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Front end suspension - A frames

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Front end suspension - A frames

Post by MC247 on Fri Oct 21, 2016 12:01 pm

Morning,

I've been looking over the manuals which came with our kit and also looking at the front end from the 1989 ford mustang doner car we got (see picture). Question. I'm assuming we have to either remove the A frames of the ford front end to put on the healey frame and not that main frame (grey) as one piece. Or is it better to purchase new a-frames from Q1 like i saw in another thread?

I have been considering just buying all new A-frames, struts etc as we're starting from ground zero. Also toying with idea of replacing drums with disc and 5 bolt hubs all round for a wider selection of rims and tires.....hmmmm.

Front end of Ford: [You must be registered and logged in to see this link.]

Sorry for question; haven't done a kit in years and the manual while good to have isn't 100% clear on some stuff.

Cheers,
Mark

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Re: Front end suspension - A frames

Post by Hermn8r on Fri Oct 21, 2016 3:33 pm

I will assume you front end is a mustang II. So you can upgrade to the ford granada
5 stud rotors and you can get the disc brakes that bolt right on. Some
guys go with the GM adaptors and calipers as they give more clearance.
All kinds of after market upper and lower control arms you can buy as well
as the shocks and sway bars. Most people don't realize that The mustang II ball joints are actually bigger than the GM stuff. This is the easiest and cheapest way to go.

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Re: Front end suspension - A frames

Post by MC247 on Fri Oct 21, 2016 3:37 pm

I don't believe my Mustang is a Mustang II. I have the original bill of sale from the wreckers, it was a 1989 Ford Mustang LX with a 5.0 V8 HO engine, T5 transmission etc. Confirmed, nope, not a ford mustang II. But appreciate the input.

Mark

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Re: Front end suspension - A frames

Post by aronhk_md on Mon Oct 24, 2016 12:35 am

Normally if I am not mistaken much of the donor car DRIVETRAIN is a later model mustang....but the manual calls for a Mustang II front end for the car.  Your donor car front end is probably not what the manual had in mind.  No idea what your previous owner had in mind.

That said, one of the drop in MII kits from a place like Heidts is a good idea.  They give you a real lower A arm instead of the arm and strut of a mustang II. Personally I will be replacing my MII front end with one also designed off the MII front spindles, BUT it has a fully adjustable upper and lower A arm.  Its made by Checkered Racing.  Keep in mind that whatever you use, try to match the springs to the weight of the car. The springs on my car right now are too heavy and the car rides like a skateboard. My guess is that 200-250 pound springs are the max, and I plan to use double adjustable coilovers...either QA1 or viking.

In addition, I will be using the Wilwood Pro Mustang II spindle which is half an inch taller for better geometry.  Finally, I will be using the Kore3 front and rear Big Brake brackets to fit the MII Wilwood spindles.  They dont have it advertised on their website but they do make it.  With that spindle and 18" wheels I can fit the C6 calipers with their 12.88" GM rotor.  In fact, if I check my wheels carefully with their fitment tool, or go 19" wheels I could even fit the Z06 calipers with a bigger rotor, but not sure its necessary on a 2400 lb car.

For the rear end I have a 9" rear which is far superior to the 8.8".  Kore3 makes the GM big brake brackets to use C6 or Z06 brakes out back too.

The C6 vette brakes are great pieces, far less expensive than the Z06 and for a car with this weight more than capable even for racing. One can pick them up in great condition reasonably on ebay and combined with what Kore3 has to offer and the Wilwood Pro mustang II spindles it should be an awesome handling and stopping car.
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Re: Front end suspension - A frames

Post by David V. on Mon Oct 24, 2016 12:39 am

Does not look like an MII front end, you might want to look into a Fatman fabrication MII kit. From my experience, the best place to look for MII components is in classic truck and streetrod magazines and forums.

In theory... you could use that front end, but it would require a boatload of suspension geometry calculations and custom bracketry. You'll most likely save yourself a major headache by just going out and finding an MII kit.

