Nylon Lock Nuts And Fuel

[cv2065]

Anyone know if nylon lock nuts are fuel resistant? My Pro M Racing fuel pump is secured in the housing by four 6-32 screws and thought I’d put a lock nut on them to ensure they don’t come lose from pump vibration. Some sources say they are but wasn’t 100%.

[Papa]

I'd recommend using a deformed thread lock nut like these: https://www.mcmaster.com/90045a010

No concerns with a bad reaction to whatever the particular "nylon" locking nut compound may actually be? With all the cheap knockoff stuff on the market today, who knows what that locking material really is?

[GFX2043mtu]

Either use blue loctite or conical washers. Stover nuts are great but on 6-32 studs you may have issues. Nylock nuts should use a nylon insert, how ever not all of them do. If they use nylon as they should then yes it is fuel comparable. Just be forewarned some cheep hardware doest use nylon.

[cv2065]

Thanks guys. I've already put a little blue loctite on the threads and tightened them up pretty good, but very little of the threads are actually engaging anything. I'll stop by Ace tomorrow and see if they carry the Hillman nylon lock nuts. I'm pretty confident those are good to go.

[Connedale]

It is my understanding that nylons in general are not affected by gas. I had a brief stint designing chainsaws, which are almost entirely made of glass filled nylon. As you know, the oil and gas tanks are integrated in the nylon chainsaw chassis.

[edwardb]

Thanks guys. I've already put a little blue loctite on the threads and tightened them up pretty good, but very little of the threads are actually engaging anything. I'll stop by Ace tomorrow and see if they carry the Hillman nylon lock nuts. I'm pretty confident those are good to go.

For the record, you shouldn't use blue Loctite with nylon lock nuts. It breaks down the nylon. Loctite has this information in their instructions as I recall. I realize in this thread you're questioning the use of nylon lock nuts for this application. But just wanted to point that out.

For the application in question, I don't use anything on those particular screws and just make sure they're tightened properly. Never had any issues. If you want to though, blue Loctite wouldn't hurt anything. Supposedly it is tolerant to gasoline.

[cv2065]

Ended up using the best of both worlds. A locking nut with built in star washer and blue loctite.

[Connedale]

I hate to break it to you, but star washers are at the bottom of anti-vibration technology. Split washers do nothing as well. If you have good torque and loctite though, you are good to go.

[cv2065]

I hate to break it to you, but star washers are at the bottom of anti-vibration technology. Split washers do nothing as well. If you have good torque and loctite though, you are good to go.

Thanks. I figured with loctite, they should serve their purpose. Just have to watch the torque on these small 6-32 screws.