stupid koni stupid things
 

So like, my car has felt pretty crappy lately. First I thought my skills were just way deteriorating, but I started to get a sense that my shocks might not be up to snuff.

(My shocks are Koni Sports (yellow) which had the first set of "race" valving in them, which was later released as its own shock. I'm not sure my Fat Cat Motorsports bump stops and sort of prototype mounting from FCM are correct, so maybe they bottomed out. They always felt harsher when bottomed than the fronts which felt awesome since the FCM bump stops.

I bounced the corners of the car by hand, and I guess they stopped quick?

Then I turned up the stiffness, and it got much better for a couple days. Then it stopped being better. I noticed the car bottoms out a lot now where it didn't used to.

So I looked and my rear bump stops are both soaked with oil. One of the fronts is mint, the other is a little tainted.

Just recently, I noticed my rear end doesn't make the squish-squish sound it used to.

Is there any more definative test to do, or should I just send off the shocks for rebuilding? Is there any point to doing it myself?

One of the reasons (money aside) I'm wary to send them off for rebuilding is last time it took 3 months to get this done at Koni. Then I had AGX's (since sold), so now am I going to have 500 lb springs on OEM shocks? Seems a bad idea.

Lastly, I'd like to come up with a way to keep them from going boom every year and a half.

get illuminas

If you've got oil coming from the top of the tube where the rod comes out- that's bad. The SM Bilsteins are badass IMO for a cheap performance shock. I've saw an SM catch multiple feet of air and come down on the front tires - neither shock blew. And the ISC shock hats will give you all the travel you need.

sounds like you are too low for the konis, your cure will be shorter bump stopms and some taller top hats. search for what mxv did to make cheap top hats that seem to work pretty well. Do not downgrade to Illuminas, re-valve your konis to race spec and get some stiffer springs, i am sure you can make most of your money back by selling you current springs off
good luck man

fuck, I noticed oil on one of my bilsteins last week. fuck me in the ass.

have you tracked them yet? damn. All I can say is we beat the shit out of one set for three seasons and they never once had an issue.

cheapest top hat for extended shock travel evah- just add washer and bushing
http://i158.photobucket.com/albums/t...d/P7160002.jpg

Yeah, I would think that, but... I'm near stock ride height (maybe 1/2" low), and I'm running FCM mounts (not sure what these are doing for me). The springs are already 3 or 4 times stock, so they are pretty stiff, and I already have the race valving in there.

Basically I have no idea how this happened.

Why would I want shorter bump stops, shouldn't they prevent the shocks from bottoming?


ISC? Whazzat?


I'm thinking stinkdick will only further complicate my life, so I'm going to skip this. Maybe someone else on the board can help.

I'm talking out of my ass here, but isn't street driving exponentially worse on dampers than the track?

I don't get it man. Only thing I heared of blowing these is bottoming them out i.e. hitting the bump stops too much, that's why top mounts that give you more travel are such a good thing. Fatcat sells shorter bumpstops as well giving you a little more travel. I'm not sure which ones you have.

Yes, you don't have potholes the size of DC on the track, again, that's what kills Konis, bottoming them out repeatedly

I've never caught 2 ft. of air driving on the street. Maybe I'm not driving hard enough? :dunno:

Here's the ISC shock hat:
http://iscracing.net/images/01miataupperplate.jpg

Samething mxv made - gives the stock length body somewhere to go under compression and keeps the rod centered in the stroke at rest when the car is lowered. Dan is doing the same thing for the TEIN (more elegant with a spherical bearing).

What could be bad about hitting the bump stops? If you don't hit the bump stops, the rods will bottom out inside the shock, that does damage them.

The bump stops prevent the shock body from rising to the point where things connect inside.

So I would think a taller bump stop (while more likely to give you a sudden jolt in a turn and be bad for handling) can only increase the life of the shock by preventing this internal mashing.


Also, any feeling on running spec miata springs on the street? My current 500/300 # set up feels incredibly soft. Before I had FM springs (275/150 or so) on AGX's and they were super stiff.

Well, bump stops do compress, I am not an expert so I can't really explain it that well, but bump stops are more of like a safety net, you are not supposed to be hitting them or rideing on them with your shock body, every now and then is what they are there for. if you hit them repeatedly, that's how you blow your shock.

