Technical Strut Top Mount Replacement Guide

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Technical Strut Top Mount Replacement Guide

Joined
Mar 30, 2005
Messages
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Location
Caithness
*Disclaimer - this is an amateur guide only and as such I won't be held responsible for any personal or property damage occuring by following it!*

Why replace them?

  • Untraceable knock when going over a bump or when steering?
  • If you are thinking of up-rating the suspension, you might want to consider changing them. When I put my G-Max kit on, I put the old ones back on with their perishing rubber. 3 months later I started to get knocks, bangs and all sorts because the harder suspension had done them in totally.
fookednew2.JPG


Here’s how to change them:

Tools required:

  • 13mm socket ¼” or ½” drive
  • 17mm socket ½” drive
  • 18mm / 19mm socket ½” drive
  • Breaker bar ½” drive (long bar in a socket set – usually with a flexible end)
  • Ratchet – ¼” and/or ½” drive
  • 18mm / 19mm RING spanner NOT an ‘open-ender’
  • Jack and an axle stand
  • WD40 or similar
  • Wire brush and Safety glasses MANDITORY
  • Bench vice
  • Optional: bench grinder with wire brush wheel to clean up old bolts

Hardware Required:

  • 2 x 17mm Nylock nut for replacement of top of shock absorber piston (were included with my suspension kit).
  • 2 x 19mm Nylock nuts for replacement of shock absorber to hub.
  • Multi-purpose grease - recommended
  • 2 x strut top mounts:p
  • Possibly: 2 x Top plates (looks like a big, thick washer with two notches cut out of it, viewable when you take the rubber dust covers off the top of the strut under the bonnet).

Before we start:

  • Park the car on a flat, level surface preferably off the road so that you can all the way around the car.
  • Make sure you have some daylight hours to do this

Removal

  1. Crack off the wheel bolts then jack the car up at that corner. Lower the car onto an axle stand – DO NOT work under the wheel arch with the car supported only by the jack. Remove the road wheel and put it to one side along with the bolts.
  2. Put on your safety specs and get your wire brush and clean as much of the mud, grease and rust off the two shock-absorber-to-hub nuts and bolts as possible, then liberally spray oil on the threads of the bolt, especially where it protrudes through the nut.

    Go and have a cup of tea while the oil penetrates. When you come back give it another spray – these things are likely to be SOLID.

  3. Use a breaker bar with 19mm socket on the nut side (don’t use a ratchet to break it off as it will wreck the internals) and an 18mm ring spanner to keep the bolt head from turning. Assuming you are at the driver’s side and the bolt head is on your right (at the front of the car), the breaker bar will need to be pushed upwards to slacken the nut. Be careful when it ‘goes’ as you may smack the wheel arch, or worse, your gob. After this, you can exchange the breaker bar for a ratchet to make life easier.
    If it’s the passenger side, the breaker bar goes DOWN to undo the nut.

    On both sides of mine, the lower of the 2 nuts were utterly doomed and I had to replace them. They were so corroded in fact that I had to use a smaller spanner and socket.
    strut.JPG

    You can see in the photo below that I have the ratchet on the (18mm) bolt head and the spanner on the (19mm) nut. Personal preference once the nut is …errr…. cracked off. Once you have taken both nuts off, take off the two thick washers that are probably rusted to the shocker – put all of these somewhere safe.

