2006 XC90 Rear Shock Questions

fivexdad · Post by **fivexdad** » 02 May 2021, 15:34

I posted this in a different forum and only got one response (which was helpful) so I hope I'm not annoying people on both but I wanted to get some additional input. In the course of replacing a my left rear bearing on my 2006 XC90 we found out the left rear spring was broken. My mechanic said it was not something he could get through his traditional suppliers (Napa and Advance) but told me I could probably find one on ebay. In doing my research I discovered some models have Nivomat self leveling shocks and some don't. I determined that mine does have the Nivomat shock based on the code on the engine plate (contains "26"). I found the right aftermarket spring made by Lesjofor for the self leveling shock and brought it to my mechanic. I go to pick it up today and he says there was a problem with the shock. When he removed the shock to get the spring in, the top mounting bolt of the shock broke. So he got a new one from Napa and put it in. I asked if it was the self leveling gas shock and he said "I don't know. It was the one they said fit my vehicle and it went right in." He also said it was a lot thinner. So I asked to look at the old one and it did have the accordian boot which is another indicator of the self leveling shock. I asked if the new one had a similar boot and he said yes. I told him I don't think it was a self leveling shock because they are more expensive and probably not available through Napa. He says "I wouldn't worry about it. It fits." The car has 210K miles on it. I looked up the part number for the shock he put in and it is not self leveling (KYB 553382). So my question is do I just drive it with one self leveling shock and one that's not (with the lighter spring)? Will I notice dfference or is there a safety issue - we bought this for my teenagers drive - slow, safe, very uncool and good in our Maine winters. My mechanic is good but not familiar with volvos - no one is around here - so I think it was an honest mistake. If anything I blame the Napa for not telling him there was two options. Or is it worth the trouble and money to order the right shock and pay him to replace the one he put in. Or would I be ok just getting the matching spring and putting that in. (much cheaper)

Post by **ggleavitt** » 04 May 2021, 10:13

You have one side as a spring and damper, the other as a spring and self leveling damper. At some point the vehicle could get a little diagonal in the rear as the Nivomat side levels up in height.

The 26 is the standard ride Nivomat (48 is Sport), the logical thing in my mind would be to replace the rear shock with the correct part (Volvo 30683451) or move everything over to a standard spring like a 35 (PN 31329367) and regular shocks (I don't know KYB so cannot comment).

I'll be surprised if the rear handling is acceptable with what you have on right now.

fivexdad · Post by **fivexdad** » 28 May 2021, 19:07

Thanks! That's what I did. The only problem now is that when we hit a big bump on left side there is a loud rattle. My mechanic thinks that it is the after market spring which was all metal. The original which was broken ( how this all started) had a rubber bumper molded into it.

Post by **cn90** » 28 May 2021, 21:39

I do not have Nivomat, just regular suspension.

I refreshed my REAR suspension using quality parts (Lesjofors, Bilstein shock etc.).
The DIY is below...

DIY: REAR Suspension Rebuild (2005 XC90 2.5T AWD with 120K)

viewtopic.php?t=92099

Post by **ggleavitt** » 29 May 2021, 10:04

cn90 has some very good write-ups, I still use his fluid swap thread to this day.

Couple of things come to mind as I read your response- If the spring is rattling I'm guessing it's not the correct length for the throw of the shock as I would assume that you should have no extra space at the top of the travel to make a rattle. As well, there's normally an insulator on the bottom of the spring, PN 30645888. Can see the photo and this link https://photos.app.goo.gl/TFMAWDYSTmaVC4SG6 with more photos for orientation:

: Rear Spring Insulator_2008 XC90.JPG (157.47 KiB) Viewed 2104 times

I'll still guess though that the spring length is not correct. If you can get the information on the lower left corner of the large black label that's behind the passenger side B-Pillar (front of the rear passenger door opening), it'll tell you what is supposed to be there. The information in the lower left will look something like 33AB65426952 (my '06), please post this if you can find it. Also on the bottom of that label are your interior (Cxxx) and paint codes (xxx-xx).

**Anyone who's done a spring replace will soon note in my photo link that I had no real clue how to easily get the new insulator on. I should have taken a few more parts off to get lower link arm to drop on its own.

Scycotic · Post by **Scycotic** » 06 Jun 2021, 16:24

Wow so much deja vu reading this. I had a very similar situation almost two years ago that I posted about in another forum. What I determined at the time was that the most important thing is matching the spring with the correct shock, regardless of fitment codes. In my case, my Nivomat spring and shocks failed so I did the conversion to non-Nivomat and provided all the parts (Bilstein B4 shocks, Lesjofor springs).

It sounds like you supplied a Lesjofors spring intended for Nivomat shocks (4295851/30666641), but your mechanic then replaced the shock with non-Nivomat KYB shocks which require Lesjofors spring 4295849/30645929, while keeping the first spring you provided.

Assuming you then swapped the alternate side with correct non-Nivomat shock+spring, then all you should need to do is replace your new but incorrect left spring with the Lesjofors spring 4295849/30645929 or Volvo equivalent.

@ggleavitt is also correct that you would need the shock mount (31277888), coil spring insulator (30645888) and screw (985215), but I assume your mechanic would have reused the originals. I'm fairly certain these parts are common regardless of Nivomat or not.

fivexdad · Post by **fivexdad** » 07 Jun 2021, 08:03

The rear spring I bought was LESJOFORS1 4295851. According to the seller it was supposed to be the correct one for the Nivomat. I ended up buying a used Nivomat from a volvo dealer and swapped out the new KYB traditional shock rather than do the full conversion. What is missing is the insulator and I suspect that is what is making the rattle. I think my mechanic chucked it with the broken spring which is where this whole thing started. There are very few volvos around here and my mechanic is not familiar with them. How important is the insulator? I really don't want pay my mechanic to take apart the whole thing again so put on an insulator. I do some mechanic work myslef but not sure if this is in my range. Unfortunately I don't have access to the car right now. My daughter drove it back to her college campus and is on a 7 day trip with a group from school. I'll have it back in about a week.