I have the legendary 2.8i Bilstein struts and last MOT Tom noted that there was some play in the middle. Basically the bushes which the damper slides through were worn
I phoned around and none of the specialists I called would recon them. GAZ could do a conversion to their dampers at around £350 for the pair. But me being me I decided to do them myself. I accept no responsility if you follow this and it goes wrong. This is how I did it......
These were the struts as they came off the car. Although they are not adjustable (who needs to adjust perfection) Bilsteins dampers are second to none on quality. Independent specialists I spoke to rated them top for performance and durability. On the outside these were a sorry state, unknown age and bought second hand from Speedshack a decade ago, see below.......
the first challenge is the retaining ring, this thing is on really B*STARD tight :evil: . You can see it here holding in the rubber wiper seal at the top.
I drilled a 10mm hole here...
Then heat it....
So that a screw driver could be applied at a far better angle to knock the retaining ring off....
The hole then serves as a good drainage hole and helps prevent the bottom of the cup rotting out. :wink:
At the bottom of the strut there is a locking nut which threads over the end of the damper rod which pokes out the bottom. A factory adhesive holds it in place. If the nut is stubborn or you at risk of damaging the thread on the rod then f*ck the nut (I don't say that often in a thread). Here you can see I have drilled it ready to split and remove.....
The rod can then be screwed all the way in with a flat head screw driver and the damper can then be pulled out and checked for wear.....
Check the hard chrome plating, mine measured 39.99mm to 40.00mm and seemed in excellent condition. They were stamped 300/70 which is a hard tarmac spec and they took 5secs to rebound from fully compressed. If they shoot up then they are probably worn out. Rally design do them for £93 each.
A specialist told me that the bushes (2 per strut) are a nightmare to get out. I used an jig-saw and file very carefully to cut the inside of the upper most and split it. You might have to do both sides. Take your time to try and minimise cutting the inside of the strut.....
and then extract it once it is split, swear aggressively at it then chuck it in the bin. Use a long screw driver and hammer to push the lower bush 2" further down, you see why in a bit.....
At this stage I sent them away to get shot blasted and dull Nickel plated (Collins Chemical Blacking Ltd). This cost £45 each but painting them is obviously cheaper and more original. I specified that the stub axle and interior remained unplated and they came back like this.....
New phosphor bronze bushes and wiper seals can be bought from COMPBRAKE at around £25. Only problem is that they are 45mm OD and my strut is 44.0mm ID. They are quite thin so distort when they are clamped in the lathe. So after having a word with Steve & Aaron at Vulcan/HT and coming up with an engineering solution they are now set up to machine them down to your spec. If possible bring the strut to them and go for a light interference fit
With the bushes back, make sure there are not any lumps or bumps inside the strut and freeze your bushes! Must.... resist.....ice ....cream:
You can get a mate to warm the strut and oil the strut (pwhoar) so that the bushes can be lightly tapped in. If it is immediately apparent that it is too hard to get in stop, sand it down and start again! I use this old bearing race to tap it down:
Remember pushing the old lower bush 2" down? This locates your new lower bush and stops it going to far down the strut. PUt the second one in the same way but position it just below where the wiper seal goes.
See if the damper fits in, it should slide in smoothly, if not the bushes are probably under too much compression. I had this problem so I used progressively finer grades of sand paper to gently hone them out evenly all round. Again, take your time until you have a perfect fit. Flush the strut out thoroughly after.....
I'll let the pics do most of the talking. I chose Lithium grease from the can because there is much less chance of dirt inclusion ......
Carefully screw the damper rod out through the bottom of the strut....
Waterproof adhesive for the locking bolt as they left the factory
New M10 fine pitch stainless bolt, some Bilsteins have different thread so check.
Wiper seal on, its incorrect here and needs turning the other way.
Then retaining ring on again
And re-assemble the rest for the finished article! Ready for another 20 years....
Total Cost
Bushes and seals £25
Machining of bushes to fit £20
Paint £15 or Plating £90
Bookmarks