FYI: Troubleshooting SMG Relocation Problems

[YulCmr]

Try what eacmen suggested first if you haven't already. You can raise either end of the car, really just trying to shift any air bubbles around to perhaps aid in their escaping. If you do both and still have progressively worse buzzing then air is getting in your system somehow. The O-rings where the reservoir hose connects to the pump unit could be the cause and what I would suspect, but you also have O-rings at the solenoids, temp sensor, and pressure sensor. Plus the seal around the reservoir that is attached to the unit itself. Could also be the hydraulic line connection at the extension harness.

Yeah I always bleed with the pump in its original position + the reservoir higher to be sure air goes away.
I had a discussion with my mechanic this morning who told me that it's not uncommon for aging E46 slave cylinders (even on manual) to start getting air vacuumed inside due to internal seal failure. I ordered a replacement refurbished slave cylinder (new internal seals) and will replace it shortly. I'll give my feedback in few days 👍

Thanks guys 👌

EDIT: o-rings are all brand new on my hydro unit. My only unknown is the accumulator. I need to test it, but anyway ... it would only lead to more frequent pump motor activations. Slave cylinder first, then .... if I'm still stuck in my basement .... accumulator !

[oceansize]

oceansize I relocated my SMG unit back in August 21, and had a clutch change around last Christmas. I've had a growing loud buzzing sound over the last months, then, all of a sudden ... Stuck in neutral ! I've proceed to few clutch slave cylinder bleed and it solved my issue for few days. I still had some buzzing at first, then ... More and more until it failed once more....

I will try to bleed again this weekend. I have one question for you though: why jacking up the rear can help bleeding ? I mean... It sounds counter intuitive. I would rather think that lifting the front could help. Can you explain why the rear ?
I've seen that the slave cylinder has 2 pistons to be able to bleed without a bleeding screw. If you have infos on how it works... I'm interested too !

Thank you !

Try what eacmen suggested first if you haven't already. You can raise either end of the car, really just trying to shift any air bubbles around to perhaps aid in their escaping. If you do both and still have progressively worse buzzing then air is getting in your system somehow. The O-rings where the reservoir hose connects to the pump unit could be the cause and what I would suspect, but you also have O-rings at the solenoids, temp sensor, and pressure sensor. Plus the seal around the reservoir that is attached to the unit itself. Could also be the hydraulic line connection at the extension harness.

[eacmen]

oceansize I relocated my SMG unit back in August 21, and had a clutch change around last Christmas. I've had a growing loud buzzing sound over the last months, then, all of a sudden ... Stuck in neutral ! I've proceed to few clutch slave cylinder bleed and it solved my issue for few days. I still had some buzzing at first, then ... More and more until it failed once more....

I will try to bleed again this weekend. I have one question for you though: why jacking up the rear can help bleeding ? I mean... It sounds counter intuitive. I would rather think that lifting the front could help. Can you explain why the rear ?
I've seen that the slave cylinder has 2 pistons to be able to bleed without a bleeding screw. If you have infos on how it works... I'm interested too !

Thank you !

If your smg pump is relocated you need to remove the pump and orient it in its original horizontal orientation when doing the bleeding procedure. Sometimes you need to run the procedure several times.

Air in hydraulic system will tend to move to the highest point.

[YulCmr]

oceansize I relocated my SMG unit back in August 21, and had a clutch change around last Christmas. I've had a growing loud buzzing sound over the last months, then, all of a sudden ... Stuck in neutral ! I've proceed to few clutch slave cylinder bleed and it solved my issue for few days. I still had some buzzing at first, then ... More and more until it failed once more....

I will try to bleed again this weekend. I have one question for you though: why jacking up the rear can help bleeding ? I mean... It sounds counter intuitive. I would rather think that lifting the front could help. Can you explain why the rear ?
I've seen that the slave cylinder has 2 pistons to be able to bleed without a bleeding screw. If you have infos on how it works... I'm interested too !

Thank you !

[Ahmed.Alghoul]

If you aren't dropping out of gear or getting the cog of death you are ok. I get some buzzing from time to time that seems to be unrelated to air in the system (or there is a very small amount) and more a function of pump noises not being disguised by engine noise due to the relocation.

yes I do not have any issue rather than the air buzzing when i come to stop.
thank you for your helping appreciate your kind and your time replying to me

[oceansize]

I have burkart relocation kit
I don't use my car often but when I use it I hear some air buzzing
so I place the pump horizontaly over the side of the engine
and did my first actuator bleeding
so I was thinkingdo I have to blead actuatorand the clutch everytime for 10 time to be sure the system is freecof air

If you aren't dropping out of gear or getting the cog of death you are ok. I get some buzzing from time to time that seems to be unrelated to air in the system (or there is a very small amount) and more a function of pump noises not being disguised by engine noise due to the relocation.

[Ahmed.Alghoul]

I have burkart relocation kit
I don't use my car often but when I use it I hear some air buzzing
so I place the pump horizontaly over the side of the engine
and did my first actuator bleeding
so I was thinking if I need to blead actuator and the clutch every time for 10 time to be sure the system is free of air.
or when should I stop bleeding??

