Well, I now can say that I have!

The car is at the shop this week for some suspension issues. There is a pretty good clunk coming from the drivers side front corner when going over bumps(currently unresolved) but the back end had also been feeling really weird for a few weeks.

Seems like I was bottoming something in the suspension when going slowly over speedbumps, and on washboard stuff, the back end seemed to be doing the cha-cha. No issues on smooth pavement, but I told him when I dropped it off that something seemed weird.

Just before this started, I noted a big-*** puddle of oil on the floor in the garage by the drivers side rear corner. Having just had some oil line work, I assumed it was just a loose fitting. But my wrench said there was really nothing in that area that should have leaked oil.....but, the shock has oil in it!

Sho'nuff, when I called today, he said the left rear HD was blown. They have only been on the car for about 1 year. He is working with my supplier to see about a warranty replacement.

Good to know that I was not crazy and that there absolutely was something amiss out back! Now if he can find out whats messed up in the front, all will be right with the world.

BGL

 

Bilsteins are, in general, warrantied for life (I only say 'in general' in the event there's a circumstance I'm not aware of). I replaced two Bilsteins that were not working up to snuff, directly with Bilstein.

 

I drove the snot out of my 70 911T for 26 years on the same set of Bilsteins. They were working fine when I sold the car. I gave the new owner the lifetime guarantee certificates. I have never had the replace a Bilstein, so I would say you had some pretty bad luck.

 

I replaced a Bistein on my truck. I went to the original seller and they charged my credit card and sent me one. When I returned the bad shock, they credited my card.

All in all a pretty easy transaction.

 

My wrench is going to see if his normal Bilstein wholesaler will do a warranty exchange for us, and overnight a new shock. If not, I will give Bilstein a ring and see what the procedure is.

I don't have any worries that they will sort it out for me.

Would agree on the bad luck. But, as I posted a while back, it recently came to my attention that, for unknown reasons, the left rear perch was significantly lower than the right (maybe 1 1/2 inches lower). The car had been corner balanced, and while not perfect, was not too bad.

I can't say for sure if it had always been that way, but I am almost positive it was higher at one point. Leads me to wonder of the perch had somehow backed itself down over the year since they were installed?

Adrian did say he did not see a cause for concern, but I do wonder if there may have been an issue with the spring not properly tensioned leading to the failure?

BGL

 

How tight was the locking ring on the spring perch? It seems hard to imagine the perch could back down all by itself, and it seems by the time it went 1 1/2 inches the car would be leaning on one side, and have very strange handling characteristics. It is possible that the defective shock had lost its gas charge, and the difference in the spring setting was needed to compensate for the lack of gas pressure during the corner balance.

If the spring perch really did back off, your shock could have been over compressed and damaged by hitting an internal stop. In that case, it was not defective, but rather was not installed correctly. Bilstein would not owe you a new shock, but the installer definitely should make good on his mistake.

 

The rears do not have locking rings. That does seem odd to me, as the fronts do appear to have locking rings. Even without them, I can't imagine the ring backing off that far.

Not being a wrench myself, I don't know if thats right or not, but there are none for the rear. My wrench, when I first asked about the dissimilar perch heights, asked about the locking rings. When I said there were none, he said yes, there are none on the rears. So, it seemed that he was aware that the rears lacked the rings.

When the car was corner balanced immediately after the install (but at a different shop), I was sitting in the drivers seat up on the lift. I recall the tech commenting to another fellow that something looked odd on the left rear corner. I could not hear what he said, but with 20/20 hindsight, I wonder if he noted the disparity?

I would agree 100% with your comments on it not being a defective shock if the failure were due to improper installation.

I can say this, though. When the new damper goes in, and the corner balance is complete, I will place some paint marks or something similar so that I can keep an eye on things.

BGL

 

I did not want to mention this before, but if it takes a 1 1/2 inch difference to get the correct corner balance or ride height, it says some bad things about how straight the frame is.

They were very pickey if they asked you to sit in the driver's seat for the corner balance. The driver's weight makes both left side wheels carry more weight. The corner balance is affected very little - zero if the driver is mid-way between the wheels.

 

Well, they didn't ask me to sit in the car, I insisted. I always have my alignment work carried out with my butt sitting in the drivers seat.

I am not concerned about the frame. When I had the OE dampers, I also had it corner balanced, and the perch heights were just about even (still have the dampers up in the attic, and when I first noted the difference, I immediatly went up to have a look).

