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Well I got bored again and since I've done my rod bearings, new clutch and fly wheel, the only thing left is to zero out or install a new smg hyd pump motor. We read here all the time about guys getting stranded from these. With usually no warning. So I like working on the car as much as I like driving it. Haven't seen a DIY on this so I took A LOT of pictures. In the latest Roundel mag, there is an ad from Roxbury BMW for 25% off on parts. I called them up and the motor kit is only 264.87. About the price for a set of front brake pads. The kit comes with new o rings, motor, and high temp zip ties, and new bolts and a tube of grease. I'm not going to wait for this component to strand me. Change it before it goes bad, especially for how cheap it is.

1. First thing is to remove the right micro filter tray so you can get access to the relay box up next to the firewall. Remove the 5 cover bolts and slide the white lock tab to unlock.
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2. Now fire up the computer as you have to depressurize the hydraulic system before you work on it. Once depressurized, you pull the relay out so the pump won't inadvertently run while you're working on it. After the new pump was installed, I saw 69 bars of pressure which is around 1000 psi so there is some serious pressure here.
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3. Now raise the car up and pull the panels off the bottom of the motor/transmission area. The large black panel under the radiator can stay on. Also the metal pan under the motor must come off. All the insulation around the transmission and the one covering the drive line. Remove the exhaust system. Remove the drive line. Then get a jack to support the back of the transmission and put in place. Remove the 6 bolts holding the rear transmission support plate and lower. It will go down about 10 inches and stop. I then slightly jacked it back up to support it.
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4. TIS has you take several things apart around the smg motor. There is a metal bracket in front of the smg motor that has to come off so you can remove the motor later. It holds the O2 sensor plug. There are 4 zip ties to cut, 2 of them hold the PLCD cable to the reservoir. Once that it done you remove the 2 plugs on the bottom of the block. There is also a hose clamp holding the reservoir on that has to be cut off. A new one comes with the pump. I measured the fluid coming out of the reservoir and that is 30 oz. About a liter. This also allows you to refresh your hyd fluid. You just slide the reservoir to the rear and catch all the fluid. There is a black rubber return hose for the reservoir on top but TIS says to leave it attached. It has enough room to slide the tank back.
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5. Now you have access and can remove the hydraulic pump from the block. The electric motor screws that hold the motor to the block are behind the pump so that's why the reservoir and pump must be removed. There are 4 screws on the pump and TIS says to only remove the 2 that hold it to the block. The other two hold the pump together and warns that pump damage will occur if you remove those. The 2 you want to remove are at the 1 o'clock and 7 o'clock position. Mine at the 1 o'clock position was finger loose. I reassembled with blue loc-tite. Once the pump is out you then remove the 2 screws holding the electric motor and those two are at the 12 o'clock and 6 o'clock position. There are 2 o rings on the pump and new ones are included in the kit. I'll post a lot of pictures in this area but the way this works is you will see a green o ring inside the reservoir and that plugs right into that open port on the pump. That draws in fluid, rotating pump pressurizes it and discharges it through the small hole that has an o ring. That is what gets fed into the block. You will see that hole in the block at the 3 o'clock position. I assume that charges the accumulator.

The electric motor, on the front of the block housing has a clamp on it that wraps around the accumulator. Just pry that back to give some clearance and twist the pump out. Reinstall in reverse order. I topped off the reservoir and ran the ISTA block bleed and slave cylinder bleed procedure. Takes about 30 minutes and rechecked fluid. It took about 5-6 more oz to top off. I then reran the entire bleed procedure. Pump sounds louder and as I said before saw the pressure spike at 69 bars. A fun and very easy project to do. I installed a new relay too as I wanted a new relay with a new motor. Total cost less than 300.00 with a liter of CHF 11.
Oh I am donating the old pump to the BMW North American Forensic Part Analysis lab located in Maine where Dr. Colley resides. Maybe we can get data on how far gone this normal operating pump is.
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First off, Amazing write up and DIY! Thanks for taking the time to document, take pictures and explain! I appreciate it and im sure the whole smg community does aswell. This has greatly increased the understanding and DIY for me!

