WOW it's tight in there. Is there any easy way to get that bottom nut off the solenoid or do you have to remove the heat shield?

Those old braided hoses did not want to budge from the solenoids at all either. Most of the DIY guides out there are for the 335i and I assume the e60 is easier to work on due to the M5 fitting a V10. Nope

 

Figured it out. Just had to move the vacuum canister out of the way ....however the new solenoids did not fix any of my problems

 

What's the problem? 30FF underboost code?

 

yes a progressively worse 30FF until I was getting 0 boost these last two weeks. GOOD NEWS is that the 2nd time I drove the car after replacing the solenoids, all the boost seemed to be back!!!! Weird that nothing happened right after...maybe I should have reset some adaptation values?

When I went for a spin this morning I was definitely hitting stock/at least 8 psi levels but did not want to push it yet. Solenoids seem to have fixed the problem

 

I just finished diagnosing a 30FF low boost code also. Both my solenoids were bad, and I had a collapsed vacuum line to the rear turbo. I found the trick for the bottom bolt was a 1/4" drive long socket, there is a recess in the top of block heat shield that allows you to get the socket in there. I did a full writeup on testing the components here: https://www.fightchaos.com/2020/09/b...nd-repair.html

While doing the troubleshooting, I also had a bad Pop-off valve on the charge air side, which I changed as well. Car is running like new now.