David
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Suspension

Post by DrJ on Mon Oct 24, 2016 9:03 am

I have recently test drove my MX after well over a year of analysis, searching, fabrication and installation and I will call those efforts a win. My MX, like most, handled great but drove harsh...really harsh. The goal of my build is to have a touring daily driver that could, with a few adjustments, be run on a track. The first goal was to try to understand what I had and why it did what it did. David was good enough to post the analysis work I did. Check out the "Data" section under "Sebring Suspension Analysis". It gives data on sprung and un-sprung weight, OEM spring rates, their natural frequencies and natural periods. There is also information on the limitations of travel, the lack of anti-dive in the front end and the issues with how the attachment of the OEM upper control arms are problematic. It's a lot of words to essentially understand the following conclusions.
1. The spring rates, both front and rear, are to high
2. The natural frequencies of those springs, front and rear are to high
3. The relationship between those frequencies, front vs rear is opposite to ideal leading to undesirable pitching.
4. There is no allowance for adjustment
5. There was no anti-dive geometry built into the front of mine
6. The suspensions are old and the upper and lower control arm attachment pivots are fairly well frozen up adding to stiffness.
7. The vertical upper control arm attachment to the cross-member via slots is prone to shifting changing your caster and camber
8. The lower control arm is a rectangular beam stabilized by a strut rod. Those two structures generate different arcs during their travel fighting each other. Rubber bushings have to distort for it to work.

Otherwise it's a great system!

What I came to use was to fabricate and weld in new attachment brackets at the rear (My OEM was a 4-link coil but Hotrod started with a leaf spring set up). I installed coil overs utilizing a Vi-King double adjustable shock (spring height adjustment makes it a 3-way adjustable unit)-C208 and installed bearings at both the upper and lower eye's. The spring came from Gayle Bridges who was the only guy I found who could provide springs at the correct length and rate. Used 12" DP110 (110' per").
Up front I made up angle steel upper control brackets and welded them to the top of the cross-member. These were drilled horizontally in such a way as to provide 4* of anti-dive (the forward hole being higher than the aft hole). This also allows me to align the front with shims. I used Gayle Bridges upper control arms, 20001XR Fat Man style with XRF 772 ball joints. The spring are 13" 175 #per". Shocks are Vi-King C218-R.
The lower control arms are real triangular arms, strut rod is gone. There is some drilling and welding involved here as well and there were some issues that came up that required some didling but it's all in. The spring rates are within a correct mathematical range, the natural frequencies are now lower and the front/aft relationship is now correct eliminating the pitching issue.
So how does it drive? See my second post.

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Suspension

Post by DrJ on Mon Oct 24, 2016 9:29 am

With more room to write let me touch on some of the front end "complications". First up was that at full droop, the sway bar was contacting the outer tie rods. By making taller vertical sway bar links (the link from the bar to the LCA) I was able to rotate away the interference. That created problem #2. Now when I turned the wheels right or left the sway bar wanted to sheer off the flexible brake hose at the brake caliper fitting. To fix this and to improve the front brakes, I replaced the OEM 9" discs with the 11" upgrade kit from SSBC. The rotors are slotted (23059AE2R and 2L). Calipers are much larger single piston powder coated units (2206BK and 2205BK). Pads are semi-metalic GM D154 1084-2. What this gave me besides better brakes is the provision to use banjo bolt fittings for the flex hose. That allowed me to route the hoses away from the sway bar. The only other issue that came up with the parts I quoted was that I had to pull the rack of the cross member and file away 3/32" of material off the drivers side mount boss to clear the LCA pivot. A extra issue as well was that when I bleed the brakes some scale must have scratched the rear seal of the master and now it leaks so a new master is in my future.

So I have run a dozen test drives, each time carefully checking my welds and tuning the shocks and springs and it's a win in my opinion. I have a stretch of parkway that runs along Lake Ontario that is the New York State gold standard for undulating, pot hole impregnated concrete. The kind where most people drive on the shoulder to save their cars. Prior to the work I could only drive that at about 35MPH without breaking both the car and the driver. Now I can cruise it at 60 MPH and it drives as well as my F150 does. On your average road with average deficiencies it drives great and I still have softer adjustment levels remaining. No signs of the shocks bottoming out.

So there you have it. I have pictures documenting all of this which I hope to post in a formal builders blog once I figure out how to post a picture. I not dat smart digitally. Will also post the drive train work I did, essentially swapping out a Muncie 4-speed with a WC T5. That required replacing everything from the pilot bushing back to the rear end pumpkin with new clutch/brake pedal geometry and clutch master.

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Re: Front end suspension - A frames

Post by MC247 on Mon Oct 24, 2016 10:37 am

Hi DrJ,

Thank you for all the information, I have a lot to consider with the suspension front and rear, its simply a frame at the moment, a blank canvas, so to speak, of what can be done without breaking the bank.

Mark

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Re: Front end suspension - A frames

Post by aronhk_md on Mon Oct 24, 2016 2:07 pm

Without breaking the bank was my biggest consideration as well.

Most reasonable rear suspension would be leaf springs. I would mount them further inboard than the manual says to retain as much tire and wheel space as possible. I would also use a 9" rear for a few dollars more as it is stronger than the 8.8. You can buy used and cut to the width you need or buy new and just order the width.

