EFII boost pump

[bearcatr2800]

To all wise and knowlegable RV builders, Mounting boost pump. Should I be using lock tight on all the bolts or are the lock washers good enough ? Bearcatr2800

 

[rmartingt]

As a general rule, I would use locknuts (AN365 or MS21042) instead of lock washers or locktite. I'd save locktite for blind holes or non-critical places where you have a regular hex nut for some reason.

 

[RV7ator]

A star washer between flat washer and bolt head are just fine. Look around the engine; that's about all there is.

John Siebold

 

[grayforge]

Lock washers are good when you can't use a locknut. IE, you shouldn't use nyloc nuts firewall forward. But for a boost pump on the aft side of the firewall, I'd think nylocs would be fine.

 

[rmartingt]

A star washer between flat washer and bolt head are just fine. Look around the engine; that's about all there is.

Lock washers are good when you can't use a locknut.

True, there are places with blind holes; a lockwasher can work there. But you shouldn't generally be using them when you can put a nut on the back. The airplanes I deal with professionally prohibit them unless a special exemption is received.

IE, you shouldn't use nyloc nuts firewall forward. But for a boost pump on the aft side of the firewall, I'd think nylocs would be fine.

Not all locknuts have nylon, and there are all-metal locknuts available that are suitable for use in the engine compartment.



However, the boost pump isn't in the engine compartment, nor should it be mounting to blind (tapped/threaded) holes. Either a locknut or a nutplate (which also has locking features) would be more appropriate.