Ideally you want a bump stop that provides a good transition from your spring rate to the bump stops rate. Even more ideally you don't want to bounce off your bump stops- the idea behind the taller/deeper hats. Racers were trimming the bumps to increase travel w/o disturbing the actual spring rate with the bump - leaving the trimmed bump as a safety measure.

Springs? No problems. Mine are higher than SM and they ride great on the street. Shocks? Utter shit.

Currently i have the stock ones trimmed down, I think the Koni instructions even said to do that. Or it could have been the GC kit, i don't remember.

Well, I've got piles of travel, so I doubt that's the issue...

I'll see what I can do to get more travel, but at this point I'm thinking raising it up more might start to limit droop. I already can't get off my springs.

I still don't see how bump stops are going to hurt the shock.

What springs are y ou running? Which shocks? I didn't think the konis were stiff enough, even with the 'race' rates. But the car sure sticks.

I'm thinking I'll move the 500's to the rear and pick up ~700 for the front to make a set.

So, rebuilding your shocks yourself is not an option? I guess, at minimum, they'd be hard to pre-charge....

And, um, any suggestions on how to keep them alive longer?

again, shorter bumps from fatcat, and diy homemade tophats if you wanna go cheap, or just buy some tophats that give more travel, other than that, i dont know what to tell you

I'm sure that somebody around here will loan you a set of stock springs for long enough to get your 'Sports rebuilt.
Or you could just buy a new set of Koni Race shocks that won't leak and the shorter bodies will buy you a trifle more travel- you could even go back to a proper NB setup at that point. ;)

I like the idea. Except the part about buying it. Man those things are pricey....

a re-valve cost almost as much unless you make it down to Topeka and get them valved there at the nationals...they'll do it pretty cheap

Herm... I'll have to check - I think I remember getting them done for like $70 each...

700/450, RB tubular FSB, MSM RSB. Koni Race shocks. The ride is pretty smooth, as tolerant over rough roads as can be expected with full-blown racing spring rates, and it's a dream on tracks/autocross courses. I love it and I will never run anything softer.

Sav, we agree on that. Even though I'm at a measly 650/450 combo lol, believe it or not, but I found myself saying that i need more spring up front, but I am affraid my poor Yellows can't take much more abuse if i go higher spring rate. I plan on having my front ones re-valved to Race spec and to upgrade to a 750-800 spring.
Abe, $70??? Maybe that's why they keep blowing, lol. But seriously, the prices i remember reading were more like the in the $200's per shock. If you have a connection to get them done for $70 ea. please do share, i may end up re-valving mine sooner than expected.

Guess I'll have to check my numbers, I got them done at koni.

650/450 sounds low in front for sure.

That's a lot of sway bar! I'm sure it keeps it flatter/faster, but I bet it would stick better with a little lighter bar, esp in the rear. Have you played with that at all?

Anyway, glad to hear the konis hold up for you with those springs. I think a pair of 850s are in my future.

I have the FM front bar, and the smallest of the OEM rear braces in, with two bigger sizes plus the FM on the side in case I want to change.

I have the stock rear bar, may take it out completely though...
may even consider 850's when i do the re-valve
the front sticks real well, only downside is that i really feel the need for more spring, i am super pleased with the rear though, i would like a bit more travel though, i hit the bumps a few times and wasn't thrilled

Have you tried the FCM bumps? They are super nice - it's more sudden, initially, when you touch down there's more resistance than a light brush on the stockers. But they stay constant throughout. The stockers get suddenly stiffer (by design) as you progress through them.

Anyway, in the fronts I love the set up. In the rear it always felt way more harsh. My guess is the stops aren't long enough in the rear, and I'm feeling the shock bottoming.

I have the stock BS trimmed down to about 45mm IIRC.
In the back, I run my shocks at full soft, don't really bottom that often, i have an auto-x this sunday, i'll try to make it, if I do, I'll mark my rods in the back to see how close i get to bottoming out.
I don't think your rears are too harsh, I think you are bottoming, when you do your re-valve, sell those bumps over at Mnet and get the short fatcat ones and get different tophats, either NB, or the DIY ones like MXV has, or sell a kidney and get the FM ones...I still feel that the rear is more important than the front as far as top hats go, so do at least those, and get the stiffer springs up front...

man, this thread makes me want to redo my suspension, but I IS BROKE!

