Anyone know how the brew water fitting at the HX block is built? I have a leak at the point shown in the photo. Do I need to pull the HX apart to address this leak?

I don't think you do, but I can't say for sure. Apparently, I don't have a picture of this part disassembled.

If this is a vintage machine, it might be telling you that it's time to show it some love and attention. These are easy machines to descale and fit with new gaskets and seals.

The factory used something similar to Loctite to seal the thread. The original color is red, I think. I have successfully used Loctite 242 (blue) because that's what I have at home. Here's a thread discussing thread sealer:

"Food-Safe" Loctite thread sealer

If you search Maximatic Restoration you'll come up with a thread that includes Sherman Chong's
detailed instructions for disassembling the HX. It's in the post linked below.

Pasquini Livietta (Olympia Maximatic) restoration

The post linked below in the same thread has photos of my disassembling the HX.

Pasquini Livietta (Olympia Maximatic) restoration

In looking at one of the pics in the link that Gary provided, here is that fitting disassembled:



The surfaces which seal are indicated by my red circles, i.e., while some sealant may be on the threading, that is NOT the primary surface. The two brass surfaces should be clean and a seal is typically achieved by using one or more copper washers such that the tube and nut combo is properly positioned. Early production models of the Rancilio Silvia used the same washer combination to effect a seal at the water inlet elbow at the boiler as shown below.



I do know that Espresso Parts sells Teflon seals in various sizes to serve the same purpose.

Thank you for the thorough insights and helpful photos HBer's. I really appreciate the help. If I understand the info it appears that that fitting IS attached via threading and CAN be adjusted/removed ( although I got a PM from Eric indicating he felt perhaps it was a permanent and unremovable item). But then Eric's helpful post seems in the end to support removable/threaded. I'm going to move forward as if it's threaded and I can tighten this fitting for the moment and see if it at least reduces the leak. With the intent to replace the washers and utilize food grade loctite in the threading. Will report back with photos and results.

I would NOT recommend trying to tighten the fitting/tubing as they are a unit. The hex portion of the fitting looks as though it is flush with that top plate.

I would remove the fitting/tube and install one or more sealing washers or the Teflon washers I mentioned previously. After fully tightening, the tube must be properly orientated. I would NOT apply any sealant to the threading because that is not/should not be the sealing mechanism.

Keep in mind that this is coming from someone who has not seen the insides of one of these machines.

Food grade Loctite is expensive and not necessary. If you must use a thread locker or sealer, apply it so it doesn't contact the stream of water or steam.

Thanks Gary
I'll skip the loctite for now. And Eric...I think I understand you now: you'd recommend that I could remove the fitting entirely (by pulling off the hx block) and then replace Teflon sealer rings inside the brew water exit coupling and be careful that at full tightness the tube falls into proper alignment. But simply trying to tighten in place as it is would be a mistake.

Brian

But simply trying to tighten in place as it is would be a mistake.

That's correct.

But, keep in mind that I do not know how this sealing arrangement was originally configured, i.e. copper washers, Teflon washers, no washers, whatever.

What I do know is that this is no trivial exercise unless you are on the assembly line with complete freedom of movement and then it is "duck soup". I also know that the hex "nut" should NOT "bottom out" against the face.