Loose new bearing fit in new strut top mount?

OK, so I'm starting to reassemble (for the second time) my front suspension, with pretty much all-new components, but mostly 3rd party, so I've run into a potential issue which I'm hoping someone can verify for me: The top mounts on my car were really rusty, so along with many of the other parts I got replacements from Meyle. I also got new top bearings from Hamburg Technic. The first time I put the struts back in I could hear a knocking noise on the test drive. After going through everything, the only item I could find was that, with the car jacked up, no load on the front wheels, if I grabbed the top of the spring, I could move it from side to side slightly, making a clonk each time. After diassembly, it was clear that the movement was between the bearing and the top mount. There was perhaps 0.5mm of clearance between the two where the raised areas of the plate contact the outer shoulder of the bearing. I carefully measured the outer diameter of the original bearing and the new replacement - they appear to be well within 0.1mm of each other. To back this up, both bearings were a snug fit in the original top mount, but had the same slop in the replacement. Based on this, I returned the Meyle top mounts for a refund and bought a pair of Sachs top mounts..... which have exactly the same issue. So, I'm going a little crazy here - has anyone else run into this issue? Is the clunking sound I heard likely to be this, or will it just turn out to be the inner & outer track rods that I've also just now replaced as the last wearing part that I hadn't touched before taking it all out again? Am I on a fools errand expecting 3rd party top mounts to be the correct size, or is there some elegant way to take up the slack between these two components (cable tie, rubber band, thick layer of paint...)?

C2 or C4?

Sachs are OE parts - mine from Autodoc were identical to the ones I took off apart from the Porsche part number being ground off! Have you got any pictures of it disassembled and laid out?

It's a C2 rather than a C4. I don't actually have any photos of my own parts - I've just come back in from the shed, so it would mean an arduous walk back out there to take one - but I've attached one of the relevant parts from the Autodoc site. The bearing is located by the three raised features of the top mount against it's outer edge rather than on it's inner face, which doesn't make contact with the tubular part of the mount with the rubber bonded bush.

Have a look at the parts diagram associated with this kit. I wonder if there is a bit missing / something not carried over / something fitted the wrong way around? Did you check old against new to ensure a match? I put new strut tops, struts, springs and bump stops on mine. I needed a couple of individual parts - one of the little support collars which goes on the strut first and the bigger pressed steel collar that sits on top of the spring rubber insulator (both were rusty). On the advice of Centre Gravity I just cleaned and re-greased the bearings. https://www.design911.co.uk/fu/prod...MI6JfMz4fS7QIVB-7tCh2ecgDsEAQYAiABEgIOcfD_BwE Regards Ian

Hi, Have you got the metal plate bits that sit between the bearing and the isolator pads? I bought some suspension from somebody who was not getting on with it and on disassembly I found that the garage had omitted these. Once fitted, everything was fine

Lenny, That was my thinking too - retrace steps and ensure every part of the assembly is present. Ian

Front exploded diagram to help.

If they are missing (number 4 on that diagram), I have a used set in my shed that you can have for the postage cost. From what you are describing it would certainly sound likely...

I replaced one of item 4 on mine. One side was perfect and the other was rusty and starting to bulge / thicken so was swapped for new.

Thanks for the replies all of you. From the top of the diagram, I've replaced parts 10, 6 (both of them), 3, 11, 4, 5, 9 and 1. The issue I have is the fit of the bearing (part 11) and the mount (part 3) - just a slight side to side movement. The top of the spring, and hence it's tension acts through the rubber "compensating plate" (5) which sits on the metal support ring (4), which is a good fit on the lower half of the bearing (11), but the top half of the bearing isn't such a good fit in the recess of the top mount (3), so I'm able to move the top of the spring and the other parts on top of it side to side. Part 2 sits on the shoulder on the shaft of the damper/shock absorber (1) and the lower large washer (6) sits on it, then the top mount (3) on it, then the upper large washer clamps down under the force of the top nut (10). I'm 100% sure I've not mislaid any parts and I'm sure I've got it together in the right order. As I say, the bearing doesn't have that play in the old top mount, just the two replacements that I've bought so far. Are any of you in a position to try push/pulling the top of your springs to see if you can replicate what I'm talking about? Maybe I'm just worrying unduly because everyone elses bearings have some clearance with the top mount, but right now this is the only part that I've found any movement in. Right now I'm tempted to use some Devcon "Plastic Steel" to bed the bearing into the top mount so there's no movement...or, dare I say it, fork out for genuine Porsche mounts, but they are massively overpriced for what they are.

I wouldn't devcon it.

You're right - there's really nothing for Devcon to key into on that shape, so it'd likely just crumble & fall off, especially in such a thin layer. Just now I did a bit of experimentation to see how much slack there actually was and there seems to be about 0.6mm - definitely enough to annoy. I tried wrapping a narrow strip of electrical tape (thickness ~0.12mm) around the circumference of the old bearing and I found that two layers was slightly too much, preventing the bearing from seating fully home. A single layer of tape was just not quite enough, with a small amount of movement still detectable. Clearly electrical tape isn't the answer, but there aren't many items that I could use that are that thin, so I've decided to put on a thick later of Jotamastic epoxy primer paint to see if that will take up the slack. I'm sure this will be frowned upon by some, but this isn't a moving joint and this paint is very strong - if it fills the gap properly there will be no movement and will provide some additional rust protection to this part - my originals were quite remarkably rusty. I'll report back on the fit tomorrow when the paint has dried. If it's a dismal failure I can always sandblast the paint back off and try something else...

If you have ever read "Zen and the Art of Motorcycle Maintenance" you'll know that drinking beer can often come in handy in these situations Have you tried making a shim out of a beer can (the thin aluminium)? I'm having trouble visualising where your issue is but perhaps this could work? I have an old set of 987 front shocks in my shed. If you can explain what you want me to check (top mount in the bearing?) I'll go out at lunch time and have a look.

Beer there, done that! http://911uk.com/viewtopic.php?t=134032