Yeah, I'd love to see that!

Oh, I'm sure I'm bottoming. There are some bumps on which you will ALWAYS bottom. The idea is to bottom onto a bump stop, if they weren't there for that, why not take them out entirely?

Some things to concider:
1) I drive an NB
2) I'm nearly at stock ride height
3) At 300 lbs/in, they aren't exactly soft springs
4) I don't have the shortest bumps FCM makes, but they are shorter than stock
5) I have the little split ring in there to let trapped air out

So I'm not riding on the stops. And I don't want to argue, but I've yet to understand what it is about hitting the bump stop that will damage the shock. It seems to me a TALLER stop would prevent me from pounding the shock, metal-on-metal, with the full force of the car on a hard bump.

Does anyone know the mechanism by which the shocks are damaged by hitting the bump stop?

Sorry, i should have specified more on my view on the bump stops.
Bumpstops are a must have!!! No if's or but's about it.
You need bumpstops, but at the same time, you don't want to ride on them and/or bounce of them, they are literally the very last resort to stop your shock from going further up.
http://www.fatcatmotorsports.com/suspension.htm
Look at pic in the link, when you lower the car your shock body moves closer to the bump stop. This means it has less travel then before and is now closer to the bumpstop. So you get a shorter bump stop or you get e top hat that gives you more room up top. Your shock body stays in same place, but you extended the rod length now and gave the shcok body more travel room/space and it has to compress more in order to hit the bumpstop. Sorry I suck at explaining things, but do you get what I'm saying?

My car won't rotate for shit without the MSM rear bar in. I had the stock rear bar in before, and it was better, but still pretty bad. The MSM rear bar really made it nice, and with the sticky tires it's great. I may drop a degree of camber out of the rear and pull the sway, just for shits and giggles.

Remember my shocks are factory Koni Races, not revalved/shortened Sports.

You're explaining it fine.

What I don't get is where the damage comes from.

As I understand it, the problem is the inner parts of the shock hitting the bottom of the tube.

So a bump stop would prevent that, and therefor a longer bump stop would prevent damage. Maybe my stops are just upside down.

Whose stops are you using? I am using the bumpstops that came with my shocks. They are pretty similar to the FCM, little short things.

Right, but your bumpstops compress, and everytime they compress they get weaker, and if you compress them too much, your rod still bottoms out inside the shock body, that's why a tophat with more room up top alows your shock to live longer, by keeping it from hitting the bump stop all the time...
it you can keep your shock from hitting the bumpstop as hard and as often you reduce the chance of bottoming it out, therefore prolonging shock life...

I've been lurking on this thread, and the same thing has been bothering me. Either I'm misunderstanding what Zabac et. al. are saying, or they're misunderstanding what you're describing.

Here's a hugely simplified view of the inside of a shock. Yeah, it's a monotube and I'm sure I got the oil/gas ratio wrong, but this is essentially what it looks like:

http://img28.picoodle.com/img/img28/...km_4b81af2.gif


If distance A is greater than distance B, then there is a potential for the piston to bottom out in the chamber, which is what bends rods and destroys shocks. As the overall length of the shock body decreases (and Konis have shorter bodies than stock), then the ratio of A to B increases. This buys you more useful travel before the bumpstop, but also increases the potential for bottoming the shock.

Now, to be honest I have no idea whether the internal design of the Koni Sport is such that it can bottom when installed on a Miata. It depends on the length of the rod (which I don't know) relative to the amount of travel before other pieces of the suspension come into contact- either spring coil bind or just control arms hitting solid things.

However, if we assume that it is capable of bottoming, then I don't agree with Zabac when he says: "I don't get it man. Only thing I heared of blowing these is bottoming them out i.e. hitting the bump stops too much, that's why top mounts that give you more travel are such a good thing. Fatcat sells shorter bumpstops as well giving you a little more travel."

First, hitting the bumpstops repeatedly does not kill the shock. Hitting the bumpstops routinely is just a fact of life when driving a Miata, particularly a lowered one with otherwise stock-ish suspension geometry. What kills shocks is if the bumpstop is too soft, too short, or both, such that you are able to compress it so much that the shock does indeed bottom.

Thus, stating that "that's why top mounts that give you more travel are such a good thing." makes no sense in this particular context. More travel is a good thing in terms of improving ride quality and predictability, but gaining more travel by either shortening the bumpstop or raising the upper mount, in theory, increases the likelihood of killing the shock.

