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Discussion Starter #1 (Edited)
I wasn't going to post yet another boring SMG rebuild thread but since everyone is posting today about SMG problems and we're all geeks that like to analyze things I figured why not.

So Two years ago i replaced my SMG motor and everything was fine till last october I'd get an yellow light on harder driving. Eventually it happened more frequently , for the record I have 91k on my 2010 M5. I'd hear the pump always running blah blah blah. I hooked up INPA and went for a ride and noticed btw shifts pressure wouldn't build then would then wouldn't. I figured it was a seal leak somewhere.

I pulled the tranny and was annoyed at FTE and BMW for the ****tacular wires on the sensor strip and decide I'm going to go balls out with a rebuild and it's either gonna work or with boat season coming up I have new anchor and will just bite the bullet and buy the whole unit from BMW. insert typical rebuild story here.

I did decide to replace the internal hydraulic pump seals (Burkhart) , go with the MLR Engineering motor the old one has been working really hard lately, new accumulator because it was towards the end of the range, iirc 29 bar and 28 is the lowest of the range, new seals for all the solenoid( MLR Engineering) and I also went with the Burkhart engineering unicorn piss fluid.

Since I haven't seen a pump rebuild thread I'll say don't be too scared of it, it's just like any hydraulic gear pump or motor. It's all of 10 parts orientation matters but it's not a big deal to figure out if you mess up as it's like any other pump.

What I found though was the internal pumps seals had a crack in it and a few of the shift orings had squared themselves off and were hardened. I assume these were my issues.

The pump runs very little now, the system holds pressures very well, it used to drop like a rock while cruising/sitting but now it barely trickles down and then between shifts when it needs to rebuild it shoots up rather quick.

The attached pic the circled area is where one of the cracks are, and one of the oring what was squared, it's hard to see in the pics Oh well

You have to write MLR for the orings, I actually measured the old ones but decided to go with them since they had them all ready properly sized.

Also big shout out to Rob an MLR, he was very communicative.

https://mlreng.com/collections/bmw-m5-m6-smgiii/products/copy-of-smg-iii-electric-motor-23017841032-without-connector


https://burkhart-engineering.com/epages/c2babc39-3494-4a11-bfa8-9e28d50a3799.sf/de_DE/?ObjectPath=/Shops/c2babc39-3494-4a11-bfa8-9e28d50a3799/Products/54443


https://burkhart-engineering.com/epages/c2babc39-3494-4a11-bfa8-9e28d50a3799.sf/de_DE/?ObjectPath=/Shops/c2babc39-3494-4a11-bfa8-9e28d50a3799/Products/54134
 

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When I just bought my car, on way home I stuck in middle of motorway with red cog. Car was under dealer warranty, first they replaced pump motor, no luck, on my second attempt to get home I stuck again nearly at same place around 20 miles away from dealers. Second attempt was to replace pressure accumulator, car was fine for first 50miles and then red cog again. I was about to demand my money back, but i just really want to have this sepang bronze. On third attempt they rebuild pump with new seal kit from above online shop and since then my SMG works like Swiss clocks.

Sent from my LYA-L29 using Tapatalk
 

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@Ferris do you have more pics from SMG hydraulic pump? What torque spec you used for pump bolts, 5Nm? I'm going to overhaul my SMG next month so every tips and pointers are more than welcome.
 

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Discussion Starter #5
5NM is the correct spec from what I can tell for the bolt size and from Burkhart.

I only have one other pic.. see attached

Just remember it flows bigger to smaller. if you get stuck I can talk you through it.

The only advice I can give is make sure the seals are seated right, they sit in a grove, keep it as clean as possible, lint free paper towels ftw I personally oiled up the seal as well as oiled up the gears with fluid and added a bit into the intake chamber after.

After the pump, motor and res was together I removed the accumulator and applied 12v to the pump in short cycles ~ 1 second on time till it drew fluid and it came out the accumulator hole.
 

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Is that right? 150 euros for 5 orings? I know Jim has said he's not willing to sell these, but for that price he might be swayed... Just saying.
 

