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Discussion Starter #61
Sooooo!...in reading, basically I've learned that the shorter arm will bring the wheel up on whatever camber change is going to happen...more quickly. Since I'll have moved the arm upward (and have a bit of static negative camber...probably something less than 1°), the arm will have to move outward through the lower part of the arc...increasing negative camber first in order to even reach horizontal with the mounting point of the control arm (which may be nearly at the limit of upward suspension travel anyway). This would be right at the point where the camber curve would begin to turn positive...so it works. in addition, I'm relatively sure that the amount of caster I'm running (unmeasured as of yet...but as Dennis mentioned...visually it appears to be relatively substantial) will be a serious help with negative camber gain on turn in.

For those of you that don't know, negative camber is what helps keep the tire surface flat on the road in turns, or any other time the car transfers weight to one side or the other. It's most important in regards to cornering ability, but I think it's semi important in straight line driving as well...particularly if the car gets out of shape. A bit of negative camber stabilizes the car, and a stable car is a good thing.
 

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Caster is a big part of what provides straight-line stability. If you have manual steering, it'll get hard to turn. I think 3 degrees is recommended for manual steering, 6 degrees for power. Drag racers run like 10 degrees I've heard.
 

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Caster is a big part of what provides straight-line stability.
+1

I also see where Cris is going with keeping the tires flat on the pavement during turns. He is wants the best of both worlds.

I assume that Cris does his own alignments and probably knows what I'm going to write about Caster, but I'll write it anyways. ;)

Caster has no effect on tire wear so you can experiment as long as you remember that a change in caster can affect camber and/or toe.

For a street/strip car with manual steering, use at least 3 degrees positive caster for straight line stability and maybe up to 5-6 degrees max. You may want to go toward the lower side for lots of daily street duty but add more than 5-6 degrees and it won't be fun to turn.

I run 3.25 degrees positive and the car goes down the track straight as an arrow and drives good on the street. When I ran less it was pretty much always a puckering affair on the top end, especially with a cross/head wind. After such a harrowing experience, I added adjustable front strut rods and learned to do my own alignments. This also opened up the possibility for me to tweak the spindle tie rod arms downward in order to improve toe-in stability through a wider range of up an down motion.
 

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Discussion Starter #64
Caster is a big part of what provides straight-line stability. If you have manual steering, it'll get hard to turn. I think 3 degrees is recommended for manual steering, 6 degrees for power. Drag racers run like 10 degrees I've heard.
+1

I also see where Cris is going with keeping the tires flat on the pavement during turns. He is wants the best of both worlds.

I assume that Cris does his own alignments and probably knows what I'm going to write about Caster, but I'll write it anyways. ;)

Caster has no effect on tire wear so you can experiment as long as you remember that a change in caster can affect camber and/or toe.

For a street/strip car with manual steering, use at least 3 degrees positive caster for straight line stability and maybe up to 5-6 degrees max. You may want to go toward the lower side for lots of daily street duty but add more than 5-6 degrees and it won't be fun to turn.

I run 3.25 degrees positive and the car goes down the track straight as an arrow and drives good on the street. When I ran less it was pretty much always a puckering affair on the top end, especially with a cross/head wind. After such a harrowing experience, I added adjustable front strut rods and learned to do my own alignments. This also opened up the possibility for me to tweak the spindle tie rod arms downward in order to improve toe-in stability through a wider range of up an down motion.
Absolutely to both of you.

And definitely on the alignment thing Dennis, lol. I think 3-5° should be a walk in the park to get with this setup as/is. I used a straight edge and tape to rough check, and it's sitting at roughly 3.6° right now (there was 3/4" variance from vertical over 1' of length from the lower ball joint to the upper strut mount). I have an easy 3/4" of positive travel I can still tune in with the caster/camber plate.

