Whell liners on sprinter chassis

Has anybody had any problems with the wheel liners staying on mainly the back ones.My left one fits but the right one just won't stay on.

I've had problems with the rear wheel liners on my 2350S too. While they will stay on the wheel, they rotate due to braking and jam up against the extended valves I installed. I could not believe that this was even possible until I reinstalled them and found that I could rotate the liner by just gripping the center and twisting it with my old arthritic hand. After removing them and closely inspecting the pointed spring grips, I saw that the tips looked worn. I called Dicor and the customer service person said this is what I should expect. The warranty is only one year. In more than a half century of driving, I cannot recall a "hubcap" ever wearing out!

I looked at Dicor replacements or alternatives but was turned off by the cost.

Solution: Leave the liners off. Doing so reduces unsprung mass and saves fuel by not having to carry, accelerate, or decelerate any wheel decorations...

Help.  Please explain what you mean by a wheel liner.  ???

The black thing behind one of my Sprinter's tires is loose and makes noise.
Should I be worried?  Is it hard to fix?

Thanks.

Wheel liners are the polished stainless steel covers that fit onto the wheels. You may be looking at the wheel well liners on your PC that are part of the coach/chassis.