Creaking strut
 

I had a slight but annoying to me creak from the front left since I bought the car when driven over speed bumps or rough road. I couldn't identify what was wrong as the noise couldn't be replicated on the stationary car no matter how hard I shook and wriggled it. All suspension elements were tight.

I tried to bounce the car up and down the other day again, holding on to the wheel arch starting by moving it up and finally got the noise which helped me find it was coming from around the front left strut mount.

What I did I turned the center strut nut (under the plastic cap) just half a turn (the inner strut rod was turning with it) and the creak was gone.

Happy now but I wonder if its ok that the inner strut rod could freely turn in both directions. I tried the other side and it turned too. Both sides made loud rubber on rubber or rubber on metal creaking noise while turning.

I know there's a bearing in the top strut mount that allows the spring to turn a bit against the top mount but I'm not sure the inner strut rod should freely turn in the upper mount.

If the strut shaft is turning with the nut, the end of the strut shaft protruding through the nut should have a female Allen socket feature, that allows it to be counter-held to obtain the proper torque specification.

However, based on what you describe with the squeaking strut, it sounds like your Boxster is overdue on having its shocks replaced and having some suspension maintenance work.

I wouldn't have thought it should be possible to turn the nut half a turn in each direction. The nut tightens the top of the strut shaft to the inner metal part of the strut mount. This is bonded to a round 'doughnut' shaped piece of rubber which is bonded to the metal mount that actually bolts to the car. A mounting in good condition is very stiff and resists rotation. Rubber on rubber or rubber on metal sound would point me to a mounting that has perished/split rubber or rubber that is starting to part company with the metal. I replaced mine at 18yrs/68000 miles. They weren't making a noise but they were starting to show these problems. Try pushing down on the car whilst looking at the nut - if it moves upwards noticeably I'd also question the condition of the strut mount.

Thank you for your reply. I was a bit exaggerating when saying both freely turns and that I could turn half a turn. I've just checked them again and I can turn both max 1/4 turn and it requires some force. It makes a clear a rubber sound when turning and it requires more force as I turn it more after a while. Can it just be the rubber stretching? The car has only 47k miles.

Found this pic online:
https://c1552172.ssl.cf0.rackcdn.com/380702_x800.jpg
It seems it's all rubber around the metal part which may confirm my theory about stretching rubber that allows 1/4 turn.

Sprayed silicone lubricant under the metal washer that's under the nut and also onto the lower part of the shock and now I'm able to turn it infinitely even the rubber noise is gone.

I guess I should remove the nut and look under the big washer to see if the rubber is parted from the metal. Won't be easy as the nut is inside the tower so I can't access it with a spanner. If I use a socket from above I won't access the allen socket. Any ideas?

I'll buy a 21mm deep offset ring spanner tomorrow and let's see. I'll probably have to get the strut mounts replaced. Do you have any idea what cost I am looking at with labour?

Unfortunately nothing can be seen without removing and disassembling the strut. The washer (upper strut stop) is so big that I can't see under it and I can't take it off from above as it can't fit though the hole in the strut tower.

Anybody swapped strut mounts on their own? Can it be a DIY job? I've found several posts and videos on removing the struts but all of them do it differently. What's the least pain in the * way if you do it yourself?

ttomtom:

Yes it's an easy DYI, but I would recommend doing in this sequence:

1) to remove the strut:
* remove brake caliper
* remove the bolt for the control link (sway bar to strut), and disconnect the ABS sensor (these are pricey..)
* remove the inner bolt holding the lower control arm to the subframe (to avoid damaging the ball joint rubber seal) and then lower the control arm from the bottom of the strut (put a piece of wood or something to support it underneath) as the hub will be held only by the ball joint to steering rack link.
* remove the three 13mm nuts on top of the strut (top of fender) while holding the strut with one hand and remove strut from the car.

2) to disassemble the strut:
* install a spring compressor (borrow one from Autozone)
* remove the top nut (21mm..?)
* I would recommend laying the parts in order as you remove them from the top of the strut to remember where they go.
While in there inspect closely the condition of the bearing (where the spring seats) the condition of the rubber perch for dry rubber and cracks (on the picture on one of the previous posts) and also inspect the dust booth and the hard rubber bump stop.

