Attempting to clean an e39 M5 ABS valve body

I’m using denatured alcohol to try to free up a stuck valve in my ABS hydraulic unit from an e39 M5. The port labeled HL (rear left) was fully clogged before I started this process. As you can see, it is now moving air (although not as much as the VL port (front left). It took about 15 minutes of persistent effort before it started to free up.

I didn't want to lug my compressor inside, so I'm just using my power bleeder with an air-hose at 20psi.

I would not recommend using anything other than denatured alcohol. Stay away from penetrating oils. I’m not even sure this is a good idea, as your brakes are really important. In fact, I didn't end up using this valve body - I purchased a second hand unit from ebay. This will serve as my emergency backup.

[owlclaw]

Saw your post with the explanation. I was able to open the valves with a magnet. You can hear each one opening and closing as the field nears. Amazing how there is no information on these "black boxes" for there being one in nearly every vehicle on the road?!

[medaliazouz]

I saw someone that he opened a stuck valve with the magnetic while heating it with hair dryer and it worked for him

[nikekira]

My 2016 renault master is having a problem with the back wheel. It keeps a bit of pressure, i will take out the pump and try to let the pistons move. I took an old pump and removed the solinoids put 12v to them...first test makes them click. What product would you use to clean them?Brake cleaner?

[shaheedpetersen]

I tried this with no luck. I got another unit from the junkyard but still the same. ports for the rear are shut.

[giberish]

Tempted to try this on my buick. Replaced all the brakelines after a line failed, now only getting pressure to the rear drums

[cyberkiller]

I think that what you were missing maybe is a bath of brake cleaner in a ultrasonic, that would fix it i think.