As far as the best of both worlds thing goes...you're right!...but honestly its for a couple different reasons. I figure it like this. I'm designing this suspension virtually from scratch, and this car may not always be a straight line dedicated vehicle, you know? It would be shortsighted in the extreme not to build the best possible geometry into it that I can initially. Additionally, the fastest I've been is 132mph in the 1/4...and an out of shape car even at that speed would be 'puckering' as you put it, to say the least, lol. But it can happen easily, and I want a car that's going to be working to HELP me recover (via the caster as you mentioned, along with negative versus positive camber on body roll), rather than help me put it in the wall or worse.

To do anything less seems silly to me.

Oh, one other thing! I was over on Vintage Mustang Forums, and saw a post about a guy who built a $100 box to make the electric/under dash power steering work in our vehicles. Since the power steering units are only $60 or so from the junkyards...I'm seriously considering it. These cars aren't incredibly heavy on the front, and 4" wide front tires help with steering effort as well...but as you mentioned, more caster is just going to make that effort increase. An electric power steering system could be just the ticket to make whatever caster setting I decide is best into a realistic possibility.
 

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Discussion Starter #65
So, I made another change in the direction this thing was headed last week, when I sold the Versailles 9" for $900, and picked up an Explorer 8.8 for $195 today. Basically the main impetus was value. The 9" needed a complete remodel, and to get it where I needed it would have been about $1200 more. The 8.8 is probably 3x stronger as it sits than the old 9" was to begin with, and about 45lbs lighter as well. For those that don't know, the Explorer 8.8's come with 31 spline axles and limited slip differentials from the factory. The one I got happens to have 3.73 gears (wanted 4.10's but didn't feel like waiting as eventually I'm going spooled 4.56 anyhow, and the 3.73 traction lock will be worth more money than a 4.10 would), which is fine for now.

About the only pro I could see for the 9" is that...well, it's a 9". Everything else was a negative. Pros for the 8.8 were many. First we have the 31 spline axles, better gears, and LSD. I'd be comfortable putting the car on the road or even the track with that setup...whereas a 28 spline 2.78 open rear end would have been pointless. Another benefit is that the braking system is better, lighter, and I can still get pads and rotors for a reasonable price (crossdrilled/slotted rotors and pads from BrakeMotive are only $75/pair). After that comes the weight...as I said, the 8.8 is about 45lbs lighter overall. The final benefit is cost/value. The Explorer 8.8, with a new aluminum diff cover/girdle, new u-bolts, and new spring perches comes in well under $400 (it only cost $195 rotor to rotor, including the ARB which I think is going to bolt right into my car), versus $1200-$2200 for a similar 9". The negatives to the 8.8 are that I have to weld on new spring perches and cut off any brackets I don't want. Another negative could possibly be the passenger side offset on the pumpkin (roughly 3"). Before I cut anything up I'm going to set the perches on the springs in the car, and center the rear end over them so I can check the overall u-joint angle and see how it looks. If I'm not comfortable with it, I'll go ahead and press out the long side axle tube, cut it down to the same length as the short side (or possibly just pick up another short side tube), press it back in...and then weld both tubes to the center section for strength. At that point two short side axles will work perfectly.

Anyhow, there we have it. I have a better, stronger rear end...and $500 in my pocket to go with it :).

Here's some pictures:


The poor 97 Exploder who donated its rear end to the Cougar cause, lol. It was crazy...I watched them come to get the thing to remove the rear end. They took a huge freakin forklift and slid it under the thing from bumper to bumper (the grinding made me cringe!), then just picked it up and carried it back to their shop...dropped the rear end, then brought the truck back and literally dropped it in the same spot it was at previously. Nuts.


The new axle already home. You can see the ARB hanging out in the background.


Axle tag. If you go on a junkyard search, that little 'L' between the 3 and 73 is very important. Numbers you want are 3L55, 3L73, or 4L10. If it doesn't have an L, it's not a limited slip and you should pass.




Granatelli diff cover/support, Jeep 8" long u-bolts, and aftermarket 3.25"x2.5" perches. Grand total...less than $200.

Anyhow, I'll let you guys know how the driveline angle works out once I've got it roughly in the car. I don't foresee too much of a problem...but I won't know for sure till its mocked up.