Assemble is in reverse, then you can get a good alignment.

Good luck!

Thank you, Gilles. I appreciate your help. Will post a photo of the condition of the rubber bushing once it's out.

How many miles on the car? If it is over 60K, then I recommend replacing the shocks, mounts, and bump rubbers while you have it apart. In fact, I recommend you replace the shocks as well, since they are probably shot by that point.

I'm also guessing that the creaking sound you heard is not the strut mount, it's the control arm that is making that noise.

When these cars get very many miles on them, the suspension parts all wear out rapidly. My car was making all kinds of noises, and with 144K on it, everything was shot. I replaced every part in the suspension except for the rear toe control arms, and now it is quiet and a pleasure to drive.

Only 47k. All four control arms were changed by the previous owners at 38K. Everything is tight no suspension noise at all apart from that creak.
Btw I could eliminate the creak by rotating the centre top strut mount nut a bit. The shaft turned with it. And as it was rotating it made the same creaking noise. That's how this thread started. I suspected that the shaft shouldn't turn in the mount.

The shocks seem good at least if I push the car down it comes back without bouncing. Is there a better way to check them? Once they are apart I'll see how easy it is to push them down and how fast they come back.

How can I check the bearings?

I'll also check the rubber boots and stops and bearing.

Unfortunately the bearing is at the top of the spring and you cannot see it unless you remove it.

Why don't you first try first tightening the nut by holding the shaft with a (torx or allen) wrench?

Goid luck

PS: look at Sunset Porsche Parts, under the front suspension section you should be able to see the bearing on their exploded view

It was tight. Still the shaft could turn in the mount.

I had similar creaking on my 986 S and replaced the coffin arm and this solved it.

Thanks but as I said they've been "recently" (9k miles ago) replaced and I could replicate the noise and even eliminate it by turning the strut shaft a bit. My problem is that I was able to turn the shaft in the mount.

Btw all google searches for creaking noise from front left bring up exactly your problem that's why it took me so long to identify the source of my creak. Interestingly others with worn out strut mounts experience knocking and clunking noises, not creaks. But things have always worked differently for me than for everybody else and the strangest faults come out for me all the time. Things that nobody else ever had. :confused: Not just with my cars. I've had enough time to get used to that.

If the hard chromium plating on the strut shaft is worn, it could certainly cause a creaking noise. And after rotating the shaft a bit, since it would reposition the shaft to a different area which is rubbing against the seals and guides, it could certainly quiet down the noise. MacPherson struts, such as exist in our Boxster in both front and rear, place demanding, bending loads through the strut shafts. That said, the mileage your reporting is fairly low. I'd say the noise, being non-uniform from the strut shaft being turned, however, is evidence itself that your front struts are shot. The best way to test shocks would be cost-prohibitive for average case (as its labor intensive) - remove shocks/strut, place on shock dyno, compare result to manufacturer specs. This makes sense for expensive/custom racing type shocks, but for off-the-shelf shocks, it probably would make more sense given the the relatively low cost of the shocks to just replace them if they're exhibiting any bad symptoms or have high miles.

Update. Strut mount was changed yesterday. The rubber bushing as expected was parted from the inner ring. Probably I shouldn't have rotated it especially not with force. Otherwise it didn't look too bad. But since it was the source of the creak it must have been worn before I touched it. Other strut parts look ok, bearing ok. The shock needed a lot of force to push all the way down and it took about 5 sec or more to come back up which I think is ok.

Only problem was I couldn't pull out the bolt that goes through the strut base and ends in the sway bar drop link. I removed the nut but the bolt didn't budge. I tried to to rotate the nut on the drop link side but that didn't budge either I even stripped it a bit. I ended up changing the mount while the base of the strut was in place.

It also took some time to put the rings back to the rubber boot on both sides of the control arm (tuning fork) ball joint or whatever it's called. They came off when I tried to push the arm back to where it belongs between the chassis and that L shaped plate.

So what probably happened is the rubber had come off the inner metal ring except a few patches that held it to the mount. The creaking noise was probably made as these patches were stretching as the shaft moved up down. That's also why I was able to rotate the shaft in the mount a bit. Then when I applied more forced those patches also gave up but interestingly they didn't come off at the metal but inside the rubber.

