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Koni STR.T shock and strut discussion.....

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#41
Yes. Right now i am preparing to put the STR.T Koni dampers on my 2011 and also putting the Bilstein B6 dampers on a 2011 Fiesta project hatchback. I will post pics of the experience.
Thanks. I'm looking forward to seeing how things go. I'm at a pause at the moment while life gets in the way, so it might be the weekend or so before I get back to the garage.
 
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scotman

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Thread Starter #42
I received the rear shock bellows kits this afternoon. KYB. #SB125. They require some assembly involving pressing the foam bumper into the top of the cylinder that protects the piston from debris. I found that a small pair of scissors worked better than a screwdriver or knife.
Once assembled, these are a perfect dimensional match to the O.E. bellows that cannot be aquired over the dealer parts counter.
20210421_214928_HDR.jpg 20210421_215446.jpg 20210421_215534_HDR.jpg
 
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Thread Starter #43
A vise is nice. But not critical to the assembly of the few bits onto the piston. Once you remove the retainer strap the shock piston will extend itself.
In the second image the bellows is slid onto the piston and the mount is pressed onto the foam bumper. It takes a bit of squeezing to seat it fully.
Koni supplies a new, 13 m nyloc nut. The thread size and pitch is the same, koni just gives us a meatier nut than the 10 m nut Ford shocks got. And the next image is the completed shock.
Front struts next.
20210421_215736_HDR.jpg
20210421_214649_HDR.jpg 20210421_215736_HDR.jpg 20210421_214813.jpg 20210421_233408_HDR.jpg
 
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#44
I received the rear shock bellows kits this afternoon. KYB. #SB125. They require some assembly involving pressing the foam bumper into the top of the cylinder that protects the piston from debris. I found that a small pair of scissors worked better than a screwdriver or knife.
Once assembled, these are a perfect dimensional match to the O.E. bellows that cannot be aquired over the dealer parts counter.
View attachment 5054
I have the KYB bumper and shroud as well. I should have taken better photos earlier, sorry. What I'd found is that there's that angled cut or divot in the inner diameter of the opening of the plastic shroud that if you start pressing the bumper in at the right angle, you can twist the bottom of the bumper into the lip at the top of the shroud. It's like it screws or threads in. I also used the KYB upper mount. Like you, I found it takes some working to get the bumper seated in the mount but it does fit well and nicely tight. Given what I've seen of the KYB parts, they did a very good job with this set.
 
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#45
So I received official word from a tech service rep, named Mason, at Koni regarding the strut mount/bearing turning effort. I'll copy paste our exchange here:

Me:
I have a concern regarding an application with your struts and wanted to get some input from Koni. I have a 2011 Fiesta (non-ST) into which I’m installing a new set of OEM springs, strut bearings, and mounts with your 8750-1101L and -1101R STR.T struts. When assembled, but not installed in the car, with no spring pressure, the mount/bearing turns as normal, with the strut shaft tight in the mount plate. When the spring compressors are removed and the springs loaded up into the bearing/mount assembly, the bearing/mount become very difficult to turn.

At first, I thought this was an issue with the bearings. Replacing the new OEM with a set of KYB bearings/mounts made no difference. My thought is the spring pressure is simply pressing the shaft/piston assembly upwards in the strut tube with enough force that the piston is topping out in the tube and creating drag, and once on the ground and the shaft/piston moved within the normal travel range, there shouldn’t be an issue. Is this a valid theory or is there a concern that I would damage the struts? I’ve run Konis on various VWs in the past, but their mount/bearing assembly is different in principle and practice. I’m not used to the Ford style assemblies.
Mason:
Thank you for contacting us here at KONI NA. That is normal with the upper strut mount design. Once the spring is released it preloads against the rubber upper mount. There is no actual bearing in the front strut mount for the 2011 Fiesta.
Me:
Mason, thank you for the reply. I'm a bit confused, though. There's a swiveling assembly that the spring presses against underneath the mount that Ford calls a bearing (#9). Did you mean that there isn't a traditional or conventional roller-type bearing?
(I attached a parts illustration of the exploded front strut assembly, with the bearing labeled as #9)

Mason:
There is a thrust collar inside the upper rubber spring isolators that allows the mount to rotated once attached. Though once your release the compressors from the spring and it is allowed to preload, the force to spin that upper mount will significantly increase compared to when you have the mount under no tension. It should still spin, but will require more effort to do so.
So, it seems Koni considers the assembly a thrust collar and not technically a bearing, and that increased effort to get it to turn would be expected.

I guess the question, then, recalling the photos of the top mount/bearing assemblies, is to go with the OEM top parts, with the slightly tighter mount-to-bearing fit, or the KYBs which offer rotation at a very slightly lesser effort.
 

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#46
Thrust Collar?
1619194709697.png

Excellent!

I'll get more about this approach. As I learn more, I'll keep you posted.

This wording may have some answers as to what I'm looking for.

Although "Thrust Collar" in appearance, may not look right in being applied, in principle, it is. Bearing? Again, this can be applied but in either case, this simple cup provides several resources to handle the jarring of everyday life. It's simply absorbing, transferring the vertical motions to the cup, the Strut itself works to counteract the torque using friction to dampen the motion - the axial twist is thru the cup to allow the strut to only handle the vertical axis motions - the side to side or rotational torque can also occur thru steering - hence the "bump steer" effect experienced by an experienced user learning the performance curves of the vehicles driveline and powertrain.

This just helps me go in a direction to look for other methods and answers - Be sure to Tell them that we really appreciate their help in this.
.
 