Oh also, on another note!...I got my other strut/coilover setup in today. I also cut my control arms to bend them at the proper angle for the spindle and welded them back up. Once I get the strut rods converted to adjustable...I'll be setting the car down on its own suspension again.

I'm really hoping for this week :). I'll keep you guys updated for sure.
 

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Do those axle housing sides come off easily? As in, swapping the long side for another short side, or do you have no choice but to cut it down?

What's the difference (or advantage) between using this 8.8 and one from a Mustang or Lincoln?

I'm interested in swapping in an 8.8 in my 68 Cougar.

And I love this thread. Keep up the great work!
 

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Pros for the 8.8 were many. First we have the 31 spline axles, better gears, and LSD. I'd be comfortable putting the car on the road or even the track with that setup...whereas a 28 spline 2.78 open rear end would have been pointless. Another benefit is that the braking system is better, lighter, and I can still get pads and rotors for a reasonable price (crossdrilled/slotted rotors and pads from BrakeMotive are only $75/pair). After that comes the weight...as I said, the 8.8 is about 45lbs lighter overall. The final benefit is cost/value. The Explorer 8.8, with a new aluminum diff cover/girdle, new u-bolts, and new spring perches comes in well under $400 (it only cost $195 rotor to rotor, including the ARB which I think is going to bolt right into my car), versus $1200-$2200 for a similar 9".
I believe that another benefit of the 8.8 is that there is less of a power loss compared to the 9".
 

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Discussion Starter #68
Do those axle housing sides come off easily? As in, swapping the long side for another short side, or do you have no choice but to cut it down?

What's the difference (or advantage) between using this 8.8 and one from a Mustang or Lincoln?

I'm interested in swapping in an 8.8 in my 68 Cougar.

And I love this thread. Keep up the great work!
Thanks! I'm glad to share! It helps me out as well though...because when the time comes for me to do something similar to another car (or even sometimes when I go back to an area I had already done work on on the SAME car, lol), I have a documented step by step, made at the time I was performing the work. So often I have notes and measurements, but without being able to remember what I was thinking or what my intent was at the time...they're basically gibberish lol. Threads like these, and the discussions they cause, are like a diary of sorts. It really really helps. Every time enough posts have been made to cause the page to roll over to a new one...I save the last one as a complete webpage in .html format (I learned to do that when Woody deleted my entire build thread on SBFTech for the last Mustang). That way I have my own permanent copy :).

Anyhow, on the axle tubes...you have to disassemble the axle to a bare housing. My understanding is that you then just remove the plug welds (most drill them out), then press out the tube you want to remove. At that point you can just cut that tube down to exactly the right length, and get a short side axle to fit the new tube length.

The differences on the different housings are many!! The Explorer is the only housing which comes with 31 spline axles from the factory. These axles are substantially larger in diameter than the 28 spline units from the other vehicles...and so have a different bearing (so they can't just be swapped over to one of the other rear ends). Additionally, the Explorer has more aggressive gear options from the factory (3.55, 3.73, and 4.10...3.73 is the most common). The Lincoln axle is far too wide with a weird disc brake setup...the Fox body 8.8's are 4 lug, and even if you swapped in an Explorer 31 spline carrier and good gears, you'd need $pecial aftermarket axles with a necked down bearing end...and the same goes for the SN95 8.8's (regarding the aftermarket axles). The later model (99-04) axles are wider as well...at like 61-62" if I recall.

Dennis, you're 100% correct, although that comes at the expense of a bit of strength (probably not enough to mention). The reason is that the number of teeth engaged is higher on the 9" due to the lower position of the pinion relative to the ring gear. This provides more strength, at the expense of more frictional loss and less leverage.
 

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Some people have drilled the rosette welds that hold the tube into the pumpkin on the 8.8" and are able to pull them out.

My Dad and I tried to do that. We finally gave up and just cut 3" out of the tube.

Jet
 

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I cut sections out of my tubes also. I used an 8.8 from a mustang/t-bird just because it was lying around. I'm not making that much power anyways. I used two short side bronco II axles to get the length I needed.
 

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Discussion Starter #71
Some people have drilled the rosette welds that hold the tube into the pumpkin on the 8.8" and are able to pull them out.

