[cribbj]

I'm preparing the tools & parts to pull and reseal my fuel tank in a couple of weeks, and need to purchase a couple of ring nut wrenches.

I have it on good authority that this FSS-01 Hill Engineering wrench: Ferrari Parts : 95975227 : 95975227 Fuel Sender Socket (FSS-01) works for the fuel level sensor.

Now I just need to source the wrench for the fuel pump covers. I've spoken with Hill Engineering, and they're on the case, but if anyone knows the diameter required, or a source for the wrench, it'd be helpful. I would think it must be in the range of 100-125mm, but unfortunately I'm in North Africa for another two weeks so I can't measure it myself.

[cribbj]

Hill Engineering have just advised they do not (yet) make this ring nut wrench. Would anyone know the diameter required, and/or where to source one (other than from Ferrari)?

[Granucci]

Originally Posted by cribbj

Hill Engineering have just advised they do not (yet) make this ring nut wrench. Would anyone know the diameter required, and/or where to source one (other than from Ferrari)?

I would hate to ask him, but Daniel or such at Ricambi might just give you that info regardless if they make a sale or not: They are very helpful, and a sponsor here.

I do not know those measurements, and it might take me a few days to find out.

sorry.

rik

[cribbj]

Thanks Rik, already been down that road with Daniel, and he steered me to the Hill fuel level sensor wrench on his site, but he didn't know what size the fuel pump covers were.

I'll just get it measured when I get home and post up the results. I'll probably go ahead and fabricate something and will keep it handy for "loan outs".

I'm thinking something similar to this Miller tool shouldn't be too hard to fab up:

[cribbj]

Posting these fuel pump cover & ring nut dimensions up for those who may want them in the future.

1st pic is a closeup of the cover & ring nut. The nut has 8 x 6mm holes on a 115mm BC (as close as I can measure with a set of calipers.

The 2nd pic is a sketch of the tool I'm going to get fabricated. Apologies for the art, but Excel is my default sketching too, and my artistic abilities are pretty bad. This will basically be a round aluminum plate with the center removed by water jetting. I'll have only 4 holes in it, instead of 8, and will tap them for M6 screws. 4 engaged holes should be plenty to remove the ring nut. The "X" bracket in the center will stand off the main ring probably an inch or so, just to clear the fittings, etc. on the fuel pump cover.

The maximum OD of the ring wrench can't exceed 132mm, which is the diameter machined into the fuel tank, and the ID shouldn't be any less than 97mm, as there are objects on the fuel pump cover that it'll foul.

I used 127mm for the OD, which happens to be a convenient size of disc stocked by McMaster-Carr.

We'll see how this fits, and I'll come back and correct any dimensions that weren't correct.

[cribbj]

Just as a followup for anyone who might need to do this in the future, below is a pic of how the fabricated ring nut wrench turned out.

The OD of 5" was spot on and it fits well in the fuel pump cover recess of the tank, and the round disc material sold by McMaster Carr here: McMaster-Carr worked well without having to modify the OD. The inner part was machined out to 100mm, and the 4 x M6 holes on a BC of 115mm were correct too.

It would have been better to draw this in CAD then have all the cutting done on a CNC waterjet, then tap the holes for the M6x1.0 threads. My piece was completely hand built and the tolerances are not that good. The M6 holes were drilled and tapped not quite square with the piece, and hence, two of the screws miss the holes in the ring nut. Hopefully it'll still work with only 2 pins.

[mbalk]

i bought a toyota spanner wrench. the circle is about 5" and the studs are 6 mm. it worked find. bought it online- cheap- worked great.. OTC 6613 - google it

[tazandjan]

John- Not sure if this works on the 550 or not. Even if it did, you saved $100 or so.

Ferrari 360, 575 Wrench AV1870 ( fuel tank) # 95971870 | eBay

[cribbj]

Thanks Taz, yes the 550 uses a different type of ring nut than the 575, but as Mbalk and Moorfan have found, the OTC adjustable pin spanner works fine, and can be used for different size ring nuts. Sure beats buying several ring nut sockets at $100 a pop.

Amazon.com: OTC 6613 Variable Pin Spanner Wrench: Automotive

[tazandjan]

John- Affirmative, that OTC looks like the trick, especially at half the price of a specialized wrench.

One of these days we need to look and see if the entire 550 fuel pump and ring nut assemblies can be replaced with the 575M parts. For about $800 worth of parts, someone would be set with no fiddling.