If you look at the picture of the rear strut. It appears the top of the strut rod has a larger spot before the top threads. The spacer is to mimic the OEM strut rod. The KWB mounts should also be built to mimic the OEM. So the spacer is not meant to pass through the mount, only to be the main point of contact. Also probably there to hold your dustboot/helper in place. You maybe able to look at your old struts confirm.

 

I wonder it if is an adapter to make this Bilstein p/n fit both the 2010-12 as well as the 2013-14 models.
There was a design change between those years. If you look up the mounts, they are different as well as the strut itself.

If you cannot find a good answer, you might try taking the old units apart and do some forensic investigating.

 

OP, did you finish the install?

 

I have completed the swap, including front and rear sway bar links (Moog, Amazon), shock absorber mounts (KYB, Amazon), and struts (B6, Raptor Racing, Ontario).
The process went well, and I don't find B6 overly stiff. The car now feels disciplined and composed. It doesn't get swayed by crosswinds or passing 18-wheelers, hydroplanning resistance is way better, and even avian feces are repelled and immediately returned to sender by an invisible force field. Rattling noises are mostly gone, except on bumpy gravel - I suspect the front brake caliper brackets/pins, a known recurring issue on Gen4 and this car in particular.

Front: pretty straightforward, I removed the strut assembly, then compressed the spring with a pair of standard spring compressors, disassembled the strut, and reassembled with the new B6 and KYB strut mount. Then gradually released the spring compressors.

• once compressed, add a few high-strength 175 lbs zip ties around the perimeter to prevent the spring from bulging
• the top nut can be tightened using a shallow socket and a hex key. my impact sockets have a hole in the wall near top that can be used to turn the socket. can't torque to spec, however - will have to ask the mechanic to do the final torque before alignment. alternatively, one could sacrifice a deep socket and cut away the side wall to allow access with a hex wrench to hold the center stud, BUT... front and rear B6 will require 2 different sockets
• when reassembling, make sure to transfer all the parts and watch for the correct orientation: paint mark on the spring and "AA100" on the upper spring seat are on the outside
• reinstalling the strut assembly requires a helper to guide the 3 studs on the top hat into place
• front end links are a [female dog] to remove. I cleaned the bolt threads with a Dremel wire brush and used plenty of rust release WD. the top nuts removed ok. the bottom nuts didn't want to bulge, so I cut them in half with a rotary tool (Ryobi PCL480B)

Rear: can be very hard without a helper. Subaru FSM instructs that the lower control arm should be disconnected from the subframe (the inner end), then the sway bar end link and the strut can be taken out easily. I didn't want to disconnect the control arm and decided to try uninstalling/reinstalling the struts while pushing the LCA downward as demonstrated here:

I used an old sway bar to push down on the LCA - this is where a second person is pretty much required as you need two hands to manipulate the strut assembly in and out. After a few attempts, I managed to do it on my own by pressing on the sway bar with a 2x4 and sitting on it. Not recommended.

• since the rear springs are longer, they have even higher propensity to bulge - 6-8 zip ties really helped to keep things straight
• the Bilstein rod spacer I asked about in the OP is pictured in the correct orientation. the wide part supports just the bumper and the dust boot.

 

 

FRONT: Before you disconnect the knuckle, put 2 wheel nuts back on and sling them in an X pattern off the subframe/LCA to prevent the knuckle from dropping outwards. Otherwise the drive shaft could undergo an unscheduled disassembly - will be difficult to fix.

First half of the X:

 

Good job on completing the swap. I was asking hoping you did not finish it , so that you could provide some measurements for me. This is what I am contemplating at the moment: https://www.subaruoutback.org/threa...fitting-gen-4-or-5-bilstein-b6-rear-struts-to-gen-3-outback-bl-bp.567211/unread

 

Thanks for this write-up, I will probably be facing near identical situation soon on my 2013.

QUESTIONS to @error (or anyone): I fully understand replacing the front top hat/upper mount, as there is a bearing wear-item involved, but how necessary do you find replacing the rear top hats…in retrospect? Nice-to-do vs need-to-do? Mine is pretty rust-free (I hope).

Also, I did something similar (Bilsteins) on my 2007 Gen 3, and don’t recall any spring bulging…is this something that happens only while in the compressor tool, or does it persist after releasing the compression? Is the spring then “deformed?” A picture would be worth 1000 words, but assuming that’s not possible, could you re-describe where/how you are using the zip ties? And on the 2007, I don’t remember issues with the front knuckle flopping / disengaging from the axle. Is this a Gen 4 things? But for 07, the front Bilstein struts are inverted monotube, and quite stiff, more NVH, great for performance, relatively sucky for comfort. I’m looking for more comfort, willing to settle for less performance. Of course, those were not true Outback front struts, rather were 35-118305 & 35-118312 for Legacy.

do your rear Bilsteins have multiple grooves for a C-clip to adjust the height of the spring perch (My rear JDM shocks for the 07 did). if so, did you adjust the height?

do you still have the stock RSB?

and to anyone else who might have similar experience with Gen4, any thoughts on using RSR springs with the Bilsteins? I want comfortable / quiet, not overly firm, but a slight (~1”) lowering would be OK with me.

sorry for the “million questions”