My Dad and I tried to do that. We finally gave up and just cut 3" out of the tube.

Jet
I went over mine pretty closely yesterday, and it turns out that the three plugs on each side to hold the tubes on the Explorer aren't welds. They're pressed in plugs. I'm wondering if I can grind off the head, then press them all the way through the tube.

If I need to narrow it lol, I guess I'll find out!
 

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Discussion Starter #72
So last night I ordered $160 worth of rod ends and the drop links for the steering last night for the front end. Should cover me for both the suspension and steering. I could probably have picked up the grand total of six rod ends with the bump steer links for less, but in my opinion the front end of a street car is not a place to mess around. We'll often use aluminum units on the dirt cars...but the worst thing that will happen if you lose a tie rod on the dirt car is you end up in the wall. Yes, the car's damaged...but I've seen those cars hit walls at over 100mph and the driver walks away unscathed. On a street car, whether in traffic or on the track, the consequences are almost guaranteed to be exponentially worse.

Again, not a place to skimp for the purpose of saving money. I mean, my kids will be riding in this thing, you know?

On the rear end...I'm kicking around the idea of moving my springs inboard by 1.75". It'd be easy to do on the rear with offset shackles (or leaf spring sliders!), and it would allow me to build a front spring mount that has multiple mounting points for messing with instant center and anti squat, which I kind of wanted to do anyhow. Side benefits include greater tire clearance (not too big a deal as I'll likely never run more than a 275 radial), and that it would fit the factory spring perches on the Exploder 8.8 perfectly lol.

Anyhow though, just a few thoughts rolling around in my head. I probably won't decide a direction on the rear suspension until my front end is at least mostly together (meaning I can set the car on its front tires), and I'm at least most of the way through setting up the steering.

I'll be sure to keep you guys updated :).
 

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Glad to hear that safety comes first!

As far the rearend, from what I've seen offset shackles are longer and would raise the rear of the car somewhat more than stock. It would be better to relocate the rear frame rail inward somewhat and use straight ones for what you are planning.

I was also told not to use sliders on the street as they won't last that long, unless you know of some bushed ones. Otherwise sliders are cool and wouldn't have the height problem so you can fine tune the rear spring height to wherever you wish. You would still need to fabricate some type of mounting system. If the mount is something that you can bolt the slider to and be easily replaced, then it might not be a bad thing to try. That would also open up the option of using shims for adjustability.

In either case first check out the leaf spring-to-gas tank spacing on the LH side if you want to route big tailpipes in the stock location (that is IF you want tailpipes.) When I located my springs inwards 3" I lost nearly all that space and ended up routing the tailpipe to the outer side of the spring. We're required to have them here in PA.
 

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Discussion Starter #74 (Edited)
Glad to hear that safety comes first!

As far the rearend, from what I've seen offset shackles are longer and would raise the rear of the car somewhat more than stock. It would be better to relocate the rear frame rail inward somewhat and use straight ones for what you are planning.

I was also told not to use sliders on the street as they won't last that long, unless you know of some bushed ones. Otherwise sliders are cool and wouldn't have the height problem so you can fine tune the rear spring height to wherever you wish. You would still need to fabricate some type of mounting system. If the mount is something that you can bolt the slider to and be easily replaced, then it might not be a bad thing to try. That would also open up the option of using shims for adjustability.

In either case first check out the leaf spring-to-gas tank spacing on the LH side if you want to route big tailpipes in the stock location (that is IF you want tailpipes.) When I located my springs inwards 3" I lost nearly all that space and ended up routing the tailpipe to the outer side of the spring. We're required to have them here in PA.
You know Dennis, it's funny how often you and I are on the same page, lol.

On the exhaust clearance though, I'm either going dumps or side exit, so it shouldn't be an issue. Plus I'm only going 1.75" inboard, which lines the springs up with the frame in the front, and only a bit inboard in the back. Besides, I run 3.5" exhaust lol...tail pipes were never really an option.

