catmanJim

My Feedback: (1)

I have 3 3w 75's and cant keep the muffler on, I tried red loctite, bronz hitemp gasket sealer and the bolts come off after about 8-9 flieghts, and I also cleaned the bolts with acetone I NEED HELP
Jim

airega1

My Feedback: (204)

Try external star washers and retighten while hot after a flight (IF POSSIBLE)

going vert

My Feedback: (11)

Had the same problem w/ my ZDZ. If the bolts that hold the muffler on are exposed (supersonic mufflers) you need to drill the heads of the bolts and wire tie them together (with metal wire) so they don't move. The hole I drilled was 3/32 I think. They don't move at all.

I was so frustrated that I almost JB welded them into place. Fortunately RC Showcase helped me with this solution and it's working great!

CDignition

My Feedback: (9)

Wire is the only way, Loctite melts with heat and does nothing

Geistware

My Feedback: (16)

Make sure that all surfaces are clean and then add gasket material to the mating surfaces and bolts. Install and let dry. Should work with no problems.

I would not use washers since the heat will cause any spring action to relax and allow the bolts to come loose.

H. Wayne S

My Feedback: (18)

I have had that problem in the past until I started adding a brace on the opposite side of the muffler. A short pc. of alum. welded or bolted on the muffler, then bolted to the engine mount bolt works wonders.

greenboot

My Feedback: (1)

I drilled out the aluminum threads and installed locking inserts on my ZDZ 80. It has not come loose since.

Tom

NavyE6FE

1. Don't do anything with it while its hot, thats a good way to strip threads.
2. Remove the gasket between the engine and muffler.
I used the red high strength permatex and no gasket of any kind, and have more than a dozen flights with my 3w-75 and the muffler is still tight and there is no leakage past the joint.

F4u5

My Feedback: (81)

Safety wire is best...as mentioned earlier.

Dave763

My Feedback: (1)

Drilling holes in the head of a cap screw is not so easy, but can be done. Center punch and drill press. Install the wire in an s configuration from bolt to bolt pulling clockwise, and twist the wire between the bolts. They can't loosen because the wire is pulling each bolt in the clockwise direction.
I did my share of safteywire, as a hyd./pnue. mechanic on F4J Phantoms. VMFA 251