W209 CLK A/C condenser seized

[IanW]

Your advice sought...
I've traced an AC leak to the condenser. The system is now empty, so I'm replacing the condenser/dryer. Unfortunately, I've hit a snag. While almost every nut & bolt has eventually decided to co-operate, the final connection of the refrigerant pipes into the base of the condenser/dryer refuses to come apart. The nut (item 110 in the diagram) came off easily enough, but the clamping block (next to 315) remains stubbornly locked onto the thread of the stud welded into the condenser. I suspect it's because the stud looks like steel, and the clamp is aluminium. I've tried the usual assortment of release agents (Crack-It, Freeze-Yer-Nuts-Off, Penetrating oil etc) to no effect. I'm unwilling to try the blowtorch just yet as the area is now covered in light oil and aerosol propellant, and is very close to plastic shrouds and the fan control module. Brute force is out due to the lack of space & the delicate nature of the condenser.

Anyone have any suggestions for undoing 18 years of aluminium corroding into steel?

It's particularly frustrating as it appears the MB changed the design at some point to permit the AC condenser to be replaced from below without having to dismantle the front end.

thanks,
Ian.

 

[Dodipops]

I’ve had to bring the condenser block from the pipes in the past. I used a belt sander but some sort of dremmel attachment might work??

Otherwise a bit of gentle heat and make sure you replace the o rings in there

Does the stud not unscrew as well? (Female torx)
Allowing a bit of twisting motion on the block

 

[Trickythemerc]

I bit the bullet and dropped the front end off when I did mine and to be honest the difference between taking the slam panel out and dropping the bumper, is not such a big deal. Bear in mind that the condensor is scrap, so you could chop the connector block out to give more room to tackle the issue.

 

[IanW]

Thank you. I think you're right - I need to bite the bullet & cut the connector block away from the condenser. I didn't want to open up the system to atmosphere until I was ready to install the new part, but I think that's a none starter. It's time to reach for the Dremel & blowtorch.

I bit the bullet and dropped the front end off when I did mine

A combination of rusty fasteners & the damage caused by a Volvo make that v. difficult. A definite last resort. Though if I had to, I'd splash out on a replacement bumper & wing. Luckily, black is a common colour for CLKs.

Does the stud not unscrew as well? (Female torx)

Hard to say, that's one of the items that's rusted solid. I'll have a look at the new condenser to check.

Once the weather improves, I'll give it another go.

Thanks,
Ian.