On the offset shackles, I was just going to bend my own up out of one of those cheap lift kit sets (they're good, thick plate most often), cut them to the length I need, possibly run a brace between them if I think it's necessary, then box them in the back with a piece of 12ga plate for stiffness. Should be pretty easy to control the ride height in the back at that point.

On the sliders, I know a couple of local guys running them. I've also read that the bearing based sliders (the expensive ones) are the first ones to crap out. The nylon/Delrin/Teflon based ones, with the pucks...last forever, and even if they didn't you can buy enough to last a lifetime for less than $10, lol. A bit of graphite spray couldn't hurt the cause either, and wouldn't attract dust like grease does.

This is how I'd probably mount my sliders, when/if I go with them (only with a downward tilt):



Not too bad a setup, and easy enough to replicate.

In all honesty I'll probably just go the shackle route if I narrow the springs. There will be enough fab work in the front at that point, to keep the ride height from changing. I'm thinking of replacing the frame section that the leafs bolt to with a piece of .250" wall, 3"ID wide x 4" or 5" tall piece of channel iron. It would replace the frame completely in that area (and I'm sure increase the stiffness at the same time), and drilled properly would allow multiple mounting points for the front spring eye....sort of like the adjustable lower link on a 4 link. No bending...actually no real fab work at all other than the cutting and welding.

Here's an image showing what I'd cut out and replace with the rectangular channel for an adjustable setup. A single mount unit would be even easier:


The idea is that cutting that much out would allow the spring and caltracs plenty of room to fit with different mounting locations.

It's definitely something I'm considering.
 

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You know Dennis, it's funny how often you and I are on the same page, lol.
Kind of scary, huh??? :)

Here's an image showing what I'd cut out and replace with the rectangular channel for an adjustable setup. A single mount unit would be even easier:


The idea is that cutting that much out would allow the spring and caltracs plenty of room to fit with different mounting locations.
I suggest cutting all the way back to the rear to account for possible spring wrap-up if the springs are mounted all the way up like the factory. Its kind of important on the street to if you soften the shocks. Here is the way Heidt's does theirs and I can attest that it works:



You could still scab up the side of the rear frame. At the front you can get a good attachment to the torque box. I also incorporated the subframe connector into the mix since the front of the spring takes the most abuse. The Crites kit uses 1/8" plate, but for what you are doing I would also consider 1/4" and maybe a couple of gussets if the springs like being lower on the perch.

Also if you are looking at a traction aid, such as Caltracs there are other things to consider with your drop front mount.

I have lots of other photos if you're curious.
 

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Discussion Starter #76
The more I think about it...the more I like the idea of mounting the front spring eye centered in the frame. I have some 4" square tubing, and some .250" thick plate that's the right width to put inside for a just over 3" ID for the springs and caltracs. The idea is to cut one face out of the square tubing, which will be the bottom of the bracket. Shape it to fit the frame cutout, box it, and weld it in.

Basically this:



Would look like this (excuse the VERY rough sketch!):



I think it would be relatively easy, and there would be no compromise of structural integrity. About the only drawback is that I'd have to modify later subframe connectors to fit, lol.
 

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Discussion Starter #77 (Edited)
LOL Dennis!! I was posting while you posted...but yes, your picture would be even easier to pull off. Just replace the rail entirely with the square tubing, and weld one straight line.

I like it, and yes I would absolutely love more pictures. Anything you felt was pertinent. You could post it here, or email it to me if you preferred, whichever you like. The email is cris at blackbulletracing dot com. I live literally a mile from Valley Steel, and I get this scrap plate and tubing for $0.50/lb. That chunk of tubing would be literally $6.

I definitely appreciate it.

On a side note, this is almost exactly what I was picturing for the rear shackles:

 

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Forgot to mention that I like the slider mount that you pictured. Nice!

Spring at the center of frame ends up being a 3" inward spring move so it may not be what you want.

Personally Chris, if I was going through the motions of cutting and welding a new front perch, I'd move the springs in the full 3" from the get-go as its pretty much the same amount of work. The exceptions are that you would also need to relocate the spring perches on the rear housing to accommodate the relocation and you need to use a different shock or modify the u bolt perch because the travel is less and the shock will bottom out.