Thus, Abe is dead on with "So I would think a taller bump stop (while more likely to give you a sudden jolt in a turn and be bad for handling) can only increase the life of the shock by preventing this internal mashing."

Incidentally, that's what those split washers that Shaikh gave you are for- they increase the effective length of the shock body.

Thanks for the pic Joe.
A taller tophat will make "A" longer and therefore reduce the chance of you bottoming out the rod inside the shock body.

when i said bottom out in previous posts, I implied the shock body hitting the bump stop and compressing it...this causes you to get closer to bottoming out the rid inside the shock

Assuming that the rod length and relative spring position remains constant, it simply lowers the car and increases the likelihood that some other mechanical interference will become the limiting factor. Assuming the same bumpstop, it does not alter the relationship between the piston and the bottom of the shock at full compression.

And this is wrong, at least insofar as a recommendation for shorter bumpstops is concerned. Assuming that the upper mount, length of rod, and length of shock body remain constant, increasing the length of the bumpstop will cause the top of the shock body to contact and compress the bumpstop more often and by a greater amount, however this does not in any way increase the likelihood of damage to the shock. Quite to the contrary- increasing the length and/or stiffness of the bumpstop will keep the piston further away from the bottom of the inside the shock.

Check out this illustration. A and B are the exact same setup. A is at rest, and B is at full compression. In B, the bumpstop has been compressed fully, and yet the piston has not quite bottomed out. This might be considered an "ideal" bumpstop choice for this particular combination.

C is the same setup, at full compression, but with a longer / stiffer bumpstop than B. The longer / stiffer bumpstop has not allowed the shock body to travel as far upward, and so the piston is further away from bottoming out. No damage, but you've sacrificed some potential suspension travel and roughened up your ride.

D is the same setup but with a shorter / softer bumpstop than B. The shock has fully compressed the bumpstop, and the piston has bottomed out. It's now rebuild time.

E is the same shock, spring, and bumpstop as A and B, however the tophat has been raised. The static ride height is lower. At full compression, the bumpstop has squished down to the same thickness, and thus the relationship between the piston and the bottom of the shock body is no greater or less than in B, using the same bumpstop but with a lower tophat. The only difference is an increased likelihood of coil bind or other interferenace.

Now, I'm not arguing against raised tophats. Quite the contrary- I use them myself, and for a given ride height they will provide more usable suspension travel relative to stock tophats. This is subject to the assumption made in F, that the spring perches have been raised up to achieve the same static ride height. Note that the bottom of the shock body in F is at the same place as in A, however the piston is further up inside the shock. That's the one penalty for this setup- decreased droop travel.

http://img30.picoodle.com/img/img30/...gm_cae2e83.gif

I don't think so, as Joe said, if A gets really long, what stops the rod from hitting? Nothing.

In my case, I have 7" springs, so I would assume the springs would keep me from hitting, and the bump stops, but I can't say for sure.

The plastic ring, Joe, as I heard it is to give air a chance to escape. Since the bump stops are custom why would they be 8mm short just to put plastic in there? The 'ring' has a cut out of it, I forget where the air gets trapped, maybe it was just making the bump stops suck down and wear out on the shaft, but whatever the reason, the ring is there to allow air to flow out (perhaps the top of the shock).

Anyway, I'm glad you tend to agree with me. I'll just have to find out what all the travels are and see if that's what's going on. Much more likely I hit a giant bump going 100 mph with a full trunk, and blew the seals.

That sort of thing happens all the time to me. I should be an action adventure hero. Instead of a 1.6 liter zero. hahahaha. Oh, I'm funny.

I do wonder if soaking the bump stops in oil is bad for them. I haven't gotten any love from Shaikh, I wonder if he's out of town or something....

Could be... I talked with Shaikh about this a while back. First off, they come in two thicknesses. We have the thin one. The thick one was something like 9mm and non-slotted, and definitely intended to increase the effective shock body length. My impression was that the primary purpose of the slot was to allow you to install it on the shaft without having to dismount the shock. The thinker one was non-slotted simply because the slot would do no good- the piece was too thick to allow you to flex it into position.

