mechanics and a pastry supplier and it could have been a clogged filter all along - we'll see!

Thanks for your help above...

[Brucey]

'flakes'...? Flakes of what?

As per my above post this may indicate a failing hose; what happens is that the lining in the hose comes apart and (amazingly) it can cause a blockage that is only apparent when the system is in operation; I've not seen this with my own eyes but I am reliably informed that you can have a failing hose off the car and it can look fine, but refit it, and the liner is pushed back into the flow and clogs the line again.

BTW if you replace the high pressure lines to the steering box, best way is to take them to a hydraulic specialist and have them crimp new hose onto your fittings. This works out a lot less than buying from BMW.

cheers

[Mamod17]

I'll find out from my mechanic tomorrow. I think it was the clogged filter you were talking about. I think they've pulled apart the whole system, cleaned it up, blown air through the lines, flushed it.

[Mamod17]

So looks like we're finally resolved. Reconditioned BMW pump, new filters and fluid. Hoses flushed and blown through. Wheel alignment, camber adjustment, new $380 Michelin tyre (previous BRAND NEW type was punctured right in the wall...) Drives like new. I've only taken it our in bumper to bumper traffic now but looking forward to a big drive over the holidays...

Thanks for all your help and suggestions!

Now I just have to find the drivers door key barrel which disappeared somewhere along the line...