do weight distributing bars weaken with age?

[Timeking]

I have been towing a 24ft 5500 lb TT with my 5.3L V8 Trailblazer for over 40,000 miles. Back when I first got the hitch, the trailer and the trailblazer sat level. Now I notice that the rear sags enough to notice, and it would seem that those bars being springs might have lost some of their original tension. Does this happen?

PS: I think I read all the posts on WD hitches here.

[TucsonJim]

On our first TT, I noticed a similar problem over time. I found out that my hitch was actually starting to fatigue and I needed more and more tension to keep it level. It finally became obvious what the problem was when I could see the hitch was bent.

[Timeking]

Maybe I should go up a link? There are 9 links in the chain, and I have been using #3, so if I went up a link then I'd still have 5. That said, my "inner voice" says "don't screw with things that are working fine, especially when you are 3000 miles from home".

[Timeking]

I grease those points, but not as religiously as I do the ball. Visual inspection indicates that if there is wear, then it is on the millimeter scale. I'll have to have someone look at the Trailblazer springs.

[Hondavalk]

I would be more suspect of your Trailblazer's suspension changing with age.

[BarneyS]

Perhaps the bars have worn where they insert into the hitch head, or the head itself has worn where the bars insert. This is especially possible if you have run without greasing those areas.

I suppose it is possible that the bars themselves could have lost some of the temper or hardness but that doesn't seem likely unless they were grossly overloaded.
Barney