Now a few questions :)

Is it necessary to lower the tranny?
Is it necessary to remove the drive shaft from both end tranny and rear diff? Or even necessary to remove it at all?
 

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Discussion Starter #6 (Edited)
First off, Amazing write up and DIY! Thanks for taking the time to document, take pictures and explain! I appreciate it and im sure the whole smg community does aswell. This has greatly increased the understanding and DIY for me!

Now a few questions :)

Is it necessary to lower the tranny?
Is it necessary to remove the drive shaft from both end tranny and rear diff? Or even necessary to remove it at all?
Great questions as that went through my head too. TIS says to lower the tranny. It really gives you a lot more room. I think it would be very hard without lowering it.

I only loosened the drive shaft from the front at first wanting to just lower the tranny with only that disconnected. It doesn't have room to slide back but the big caution here is when I did my clutch, I remember warnings about not letting the drive shaft bend at the joints or it will cut the rubber boots. It's not too bad as there are 2 center brace bolts and 6 on the rear end. I bought 3 new bolts and lock nuts for the front attachment as they are one time use and I didn't replace them when I did my clutch. I thought I better this time. They redesigned the lock nut too. You need two people to lower it so you don't max out the bend at the u joint. You need 2 people anyway for the exhaust. That sucker is heavy. That's twice now that I've pulled the exhaust and boy does my wife hate it.:haha:

Edit: here are the instructions I used. It says to pull all.
http://workshop-manuals.com/bmw/6_series_e64/m6_s85_conver/2_repair_instructions/23__manual_transmission_(mech)/42__hydraulic_add-on_parts_smg/3_ra__replacing_electric_motor_on_hydraulic_pump_(gs7s47bg_smg)/
 

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Great write up, I'm getting temped to do mine, specially since I have my car already lifted up on 4 jackstands. I doing a brake fluid flush and detailing the under carriage. :wroom:
 

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Discussion Starter #8
Great write up, I'm getting temped to do mine, specially since I have my car already lifted up on 4 jackstands. I doing a brake fluid flush and detailing the under carriage. :wroom:
Absolutely, go for it.
 

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Great questions as that went through my head too. TIS says to lower the tranny. It really gives you a lot more room. I think it would be very hard without lowering it.

I only loosened the drive shaft from the front at first wanting to just lower the tranny with only that disconnected. It doesn't have room to slide back but the big caution here is when I did my clutch, I remember warnings about not letting the drive shaft bend at the joints or it will cut the rubber boots. It's not too bad as there are 2 center brace bolts and 6 on the rear end. I bought 3 new bolts and lock nuts for the front attachment as they are one time use and I didn't replace them when I did my clutch. I thought I better this time. They redesigned the lock nut too. You need two people to lower it so you don't max out the bend at the u joint. You need 2 people anyway for the exhaust. That sucker is heavy. That's twice now that I've pulled the exhaust and boy does my wife hate it.:haha:

Edit: here are the instructions I used. It says to pull all.
BMW Workshop Manuals > 6 Series E64 M6 (S85) CONVER > 2 Repair Instructions > 23 Manual Transmission (MECH) > 42 Hydraulic Add-on Parts SMG > 3 RA Replacing Electric Motor On Hydraulic Pump (GS7S47BG SMG)
:applause: the wife help! Thanks for the link, to me the job seems very straight forward, the motor kit comes with everything you need, doesn't seem very difficult, to me the most time consuming part seems to remove the exhaust, head shields and propeller shaft. From looking at pics, it might be possible but might be really tight with the tranny in place and propeller shaft.

Another question, anything special with the driveshaft to remember when removing/installing besides not letting it bend down from both ends and using new bolts/nuts?
It just unbolts, and then just bolts back up?

Thanks again man! Interesting to hear on what Jim finds with the motor aswell!
 

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B767capt, just curious what service manual do you recommend for our E60 M5's to do maintenance?

And can average Joe like me tackle this kind of job? I can do oil changes, spark plugs, etc. (not on the M5's but other cars). How do you rate the difficulty of this? Thanks.
 