I didn't originally get them, but Shaikh sent me a set just after I got my revalves and bumpstops under the guise that they were there to protect the upper seals. Apparently he felt that when bumpstop squished and deformed against the top of the shock body, there was a possibility of the bumpstop material pinching the upper rod seal and damaging it. So I stuck 'em on and never gave it a second thought.

I can't really picture air being trapped inside the bumpstop. Mine (46mm linear) are a pretty snug fit against the rods.


Zabac, I'm really hoping that some of this is starting to make sense. Drawing those pictures in PaintShop and trying to keep them all consistant is damn tedious. :D

I'll draw some pics as well as i believe you are simply missunderstanding me, and that's my fault, ESL FTW, lol
So here is what I'm trying to say.
We are not really disagreeing, bump stops are needed, but a bumpstop can cause damage to the shock as Shaikh shared with you and that is why you want to stay away from being on it as much as you would if you kept the stock length.
The thing i was really trying to emphasize is what is depictesd in my poorly made paint work below. Your spring height does not chance, so when you compare the examples i have made, you can see what I am trying to explain all along, i just suck at it as much as I suck at paint

I realize my painting is not to scale by any means nor is it really relative to what actually happens, I really am no expert, but i firmly believe that taller tophats along with the right bumpstops (and if I understand correctly Abe does have the right bump stops, 46mm, that sounds right) will solve his problem.
Keep in mind, the springs will only compress so much, that's why you have to be very careful when setting your suspension up, especially when designing your own tophats as I plan on doing. Too tall of a tophat can lead to the springs seizing, and that's no fun at all. You have to retain proper geometry when doing this. Idealy, if I understand this correctly, you never want to fully compress the bumpstop, when at the bottom of your desired travel, you should be barely touching your bumpstop and only in extreme cases compressing it. To maintain proper handling characteristics, your bumpstops should be utilized, but not for the sole purpose of simply stopping your shock from being able to go any further.
Look at it this way, cars are equipped with 5MPH bumper covers, meaning that they will not sustain any damage at low energy impacts, but what happens to those bumpers if you hit a wall at 50MPH? Now i know this is an extreme example, but you get the point, right?

I think that's the issue, we don't really agree on that. The reason a suspension designer wants to keep you off the bump stops is they will creat a high jerk, using jerk in the technical term of rate of change of acceleration. This will tend to get the whole car body moving rapidly away from the ground and overall cause uncontrol suspension happenings. :-) You want things to be linear, or at least have no step-function changes.

The issue with your drawing, your assumptions, is that something will just magically stop the car from rising. Either the spring will bottom (terms like 'sieze' and 'bind' are misleading if you asked me, at least in the case of cylindrical coil-overs. 'Bottom' would seem a better word), and keep the rod from further enterting the shock, the bump stop will do it, or the shock will internally contact. If you don't design your suspension in such a way as to prevent that last issue, you WILL destroy your shocks and have to buy new ones if you ever hit a big bump.

This is not a blown seal needing a rebuild, it's utter ruin.

In the picture you have on the right, imagine the wheel still moving up, the little black plunger will bottom out in the tube.

For instance, not all cars have the bump stops on the shock, on some it's a rubber bumper between the a arms, or the a arm and the frame. These are obviously not bad for the seals in any way.

The issue with flattening (and touching to a lesser extent) the bumpstops is it shocks the car and will make you lose traction in a turn. Another issue is if you raise the hat too high, the wheel can not fall, and in a dip the wheel will leave contact with the road, reducing traction you could have had, as well as causing you to hit harder when you come back down, increasing the risk of blowing the seals.

I think it's very important to understand exactly what's going on here, and the range of travel you need, before blindly raising the hats. It's mainly done to offset the shortened travel of lowering a car, but keep in mind this messes with many things, camber rates and other such things.



As an aside, one thing I'm curious about is why you don't see more offset spindles.

Lets not get into the spindles yet, lol....lets agree on the konis first heh

As far as my inferior drawing goes, keep in mind that it is not to scale whatsoever.
My goal with taller tophats is to be on the safe side of things even though I may loose 1" of droop, I know too many local maita auto-x'ers who blew their rear Konis due to the lack of suspension travel. They kept bottoming them out. A good friend of mine who blew a rear shock three different times, went with FM rear mounts and never had an issues in 3-4 years since then. That says something to me, they are important, not so much up front as they are for the rear for this very reason.
When both A&B are equaly compressed, B has more room to go.
All other factors are constant, sprint rate, spring hight, shock body size, dampening rate of the shock, only thing you change is the upper mount localtion by extending it and giving the shock more safe travel.
Can we agree on that

I've briefly scanned most of this thread and it seems it is mostly of bumpstop and clearance discussion. If what I am adding has already been stated, forgive me for over looking it.

