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Changing Front Strut Bearings

Changing the strut bearings means getting the struts out. I can deal with engines and drivelines, but I know diddly squat about suspension, so I got hopelessly confused by both the terminology, and by what attaches to what, functions how, and can move in which way. Hence, here's a pictorial guide to changing strut bearings. You know you will want to change yours if there are large cracks in the rubber support, even though I now realise that the consequences of the rubber support failing are not as dire as I originally had thought - it supports the damping rod, the force of the spring is on the metal plate on the bottom of the strut support.

So, what is a strut bearing ?

This is a strut bearing:

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It lives right under the top of your fender, and you come across it as you open the hood. It looks innocuous, this tiny little black rubber contraption, fixed with three little nuts around the perimeter, and if you open up the half-domed cap on top, which just snaps on, you can see a self-locking 19mm nut.

Let's first look at a diagram. I hope Kenneth Ball won't mind I stole his:

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You recognize the strut bearing at the top. If the strut has to come out to change it, you have to somehow disconnect it at the bottom as well, or else make the wheel hub drop far enough down so that it can move outwards from the top of the fender.

I thought I might be able to disconnect the three nuts at 24. They are safety wired, but more importantly, one of them cannot be reached at all with the brake backing plate in place, and to remove that, the wheel hub has to come off. That is a big no-no in my book.

Disconnecting the strut bearing at the top will not allow it to come down far enough to move past the fender. The limiting factor here is the sway bar - nr 28 on the picture, which connects to the wishbone through the long bolt nr 33. So this is the first thing you do, before even jacking up the car - soak that bolt and the double nut on the other end in penetrating oil, and brush off all the dirt and rust with a brass brush.

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While the penetrating oil soaks in, crack the wheel nuts loose. They are 19mm.

Bolts and nuts are 13mm, so get a long spanner or a ratchet, and remove the nuts. This is easier said than done. 48 years of rust will have you breaking a sweat, as the bolt is far longer than it needs to be. If the rubber bushings turn out to be shot, order new ones. Mine were fine. The bushings are in two parts, make a note of the order and orientation of the washers. The diagram has the bolt head pointing upwards, on my car the bolt head was on the bottom. I have no idea what is smarter, but it would have been easier to undo if the nuts would have been on the bottom I think. Obviously, you turn the nut, not the bolt, in order not to unduly stress the bushing.

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The rest of the pictures are of the right side of the car, but here is a comparison picture of how far the wheel can move down with the swaybar undone on the left side, as compared to the fully extended suspension with the sway bar fixed - on the right side.

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Once the sway bar is undone, you can crack the 19mm nut in the middle of the strut bearing loose. You may need to hold the 8mm hex head at the end of the damper rod with a spanner in order to do this - sometimes you will just spin the damper rod instead of the 19mm nut. In fact, if you are able to follow the instructions below to the letter, it makes little difference if you undo the nut completely. The shiny steel end of the damper rod may disappear out of sight into the depths, but that is fine, we'll get it back later. If you have a spring compressor handy, it might be wiser to not undo the nut completely, so you can keep track of the damper rod.

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If you have a spring compressor, now would be a good time to put it on the suspension spring as it is compressed by the weight of the car.

I had no spring compressor. If your springs are tired and 48 years old like mine, you can get away with this. I'm not saying it is a very good idea, but you can get away with it. If you installed new, stiffer springs, there will be a moment in this story where you will get stuck. You will not endanger yourself, but you will get seriously stuck, until you get a spring compressor, and then you'll have to compress the spring with the compressor instead of using the weight of the car. Best to beg, borrow or buy a spring compressor before you start.

Now, finally, you are ready to jack up the car. Place the car on sturdy stands. The middle of the subframe makes a good jacking point, the framerails or the end of the subframe right inside of the hinge point for the wishbones are good for placing stands.

Once the car is jacked up, remove the wheel.

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The two bolts at the back of the brake backing plate which hold the brake caliper on are also 19mm, and can be undone with the same tool as the wheelnut. Once you have the brake calipers off, remember NOT TO TOUCH THE BRAKE PEDAL until they are installed again. You have to tie them to something so the rubber brake line is not stressed in any way. The swaybar, which is disconnected from the rest of the assembly anyway, is great for this.

 

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Now we are ready to undo the three nuts and their washers at the top of the strut bearing. Once you do this, the whole shebang will drop out of sight. Make sure it does not dent the fender from the inside.

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I suspect that if the spring has a compressor on it, that you can now simply move the whole strut outwards, and if you press down on the wishbone with your foot, it will clear the fender.

However, I had no spring compressor. Which is why I undid the 19mm nut at the end of the damper rod competely and made a note of the order of the washers and spacers. Then, pushing down on the wishbone, I wiggled the strut bearing off the end of the strut while it was still inside the fender. The damper rod will slowly slide inwards under its own weight, but that is fine, we will get it back later. Now you need to concentrate on getting the strut out from under the fender. This requires a combination of leaning on the top of the spring to compress it and pushing down on the wishbone with your foot.

I used a nearly finished roll of kitchen paper to make sure I didn't damage the fender.

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Once it is out, it will look like this:

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As the spring is uncompressed, it is very easy to reach through the coils, grab the damper rod, and push it back up until it fits through the hole at the top of the strut.

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Now is a good time to unpack the new strut bearing:

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Then mount it on top of the strut, and thread the 19mm nut back on for a few turns, using only a single washer, not the stack of washers and spacers that came out. We'll get to that later. However, do make sure that you thread the top of the nut past the hex bolt head at the end of the strut - you will need to be able to reach that later!

Since your strut is now higher by the height of the rubber strut bearing, getting it back under the fender, using the same roll of kitchen paper, will be more difficult. This is where a spring compressor comes in really handy, as it would avoid all of these shenanigans - you could just place the strut bearing back on top, complete with its stack of washers and spacers, tilt the strut back under the fender and be done with it. Still, I managed to do it without, just pushing down on the wishbone and compressing the strut by hand.

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At this point, reassembly is really just the reverse of disassembly. The strut bearing has a fixed orientation, the bolt pattern will only fit one way. As soon as you have the studs through the holes in the fender (you will have to lift the wishbone with your foot e.g. under the brake disk), put the small 13mm nuts and their washers back on. The difficult part of the job is now done.

Reassemble the brake caliper and put the wheel back on. Jack up the car, remove the stands, and drop the car back onto its suspension. While doing this, double check that the bolt for the sway bar is going back though the hole at the end of the sway bar. The weight of the car will now compress the spring, and also the damper rod. Get a pair of flat pliers, grab the hex head at the end of the damper rod, and pull it up as far as will go, which should be very easy. There is a definite positive stop to it. Then undo the 19mm nut, put the whole stack of washers and spacers back where they were, and thread the 19mm nut back on until it bottoms out. Hold onto the hex with an 8mm spanner if the damper rod turns along with the 19mm nut.

The last thing to do back up is the sway bar, with the wheel on the ground (n order not to unduly stress the bushings, and also because the bolt head or nuts will be much further away from the struts, making it much easier to fit a spanner), and finally torquing the wheel nuts with the wheel on the ground. You are now ready to start over on the other side.

Total time for me doing both sides, finding my way as I went along, was about 4 hours.

Cris

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