e36 M3 SMG accumulator

Discussion in 'E36 M3 (1991-1999) and E30 M3 (1986-1990)' started by Aglanm3, Dec 27, 2019.

  1. 27 Dec 2019 at 4:29 AM #1
    Aglanm3

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    Hi All
    I'm new to this forum. 3 months ago I got my second e36 M3 SMG. It's convertible and estoril blue with hardtop. I knew from the start that it will need a bit of work. First observation was very frequent priming of the SMG pump. And as we all know the accumulator needed replacement. I live in Dublin and it did cost me around €800 and I did ity self. My question and I know that we have lots of SMG experts in the forum, is there anyway of getting these accumulators recharged? Or any after market replacements?
    I've seen accumulators from febi bilistein and other makers used for brake boosters. Would these fit to our system even with some modifications,?
    Just an idea and I'm sure some members here might have an insight or thought of something like that. Let me know what do you think. Thanks a million. Wish you all Happy Christmas and happy New year.
     
    suraj likes this.
  2. 27 Dec 2019 at 5:42 PM #2
    yojoelay

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    I have always wondered whether an off the shelf replacement would work - if you found one with the right thread and internal specs surely it would do the job - nevertheless I bought mine off BMW.

    Apparently they’re supposed to be replaced regularly - every couple of years. I have kept my old one and might have a go when it comes due. For now though there are other challenges - like a leaky steering rack - so it sits on the shelf and I try not to look at it for fear of remembering how much the replacement cost.
     
  3. 27 Dec 2019 at 6:07 PM #3
    Aglanm3

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    I was looking on eBay and found brake pressure accumulator made by febi. Around €80. With a bit of modification ( if the thread isn't the same, a decent shop would do it) could be a replacement.
    It's a theory. Needs an attempt. Don't have the courage to do it yet.
    That's the link for the pressure accumulator. I'm sure there are different types.

    https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/392308547148
     
  4. 27 Dec 2019 at 8:33 PM #4
    Aglanm3

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    another question. when I replaced my accumulator few weeks ago I noticed that the smg pump when idling will prime every 5 minutes approximately. this made happy that I replaced the accumulator despite the cost. today I noticed more frequent priming, almost every 1 min 30 sec. i have to say the car will start straight away with no delay but its priming very frequently again?? where is the problem now? is it the accumulator again? faulty one or i have to recondition my pump and replace the seals? and if so where to get the seals from? advice please.
     
  5. 27 Dec 2019 at 11:26 PM #5
    Mikescx

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    M Parallel is your man. When he reads this he will be able to give you all the advice and information you need as his knowledge of the SMG is outstanding.
     
  6. 27 Dec 2019 at 11:54 PM #6
    Aglanm3

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    Thanks a million. I hope that M Parallel would post soon. I need expert advice.
     
  7. 28 Dec 2019 at 11:44 AM #7
    Aglanm3

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    Quick update.
    I have an old smg1 pump from eBay. Got it a while ago. I decided last night to go ahead and explore every single part of it. To be honest the design of the pump is amazing. I do respect German engineering. The block of the pump itself has lots of connecting channels made me confused unable to find out where or what connection between different chambers. This pump had faulty accumulator. And further I was able to discover what might go wrong with these Pumps.
    All seals dry and break by time. Including mainly solenoid valves 3 seals. These seals might be the cause of inner leaks.
    [​IMG]
    [​IMG]
    Other seals might also leak and causes external leaks.
    The pump seal itself could causes leaks.
    [​IMG]
    Inside the pump there was a metal piece that has 2 teeth. One of them was broken.
    [​IMG]
    [​IMG]
    Another issue I noticed that wires dry by time and breaks.
    Also lots of dirt inside the pump accumulate over time.
    [​IMG]
    I'll try to post some photos.
     
  8. 28 Dec 2019 at 12:10 PM #8
    Aglanm3

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    More photos
    Pump filter and seal
    [​IMG]
    Dry filter seal
    [​IMG]
    I don't know what's that if Someone can tell me. It was inside the pump filter. Looks like some sort of seal.
    [​IMG]
    Pump removed from the block
    [​IMG]
    The back of the pump
    [​IMG]
    Side of the pump
    [​IMG]
    I don't know what's that plug for?!
    [​IMG]
    Pressure sensor with dry wires
    [​IMG]
    Again I don't know what's that. But you could notice dry stiff wires cutting.
    [​IMG]
    More parts of the pump. Might act like master cylinder for the clutch?!
    [​IMG]
    More parts. Tell me if you could recognise it? I don't know what's that!!
    [​IMG]
    Finally bare pump block
    Top
    [​IMG]
    Front
    [​IMG]
    Back
    [​IMG]
    [​IMG]
     
  9. 28 Dec 2019 at 6:34 PM #9
    Aglanm3

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    Updates
    Today I decided to recheck my SMG pump. Time between priming was 2 min 55 sec. Almost twice the time I got yesterday.
    [​IMG]
    So, I decided to do the venting procedure for the clutch and transmission actuator. My theory is that dirt might causing the pressure to drop quickly. So by flushing the hydraulic fluid it will help to flush any dirt. Just a theory.
    I did it using DIS program. And guess what was the time between priming? Almost 5 minutes. Horray.

    [​IMG]

    I don't know if my theory is valid but it did the job and I'm delighted.
    All comments are welcome. Please let's share the knowledge regarding smg1.
     
  10. 29 Dec 2019 at 10:06 AM #10
    MParallel

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    I know a few things about the SMG system, but not how to refurb pumps etc.