Aother option would be to just buy a universal 4 link kit on ebay and use coilovers for the rear. This would give you much more option in the way of spring rate than the leafsprings will.

Either way, I would get the Kore3 C6 corvette brake brackets. Allows you to watch and wait for a nice used set of C6 brakes from ebay at a reasonable price. They'll make this car STOP.

Up front you can go with a drop in mustang II suspension. I would do one with adjustable upper and lower A arms as well as coilovers. You're going to spend some money here unfortunately and it will likely require work to fit. But it will be far better than original MII stuff.

I'm not sure what DR J used for a spindle in his front end setup, but my springs arent going to end up 12" for sure. Mine will be shorter.

Again, even though its not on the Kore3 website, if you use the Wilwood pro spindle up front it is 1/2" taller and Kore3 has a set of brackets to use the C6 corvette brakes up front as well.

I like the idea of C6 brakes because they are plentiful, very strong, inexpensive and available at any parts store if you happen to be on a weekend trip somewhere and something fails.
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Suspension

Post by DrJ on Tue Oct 25, 2016 10:10 am

Just following up on aronhk_md. I did reserve my stock Mustang II front spindles. My work indicated the need for a 175 #/" spring and it would have to be configured to fit the Mustang II cross member. That requires the spring to be 2 1/2" at the bottom to seat on the new adjustable Vi-King shock saddle and to be 3 1/2" at the top to fit the OEM cross member. Gayle offered such a spring but the shortest length was 13". Now keep in mind that the front end geometry is such that the coil over attaches to the LCA about mid way between the LCA pivot at the frame and the tire patch. That's a 2:1 mechanical ratio so in effect the resistance the spring offers to the sprung weight of the car is really only half the spring rate or 87.5 #/". The sprung weight of my MX averages out to about 633 lbs per front axle. The static compression (how much the spring will compress in response to the sprung weight of the car) would be 633 divided by 87.5 or 7ish inches. Sitting on her wheels the 13" spring is now a 7" spring. That said it would have been quite a challenge to fit a 13" uncompressed spring into the car so I had Gayle weld up my tubular LCA in such a way as the attachment point for the coil over is 2.5"lower than stock. Still plenty of road clearance and with that modification a 13" uncompressed spring is the same installation difficulty as a 10 1/2" spring. The OEM 300#/" spring that came out of it was 11 1/2". If memory serves me the new springs went in without need of a compressor. No worries there.
Much of this is covered in the data I posted. It's like 14 pages and could be edited better for clarity, something I hope to get to during the winter.

Now another way to go is to read Hotrods threads on his suspension work, far sexier than mine. He modified his cross member to accept a full coil over and every conceivable variable, front and rear, is adjustable. One scary talented dude.

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Re: Front end suspension - A frames

Post by MC247 on Tue Oct 25, 2016 10:35 am

Hi Guys,

Appreciate all the feedback, awesome stuff and lots to think about as we get closer to front end suspension.

Cheers

MC247

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Re: Front end suspension - A frames

Post by Hermn8r on Tue Oct 25, 2016 8:31 pm

I as implying the front end on your car is a mustang II. It is obvious the donor front end is not mustang II.
The very early cars had something else VW I think.
You can put anything you want up front if you got the time and money.

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Re: Front end suspension - A frames

Post by Hotrod on Tue Oct 25, 2016 11:35 pm

If that's an 89 Mustang front end, you will be able to use the steering rack on your Sebring.  Your front end is a Fox body Mustang.  

You will need an offset rack bushing on the passenger side since the mounting bosses are slightly narrower than a Mustang II.  The driver side will fit as is.
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Re: Front end suspension - A frames

Post by aronhk_md on Thu Oct 27, 2016 10:34 pm

Yes, I am using a complete coilover up front, unlike Dr J.  The spring height I think is 7".  I will be doing something similar to what hotrod did.

This is partly the kit I am using.

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But I will be using the Wilwood Pro spindle instead of what they offer, and the bolt on C6 caliper and 12.88" vette rotor kit from Kore3 for that spindle.

Also will be using the QA1 double adjustable coilovers, and will call them with the sprung weight for their recommendation on spring rate, though I think Dr. J is dead on with his calculations.
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Re: Front end suspension - A frames

Post by MC247 on Wed Feb 01, 2017 3:14 pm

Cheers for all the feedback, we're going shopping for MKII front end suspension!

