Sugar Bear, after much researching on Brake hose from ASR Charging pump to Hydraulic unit Part number: A1244280735, very few websites carrying mercedes Parts have it in stock. Based on my experiences shopping mercedes parts online, very few of them carry the part in stock.

I am very intrigue by your idea of hard line using ni-cop tubing. Upon further research, I found quite a few options available:

Assuming the tubing is 3/16 inch along with brake line tube nuts 3/16 inch (black oxide coated steel brake line nuts), Here is what I found:

Nickel/Copper Brake Line Tubing Nickel-Copper Brake Line
Brake Line Flare Tool Kit

3/16 line - buy the whole roll of cunifer line - but will need a bubble flaring tool (dont do the half double) and metric bubble nuts to go with it. 3/16 line - buy the whole roll of cunifer line - but will need a bubble flaring tool (dont do the half double) and metric bubble nuts to go with it.



Flaring brake lines ensures a leak-proof connection without extra materials or sealants. If the brake lines aren't properly flared, you can lose fluid that will cause your brakes to fail. This article will explain how to flare brake lines using single and double flares.https://www.wikihow.com/Flare-Brake-Lines

What about this Brake line Flaring Tool, Double Flaring Tool kit Copper Aluminum Soft Steel Brake:
https://www.ebay.com/itm/294662315881?hash=item449b3e1f69:gkQAAOSw3ANfCN5r

Another is an In-Line Flaring Tool Kit, Low Profile | Brake Repair/Brake Flaring Tool due to the brake line is already inside the car and easier to do the job.
Details about Tools 3/16" 4.75 mm Single & Double In-Line Manual Flaring Tool Kit
Low-Profile Design Allows for Use On or Off the Vehicle
Designed to Be Used with a Ratchet to Make Flares Easier
In-Line Design Makes a More Accurate Flare
Double Clamp and Hex Screw Keeps Tubing Locked Tightly in Position
For Use on Thin-Walled Steel and Copper Tubing
Works for Double Flares on 3/16" and 4. 75 mm Tubing

In-Line Flaring Tool enables the user to flare copper or soft steel tubing in tight spaces with its low-profile design. This new patented flaring tool design makes perfect single or double flares easily. The double clamp and hex body keeps tube from slipping, keeps flares centered, and makes the job of flaring easier. Superior to bar-type flaring tools.

The only drawback is only applies to 3/16 inch and 4. 75 mm Tubing
https://www.ebay.com/itm/393572105210?epid=1555412821&_trkparms=ispr%3D1&hash=item5ba2b9bbfa:g:ajEAAOSwwzthQMj2&amdata=enc%3AAQAGAAACoPYe5NmHp%252B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSU8qUIAeVPdz29zRlje3Lg68Ua0ZFaBQ HejjLYaaSuG2suesMIuhudEuqmdd0syO3s0nuSCst2DKtJf7FNst0W%252F%252Fd%252FP9YoRXqZwn28XQKHSMcm81fZex3mMw 7EXTHJUdekuP7O7pNRZlUJOvm1GWJkKL%252Bn%252BIHkUhSlQ%252BGtorbVvE6uxTtAD3LZvZybbPp9ZHuLC3VPGAtVtejz9t O%252FmVxhW2vhI4qTwcyjC3uTYka13K%252FC6JUUeD781BM24w85k7Lw6up%252BNSV7vXIbes91LNsmAoMbVB28KlBJQzTecB G7iLYEHbJyemLmGq%252B45NBCpA2SjY65Ef%252BErmtXDckLJId1jJnwa45frc8iJzll4lrj8ol8X6uURNNdb920FIGAA7emXF a9uqvUWwqAJY%252F9CCa3qePk4r2rYBjk%252FRArpwNTcLliH%252BWx5DFNN%252BGjDaCgwFopheNS%252FCYdxHqplRd6fm ZTsGLIWIlXGDupWjVPxFnsmgv85qfwBJsadI2Kjwa7ZGIvp%252BNsc12vzESVadUoS1FziRsauGSNUdKiyp4Aow0QiDblSgD%25 2Foyts%252By9iwCDleBDjMxIi0NWDKL5lJlLqkD2KAx3Lr6SnIrY2cbnPL7jDI9nb05dLykc7Zi9jmoMibG5YC3lyBrDyFQ01l7 alqx6xjZFbr9Rv77PPBWQwbMO4RTEoDuL%252BTxY1ObunOPOfTAnBX1RRVPeRZqeTFbg%252FpS73diu1AgHP%252Ft8QhRWZAZ 0ebh1ffJRxUgD1Vw3VzcKCnurzmJBesoCdwZ0ponqboBuKDLVpk3FE8WaeeBQGhij1d5rRvh%252BZsasNaHPkQgrG2O5QFA5ssd BplIE3oAFP0J8CQ%253D%253D%7Cclp%3A2334524%7Ctkp%3ABFBMwobohMNf
https://www.ebay.com/itm/174586557118?hash=item28a62b72be:g:7awAAOSw6hhf9yz3

Steel Tube Nut, M10 by 1.0 Bubble, 3/16 Inch?

https://www.amazon.com/OEMTOOLS-24364-Line-Flaring-Tool/dp/B01DO9142G/ref=sr_1_12?crid=FOSSSQ03NT19&keywords=on-car+brake+line+flaring+tool&pd_rd_r=7071b083-69e6-4861-b7d9-a01bc60a460e&pd_rd_w=WCZnr&pd_rd_wg=tmR8m&pf_rd_p=ce8592e7-3f5d-4c47-8fd0-5053ffa3307b&pf_rd_r=MTWJY43GQ3T0TF6RV2RD&pid=eHNwVSD&qid=1641058976&sprefix=on-car+brake+line+flaring+tool%2Caps%2C121&sr=1-12&vehicle=1994-63-830-20---6-7-21530--1-2-2108--&vehicleName=1994+Mercedes-Benz+E320

Bubble flaring tool kit 3/16 in. tube size to M10 - 1.0 thread bubble flare European steel tube nut

The above options are just a few. Sugar Bear, what do you think would be the best option for me considering the stripped nut but the brake line is ok? Perhaps just use the same brake line as it is already there and put more pressure on the stripped nut to turn inside the ASR pump hole?


Any comments/feedback/advice is greatly appreciated. Thanks to all for reading this post.