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There are ways to test the pump independently but this is getting into an area that is not with the reach of your shop (or any dealer).

Simple way is to try and turn it by hand, but the input shaft is recessed and you DO NOT want to mar or damage the shaft with pliers etc.

I would strongly advise against dis-assembling the pump, on purpose or accidentally.
 

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Discussion Starter #22
Agreed I won't be pushing in the pump testing direction. After reading through the B767Capt DYI as suggested by Alan Arnesen I noticed the pump removal instructions were very specific to ensure ONLY the screws at the 1 and 7 positions were loosened to remove the pump as pump damage could occur removing the other two.

On reading the potential downside what type of pump damage might actually occur removing the wrong screws?
 

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The worst case is the gears, plates, or gaskets aren’t aligned and then when retighened, things are damaged. If the pump gears aren’t aligned you can bind the pump, spinning it with the motor or by hand destroys it. No one will admit to damaging a pump and the replacement cost is the whole assembly which is a few grand...
 

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Discussion Starter #24
Ouch.....so just spinning the pump by hand can actually destroy it??? I hope like h... no one touched it and they removed it properly (But how will I ever know...) :( Is it that the pump components are that fragile or is it that they are so finely calibrated that even being spun by hand causes catastrophic failure (which I assume occurs once reconnected to the motor)? In any event I am sitting on the edge of my seat waiting for further insight.
 

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Discussion Starter #25 (Edited)
Well shop confirmed pump now working but not holding pressure since reassembly of the pump. The motor turns the pump but car will not start due to low SMG pressure. They noted the loss of pressure is likely due to not have the proper seals for the pump. Any ideas on where I might find the seals for the pump?

As a backup I found another pump (never been disassembled) but, it's also in need of a seal kit.
 

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Discussion Starter #26
I have done some further research and would very much appreciate your help in confirming if the attached seals image are in fact for the SMG pump.
BMW Pump Seals.jpg
 

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Ouch.....so just spinning the pump by hand can actually destroy it??? I hope like h... no one touched it and they removed it properly (But how will I ever know...) :( Is it that the pump components are that fragile or is it that they are so finely calibrated that even being spun by hand causes catastrophic failure (which I assume occurs once reconnected to the motor)? In any event I am sitting on the edge of my seat waiting for further insight.
The body of the pump is aluminum. The gears and shaft are steel. There are channels made of brass. So there can be severe damage if the stuff isn’t aligned and the bolts simply re tightened. Those seals can be pinched too. Your pump seems to be working worse after it was touched. Hopefully new seals will solve it but pump should never have been disassembled for this reason, and now you have to buy new seals.
 

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Also they may have mis-re-assembled the pump, the seals and channels also can be installed incorrectly too. That might be the reason why it runs now, but with inadequate pressure. Of course no mechanic is going to admit they effed it up.

Like I said before this is not something that should be done by anyone who is not uber meticulous.
 

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Discussion Starter #30
Thank you guys much appreciated. This is without doubt a dumb question but I need to ask it....if I use the pump never disassembled do I need the seal kit? I'm simply ignorant as to where the seals fit into the picture...are they internal (ie. required once disassembled) or external to facilitate a proper seal with the pump block? Thank you for being so so patient with me.
 

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They (the heart shaped ones) are sandwiched internal to the pump assembly. The pump body is like 3 layers. If you loose the 2 hex bolts that you aren’t supposed to loosen or disassemble, the sandwich layers loosen up.
 

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Those seal are for sale at SMG society. Considering the cost of a new HPU it may be worth a try. With a clean bench and careful dis-assembly and assembly it shouldn't be a problem, its just a pump. When BMW put the engine together they screwed up, it just takes 50,000 miles for it to fail.
 

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Discussion Starter #33
Excellent, thanks Alan I see them. Any idea on what the weak point is in the pump, contributing to failure at 50k? Would be nice if it was in fact the seals given their availability.
 

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I think it is just the nature of a new type of system and age. If you were to do some research on similar systems from other brands I would imagine that they have maintenance issues as well. I know of no super car that gets off easy after 10 years and 100,000 miles. If your Ferrari needs 10 grand in transmission work you wouldn't bat and eye. That is the level this car is at.
 

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I’ve seen no data points or anecdotes that indicate the hydraulic PUMP fails at 50k or any (other mileage). Instead we have many anecdotes about how the Motor fails and people have issues after replacing the old motor with a new one. Many times due to a coupler mis-installation or an occasional admission that they effed around intentionally or unintentionally with the pump. That’s not a pump failure, that’s the tech/mechanic being unaware or careless. These gear driven pumps designs are used in a lot of very severe duty applications like construction equipment. If the fluid is clean and pump integrity undisturbed, they last for a long time.
 

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I was talking about the engine bearing problem. That is to say even BMW screws up and we should not be afraid to work on our cars ourselfs.
 

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Discussion Starter #37 (Edited)
The shop used the new seals I bought in my existing pump which they had disassembled. Unfortunately the pump is still unable to hold sufficient pressure to start the car. I have another pump on the way that has NEVER been disassembled. As the "New" seals I bought have already been used, as noted, should I purchase another set as the seals are "single use". I expect the shop WILL NOT open the replacement pump, so I assume the only seals required will be the O rings. My question is can the O rings be used again or should I buy another set?
 

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The heart shaped seals do not need to be replaced on a brand new pump. No need to reiterate, but do not disassemble the new pump. I assume when you say O ring you refer to the 2 circular orings. Those you can use with the new pump. I have a suspicion that your original pump was mis-assembled based on what I’ve read from you. However it could be that your pressure issue is elsewhere. Sorry to tell you this but this can get very expensive if they can’t properly diagnose the root cause.
 

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Discussion Starter #39
Thank you for the quick reply. I hope you are right and it was mis-assembled. Although the car threw the codes as noted above it continued to start many times. The absolute NON-START and lack of pressure discussion has come since they took the pump apart. This new pump, which was never disassembled but was "USED" would, if working either resolve the issue or, as you say, lead to another expensive problem in the system. Sad to say my fingers are crossed and I can only pray it works. Once again thank you very much for your insights.
 
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