  4. Using a small hammer gently chap out one bolt. Right after it is out, the other bolt will be loaded by the weight of the hub. Gently tap the remaining bolt until it is flush with the shock. Use a suitable metal implement (poadger) – around 5mm is ideal - to tap the bolt all the way through, expect a good bit of waggling of the bolt and poadgering to free them both. Watch that the strut doesn’t annihilate your finger when it drops down the centimetre or so it does.
  5. GENTLY pull the brake flexi-hose out of its retaining notch in the shocker (only by pulling on the retainer grommet itself – NOT the hose).
    topplate2.JPG
  6. Open the bonnet, take the rubber dust covers off the top of the struts and slacken the three 13mm nuts that encircle the top of the strut so that they are nearly, off – you will notice the strut will drop in line with them being undone. DO NOT UNDO THE BIG 17mm centre nut yet.
  7. Enlist the help of an assistant to grab and hold shock absorber to take the weight of it while you completely remove the nuts, spring washers and finally plain washers. The strut is then dropped down in front of the driveshaft towards the front of the car and with a little turning and lowering the top of the strut, it will emerge from the wheel arch. Do try not to burst the outer rubber CV gaiter and don’t pull the driveshaft out of the diff too far!
  8. With the strut completely free, thank your assistant and get them to get the tea to celebrate doing the 1st side in a few minutes.
  9. VERY, VERY important DO NOT undo the top nut until the spring has been compressed.
    comp.JPG
  10. Take the strut and grab the cut-outs of the big top plate in the jaws of a vice. You can either stick it sideways in and support it (as in the photo), or more trickily, upside down in the vice (with less need for supporting it). Tighten the vice fairly hard, but try not to deform or bend it.
  11. If you need to go and buy a set of compressors, try to get ones with large, well rounded and deep hooks so that the coil sits in it very well – some of them are shallow and a law suit waiting to happen.
  12. Get one of your spring compressors and unscrew the hooked sections to near the ends of the tool. Notice that turning the centre screw of the compressor makes the hooked bits travel towards one another? One half is a right and the other a left-hand thread – damn handy that.
  13. Wipe as much rubbish off the spring as possible, especially where the compressors are going to go to make sure they are as free from loose debris, grease, etc as possible. If you are replacing these alongside a burst oil shocker (like I did originally) be especially careful.
  14. As in the photo arrange the compressors at opposite sides of the springs and get them to traverse at least 3 coils. Arrange for the bit you tighten to be accessible to tighten the treaded part. On my particular ones, it is a 12mm hexagonal section – others have little Tommy-bars and I’m sure there are very fancy ones that I haven’t seen.
  15. Tighten the compressors down evenly - a few turns on one then a few turns on the other. Be VERY careful they don’t slip. If this is looking like one is about to slacken it of and give the spring another clean with brake and clutch cleaner or some other degreaser and make sure it is totally dry before starting again.
  16. You will know the spring is compressed as it will be able to be moved up and down the length of the shocker a little – doesn’t need to be squashed totally – just enough so that it is not acting between the shock absorber seat and the top spring cap.
  17. Now it’s time to crack off the big nut at the top. Making sure the spring is compressed as described above and that the top plate is well secured in the vice, get your breaker bar and 17mm socket and give a apply anti-clockwise heave – again, watch when it ‘goes’ that you don’t fall over or something – best to brace yourself while you do this actually..
  18. Once it has ‘gone’, take it out the vice and stand it upright on a bench. Again – make sure you don’t smack the spring compressors off any thing. Use a ratchet to slacken it off and then remove the nut.
  19. Next remove the top plate – the bit with the notches cut out, as shown in the photo. Inspect the centre of it – it should be the shape of a ‘D’ – if it is the shape of an ‘O’ it is buggered – replace it to save yourself some stress later.
  20. The top mount will then be visible in all its glory. Amuse yourself at how utterly done-in your old one looks compared to the new ones.

    Here's mine:

    fookednew1.JPG

    fooked2.JPG

    fookednew1.JPG

    new1.JPG


    Slide it off and then remove the spacer from the inside of the mount – it’s a thick-walled cylinder that looks like a washer from above.

  21. The part below the mount is the spring cap which consists of a metal upper and a thick rubber lower part. Mine had large rust deposits so I slid it off and lightly tapped off before using the wire brush wheel on my bench grinder to clean it up a little. The top mount rides on this so I figure that if there was any debris on it could cause noise or get up into the new bearing and prematurely wear it out.

Side note - if (and only if!) you are doing changing the shocks then take the remaining parts off the old shock (washer and bump stop) and fit them to the new one.

OK – now for the rebuild:

  1. Replace the spring cap if you took it off, slide on a new top mount (they aren’t left and right handed so it doesn’t matter which) and then re-fit the spacer described above into the top of the mount.
  2. Replace the top plate (remember if your ‘D’s’ are ‘O’ get new ones). You may be lucky and get away with using an ‘O’d’ one, but you probably won’t!
  3. Hand tighten a NEW 17mm Nylock nut on the top of the shock-piston to finish the sandwich before using a ratchet with 17mm socket. When the piston starts to turn, grab the top plate cut-out sections again in the vice and tighten it up till it reaches the plate. Take your breaker bar and swap the 17mm socket onto it before tightening it A LOT. 88Nm specified torque from Hayne's. Just make sure it is damn tight.
  4. Using the old 17 mil Nylock is not a good idea since once it has been slacken off, it is likely that the nylon part will be chewed up and not do its locking job properly, potentially leading to slackening, strut becoming un-seated and certain death. Seriously – they’re cheap to replace and make the difference between a safe car and a dangerous one.
  5. Next we need to release the spring, but while you do so you must make ABSOLUTELY CERTAIN that the top of the spring seats properly in the specially-shaped rubber section of the spring cap. Just like when you compressed the spring, you slacken off one compressor a few turns and then the other watch for slippage of the tool(s). Once the spring is decompressed, remove the compressor tools.

