Racor bowl fasteners 500FG obsolete model

[paulga]

yes, tpi.

as I said, mine is older than dirt. Yours may be different. Easy enough to check.

i have no clue how old are the 3 racors on my boat

all 3 are obsolete 500FG where the bracket work as the bowl ring.

the 2 engine racors have the first type drain fitting (rk 11780, see below) while the gen racor has the 2nd type drain (rk 30488)

the 2 engine racors have the Phillips head machine screw (part number unknown) while the gen racor has the hex head machine screws (rk 15081)





adding a photo taken 202311

 

[jleonard]

i'm thinking if I could modify the screw heads:

drill a hole in a scrap wood, put the screw all the way in, use a dremel tool with cutting piece ez456 (blade thick 0.045in) to cut a slot on the middle of the head, so I could drive it using a flathead

That is what I would do.
Also, you only need 3 threads for good strength.

 

[paulga]

That is what I would do.
Also, you only need 3 threads for good strength.

the screw has to go all the way to the end to really engage the top section to the bracket. the gap is still large after 3 threads

the concern is the rotary tool would make a V groove that still tend to slip rather than a U shape |_| . does it work if you could weld a hex head on top of the phillips head?

 

[TJM]

Welding on the top of a fastener will "severely" soften the screw under the head. SS melts at 2600°F. The screw head may break off upon tightening. Why cant you just purchase the correct screw ? I dont understand why the head type is so important.

 

[paulga]

Welding on the top of a fastener will "severely" soften the screw under the head. SS melts at 2600°F. The screw head may break off upon tightening. Why cant you just purchase the correct screw ? I dont understand why the head type is so important.

the existing ones are the "correct" screws. you see the head of two of the screws are stripped a bit

 

[jleonard]

the screw has to go all the way to the end to really engage the top section to the bracket. the gap is still large after 3 threads

the concern is the rotary tool would make a V groove that still tend to slip rather than a U shape |_| . does it work if you could weld a hex head on top of the phillips head?

If the gap is there after 3 threads you could shorten the screw accordingly

 

[luna]

i have no clue how old are the 3 racors on my boat

all 3 are obsolete 500FG where the bracket work as the bowl ring.


View attachment 146711

If you chose to believe Racor, according to the Part No. list you provided earlier, yours are made after Feb. 1996 as they appear to have a 1 1/4" square boss (a thickening of the body) at the fuel ports. Measure it to be sure.

That also means that P/N. RK15081 (the hex headed fasteners that you already bought) are the correct fasteners.

If the reason you want to remove the existing fasteners is a need to rebuild or reseal the filter housing, then take the thing apart so you can have a good look at the condition of the threaded bores and recondition them if required to accept the new fasteners.

As you have a diagram and some kind of assembly instructions, this should not be hard to do at all.

Cutting a slot in or welding a new head on the existing damaged fasteners is about the last thing I would do.

Finally, and as a rule of thumb, using carbon steel materials, the threaded length required to develop a full strength connection is equal to the bolt diameter. Ever notice that a standard nut is the same thickness as the bolt diameter?
In the case of a #10-24 steel fastener that would mean an engagement of 0.190" or about 5 threads develops full capacity.
A stainless steel fastener into aluminum, (depending on the alloy) means roughly double the engagement length, which is why these fasteners are 7/8" long.

Prudent connection design always allows to achieve full capacity even though you may not torque it up that high. A layman using only 3 threads runs a high risk of pulling the threads out of the filter body.

 

[SteveK]

If the gap is there after 3 threads you could shorten the screw accordingly

J. are you and he talking about the same 3 threads. If the screw bottoms out when fully tightened and not all the way in then shorten. A one inch or 7/8" has more than three threads. Are you saying only 3 from the top of the hole are needed to lock it down, he is thinking screwed in three threads leaves more than half the screw out of the hole.

 

[jleonard]

J. are you and he talking about the same 3 threads. If the screw bottoms out when fully tightened and not all the way in then shorten. A one inch or 7/8" has more than three threads. Are you saying only 3 from the top of the hole are needed to lock it down, he is thinking screwed in three threads leaves more than half the screw out of the hole.

Im sating that a fastener that has 3 complete revolutions engaged will be sufficient.

 

[paulga]

Im sating that a fastener that has 3 complete revolutions engaged will be sufficient.

this is the screw hole:

the screw really needs to go all the way in to engage the top section

understood the screws are probably already tightened enough to stop a leak, but even a slow leak is not desirable.

 

[paulga]

The gen racor has a square boss in both ports, they measure close to 1.25'

The bowl fasteners are the hex head type





But the boss on the engine racor is a rectangle shape, each dimension is less than 1.25'





Does this mean the engine racors were made before 1996?

If you chose to believe Racor, according to the Part No. list you provided earlier, yours are made after Feb. 1996 as they appear to have a 1 1/4" square boss (a thickening of the body) at the fuel ports. Measure it to be sure.

That also means that P/N. RK15081 (the hex headed fasteners that you already bought) are the correct fasteners.

If the reason you want to remove the existing fasteners is a need to rebuild or reseal the filter housing, then take the thing apart so you can have a good look at the condition of the threaded bores and recondition them if required to accept the new fasteners.

As you have a diagram and some kind of assembly instructions, this should not be hard to do at all.

Cutting a slot in or welding a new head on the existing damaged fasteners is about the last thing I would do.

Finally, and as a rule of thumb, using carbon steel materials, the threaded length required to develop a full strength connection is equal to the bolt diameter. Ever notice that a standard nut is the same thickness as the bolt diameter?
In the case of a #10-24 steel fastener that would mean an engagement of 0.190" or about 5 threads develops full capacity.
A stainless steel fastener into aluminum, (depending on the alloy) means roughly double the engagement length, which is why these fasteners are 7/8" long.

Prudent connection design always allows to achieve full capacity even though you may not torque it up that high. A layman using only 3 threads runs a high risk of pulling the threads out of the filter body.

 

[ranger58sb]

Does this mean the engine racors were made before 1996?

You may have done this part already:

How old is your boat? If the Racors are original to the boat, they'd likely be similar vintage...

-Chris

 

[paulga]

You may have done this part already:

How old is your boat? If the Racors are original to the boat, they'd likely be similar vintage...

-Chris

37 years
i have no clue if the racors are original

 

[ranger58sb]

37 years
i have no clue if the racors are original

If that particular Racor model was made 37 years ago, do you have reason to believe they're not original to the boat?

-Chris

 

[paulga]

If that particular Racor model was made 37 years ago, do you have reason to believe they're not original to the boat?

-Chris

Even if the racors are truly 37 years old, they are still working. The bowl fasteners are not a strong cause to replace them.