Shock mounts - replacement

jovani

jovani

True Classic
This is the correct forum to post my latest mod. Ford Focus strut mounts are easy replacement for low quality, hard to find or overpriced X mounts. Little machine work and 2 new holes are required, but nothing too costly. Obvious benefits are a decade of future availability at local pars store, rotatable if settle offcenter over time, cheap, and next week I will have the fronts work with the provided bearings instead of thrust washer. Pictured is the assembly in sequence. Detailed conversations are still in FS&W "Strut mounts wanted"
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Very cool!

Even with the "better" X1/9 mounts, I notice a lot more up/down movement than I would like.

I'm curious if your setup allows for a good amount of articulation (no binding) for all four corners? It should not be tight is what I'm getting at, it needs to pivot/articulate (as you steer for example or when the front/rear goes into bump/jounce).
 
Nice work Jovani. I’m just an outsider but if I may suggest creating a section just for fixes and bettering of this car. Like the brown wire mod, forward engine compartment insulation, brake and clutch reservoirs, ignition switch interchanges, this upper mount mod.
 
jovani said:
next week I will have the fronts work with the provided bearings instead of thrust washer
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This is exactly what I keep thinking about for these mounts, to use the included bearing with them. Not only will it offer a smoother steering response (by use of a roller bearing in place of the stock plastic thrust washer), but it follows the intended design of how these Focus mounts work. Although the Focus mounts are available with or without the stock Focus bearings, most sources sell them with the bearing so might as well take advantage of having it.

After taking some measurements I realized the Focus mounts are also great for coilover applications. It will be a week or so but I will post more details on that project.
 
myronx19 said:
Very cool!

Even with the "better" X1/9 mounts, I notice a lot more up/down movement than I would like.

I'm curious if your setup allows for a good amount of articulation (no binding) for all four corners? It should not be tight is what I'm getting at, it needs to pivot/articulate (as you steer for example or when the front/rear goes into bump/jounce).
Click to expand...
Answering myronx19 question. Of course the mount allows offcenter pivoting as the suspension goes up and down. These are front suspension mounts from a car with identical setup.
 
Answering Dr.Jeff. To use the provided ball (not roller) bearings, you need to replace the thrust washer with custom machined bigger version. Thrust washer's main function is to keep the top of the spring centered and yet allowing it to rotate around the strut (axle). The new one should not touch (at least not push underneath) the large thin steel original washer. It should be 86mm OD and at least 0.450" thick or little bit more at the last outer 1/2" to support the lower bearing race, also with raised small edge to provide centering for it. The whole assy will raise up the front of the car just a few millimeters, but I don't like that. Other solution is to buy 60x85x17mm roller bearing, but one is $57 and support/centering plate still need to be machined. So for now I will stay with the original thrust washer. My steering so far is light and super responsive.
 
jovani said:
Answering myronx19 question. Of course the mount allows offcenter pivoting as the suspension goes up and down. These are front suspension mounts from a car with identical setup.
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I agree. Take a look at this cross section of a similar top mount (ignore the red arrows, they were for a different purpose):

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Although this is not the Focus mount, it is the same design. You can see there is rubber between the center cones (top and bottom) and the outer frame. That allows some movement between the two sections. One is connected to the strut and the other to the car's body.

However Myron's question still has merit. I was playing with this more this afternoon. The stock Fiat mount has a much larger rubber section between the strut and the body. That allows more articulation to the sides (off axis movement) when the strut tilts (as with suspension movement):

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As with everything in life, both designs have pros and cons. The thicker Fiat version will provide a softer ride and more off axis movement, but will also allow it to degrade and sag more (as we find). On the other hand, the Ford version will last much longer but have a firmer ride and move off axis less. At first I was concerned about the difference in off axis movement.
When I put them on the car and leave the two lower mounting bolts off (so the strut body is not connected to the hub/spindle/knuckle), I can move the bottom of the strut in and out and watch the movement at the top mount. Both allow enough angle change to accomodate the car's suspension travel, so the Ford mount will work. But with the Ford mount, the more you deviate the strut off axis (beyond the normal range), you start to see it flex the top mount area inside the tower. This indicates the stiffer Ford mount will transmit more stress to the upper tower, so something like the "bigfoot doubler plates" should be used with them:

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jovani said:
To use the provided ball (not roller) bearings, you need to replace the thrust washer with custom machined bigger version.
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Understood. However on the Ford mounts the lower cup (center cone) extends down lower than the bearing. So the custom bigger version will need to be profiled on the top center portion to clear that extension. It just means a little more work to make it work.
 
Jeff, the Focus mount with my filler hat and the X with it's own have exactly the same hight, which means the Focus center (where top and bottom cups meet) is only 1mm lower than the X's, negligible difference. To use the provided bearing or go with 60x85x17, I already explained above what the only (and engineeringly right) solution is. When done, it will move the spring load from the center of the mount to its periphery, as designed by Ford, thus greatly reducing the load from more central area on the mount and the tower (Fiat or Focus with thrust washer) to a ring under the 3 mounting bolts, so Big foot doubling plate is not needed.
 
I think the difference we are seeing is I was measuring without a "filler hat" in the mount. I found the Focus lower cup is the lowest portion (when looking at it in its mounted position), and it extends down lower than the Focus bearing...at least on the one I have. This is not an issue with the Fiat parts, but more with the design of the new (custom) top plate that will interface between the Focus mount and the Fiat strut. Easy to overcome but worth noting. That custom plate will need to be turned on a lathe to include all of the needed recesses and height clearances. Unfortunately a lathe is something many people don't have, so I was looking to see how it might be done without one.
 
This all looks great. One question:

What drove your choice for which original hole to use as primary for the mount? Meaning, you chose the hole which is to the front on the X unibody and drilled the one to the inside and the rear of each shock tower.

Was there any particular reason for this? Not debating the choice, just looking to understand if there was a configuration reason (as in on a Focus it used the front hole on the vehicle’s longitudinal axis) that drove that hole versus one of the other two.

Thanks

Karl
 
Karl, the reason is that I tried to stay as close as possible to the nearest edge of the tower or nearest curve with each of the 3 bolts where the flat top is the least likely to bulge (the less flat area, the stronger it is using same gauge sheet metal) On the rear I avoid drilling holes where doubling sheet metal ends. Structurally from mount's point of view it doesn't matter how it is rotated.
 
For all interested, the Focus strut mounts come with ball thrust bearings, and even though they are designed to work with them, I tried to avoid extra machine work to keep the overall price low. (For my car I will do the extra work :) ). So, a roller thrust bearing, 45x60,3mm is added to the outside of the original thrust washer (washer will function as spring centering only). In my case I made new washers, because one was broken, but this is not necessary. I used aluminium, but next week will turn them out of ABS or acrylic, there are many plastic choices for better wear resistance. 2.5"O-ring keeps dirt away. Additional cost: 2 bearings with shims - $7, 2 O-rins - $4. As I mentioned before, I did not expect dramatic (if any) steering feel difference between thrust washer and bearing and that's what the result is. It feels just like original new thrust washer and new mount - slightly gummy, but I like it. If the new bearing is positioned as designed by Ford at the out-most perimeter of the mount, steering will be super sharp at a touch, but as I said, a new centering/support part must be made and ride will be a little harder. I will help everyone, who would like to do this upgrade, but I will not answer questions just to chat or to explain obvious stuff.
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OK so I would like to do this upgrade. Which company’s mounts do I need to buy and what are the next steps?
 