    I never took mine apart like that. I do have a second unit as a spare once my original pump motor needs refurbishment.

    Btw, on the spare pump, I have taken out some solenoid allen bolts, but even with my strength, I can’t pull thenn out. Is something else locking them?

    That gold cooling block, we suspect that’s a big resistor for when you use the emergency double-fuse tool to emergency open the clutch to be able to move the car.

    We (me and two friends who also own M3 SMG verts) have looked into aftermarket accumulators, but nothing yet.
    The Febi one looks close. We need
    to know the exact specs of the original one.
    Shame BMW quadrupled the price the last few years. Specially for a wear part.
    I’d have stocked a few in hindsight.
    Though they might have a limited shelf life.
    We haven’t figured out the OEM supplier, but even if, they probably only supply BMW.

    I replaced mine in 2014, car was bought in 2013 and also had the long priming problem. Which went away instantaneously, after the swap (and debleed which I often do).
    It still starts up withing seconds, even after winter storage.
    I do very little km’s with it though,
    so my wear might be way less than on normal use.

    I doubt the accumulators can be recharged, as the cause of not keeping one is the membrane that tears.

    Btw that pump looks very dirty. Is that the one of your car?

    We also concluded the hydraulic pump unit itself is pretty good designed.
    The only real problem is the plastic insulators of the pump motor that eventually melt and short the pump motor. And with BMW only selling the unit as a whole, at like €3500 now, people ditched the system.

    Umbolt the pump motor, have it refurbished, which will be better than new, and enjoy it for many more years.

    There is a BMW trainings/schooling document regarding the SMG system. It explaines all components and their relations with each other and has hydraulic circuit drawings.

    Made my respect the whole system even more, giving this system is over 20 years old and first of its kind.
     
  11. 29 Dec 2019 at 10:31 AM #11
    MParallel

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    PS. Maybe our accumulators just lose their nitrogen charge over time.
    Normally accumulators can be recharged, if they have a valve. Ours look like one-time sealed units.
     
  12. 29 Dec 2019 at 11:37 AM #12
    Aglanm3

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    Thanks MParallel for your reply. I would be grateful if you could post the document that explains the SMG system in details.
    This pump isn't off my car. I got it from eBay aiming to explore it to be able to know how it operates and what might go wrong with it.
    Solenoid valves are only held by 2 Allen bolts. It's snug fit by the three o rings. You need a bit of force and wiggling to get it out.
    [​IMG]
    Many things could go wrong with the SMG pump:
    1. Accumulator looses pressure by time. It's s natural process of aging, nitrogen gas leak and diaphragm damage and tear.
    2. Pump motor could burn out and brushes or commutators might need replacement by time.
    3. Solenoid valves o rings dry by time and might need replacement.
    4. Solenoid valves might become faulty ( rare).
    5. The motor metal piece in the picture. It links the motor to the pump. If the teeth get broken the motor will keep runing but no pressure is generated
    [​IMG]
    [​IMG]
    6. Wires dry and become brittle. So it could break and loose connection. Making the pump faulty and throwing errors.
    [​IMG]

    [​IMG]
     
  13. 29 Dec 2019 at 12:36 PM #13
    harrypevo

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    I'm sure even sealed units can be modified to be recharged.

    I have messed around with Rover metros before which use hydragas suspension, where the spring is replaced by a metal canister with pressurised nitrogen in one end with a membrane and hydraulic fluid (water and corrosion inhibitor) in the bottom half. Over time the nitrogen escapes, the suspension sags and loses its springing. With parts being hard to find or very expensive people have started modifiying the canisters by adding a valve to the gas end and repressurising the system, with the advantage that you can actually run at a higher pressure than they were delivered from the factory.

    Just because something is designed not to be aftermarket repairable doesn't always mean it cannot be repaired.
     
  14. 29 Dec 2019 at 12:44 PM #14
    Aglanm3

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    That's interesting. I think if we could fit some sort of valve to the to top part of the accumulator ( provided that the diaphragm is intact) might make it rechargeable. Do You mind me asking what sort of valve could be used? Do you have a photo or link? Thanks.
     
  15. 29 Dec 2019 at 5:53 PM #15
    MParallel

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    Interestingly the SMG2 accumulator is of the piston variant.

    Sure those things you mentioned can go wrong, but I doubt many will happen, besides the plastic motor insulators melting (the one big flaw imho as it’s located next to the scorching hot exhaust manifold). I’ve thought about adding some kind of air duct / pc fan to have some air flow around it.

    But things like dried out wiring or the metal connector piece breaking. Maybe it was just a trashed unit.

    My car has only done 58k mls so I’m not too worried, yet.

    Pm me for the doc.
     
  16. 29 Dec 2019 at 9:10 PM #16
    Aglanm3

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    I'm sure with low mileage and your experience, you should not be worried.

    A quick update. Today I decided to reassemble the unit minus the o rings that I need to source from some where ( any recommendations are welcome). I attached some photos after a bit of cleaning. Doesn't look too bad.
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    The O rings are dry. So I'll try to find supplier. If someone recommended please let me know.
    [​IMG]
     
  17. 30 Dec 2019 at 12:19 PM #17
    MParallel

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    Nice job.
     
  18. 31 Dec 2019 at 1:50 AM #18
    Gecca

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    @Aglanm3 I see your getting more responses in here
     
  19. 31 Dec 2019 at 10:08 AM #19
    Aglanm3

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    Thanks a million
     
  20. 31 Dec 2019 at 10:09 AM #20
    Aglanm3

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    Hi
    Yes. members here are very helpful. Thanks for the guidance.
     
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