Then, if you wish somewhere down the road for bigger meats, you could finish the mini-tub by relocating the inner wheel wells and notching the frame right behind the axle. That is the route I had to take with my smaller wheel welled 65'.

Here are some pertinent pics and you can take from them what you want. Some of these are mine and some are collected from other sources, but they all started with the Heidt's 3" spring perch kit.

Crites relocation kit:



They come with no instructions and its up to the installer to do it as he pleases. That will explain why there are so many variations found on the web. In hindsight, it would be better to build it from scratch as the Caltracs added their own set of issues that needed addressed.

Mopar offset shackles:





























Not really fond of the look of the shackles. At first I didn't think the shackles were strong enough and put undue forces on the rear frame, but they are primarily there to carry the weight of the car. Its the front spring perch that takes all the abuse. I've abused mine for several years now and have had no issues with them or the frame rail. I did sleeve the aluminum bushings where the bolt rides to keep the shackles "loose." I also need the height that the perches offered so that the racing slicks could clear above the wheel well.

Also note how that nice slider bracket you sourced would work just about perfectly in place of the funky looking shackle. ;)

I still use the factory gas tank in the factory location, although I did do a little pipe and hammer clearancing on the LH tank side for added spring clearance:



Also, you can check out GYDYUP's build thread for photos and discussion. Its on his 67' Stang so it would be even more similar to your Cougar:

http://www.fordmuscleforums.com/mustang-pages-1965-1973/520993-mini-tub.html
 

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Discussion Starter #79 (Edited)
Spring at the center of frame ends up being a 3" inward spring move so it may not be what you want.

Personally Chris, if I was going through the motions of cutting and welding a new front perch, I'd move the springs in the full 3" from the get-go as its pretty much the same amount of work. The exceptions are that you would also need to relocate the spring perches on the rear housing to accommodate the relocation and you need to use a different shock or modify the u bolt perch because the travel is less and the shock will bottom out.

Then, if you wish somewhere down the road for bigger meats, you could finish the mini-tub by relocating the inner wheel wells and notching the frame right behind the axle. That is the route I had to take with my smaller wheel welled 65'.

Those pictures are awesome Dennis. That's very much how I pictured doing the work, but its still nice to see it in progress.

On the relocation...if I want to use the stock perches on the 8.8, I need the springs to be 39.5" wide. Factory spring width is 43". That's 1.75" per side. I actually measured from the center of the spring eye, to the center of the frame, and got 2.75" (close enough to your 3" measurement...I'll put a picture below). What I think I will do, is go ahead and offset the front the full 2.75" with the new piece of tubing, but I'll run two .250" plates on the inside (remember, it's 3.50" ID tubing), and none on the outside...and just tack them on the bottom to keep them from moving around (and keep them removable...which will allow me .500" total lateral adjustability in the spring eye). On the rear, I'll run something like 1.25" offset (I'll have to calculate it out), instead of the full 1.75". This will keep the spring pad centered over the axle, and keep the front spring toe in at a reasonable 1" per side. I've read elsewhere that many vehicles from the late 60's and early 70's had a good bit more (as much as 3") built in...and know for a fact that early Camaro's had substantially offset springs front to rear.

My one concern with this, will be whether this will cause any kind of binding issue with the caltracs. I'll be sure keep the rear mounted with rubber mounts to allow some deflection which should help...but honestly I don't think I'll know for sure until I mount it up. Worst case if it does bind, I'll simply move the spring perches on the axle inboard a bit and call it done.


Center to center from the spring to the frame.


Piece of 4", .250" wall square tubing. I think if I do it right, I could make two serviceable units from this one piece.
 

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Discussion Starter #80
I just glanced through that thread you linked Dennis, and while my Caltracs are the newer style with the spring stop held in with c-clips, I think I'm going to leave out the two .250" thick spacers and just use washers at the spring eye. This should eliminate any binding in the 3.50" ID tubing section, and still give me the full .500" lateral adjustment of the front spring position..
 
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