I suspect that this will boil down to one of three things:

1. A bad shock (not likely).
2. Inproper installation or corner balance (too low a perch setting) which resulted in the failure (most likely).
3. The perch somehow backing off, resulting in damage to the shock.

BGL

 

I don't understand how the adjusting ring could back off by itself. The spring tension alone should be enough to keep the ring tight. Not to mention the weight of the car added to the spring tension.
I also don't see how the installation could have been done incorrectly. It seems pretty straight forward to me.

When my Bilstein shock failed, there was never any question as to its cause. It was just one of those things. That's why they have warrranties.

Once you get the new shock reinstalled and a new corner balance done, you may find that the mismatched perches were correct for your vehicle.
Anyway, please keep us posted.

Colin

 

Will do.

As I said, the stock shocks were really close perch height wise, but thats apples to oranges, since I was running stock springs with the stock shocks, now I have H&Rs.

Just got off the horn with my wrench...new shock arrived today, so if all goes well he will get it in tomorrow, but it probably won't get onto the scales until Friday morning, and I likely won't get the car back until Friday afternoon/evening.

Have I mentioned that having only one car SUCKS? Good thing the wife has a SUV, or I would be very unpopular with the family right now!

BGL

 

Well, the car comes back late this afternoon.

My wrench called to say that, with the new shock in place and the car on scales, the perch heights as they were (with the left quite a bit lower than the right) are almost perfect weight distribution-wise for my car. I don't have the actual weight figures yet, but he said that I was pretty damn close.

I did ask if he thought the car had been bent at some point, and he said he really did not thinks so. Since I brought this to his attention a couple months ago, he has been checking all 964's that come through his shop, and he said that most are different to one degree or another, although he did concede that mine was a bit more than others.

I am looking forward to how it drives with the ***-end sorted out! It has really felt weird as of late.

FWIW, I do know that there had been some paint work to the right rear corner at some point prior to my ownership, but all previous alignments and corner balance sessions have come out well, so there has never been any reason to be concerned.

But I am still bugged by the fact that the OE dampers/springs did not have this disparity. Now I wonder if the H&R spring somehow has a different free length?

Oh well. If the car balances, aligns, and most importantly, handles right, I think I should quit obsessing over this, don't you think?

I will try to post the actual weight numbers, assuming he has recorded them for me.

BGL

 

The car came back Friday, and all is right with the world!

To recap, it went in to the shop to investigate some problems with the suspension...seemed like there was something very loose in the left front corner when going over bumps while that side was unweighted, and on top of that, there was a noticeable noise in the rear when going over speedbumps (even when doing so very, very slowly), almost like something in the suspension was bottoming.

It felt like there was something very wrong, front and back.

Oh, and lets not forget my concerns posted in a different thread about the left rear perch height being maybe 1 1/2" to 2" lower than the right.

So, as indicated in the title of the thread, the main issue was a blown HD damper in the left rear corner. A new one was secured and reinstalled. At that point, the car was scaled, and with driver (about 200lbs..), the weights looked to be pretty good.

Total weight = 3248 (with 200lb. Driver in car)

LF = 648, RF = 622
LR = 988, RR = 990

Not sure how much closer one should try to get them, but side to side and cross corner look pretty good to me. Given the accuracy of the scales and the fact that there surely is some stiction in the movement of the suspension bits, I am not sure how much better it could be.

As for the noises in the front, my wrench would not cop to anything specifically loose or amiss. He did put a wrench on every nut and bolt, and made sure everything was correctly torqued, but he did not say that there was anything specifically lose that would account for the obvious noises up front.

They also spent some time with a pry bar to try to assess the condition of the various bushings and what not, and nothing was found there either.

And, for what its worth, the weights mentioned above were with the perches more or less where they were. So, whether or not the car had been previously bent, thats what it took to get the weights where they are. Alignment comes out fines, too, so if it has been tweaked, it aligns and balances fine,a nd most importantly feels great on the track.

But as I said, the the car feels wonderful; like it did when I first got it back after the Bilstein/H&R upgrade. No noises whatsoever from the suspension....ride quality is actually improved over the factory Boge dampers w/stock springs. Bumps and road imperfections are quietly damped.

I suppose the issue with the noises up front could have been caused be the severe imbalance in the back with the blown damper (which would also have screwed up the cross corner weighting, right?). I guess the analogy would be a 4 legged stool with one leg shorter than the rest....no way its going to sit straight.

BGL