    ---------Go and drink that cup of tea---------

  6. Refitting the strut is the opposite of removal – Feed the bottom of the shocker down behind the hub first and then swing the top under arch – I have never managed to do it easily, you just need to fiddle. Again, don’t pull the driveshaft out too far and don’t lance the rubber CV boot.
  7. Get your assistant back and line up the top mount bolts with the strut turret before pushing it back up through the holes. I got new nuts and washers with my mounts, but so long as the old ones are good then it’s fine to use them. Get your assistant to put the plain washer, spring washer and 13mm nut on as soon as the studs appear through the top of the strut turret.
  8. Tighten them up before going under the arch again to refit the two lower nuts and bolts. Use the jack to carefully align the hub and shocker then your poadgering device to help finely align the holes before putting the bolts back through. Use new Nylocks! Tighten using the ratchet until it is against the strut then swap over the socket to the breaker bar to give it a final mighty tighten.
  9. Remember to carefully put the flexi hose retainer grommet back into the shocks. If it is reluctant, some kind of non oil-based lubricant helps tremendously (spit, wash-up liquid, etc).
  10. Refit the road wheel, jack the car up, take out the axle stand and lower the car to the ground. Fully tighten the wheel bolts.

That’s it – 1 side down, 1 to go.

Passenger side is the same except that there is an additional two 13mm flanged nuts and one 10mm bolt which hold the ECU down – note their order with respect to the top mount studs for refitting.

(y) DONE!(y)

That’s it! Have fun and work safely!
 
Last edited:
Thanks chaps - that's much appreciated.

I picked up a brand new pair from ebay from a guy who got them by mistake (somehow). £40 the pair, inc delivery. Theyre not OEM; they're SKF?? but have roller bearings rather than the original ball-bearings and the bushing part is pretty damn firm rubber - very well made.

The packing slip idicates that they came from:

http://www.expressauto.co.uk/

Part #: SKF-VKDC35202

£54.52 the pair exc. delivery. Unsurprisingly, less than half the price of my FIAT quote of £60 EACH!
 
Thats got me thinking now about when my kit arrives. Do you think my seicento wants will need replacing...mine has only done 47k but I don't really want problems a couple months after fitting the kit.
 
Niles said:
Thats got me thinking now about when my kit arrives. Do you think my seicento wants will need replacing...mine has only done 47k but I don't really want problems a couple months after fitting the kit.

Yes, replacing these if they appear to be on their way out is very labour-smart. It'll save you doing the two in-out jobs I did. :D

Have a look at the one on the first strut you take out. If it is anything like either of my ones - the rubber is separating, there's excessive play in bearings, etc, you should replace them.

Don't take the strut apart until you have a look at it. If does need replacing and you can't get a lift to a motor factors to get them, you can just put your old one back in until you get them or use the car until mail order ones arrive.

Generally speaking, they should wear evenly so the condition of one is a likely indicator as to the condition of the other (unless there has been some other kind of trauma to one - I.E. you can't yell at me if you build up the first side and the 2nd side is cream-crackered;) ).
 
Cheers for that, luckily the garage that will be fitting the suspension (i haven't got the time of enough skin left on my knuckles to do it myself) it two units down from a motor factors so il get them to check before they fit.

You've been the most helpful guy on here so far so thanks for all the advise...give this man an award of something, he's clearly a legend (y)
 
how much would i be looking to pay at a garge to have new springs and shocks put in?

Front and rear, maybe 150 - 200 quid.

My only quibble with the excellent guide (which should go in the guides) is that I've seen the little top plates buggerred beyond belief by people using vices, stillsons, GOKW on them. This can make future removal impossible except by the vice method.

Correct way is to either make up or borrow/buy a C spanner to fit, or weld up a special tool (I made one with an old socket, the outer race of a tensioner, and some 4mm scrap). That way you can slacken off (do not remove or you will die!) the top nut with the strut in place on the car.
 
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