The fact that the rubber has come off all around so nicely suggests that the rubber to metal bonding was insufficient except where the patches were. What do you think?


https://i37.servimg.com/u/f37/19/34/39/30/img_3010.jpg


https://i37.servimg.com/u/f37/19/34/39/30/img_3011.jpg

The drop links come out really easy if you take the loading off them. Just use a jack to raise the LCA at the ball joint until the load is released. They will slide right out. I removed the lower bolt first and it made it easier to remove the upper one

I also removed the lower bolt. There's no load once the top of the strut and the other end of the drop link is unbolted. The wheel carrier is just held by the LCA. I even removed the fork arm.

Honestly, I would probably just bond it in the right location and call it a day(strong epoxy) . That rubber piece just acts as a spherical joint allowing the shaft to change axis without binding. The reason it failed as you can spot by the polished surfaces is micro compression cracks. Porsche lower control arms are also notorious for that. Its when the loading and unloading especially in compression creates tiny cracks that get bigger and bigger with time. I know Aluminium is a different material, but it is the easiest one to spot.

http://986forum.com/forums/uploads02...1486140867.jpg
http://986forum.com/forums/uploads02...1486141185.jpg

That is why when you sprayed lubricant it stopped making noise. The rubber surfaces stopped working against each other vs stretching as you were theorizing.

As long as the rest of the rubber looks good, go ahead and glue them back together and enjoy the cheap fix.

If the bushing is broken down, just replace the mount. They are not that expensive
Don't mess with trying to repair it

Wow, thank you for your scientific explanation WorkInProgressK!
What you say makes a lot of sense and is totally in line with what I've experienced and theorized. This issue didn't effect the handling of the car at all. If there had not been the creak I would have never noticed something was wrong. I suppose these bushings are in the same condition in most 986s they just don't creak. The shaft in my other strut can also be turned a bit in both directions and makes the same creak while rotating still it doesn't make the creak while driving.

If anyone feels like contributing please just remove the rubber cap and try turning the 21mm nut on top of the strut.

Btw, I've already replaced the strut mount I just didn't have time to take & post photos of the old one before.

Videos to see and hear what the creak was like.

This is the creak. The car made it when going over speed bumps or on rough roads. I couldn't replicate it for a long time (I always just pushed down on the car) as it only occurred when I grabbed the car at the wheel arch and pulled it upwards first. The creak went away when I turned the shaft just a bit by turning the nut on top of the strut.
creak - Sendvid

This is the same creak while the shaft is turning in the top mount.
creakwhenturningtheshaft - Sendvid

Since I'm not much of a DIY guy can you tell me what kind of money I should expect to pay for new shocks and struts on my 98 Boxster with 80M miles on it?

Also, is it a job that can be done at a "good quality shop" ( that works on my other non- Porsche cars) OR should it be done at more of a Porsche specialty shop?

Is yours making the same creaking noise?

I can't help sorry. I started doing everything I can on my own.
I don't think this requires a Porsche specialist though. It's the usual MacPherson strut most cars have.

@Rob175 - I recently paid $800 AU (approx $600 US) for a well regarded but not Porsche specific place to fit mine. I bought the shocks myself as they were cheaper to ship from the UK than to buy locally (??) and had them fit them, so that cost is just for labour and new bumpstops. I'd guess it'd be a little bit cheaper in the US because we generally pay more for labour here too.

Thanks for the reply. I suppose the best thing to do is to get a few estimates. Probably a couple from Porsche "experienced" shops and one from my normal go to repair shop that typically doesn't do a lot of Porsche work but has talented mechanics that do good work.

Well.......the shop that specializes in German cars wants about $2500 for new shocks/struts...... haven't gotten any other quotes yet, so nothing to compare that to.

Rob -

I'm in the middle of buying everything necessary for shock/strut replacement (except for springs) for my 2000 base. The part total at ***** (without shocks) is about $930, shocks from ****** are 675 Euros shipped to USA. If the $2500 is JUST shocks - none of the other stuff that should be changed - seems stiff.

Jim