Fuel pump lock ring size.

[HiFiMerc]

Suppose this is the right sub forum to post this question in.

Shop told me I need to replace the fuel pump sending unit assembly as well, the old one is crusty and the lines won't budge. It's wasted. RockAuto has just one sending unit, and makes no mention of lock ring size.

So far, my research comes up with three different sizes for the lock ring, 5" inside diameter, 4.625" inside diameter. And Summit shows a 3.5" diameter. That one seems a little small.

Any way to tell which one I need (without crawling under the car) so I can order the proper one? Or even if the Rock one is the right one?

[t65neon5]

ummmm....for which car?

[HiFiMerc]

Sorry.

The '90 MGM.

[t65neon5]

ok here is what I found......if I look up a 90 grand marquis I get craploads of different lock rings, however, when I look up a 90 ltd crown vic with a 5.0, it only list one, in a precision the part # is Z12003 , for a dorman , the part # is 55813(and is listed as a help/motormite part)....airtex part # is LR2001

[HiFiMerc]

The Dorman 55813 is listed on Rock as 5" inside diameter.

Rockauto also shows only one "Fuel tank sending unit lock ring" for the LTD, versus two for the Merc.
This changes if you click "Fuel tank lock ring"

I think. This thing is all over the map


The sending unit (of which they show only one) has a '90 part number, But makes no mention of size.

[t65neon5]

yeah...I tried looking at fuel tanks , and sending units, and could find no demensions pertaining to the lock ring either, also, I used the look up at Oreillyauto.com. (mostly because I am very familiar with that website, seeing how I use it everyday at work because I work there...lol)...I would trust the spectra part the most, they seem to be more accurate than dorman, I have no experience with the precision fuel stuff, its made by federal mogul , the same people that make precision u-joints and wheel bearings, and moog chassis and steering parts, but the precision fuel system stuff is new to me(we just added that line recently), so I don't know how accurate their listing is

[t65neon5]

dam I forgot the spectra part#....LO013....I went to spectras website....and they list the lo013 as the lock ring included with the 90 grand marquis sedan fuel tank (4 5/8 dia.) ....so that's what I would try (actually, if you use a local parts house, I would have them order/and or research this also, if I was at work I could do a better job, but I am limited as to what I can do at home without spending massive amouts of time searching google for information)

[amoss2]

junkyard or radiator shop ?

[HiFiMerc]

Everything in the yards here is wasted. And I'm not laying under junkyard cars. Some of them are propped up there quite precariously. Nothing under that car is worth it falling on me.

Anyway, been considering getting this stuff locally, as I'm not in the mood to deal with returning items and waiting for the right ones if they're not right. I got about 3 weeks to get this car ready for the highways.

[BerniniCaCO3]

I thought my '90 had closer to a mini 3.5" lock ring size. I had a two-ended tool that had the two larger sizes on it (for ford fuel tanks).
Now that I remember... I got away without touching the dang thing. I needed a new level sending unit anyway, and I got a new tank, so I just left the old one in the old tank and tossed them together.

I did have to remove the lock ring to the pump to reuse some parts there. What I did was get a strong rust dissolver from the hardware store and let it soak in there overnight! It was still a near thing, not to simply tear off the 3 frail and rusty tabs of the lock ring, but it came free.

I wish they'd just had 10 little screws around instead of a lock ring. I've seen it on other cars, I know it's possible!

[HiFiMerc]

Figured I'd post this here instead of making a new thread.

Might have a problem. Here is the Walbro pump, with the aftermarket sending unit. See anything wrong? What to do now?



Edit:
How about I just make a couple cuts, then bend it in so it wraps around the pump? Then put a stainless steel hose clamp around it for good measure?

Maybe it's the wrong sending unit?

[sly]

cut some fuel resistant hose that will fit around the pump to work as a sound deadener and then radiator hose clamp it to the bracket. dremel some slots in the back plate to make it a more secure fit.

aka redneck engineer it and go.

[HiFiMerc]

Hmmmm. This might be the missing part.


Safe to assume the old pump will have that insulator thing? If so, the shop can just switch it out. I'm starting to want to do this job myself, but....nah. Who am I kidding?

[HiFiMerc]

I'm a dumbass. The insulator was still in the box. See what happens when you don't just dump the contents of a box out onto the bench.

[sly]

at least you found it.