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Discussion Starter #11 (Edited)
:applause: the wife help! Thanks for the link, to me the job seems very straight forward, the motor kit comes with everything you need, doesn't seem very difficult, to me the most time consuming part seems to remove the exhaust, head shields and propeller shaft. From looking at pics, it might be possible but might be really tight with the tranny in place and propeller shaft.

Another question, anything special with the driveshaft to remember when removing/installing besides not letting it bend down from both ends and using new bolts/nuts?
It just unbolts, and then just bolts back up?

Thanks again man! Interesting to hear on what Jim finds with the motor aswell!
Yes the drive shaft is easy. If you're day dreaming you could try to install the center support upside down. I've learned before something comes apart, take a picture of it before. It really helps when you go back a few days later asking yourself, now which way did this go? Especially when you don't do this everyday. That helped a lot when doing rod bearings.
I would order new bolts and lock nuts (3 each) for the front attachment as they are one time use. My order was held up for the lock nuts as the dealer said they were on national hold. He said he would try to pull some strings to get them released. He finally got them. I would have used red loc-tite on the old ones if I couldn't get them. I think the rear bolts (6) are 1 time use too but I reused them.
 

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Discussion Starter #12 (Edited)
B767capt, just curious what service manual do you recommend for our E60 M5's to do maintenance?

And can average Joe like me tackle this kind of job? I can do oil changes, spark plugs, etc. (not on the M5's but other cars). How do you rate the difficulty of this? Thanks.
This is a very easy job once you get to the motor. All the prep work removing driveline, exhaust etc takes all the time. It took me 2 hours to get to the point where I started to remove the motor. It always takes longer putting everything back together. The key here is having the right tools, lift and computer to depress and bleed the hyd. Jack stands would be harder. A 2k investment on a lift goes a long ways. Makes clutch, rod bearings, brakes, engine, transmission and rear end oil changes very easy. Plus when the car is gone someday, you still have the lift. That's where I spent my extended warranty money. Once you get to the smg components, it's very straight forward and easy.
This is so easy and cheap I'm going to change this motor every 50k or so. Like I said for about the price of front brake pads and it changes the fluid too.

Edit: Knowing what I know now, I would change this motor out with a clutch change. It's cheaper than a slave cylinder or a PLCD sensor and you have access to it while the tranny is out.
 

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Another great DIY write-up Bill. Thanks for taking the time to do this for us. If you are bored, come and help me with the rod bearing job. I finally got all the parts that I needed. Just need to pick a start date.
 

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Great Doug, the more the better. Post your bearings up when you get them out. I found the more we R/R on this car, the simpler it becomes.
 

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Yes the drive shaft is easy. If you're day dreaming you could try to install the center support upside down. I've learned before something comes apart, take a picture of it before. It really helps when you go back a few days later asking yourself, now which way did this go? Especially when you don't do this everyday. That helped a lot when doing rod bearings.
I would order new bolts and lock nuts (3 each) for the front attachment as they are one time use. My order was held up for the lock nuts as the dealer said they were on national hold. He said he would try to pull some strings to get them released. He finally got them. I would have used red loc-tite on the old ones if I couldn't get them. I think the rear bolts (6) are 1 time use too but I reused them.
Perfect! Thanks for the tips! New bolts r def the way to go and pictures.. I take alot of pics in general so that is never a issue for me...

Not sure if you have an idea for this but, if we open the hydraulic black tank just to check the fluid level, do we need to bleed the system after opening the fill/level plug?
 

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Perfect! Thanks for the tips! New bolts r def the way to go and pictures.. I take alot of pics in general so that is never a issue for me...

Not sure if you have an idea for this but, if we open the hydraulic black tank just to check the fluid level, do we need to bleed the system after opening the fill/level plug?
Very good question as Jim and I were discussing this yesterday. ISTA says to depressurize the SMG hyd before checking the level. Well you would think after that statement that there is pressure in the tank. It's just plastic with a vent on top and a flimsy plastic plug. It can't be from pressure. I got to thinking and applied hyd systems like we have on the airplane, an accumulator allows pressurized fluid to be applied to components when asked for if a pump isn't running. In our case this saves the pump so it doesn't have to run all the time. Accumulators also reduce shock in the system when things get turned on and off suddenly especially at 3000 psi like an airplane..