I believe you've just worn out your shocks. The race valving setup is not designed for longevity. THis is primarily an issue if the vehicle sees much street time.

You've obviously had the shocks in their "race" valved state for quit a while as I've had the first set of prototype koni races for several years now, and you stated you had the current valving since before the Koni Races were availible. A rebuild would seem the most likely answer to me... and if you are having the rears done, then have the fronts done as well.

...but to simplify the matter; Koni North America 859 586 4100. The lead time is longest in the spring before racing season begins. $75ish per corner was what I had last heard a year or so ago if there is no damage.

If you were happy with the koni races, then you need to find a way to keep them because there really isn't anything out there in there league for what you are doing.

/twocents

Peanut, he had his Konis re-valved several times, he is trying to figure out how to get more life out of them. That is why I am suggesting he gets some tophats that give more travel.
Since you have the actualy race shocks, you do not have this problem as those are much shorter as is.
Thanks for chiming in, seems you know the Konis pretty well. Can you tell me what you think about re-valving the front only to race spec and leave the rear as sport?

Gotcha ;)

I hate to keep adding on and risking being a repeatative know-it-all (especially if i'm wrong), but, ... I think the longevity issue is the price to pay with the "race" valving. Koni may be able to offer a stiffer "sport" valving that has the longevity Abe is looking for. I don't know the design of the valvings and build materials to comment with any detail.

As far as mis-matched valving, It seems I vaguely remember someone on miata.net or rr-ax.com doing that with reasonable success and a local was looking to do the same. I can certainly imagine circumstances where that is a legitamate option.

Reason I want to do this is because I am very happy with the way my rear behaves.
Up front however, i feel strongly that i need more spring, but at 650 I am already pushing the Sprots to their limit, i feel it. I am no expert, and when i say i feel it, it could simply be the placebo effect, lol.

I don't see how installing tophats with more travel is going to make one bit of different in the lifespan of his shocks.

I think we've clearly identified that we disagree as to the purpose of the bumpstops. To me, it seems perfectly obvious that the Miata was designed to use them as a part of the "normal" suspension process, albeit the design of them sucked on the NA. The "average" Miata owner, who is running "average" springs (200-400 range, for example) simply cannot stay off them. Simply raising them up doesn't change the fact that the shock will come into contact with them during normal operation.

Again, I'm not arguing against raised tophats in general. I like them, I use them, and I agree that more travel is generally better. I simply don't see how it will make one bit of difference as to the longevity of Abe's Konis. His shocks are dead because they are old and they have had a hard life, not because they touched the bumpstops.

Peanut,
I think you called it 100%. I've only had these rebuilt once, when I first got them. The price seems right, etc, as well.

I guess I must have had them on the car much longer than I realized, I think that's all I can say. I'm not as gentle on the car as I could be, and if you've had yours for years then I am sure that's my issue.

Now all I'm worried about is getting them back in time.

Top hats might help with the hard bottoming in the rear, as might taller, slower bump stops.

It's great to know it's the worst time to get them sent out. Perhaps I'll just do it in summer, and deal with the crappy handling in the meantime.

I guess we can agree to dissagree on this subject.
I don't think the bumpstops alone are what killed his Konis, I still think it's bottoming out because bumpstops alone are not enough as a solution. OEM bump stops would have killed them sooner. Don't get me wrong, I believe in bumpstops, just not as the answer to this problem, again, proper bumpstops are important, but our rear suspension geometry needs more help than bs can offer, no matter what bs you use.

The simple question is:
What is the physical mechanism by which oil has managed to leak out of my shocks, why have they stopped working?

My theory is the valve inside is bad, though I don't see how that makes oil come out of the top. That would make them stop working, but shouldn't make them leak.

So I imagine BOTH the valving is blown, and the oil seal is blown.


I can imagine the valving wearing out through much hard use (high internal pressures and flows).

I could potentially seeing the upper seal bad from the shaft going through it all the time. Perhaps it's worsened by the valving not working.