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Discussion Starter #7 (Edited)
Is that right? 150 euros for 5 orings? I know Jim has said he's not willing to sell these, but for that price he might be swayed... Just saying.
I've seen a versions from Taiwan, on ebay ,for 80 iirc. As long as you're not having cavitation in the pump, these would be the only parts to fail as far as the pump goes. So it's a small price to pay and a lot cheaper than the 5k BMW wants for new hydraulics...

..of course with that you get new valves , a sensor strip, and tank which are the next biggest gotchas.
 

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Discussion Starter #9
Exactly why I haven't bothered with them :grin
I wouldn't be surprised if they all come from the same source. The ebays are also 150 us, btw but then I saw mysteries from CA for 80. Who knows , if I cared enough I'd buy a spare pump install them and test them out. OTOH, Summer is coming :) and if i ever have to play this game again I'd probably just manual convert it or drive it into the Atlantic whatever is easier.
 

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Discussion Starter #10
Wanted to throw a quick follow up and observations. Now that I replaced my Real main I've got a chance to do a lot more observations in inpa.

I wish I had a chance or at least forethought to log some data when the car was new. Now, after the rebuild, though there is little to no pressure drop when cruising in the same gear or over night. The pump rarely kicks on when opening the door or unlocking, Also it looks once the clutch is pushed in , ie at a light, there is hardly any pressure bleed. As we'd expect pressure drops when gears or the clutch moves. Also pressure builds right away right after the pump kicks on.

These are merely just data points , I wish I knew earlier. I may try to get testo to log all this so we can get into a spreadsheet.
 

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So, how easy is this to do?

Wanted to throw a quick follow up and observations. Now that I replaced my Real main I've got a chance to do a lot more observations in inpa.

I wish I had a chance or at least forethought to log some data when the car was new. Now, after the rebuild, though there is little to no pressure drop when cruising in the same gear or over night. The pump rarely kicks on when opening the door or unlocking, Also it looks once the clutch is pushed in , ie at a light, there is hardly any pressure bleed. As we'd expect pressure drops when gears or the clutch moves. Also pressure builds right away right after the pump kicks on.

These are merely just data points , I wish I knew earlier. I may try to get testo to log all this so we can get into a spreadsheet.
Is the pump basically 2 halfs or will it spill a bunch of parts once opened?
 

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yeah, never opened a pump up before

The pics are above to give you an idea, but basically it's a body two end caps, seals, and gears.

It's a basic hydraulic pump design.

But if I could open without parts spilling out, putting new oring in and closing it back up that would be something I can handle.
 

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Discussion Starter #14
But if I could open without parts spilling out, putting new oring in and closing it back up that would be something I can handle.
Well I don;t know you so I can't make that call.... ;)

Seriously though it's very simple part orientation matters at least in terms of the bronze sealing plates . So just take your time and pay attention and you'll be fine.

If you get stuck mail me the parts and a cup of coffee and i'll reassemble it for you
 

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Rebuilding my spare SMG Pump

Thanks for the information and thread. I will be rebuilding the one that just came out my car. I saw and item on ebay for the shaft driven off the electric motor. Has anyone replaced that whole doing this? Mine is beat up where the coupler connects.

Cheers
 

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Discussion Starter #16
Thanks for the information and thread. I will be rebuilding the one that just came out my car. I saw and item on ebay for the shaft driven off the electric motor. Has anyone replaced that whole doing this? Mine is beat up where the coupler connects.

Cheers
Post pics I'd like to see a gnarled up shaft, the coupling should've taken all the abuse not the shaft.

I don't think anyone has here replaced the shaft gear, as long as they're manufactured to proper tolerance you should be fine.
 

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Transmission overhaul is done. Car got new clutch, flywheel, slave cylinder, transmission mounts, SMG-acculator, SMG-electric motor, new o-rings for solenoids (from Fast attack motorsport) and SMG-hydraulic pump internal seals and "unicorn piss" hydraulic fluid (from Burkhart engineering).

Before repairs it took almost 8s to SMG prime in the mornings and got a sqeeking sound when changed gears. Now it takes 1.5s to prime and squeeking sound is gone. Sound was coming from throwout bearing which was original and it was sticking. Old SMG-hydraulic pump internal seals were in good condition.
 
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