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#47
I agree, it's an interesting use of terms. I see Koni's point in technically calling them that. What I'm not sure about is the degree of friction that the drag imparts on the assembly and how that affects driving dynamics. As long as it works while on the ground, that's fine. To be fair, I got my car with 22K miles on it, and I don't recall it being difficult to turn the wheel back then, so maybe premature wear or damage had already occurred. Even with the engine and ignition off, it feels like any other vehicle I can recall turning the wheel with the engine off.

Could that friction lead to increased wear? I don't know. I've got 96K miles now. Unless I find something unexpected when I take things apart, I'd guess that the Ford engineers did their jobs well. scotman had issues with his strut bearings, but they were apparently an earlier design. I have seen references on the web regarding a bad early generation design, which seems to be what scotman probably had. They were supposedly updated to the type that he and I are currently assembling our suspensions with.
 
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Thread Starter #48
Why I am going to continue to call it a bearing.
Ford has decided to deem this upper bump stop to be a bearing because they changed the part number. I guess that they can call a sewer rat a sirloin steak. but, that isn't going to motivate me to eat it. 20210423_190631.jpg 20210423_191655_HDR.jpg
 
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#49
What? What's wrong with sewer rat?


:LOL:

Yeah, I'll call it a bearing, regardless of engineering minutiae.

Is that one of your old strut bearings, the earlier style/part number? I don't think they're supposed to come apart like that, are they? :LOL:
 
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Thread Starter #50
That one is a old style used version. I just carefully popped it apart. It went right back together.
If you can guarantee that the rat will taste just like beef brisket, i will consider bringing the bbq sauce!
 
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#51
If you can guarantee that the rat will taste just like beef brisket, i will consider bringing the bbq sauce!
Maybe it would take Alton Brown, Bobby Flay, and Emeril combined could pull that one off. :LOL:

That strut bearing design reminds me of a much, much larger bearing assembly design that I've done testing work on. Is that a metal ring on the top half or shiny worn plastic? Thanks for posting that, interesting to see what's actually in there. (y)
 
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Thread Starter #52
The BB's ride on metal races.
 
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Thread Starter #53
Here is a stock front coil alongside the (non Supersport) H&R front coil. I will dust off my spring compressor and install a used, early version bearing and then i will try a new improved one and compare them, after dinner. 20210424_155008.jpg It's too rainy to get anything done in the yard. I will satisfy my curious mind, instead.... And probably drink a beer or two.. This is for science dammit!
 
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Thread Starter #54
Ok. My impression of the new versus the original upper bearing is that the new version has slightly less resistance to rotation than the original version. But I'm going to say that the difference is about 4 lbs or less of resistance.
I can turn the top mount with one hand while holding the strut pinched between my knees. 20210425_201809.jpg
20210425_194013.jpg
 
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#55
Thanks for sharing that impression. I'll bet your theory that the shorter progressive spring allows better movement is correct. If I may ask, is that a third-party dust boot? It looks like it might be upside down in that one photo.
 
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Thread Starter #56
The short spring setup is a little bit easier, yes. I wonder if that is partly why so many of the bearings split. Little preload then huge, sudden crushing impact?
I didnt put the bellows retainer ring on it and i inverted the bellows. I didn't think that would matter. That spring is under a lot of tension. When i use the short spring, that soft lip on the bellows helps cushion out some of the looseness
After twenty trips down Evergreen rd we will see if it lasts!
 
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#57
Evergreen? :poop: Good luck with that. My wife's lost at least one tire and one wheel on that road. Then again, we have a few spots around where I work that are down to the rebar.

Thinking about it, I don't know if it matters regarding the bellows direction, as long as it keeps the shaft clean. I'll be running mine with the regular assembly and put my faith in the lower isolator/seat that came with the struts. We'll see how that works out.

I'm probably assembling my struts this week, but still not sure if I'm going with the OEM or KYB set. The KYB seems to turn a bit better under spring load. OTOH, the OEM assembly fits together a bit more tightly, with less play, but this is unassembled, just on the workbench. Fully assembled, it may not make a difference. Either way, I'll have an extra set should the first set bash themselves silly and self-destruct in a short period of time, LOL! :LOL:
 
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Thread Starter #58
Evergreen. By far the worst road in metro Detroit.Just saying that word makes me reflexively grit my teeth and pucker my butthole. I am waiting for a pair of 5 inch diameter universal spring insulators to arrive. These will go on the front struts at the base of the spring. I hope that i can do an autocross event a couple of times this summer.
 

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#59
Evergreen. By far the worst road in metro Detroit.Just saying that word makes me reflexively grit my teeth and pucker my butthole. I am waiting for a pair of 5 inch diameter universal spring insulators to arrive. These will go on the front struts at the base of the spring. I hope that i can do an autocross event a couple of times this summer.
Not sure what you mean by spring insulators. Are those like big squishy washers that go between the spring and the perch? If so, wouldn't that create more spongy-ness in the ride...could be construed as more compliance? I remember throwing a couple of these in the bin when changing shocks on my AX Rabbit, ions ago. I wanted a direct feel and they seemed like they stood in the way for that. Care to clarify?
 

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#60
@scotman - SLOW DOWN!

Know that at the bottom of those Bellows, that clip on the BASE that the spring rests on, needs to be reversed!

Personal experience - you can lose a strut from debris getting caught up in the shaft and clunk/bang away until it falls out, but sand, grit and it's shards of broken rock/debris can work against that shaft - in the meantime; until it falls out. Having that bellows upside down, lets that shafts' smooth finish get exposed too much near the top and a lot of sand/road film/tar and dirt is getting ground up and tossed into there and gets sandblasted by the bellows not sealing right with the debris now sealed in there.. Working past the dust boot.

The Ford Bellows large end needs to be up - the bottom clip that holds the small end of the Bellows keeps it held to the bottom so the shock can extend and compress and keeps the struts shock absorber shaft cleaner from debris.
 


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