B7800 - Annoying engineering flaw

[Sniggle]

The muffler sits up on an exhaust pipe that ties into the exhaust manifold. There is virtually no support for the muffler, so the joint where the exhaust riser is welded into the muffler takes all the vibration. Well, after 800 hours the metal alongside the weld in the muffler failed.

Had my local welder put it back together and add 2 supports as seen in the 1st photo. Why they did not do this at the factory is beyond me....it would have added a couple of dollars at most to the cost.

 

[number two]

Bet you're glad it's fixed!
At least it held up for a lot of years of 4 cylinder vibrations!

 

[crbr]

Thank you for the heads up and the photos.

.

 

[s219]

It lasted 800 hours on a model that is 15-20 years old. Hard to call that a flaw at this point. Could be done better for sure but you’re way past the point where this would escalate.

 

[orezok]

My 7800 is coming up on 800 hours. Maybe I should check it.

 

[rScotty]

There used to be a school of manufacturing that believed that the path to success was in taking a basically good design and improving it through the years. In the best of those machine designs, many improvements were deliberately made to be retrofittable onto older models.

But that type of manufacturing requires a committment to a product that isn't as popular today.

rScotty

 

[orezok]

I checked my 7800 today and there is a substantial weld on the connection. No problem here.

 

[rScotty]

Good welds don't break. They are automatically stress-relieved. Usually the base metal cracks next to the weld.

 

[Sniggle]

I checked my 7800 today and there is a substantial weld on the connection. No problem here.

If you look at my picture, it was not the weld that failed...it was the metal near the weld.

The good news is that the muffler is easy to remove, and my welder only charged $32 to reweld the muffler and add the 2 braces. If you have welding skills might be worth it to pop the muffler out and add bracing.

 

[diesel85]

This thread reminds me of the D905 air filter bracket.