I have a 12 FX4 that I put Bilstein on about 11 years and 87K miles ago. I chose to put the boots up figuring having them boot up helped get them away from the ground and SW PA road salt. I was mistaken. I have no idea how long the right rear was FULL of water. I started having issues with hard uphill right turns and the right rear breaking loose, general steering and sway sloppiness. While rotating tires on jack stands in the driveway I lost my balance and grabbed the shock at the boot to keep from falling over. Now I'm half on my *** and wet from the boot spraying me with water. I removed the shock and drained it. There are drain holes on both ends of the boot, but the "bottom" holes near the shock body were clogged. Since I had one out I took the other side off as well, it was bone dry. Both shocks seemed to respond equally to compressing them by hand, but the right rear just wasn't up to snuff while on the truck. Ordered two new shocks, installed them boot down, and it was like going from OEM to 5100 all over again. If you have 5100's and they are boot up, you should at least check and make sure they aren't holding water.

 

They shouldn’t be boot up on anyone’s truck. The instal instructions clearly say boot down.

Theyre not meant for you to choose whichever way you want to mount them.

 

Even with the shock body up the use of shaft boots is debatable. They do protect some from dings and rocks but also hold in moisture and contaminants. I just was my truck often, paying attention to washing the rear shock shafts. Live and drive in WI so salt is a fact of life here. KM

 

This is not true according to the install instructions that came with the new shocks, there is no clear mention of mounting shocks in a particular direction. That's why this debate has raged for years, it's not clear in the instructions. Have a look, this is exactly what comes in the box:

https://productdesk.cart.bilsteinus....M5-Y217A00.pdf

 

I installed 5100s on the rear of my 2017 last year. It said instal boot down.

 

I've always gone with putting the logo facing upright when installed (as they are monotube they technically can be mounted either way depending on the design and specific application). I havent looked at mine, but I'd think the boot should have weep holes on whichever side is supposed to be lower to allow moisture and water to drain (and also allow the boot to compress without turning into a balloon).

 

https://academy.bilsteinus.com/knowl...p-or-boot-down

From the website itself. Zero debates, zero input. Label up, HOWEVER THAT MAY BE.

 

5100s here too. Boots down. The boots have a drain hole in them. Boots down.

 

just because there is a debate doesn’t mean there isn’t a correct answer. Bilstein has answered this quite a few times and would have told you boot down if you had emailed or called them…like I did years ago.

#earthisntflatdespitethedebate