My theory is if you depressurize the hyd system, the accumulator is empty with no fluid in it. It's like a second storage tank. So when BMW saying depressurize, I think all the fluid will be dumped into the res. and you will get a correct level of fluid when you service it. If you serviced it when fully pressurized, some of the fluid is in the accumulator and the res is say 1/2 full. Well you come along and top off the reservoir and this adds too much. If you depressurize the system now, where is all that fluid going to go as the accumulator gets dumped into an already full reservoir. Jim doesn't think so, so we'll wait for the doctors advice.:blabla:
 

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I seem to have lost all my SMG pics from my iphone, so this is a pure SWAG...

What's the height between the fill plug and the top of the reservoir. Basic geometry to estimate volume.

What's the max possible volume of the accumulator using a conservative estimate by calculating via outside diameter.

Which is bigger?

My "I'm tired of working on this thing" opinion is that it has a vent on top. It's easier to clean up the oil dripping out than access the thing to fill it.

Bill is like a remote control mechanic. I have silly thoughts pop into my head and convince him to be the guinea pig... :hihi:


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ouichYea and I fall for it, hook line and sinker. I love talking technical stuff here as we try to figure it out.
 

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Very good question as Jim and I were discussing this yesterday. ISTA says to depressurize the SMG hyd before checking the level. Well you would think after that statement that there is pressure in the tank. It's just plastic with a vent on top and a flimsy plastic plug. It can't be from pressure. I got to thinking and applied hyd systems like we have on the airplane, an accumulator allows pressurized fluid to be applied to components when asked for if a pump isn't running. In our case this saves the pump so it doesn't have to run all the time. Accumulators also reduce shock in the system when things get turned on and off suddenly especially at 3000 psi like an airplane..

My theory is if you depressurize the hyd system, the accumulator is empty with no fluid in it. It's like a second storage tank. So when BMW saying depressurize, I think all the fluid will be dumped into the res. and you will get a correct level of fluid when you service it. If you serviced it when fully pressurized, some of the fluid is in the accumulator and the res is say 1/2 full. Well you come along and top off the reservoir and this adds too much. If you depressurize the system now, where is all that fluid going to go as the accumulator gets dumped into an already full reservoir. Jim doesn't think so, so we'll wait for the doctors advice.:blabla:
I agree, i dont think there is pressure in the tank, otherwise all the pressure would be released through the vent on the top anyways. I think your theory on the accumulator going empty on depressurization might be correct.

But wouldn't BMW want to be at a full level on the tank with the accumulator filled? Looks like the accumulator can take a good quarter of the reserve tank of fluid if not more when its filled.
On the other hand Like the tranny oil, BMW wants the oil cooler and oil pump to be filled when checking the level at the tranny fill hole to max.

Only one way to really get a answer, check the level without depressurizing and check it after depressurizing.


I seem to have lost all my SMG pics from my iphone, so this is a pure SWAG...

What's the height between the fill plug and the top of the reservoir. Basic geometry to estimate volume.

What's the max possible volume of the accumulator using a conservative estimate by calculating via outside diameter.

Which is bigger?

My "I'm tired of working on this thing" opinion is that it has a vent on top. It's easier to clean up the oil dripping out than access the thing to fill it.

Bill is like a remote control mechanic. I have silly thoughts pop into my head and convince him to be the guinea pig... :hihi:


Sent from AutoGuide.com Free App
The accumulator is alot bigger then the extra volume of the top of the reservoir.




For both you guys, when i got a pressure undershoot code, BMW filled the tank and my car has been running great ever since with no undershoot codes. But i have always been confused how they were able to know the amount of fluid that was in the tank.

This is what my work order sheet said:

Performed vehicle test. FC#4F40
As per test module CK'D fluid level of hydraulic unit
found to be approx .5 litre
corrected fluid level
DC: D2360-00000000-09-312
 
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