Here is a quick drawing of the X spring/shock to Focus mount. Do not pay attention to the top drawing, shows provided ball thrust bearing and the interference with spring perch, UNLESS the light orange centering custom part is made about 10mm taller, which will raise up the front. So the bottom drawing is what I have on my car, works fine so far. Note the light orange thrust washer is slightly thinner than the needle bearing next to it, it is free to float up and down by 0.2mm, just enough to center the bearing's washers, but not to work as thrust bearing anymore. As I mentioned, the needle bearing is easy addition, without it you have stock X configuration. The black round thing s 2.5"ID rubber o-ring.
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Excellent representation. I see how the stock perch interferes with the Ford thrust bearing; I agree, it's not worth trying to utilize it.

Here is a thought. If you have a lathe and wish to make the aluminum "inserts" a custom fit (as Jovani did), how about integrating the two (top cup insert and lower centering piece) as races for the needle thrust bearing. I'll try to illustrate with Jovani's drawing:

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The light blue and red areas represent the custom machined aluminum "fillers" / "races". The blue one fills the void in the top cup (like Jovani's) and also locates the thrust needle bearing as it's upper race. The red one centers the spring perch (like the stock plastic washer) and acts as the lower race to locate the thrust roller bearing. The two race portions would look pretty much like in the pictures below (from the M. Plaia steering bearing kit):

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The difference is with the upper race, because here it will extend upward to serve as the filler for the upper cup.
As you can see, these locate the thrust needle bearing by acting as upper and lower races. The bearing rides here:

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This way the two machined pieces each serve dual functions. Makes the design a little cleaner and better protects the thrust bearing.
 
Another suggestion. The Ford mounts are available with or without the Ford thrust roller bearings. They are almost half the cost if purchased without the bearings, which will not be used anyway.

The common interchange part number for the mount seems to be: 903928. Or some Ford part numbers: 4S4Z3A197AA, 6S4Z3A197A, YS4Z18198AA, YS4Z18198AAA, YS4Z18198CA, YS4Z18198CAA, YS4Z3A197AA. You may have to sift through them to find the correct part without the bearing.

I found a pair of them for around $25 (shipped) on eBay.
 
DrJeff, the whole idea is to have the least amount of custom machined parts and (no offense) but to machine the parts you suggest is worthless in case all you need is already there. The filler piece (in orange) can be stack of washers and the large original steel washer (light green) should not be replaced with aluminium, because the step on the shock is so small as area, it will penetrate into the aluminium when you torque the nut on top. Your red and blue outlines do not hold the needle bearing in place as shown over my drawing. So mount, needle bearing and o-ring in my case are $30 each set. Not bad for brand new, available and easy to convert mounts. That's the point. Just drill 2 new holes on shock tower.
 
jovani said:
For all interested, the Focus strut mounts come with ball thrust bearings, and even though they are designed to work with them, I tried to avoid extra machine work to keep the overall price low. (For my car I will do the extra work :) ). So, a roller thrust bearing, 45x60,3mm is added to the outside of the original thrust washer (washer will function as spring centering only). In my case I made new washers, because one was broken, but this is not necessary. I used aluminium, but next week will turn them out of ABS or acrylic, there are many plastic choices for better wear resistance. 2.5"O-ring keeps dirt away. Additional cost: 2 bearings with shims - $7, 2 O-rins - $4. As I mentioned before, I did not expect dramatic (if any) steering feel difference between thrust washer and bearing and that's what the result is. It feels just like original new thrust washer and new mount - slightly gummy, but I like it. If the new bearing is positioned as designed by Ford at the out-most perimeter of the mount, steering will be super sharp at a touch, but as I said, a new centering/support part must be made and ride will be a little harder. I will help everyone, who would like to do this upgrade, but I will not answer questions just to chat or to explain obvious stuff.View attachment 15339 View attachment 15340
Click to expand...


I like this. I think I should redo my rears when I put in the stiffer springs for the K24 swap.

I won't need them in the rear, however can you provide part numbers or reference sources for the bearings, etc? Doing a quick search for 45x60x3mm bearings does not show any hits. Plenty of 45x65x3.... 2" x what OD oring?
 
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