strut lower nut part number

[ogatrulle]

2008 xc90 3.2 FWD, chassis 579089

Anyone have wisdom to share regarding the part number/availability of the two nuts that go at the bottom of the struts?

VIDA says: use new screws and new nuts where the strut connects to the knuckle. In the following parts diagram (also VIDA), they show two possible part numbers for the nuts, depending on chassis. My chassis is after 352988, so this says M14x19.2 987938.

However, there is confusion in the various online parts house listings. Some indicate 987938 is equivalent to or superseded by 985932 which is a shorter nut (M14x15.9). Almost no parts houses seem to carry the longer 987938 at all.

Why? It seems unwise to me to use a shorter nut for this critical application. Any insights?

vida-diagram-strut-nuts.png (144.12 KiB) Viewed 1973 times

[RickHaleParker]

The bulk of the forces are vertically not horizontal.
Horizontal forces are checked by the metal bracket.
The nut just keeps the load bearing bolt in place.
Use the 985932.

You would not see the change unless a Volvo Mechanical engineer did the math and signed off on it.

[ggleavitt]

See photo- 985932 on the left, two flavors of 987938 on the right.

StrutKnuckleNut XC90_985932_987938.jpg (200.07 KiB) Viewed 1955 times

The 3.3mm difference is the integrated washer I suspect. Up to today I was convinced that both nut versions were required, based on chassis number, and I have been using the 985932 on my '05 and the 987938 on my '08 as a "rule" (I have some stock and replace when doing any major work).

Curious again about the differences in reading this post, I did some looking around on various Volvo reseller web sites, including the Volvo main parts site- https://usparts.volvocars.com/p/Volvo__ ... 87938.html and oddly enough, the 987938 seems to revert to the 985932. Couple other non-Volvo sales sites (IPD as one) note the same thing.

Go figure.

Edit 4/4/19- typos, reverts (not superceded).

[wanderdüne]

I just replaced the struts on both my 2003 and 2004, and the nuts that came off were the 985932 style. I believe them to have been the original nuts and screws on both vehicles. I just went out and measured them, and they are more like 13.9mm, maybe 14. Certainly they are not 15.9.
I replaced them all with the 985660 (similar to the 987938) that I got from FCP (their recommendation), which is the nut from the vertical screw on the front control arm. When I did them, I lined up the nut part to the old (985932) and they were identical heights, with the captive washer adding some height. Since I was replacing eight screws between the two vehicles, I used the 982870 that's from the same vintage XC70. It's the same bolt except for the tapered end on the 982869, the thread length is identical. Torque value is 105Nm +60* for the XC70 vs 105Nm+ 75* on the XC90 spec, so I felt pretty comfortable using them (I tightened to the higher XC90 spec). The cost difference in the screws for eight pieces (about $60 difference) was enough for me to get the 982870 instead of the 966363. Not a recommendation, just what I did.

I'm curious as to the height specs of 15.9 and 19.2? because the nuts I took off both vehicles appeared to be original, as did the struts and they are, again, not near that height.