It's about a Ford, but trust me, it applies.

[Accelo]

My friend is rebuilding a 71-Mustang Convertible. Purchase a new power steering pump and hose.

The new flexible line did not screw into the pump fitting. He did some research and confirmed it was the correct flexible line. Figured it must be the pump. Owner called the pump reseller which put him in to communication with the pump rebuilder. The rebuilder told him he could remove the fitting from the back of the pump then the line would screw right into it. Attempted to unscrew the fitting from the pump. He couldn’t get the fitting out and ruined the fitting and broke his vice in the process. Then he brings the pump over to me to help remove the fitting. I figured he's already put as much torque on it as it could possibly need to come out. We then tore the pump apart to get more information on how it was assembled. Once we got it apart, we could see the fitting was welded in on the backside of the housing. No way was it removable! I also used thread gauges to inspect the TPI of the threads on the pump and hose. One was 18 TPI and the other was 22 TPI, so it would've worked even if the fitting did come out. Owner managed to get the reseller to replace the $175 pump because of the bad information he received. We attempted to modify the $40 line to fit the new pump. He managed to find a fitting that would convert a male flare fitting to a female flair at one of the local hydraulic hose outfits locally. We cut the end off of the tubing that was crimped onto the rubber hose. We were planning on sliding the new fitting onto the tubing and then re-flare the tubing to fit the pump fitting. We cut it off the flair on the end then found that the replacement Ferrell fitting would not go on the tube. It turned out to be 10 mm tubing shoved into what was listed as 3/8 hose, USA. That information was printed on the outside of black flexible hose.
We thought about drilling out the fitting .015 of an inch to the 10 mm size. But that wouldn't work because we didn't have metric flaring capabilities. Owner went on the hunt for the correct hose. Finally identified the fact Ford had changed the line type on the convertible only. Ordered a new hose it was guaranteed to fit. I just got done looking at it. And it is not correct either. It has hydraulic threads on the end and the pump is set up for a flared fitting. It is also built different so it’s impossible to flair the end. He's into this over a week and still doesn't have a simple hose that will connect the pump to the power steering box. I am sure the firs hose was made in China with a mismatch of metric and imperial parts. It's difficult enough to rebuild these old cars without that kind of crap parts. Not to mention the generic databases they are using to identify the part.
Some advice;
Make no assumptions on fitment. Measure everything and every part. Do not wait to assemble parts as any chance of getting a satisfactory resolution is out the window after a couple weeks.
I outlined what has transpired so far. Still hoping to find the correct hose, or make one, that will function. Wish I had pictures but I do not.
Isn't rebuilding old cars fun?
Cheers.