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Technical_   Interior_  Seat Shock Replacement

Seat Shock Replacement
Fred Kim


Ever since I upgraded my front plain-jane vinyl seats to sport seats from an '85 325e, the vertical and backrest height adjustments never worked on either seat. It wasn't that big of a deal to me since I quickly learned to pull the lever with one hand and grab the back section with the other. Once the height was satisfactory, I released the lever. This is how things were for, oh, four years.

Then one day it bothered me.

I started to become annoyed with it after buying another car (a 92 Sentra SE-R) that had fully functional seats. This clever design didn't use shocks, but springs! for the backrest to raise. Who would have thought? I became spoiled driving the SE-R around with working seats, so then I decided to finally take apart the seats in my E30 and finally fix the damn things.


First thing is to remove the seats from the car. There are two 17mm nuts in the front and two 17mm bolts in the rear. You'll have to move the seat forward and backward to get to it, and if they've never been out before, you'll probably have to remove those little plastic caps first. Disconnect the seat belt sensor if it already isn't. Place the seat in an area that isn't too dirty, like on a piece of cardboard in the garage. I put it in the kitchen because I'm not married and can do stuff like that.

(As a side note, if you have light colored seats and take it into an area that has bright flourescent lights, you will suddenly realize how utterly filthy your seats are, no matter how clean it looked inside the car. Or maybe it's just mine. Either way, ugh.)

Now, there are three different kinds of shocks available; one type for the vertical height adjustment and two types for the backrest support. For the latter, there is one kind for sport seats and another for non-sport (standard) seats. The load rating is the same but the tabs are slightly different. There are also some shocks (possibly older versions) that have a close-ended bottom tip. I had some of these lying around the garage and instead of spending another $80 in shocks, I just took a metal grinder and cut a U-shaped opening so it fits into the peg on the seat. Works fine as well.


For this procedure, you'll need the following parts and tools:

  • 2 shocks, P/N 52-10-1-965-645, $38.95 (500N load rating) each
  • 2 or 4 circlips (depending on how many your car has), P/N 52-10-1-916-603, $1.00 each
  • flathead screwdriver
  • pair of cutters
  • a friend or a 100 pound weight
  • very large channel locks or C-clamp

    1.) Use the flathead screwdriver and remove the thumbscrew, then remove the cover. Depending on your seat, the shock will be held either by two circlips (one at top, one at bottom) or just one circlip at the top and a metal peg at the bottom. Use the cutters to remove the circlips, or if you want to be cheap and reuse the clips then use the screwdriver to pry em out.

    2.) If the shocks are blown they should just pop right out. You can also coax them out with the screwdriver if necessary. If the shock still has pressure, it may release suddenly so be careful. If you can compress the shock with one finger and the piston never returns, it is safe to assume the it's no good:

    Blown shock

    When you take the shock out and it still feels like it has a good amount of pressure, place the base on a solid foundation (like a concrete block or garage floor) and compress it. It should take two hands and a good amount of force to do so. If you can compress it with one hand or if there is little resistance, it's no good.

    3.) To install the new shock, you'll need to lie the seatback flat and have someone sit on the forward edge of the seat bottom (or place a very heavy weight there) so it doesn't tip backwards. The reason why is you're going to need the support as you push your entire weight on the shocks. Place the bottom end of the shock into its slot and install a new circlip if necessary. You can see that you'll need to compress the new shock about 2 inches:

    New shock

    Using both hands and a lot of force, compress the shock so the upper hole fits into the slot. This is often more difficult than it sounds because your fingers will undoubtedly rub against other metal parts of the seat, which will give you some nasty cuts and scrapes, plus the rounded point that you are compressing will leave a nice mark on your hand. You may be able to get away unharmed if you use channel locks or a very large C-clamp. After it goes in, be sure to place a circlip over the peg to prevent the shock from jumping out.

    4.) Do the same for the other side. Reinstall the cover and thumbscrew.


    For this procedure, you'll need the following parts and tools:

  • 2 shocks, P/N 52-10-1-965-632, $38.95, 350N load rating (sport seat), OR
  • 2 shocks, P/N 52-10-1-965-646, $38.95, 350N load rating (standard seat)
  • 2 circlips, P/N 52-10-1-916-603, $1.00
  • flathead screwdriver and/or a pair of cutters
  • Phillips screwdriver
  • very large channel locks or C-clamp

    1.) Remove the two Phillips screws at the bottom of the backrest cover. Pull out the plastic handle on the side, then slowly pry the slot cover off from the bottom.

    New shock

    2.) Use the flathead screwdriver or cutters and remove each circlip from the shock. Like the vertical height shocks, if these are blown they should just pop right out. You can also coax them out with the screwdriver if necessary. When you are ready to install the new shock, I found it best to flip the seat so it's upside down (if you haven't already done so) and make sure the backrest is at its highest position. That way the distance the shock has to compress is minimal.

    Old shock
    It's blown pretty good...
    New parts
    New shock going in

    3.) I'd recommend using channel locks to compress the shocks into place. There isn't much room to stick your hands, plus as you can see from the last picture above, it only needs about half an inch of travel to lock in place. Stick in the circlips then put everything back together.

    4.) Reinstall the seats in your car, making sure the rails line up. If they don't, lie the seat on its back, pull the adjustment lever and move the rails either all the way forward or all the way back so they are in synch.

    5.) Enjoy the new shocks. Be sure to throw away those disgusting, blown out struts.

    Old shock

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