I bought a new fuel pump to replace what I assumed was a bad pump in my 98 Disco 1's tank because the PO had installed an in-line pump beside the fuel filter. I discovered that the tank pump had been removed, a fuel line run to the bottom of the pump unit with the old filter on it, and the pump unit stuck back in the tank loose and held down by a rag stuffed between it and the floor cover. The metal ring was there but not locked to the tank.

I have installed a new pump in the pump unit and the pump unit in the fuel tank, but I can't seem to get the locking ring started. I am sure the seal is in correctly and the pump unit is down in the tank as far as it goes with the white plastic tab on the right. The plastic threads in the ring are not broken and look OK, but it does not seem to go down far enough to get started on the threads on the tank.

The manual just says put it on and turn it and there is a you tube video that makes it look easy, but mine just doesn't want to start even with some petroleum jelly on it for lubrication. It is the metal BMW ring with a plastic liner with the threads.

Is there a secret to getting the ring started? Help!

 

Been there
It's just being a pain in the ***
You need an extra set of hands
If you can put a foot in the center, and put your weight on it, while someone taps the ring into place, it's much easier. I just went through this on my D2.
After doing many fuel pumps over the years, and with no issues, I was suprised how difficult my D2 was...even though it is just as straight forward.
I needed a friends help to get the lock ring back in.
Good luck with it.

 

I had to pull the pump unit again when the old soft 1/4" fuel line that I re-used came off the pump. I replaced it with new Gates 5/16 fuel line and new hose clamps. I used a long pry bar with an end pushed under the floor pan pushing down on a rock on top of the left side of the locking ring to hold it down while I tapped the ring around with a big screwdriver and mallet on the right side. The ring seemed to stay level but at about 1/4 turn it started to rotate the pump unit too so I stopped there. It's not what I would prefer, but it felt solid and I added a 1/2" thick block of wood and a square of carpet on top of the pump assembly so the cover plate will also hold it down "just in case".

The good news is that the new in-tank pump is working fine with no more whine and rattle from the in-line pump the PO added at the fuel filter, and I have a new fuel filter that fits in the ring clamp plus the "old" filter to bridge the gap where the PO had cut the fittings off original fuel lines.

 

There is a special way to refit the retaining ring, the arrows need to be aligned then downward pressure applied to the lock ring, one arrow on the ring and one arrow on the tank, then when you tighten the ring as the downward pressure is applied, The ring should stop at a marked point on the tank (not necessarily the start arrow) But this said if you have a plastic tank and/or a plastic locking ring they ARE warped due the ethanol in the fuel (petrol and diesel have at least 5%E) all manufacturers are aware of the problem and blame the fuel not the car so no re-recalls even though this is very dangerous as a fuel tank that can't be sealed is an accident waiting to happen, Fuel can makers changed the polyethylene they use 20 years back but the car makers have not done so for some reason. . . .be careful if you replace a pump/sender unit as resealing is almost impossible with plastic to plastic tank and rings. good luck and buy some blue hylomar to help with the fume tight seal you need !