Stihl BR 800 MUFFLER ISSUES

[StarTech]

Plus many of Stihl screws are self tappers. Once the hole is initially tap reinstalling screws are a little different. At first you turn them as if they are being removed until they jump the thread and drop into place. This prevents cutting new threads. This is especially important on self tapping plastite screws. Otherwise you will after multiple time have no material for threads left. the you either install a Helicoil or tap for a larger screw.

 

[HC6543]

You might need to brush up on HOW to use thread locker friend. You don't just glob it on, over torque the screw with your impact gun and call it good. Then come on here whining about how your muffkin fell off.

1.Over torquing CAN warp said muffler so it MIGHT fall off doing this. Was yours rusted out like the one in the video MPARR posted? If so DUH!!!!
2.You need to CLEAN the screw and engine block threads PRIOR to adding the locking agent. Maybe a tap and chase some threads? Little brake cleaner to CLEAN the threads. Then........
3.Permatex makes a primer we are all supposed to be using before applying the locking agent. I don't use it either. BUT, if you are using red and it falls off......
4.We must SHAKE the thread locker prior to using as the label states. Also thread locker has a shelf life. Also some brands like HoboFreight or Loc-tite don't make good locking compound IMO.
5.One drop of locking agent per screw and screw hole threads is ALL you need. Torque to factory specs. Blue should be all you need. If red was installed correctly, it will/can brake screws, ratchets and sockets.

Here is a video on the primer and the locker.

The threaded bolts were brand new, the tap was enough to freshen the threads, all was cleaned with carburetor cleaner, dried blown off. I do this work for my Sons company, I am 75 years old. I have extensive training on servicing weapons from my time as a Petty officer in the Navy (E5), removing a rebuilding M61a1 6 barrel 20 mm cannons, totally stripping down. I am retired as an Electrical Contractor with 45 years experience. I have used thread lock many times

You might need to brush up on HOW to use thread locker friend. You don't just glob it on, over torque the screw with your impact gun and call it good. Then come on here whining about how your muffkin fell off.

1.Over torquing CAN warp said muffler so it MIGHT fall off doing this. Was yours rusted out like the one in the video MPARR posted? If so DUH!!!!
2.You need to CLEAN the screw and engine block threads PRIOR to adding the locking agent. Maybe a tap and chase some threads? Little brake cleaner to CLEAN the threads. Then........
3.Permatex makes a primer we are all supposed to be using before applying the locking agent. I don't use it either. BUT, if you are using red and it falls off......
4.We must SHAKE the thread locker prior to using as the label states. Also thread locker has a shelf life. Also some brands like HoboFreight or Loc-tite don't make good locking compound IMO.
5.One drop of locking agent per screw and screw hole threads is ALL you need. Torque to factory specs. Blue should be all you need. If red was installed ‘correctly, it will/can brake screws, ratchets and sockets.

Here is a video on the primer

NEW BOLTS NEW MUFFLER NEW GASKET

Cleaned all parts with carburetor cleaner, dried, blown off, applied PERMATEX HIGH STRENGTH THREADLOCKER RED 27100.
FOLLOWED ALL INSTRUCTIONS, TORQUE VALUES; BECOMES LOOSE WITHIN FIRST HOUR OF OPERATION. YES I shook the tube, brand new product, less than 1 week old. By the way Condescension is of no value, in a “learning atmosphere”, ( purchased read and followed instructions on package); I was thinking that this might be a venue providing help and guidance. By the way, you might want to look at the BR800 MUFFLER, regarding over torquing/warping, it also requires an exhaust gasket, over torquing might strip threads or break the cheap metal. Two drops on each thread, not one. ALLOWED TO CURE APX. 40 HOURS, before use.
I tried using blue THREADLOCKER BY PERMATEX, did not work. I figured with all new parts again the red was called for. Screws vibrated out. STIHL has put out a flawed product, first muffler was about $80. Plus now you can get exactly the same thing for about $20. I wonder why the price drop is so great. I am not whining, by the way, just looking for intelligent discussion and recommendations.

 

[slomo]

Ok your next step is safety wire on the screws.

 

[MParr]

The threaded bolts were brand new, the tap was enough to freshen the threads, all was cleaned with carburetor cleaner, dried blown off. I do this work for my Sons company, I am 75 years old. I have extensive training on servicing weapons from my time as a Petty officer in the Navy (E5), removing a rebuilding M61a1 6 barrel 20 mm cannons, totally stripping down. I am retired as an Electrical Contractor with 45 years experience. I have used thread lock many times



Cleaned all parts with carburetor cleaner, dried, blown off, applied PERMATEX HIGH STRENGTH THREADLOCKER RED 27100.
FOLLOWED ALL INSTRUCTIONS, TORQUE VALUES; BECOMES LOOSE WITHIN FIRST HOUR OF OPERATION. YES I shook the tube, brand new product, less than 1 week old. By the way Condescension is of no value, in a “learning atmosphere”, ( purchased read and followed instructions on package); I was thinking that this might be a venue providing help and guidance. By the way, you might want to look at the BR800 MUFFLER, regarding over torquing/warping, it also requires an exhaust gasket, over torquing might strip threads or break the cheap metal. Two drops on each thread, not one. ALLOWED TO CURE APX. 40 HOURS, before use.
I tried using blue THREADLOCKER BY PERMATEX, did not work. I figured with all new parts again the red was called for. Screws vibrated out. STIHL has put out a flawed product, first muffler was about $80. Plus now you can get exactly the same thing for about $20. I wonder why the price drop is so great. I am not whining, by the way, just looking for intelligent discussion and recommendations.