[oceansize]

oceansize
during the bleeding process do you bleed the actuator only for 10-20 time
or you do the 2 step bleed the actuator and bleed the clutch for 10-20 time
or you do the three steps ??
I am lost on this point ...

My issue was that I needed to orientate the pump to it's original position and then perform both the actuator and clutch bleed. I don't think bleeding the pump 10 or 20 times is necessary but then again my pump is rebuilt and is in optimal condition.

What issues are you having?

[Ahmed.Alghoul]

one more question
do you bleed the system for 10-20 and some guy's do it for 30 do you do it in one session that mean bleed after bleed or you make some time for the motor to rest between each bleed session.

[Ahmed.Alghoul]

oceansize
during the bleeding process do you bleed the actuator only for 10-20 time
or you do the 2 step bleed the actuator and bleed the clutch for 10-20 time
or you do the three steps ??
I am lost on this point ...

[Ahmed.Alghoul]

Thank you for what you wrote and sharing your experience.

[oceansize]

I'm assuming your SMG system was in good health at the time of relocation. Relocating your pump won't fix any existing problems you may have. If your pump is dropping out of gear before relocation there is a good chance it will after relocation. If you also did a pump rebuild the potential number of places where an issue can arise increases. Mainly because you didn't reassemble the pump correctly, your new seals/o-rings have failed/slipped, you over/under tightened the bolts holding the pump together introducing gear bind (5nm), or one of your new sensors isn't working (my new oil pressure sensor was defective out of the box, read -1 pressure in INPA).

Symptoms of air in the system (after bleeding):

You will likely have a buzzing noise (loud to really loud) emanating from the engine bay. This is air passing through the hydraulic lines. The buzzing in my case was even present during the clutch slave cylinder bleed process (oddly enough not during the actuator bleed). You can grab the yellow hydraulic line and feel the vibrations easily (you won't have to wonder if these are the vibrations I'm referencing here should this occur to you as they are very apparent).

FYI: There should be pump motor and mechanical noises during the bleed process otherwise the process should be fairly quiet, i.e no buzzing, whistling, or excessive vibrations in the lines.

Removing the air:

If the pump's accumulator is vertical then orientate the pump so that the accumulator is horizontal with the pump's red snap ring (where the CSL reservoir connects) pointing upwards. Disconnect the reservoir hose from the pump. When I disconnected the hose I saw three large air bubbles exit from the pump within a few seconds. At that point I had the bled the system approximately 10 times. Reconnect the CSL hose and bleed again. After successfully bleeding you can orientate the accumulator back to the vertical position.

Another method should air be trapped elsewhere in the system is to jack the rear end of the car up as high as you can (secure the front wheels so you don't roll) to allow any air to move out of the location where it is trapped. Perform a bleed while the rear of the car is elevated.

Lastly crack the line at the clutch slave cylinder to see if any air exits. You don't have to disconnect, just crack until fluid begins to seep freely.

Car ran great but then the buzzing noise and vibration in the lines returned:

Air is entering when the system is pressurizing and eventually the car will drop out of gear.

1. Check your hydraulic line connections
2. Make sure your CSL reservoir hose is seated correctly within the pump. There is a click or snap when fully seated.
3. Your o-rings inside the black plastic housing just below the red snap ring (collet) have possibly failed.

In my case air was entering where the CSL hose connects but it was fully seated. There are two o-rings just below the red snap ring (called a collet) inside the housing on the pump. You can't readily see these but if you take a flashlight and peer down the hole one is green and the other brown/black. The o-rings were not properly sealing, I guess due to age/use, and when pressurizing air was being sucked in and once pressure was built there was a very slight weeping around the red snap ring. Fortunately I had another plastic housing piece with the collet and o-rings so I replaced the one on the pump with this and my problem was resolved. I'm going to see if I can find the o-rings that reside inside the housing so that they can be replaced. You might ask why did your o-rings go bad during the relocation? I broke my original pump's black plastic housing (that contains the collet and o-rings) on disassembly thus I was using an unknown piece from a second pump I bought. Way it goes sometimes.

My pump pressure is rising and falling way too rapidly:

Air is in your system (see above fixes) or your clutch slave cylinder has gone bad. You can see my pump pressure rising and falling in this video. You might ask why did your clutch slave cylinder fail? My guess is that air in the lines caused a problem or just a coincidence. Crap happens.

My pump motor isn't working but it was prior to relocation:

Check your extended SMG wiring harness continuity. I received a defective wiring harness but fortunately I was able to fix myself. In my case the ground wire wasn't seated in the harness housing properly.

Other notes:

The Schwaben and Foxwell tools are good but I found INPA (with the full suite of SMG utilities) to be infinitely more useful as you can watch hydraulic pressure and temperature live (plus many other SMG and gearbox related items). INPA is very quick and easy to navigate as well. DIS is good but isn't required if you have the full suite of SMG utilities in INPA. INPA can do the accumulator test with the full suite. If you can't find a version of INPA with the full suite then get DIS mainly for the accumulator test but Schwaben offers this test as well.