Locktite 272 is probably the only one that will hold up to the engine heat.
Most threadlockers require heating to extract the fastener.

LOCTITE® 272

Red, high-strength, high-temperature resistant threadlocker

next.henkel-adhesives.com

 

[sgkent]

I have 4 BR 800 TWO OF WITCH ARE SIDE PULLS FOR CONNIVENCE. THE MUFFLERS WILL NOT STAY TIGHT.
VALVES ARE ADJUSTED, SPARK IS GREAT CORRECT GAP, NEW PLUGS, AIR FILTER, NEW FUEL FILTER. IDLES FINE, GOES TO FULL POWER. EVERYONE OF THEM THE MUFFLERS FELL OFF. MUFFLERS RUINED REPLACED WITH NEW AND GASKET. USED RED THREAD LOCK; STILL LOOSEN BEFORE ONE PROPERTY IS COMPLETED. THINKING OF MAKING A WIND CHIME OUT OF MUFFLERS. PURCHASED THE ECHO BRAND, NO SERVICE ISSUES, WEIGHT IS HEAVIER.
RETAPPED HOLES FOR MUFFLER ON STIHL NEW METRIC SCREWS, RED THREAD LOCK, FALLS OFF? Seems like STIHL products are not what they use to be. Have a pallet full of warnout STIHL blowers, that earned there keep. I have two dozen STIHL stick pieces. Any ideas other than never buy STIHL again?

Why are you shouting at everyone?

 

[StarTech]

Why are you shouting at everyone?

Maybe taking someone else's social media habit. All caps is considered screaming.

When you re-tap did you go to the next size [M6-1.00] with the 10mm head? The original screws were M5-0.80 with a 8.5mm head.

Or maybe use Helicoil thread lock inserts. These are designed to basically permanently lock the screws in place. There is no easy removing later.

 

[Tiger Small Engine]

The threaded bolts were brand new, the tap was enough to freshen the threads, all was cleaned with carburetor cleaner, dried blown off. I do this work for my Sons company, I am 75 years old. I have extensive training on servicing weapons from my time as a Petty officer in the Navy (E5), removing a rebuilding M61a1 6 barrel 20 mm cannons, totally stripping down. I am retired as an Electrical Contractor with 45 years experience. I have used thread lock many times



Cleaned all parts with carburetor cleaner, dried, blown off, applied PERMATEX HIGH STRENGTH THREADLOCKER RED 27100.
FOLLOWED ALL INSTRUCTIONS, TORQUE VALUES; BECOMES LOOSE WITHIN FIRST HOUR OF OPERATION. YES I shook the tube, brand new product, less than 1 week old. By the way Condescension is of no value, in a “learning atmosphere”, ( purchased read and followed instructions on package); I was thinking that this might be a venue providing help and guidance. By the way, you might want to look at the BR800 MUFFLER, regarding over torquing/warping, it also requires an exhaust gasket, over torquing might strip threads or break the cheap metal. Two drops on each thread, not one. ALLOWED TO CURE APX. 40 HOURS, before use.
I tried using blue THREADLOCKER BY PERMATEX, did not work. I figured with all new parts again the red was called for. Screws vibrated out. STIHL has put out a flawed product, first muffler was about $80. Plus now you can get exactly the same thing for about $20. I wonder why the price drop is so great. I am not whining, by the way, just looking for intelligent discussion and recommendations.

So you have experienced a problem with the Stihl BR800 blower regarding the muffler bolts not staying tight.
You not willing to leave it at the dealer for a whole week is odd. Don’t you have other blowers (like the heavy Echo?)
We are just saying that having bolts backing out on the muffler on the BR800 has not been a problem. Special Loctite, retapping to larger bolts, and or using Mechanic’s wire may be your next step.

 

[lbrac]

From LOCKTITE website (https://datasheets.tdx.henkel.com/LOCTITE-262-en_GL.pdf) for red 262 threadlocker used on blind holes:
"Apply several drops of liquid threadlocker down the sides of the blind hole filling the lower third. Apply several drops to the bolt. If cure speed is too slow due to passive metals (stainless steel, aluminum and plated metals) or low temperature (below 5°C), use activator LOCTITE® SF 7649 (see cure speed vs activator graph in the TDS)."

Strength gradually drops from 100% at ~40 C (104 F) to ~50% at 150 C (302 F) (the upper recommended limit) in ~400 hours at temperature, and continues to gradually drop to ~25% based on more time at 150 C (~1100 hours).

You might try using studs in the threaded holes w/ them center punched at the top of the threaded aluminum holes to prevent the studs from backing out; then use serrated lock washers and nuts to hold the muffler on.