MC247

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Re: Front end suspension - A frames

Post by MC247 on Fri Feb 03, 2017 9:37 am

Morning, working on the car front end suspension and trying to figure out what spring height I should go with. Seems there is a lot of options out there or overall length spring and rating, I'm thinking of 10" 250lb rating.....hmmm

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Front Suspension

Post by DrJ on Fri Feb 03, 2017 11:26 am

My OEM front springs were 11 1/2" length and calculated to be 300#/". The new Vi-King shock/spring arrangement is a 13" spring (3 1/2" at the top and 2 1/2" at the bottom) at 175 #/" rating. The coilover attachment point on the LCA was welded at a lower offset of of 2 1/2" to allow for the 13" spring.

Rear is a traditional coilover arrangement with a 12" 110 #/" spring.

Car drives a whole lot nicer and is now adjustable for track use if required.

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Re: Front end suspension - A frames

Post by bwdz on Fri Feb 03, 2017 12:12 pm

Where in Ontario are you? I have some extra springs and I am in the Detroit area so if you are near Windsor it's a quick drive. I have one set of springs that I am definitely not using and you are welcome to it. You can install them and later cut them to figure out what height you want and then you can order the springs you really want. My understanding is that the extra set I have was included in the kit from Classic Roadsters so they would be the ones they gave you if you ordered them for the Mustang II suspension but I am not sure if they were the big block or small block springs.

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Springs

Post by DrJ on Sat Feb 04, 2017 8:55 am

Just keep in mind that the OEM springs will generate the OEM ride which no one seems to enjoy. Cutting any spring in effect increases the spring rate of that spring which would make the problem worse. Just sayin.

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Re: Front end suspension - A frames

Post by bwdz on Sat Feb 04, 2017 10:59 am

I am suggesting these springs for purposes of figuring out the ride height he desires as I would guess they are not the rate he wants but once cut to correct ride height they can be measured and he can select a spring in the correct height and rate.

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Springs

Post by DrJ on Sat Feb 04, 2017 2:40 pm

My bad.

Although the forum members could supply ride height dimensions of individual cars and possibly save him some time. Thing is, you would need to determine the static deflection of both front and rear springs and that number varies with the spring rate. So if I am thinking clearly on this a 500 lb sprung corner weight will compress a 100#/" spring 5". The same weight will compress a 200#/" spring 2 1/2". You end up with different ride heights. Now with a coilover rear you would be able to spin the lower shock body spring saddle up and down to reestablish the ride height (within the limits of adjustable travel) but it gets more complicated up front. Adjusting the lower shock body spring saddle there will affect ride height as well as the LCA which usually wants to be level with the ground as well as the outer tie rod ends. Disturbing that relationship would, I believe, open up the possibility for bump steer.

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Re: Front end suspension - A frames

Post by aronhk_md on Sat Feb 04, 2017 10:06 pm

Coil Spring Specialties is a US company with a superb reputation.  Measure your car as it sits to the fender lip, give them the sprung weight on the corner.....then tell them what height you want to add or subtract from where your fender lip sits.....as well as what spring rate you WANT to have and send them your old spring.  

They'll test it, do the calculations, and VOILA!  A box will show up at your door.  From every dealing I've heard of with these folks they are spot on.  And coil springs are what they do.
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Re: Front end suspension - A frames

Post by MC247 on Tue Feb 07, 2017 12:20 pm

Morning,

Thanks for the offer on the springs. I'm in a perplexed state at the moment, i have the original springs which came out of the 1989 mustang 5.0 doner car, they are approx 14" length, the shocks are shot so will have to be replaced, the new upper and lower control arms should be here in time for the weekend. Do I use the old springs to check for clearances, or just buy single adjustable QA1 coil overs from Jeg rated with a spring loading of 300 or 400lbs and be done with it.

The springs you have? perhaps they would work and I just pick up a decent set of shocks......the QA1 ones I have been looking at are a tapered spring 2.5 and 3.5 top and bottom. These would give me a 7.88" compressed height with a 11" extended height (assuming you go with 375 lbs rated). And looks like they should bolt right in....




bwdz wrote:Where in Ontario are you?  I have some extra springs and I am in the Detroit area so if you are near Windsor it's a quick drive.  I have one set of springs that I am definitely not using and you are welcome to it.  You can install them and later cut them to figure out what height you want and then you can order the springs you really want.  My understanding is that the extra set I have was included in the kit from Classic Roadsters so they would be the ones they gave you if you ordered them for the Mustang II suspension but I am not sure if they were the big block or small block springs.

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Re: Front end suspension - A frames

Post by MC247 on Tue Feb 07, 2017 12:22 pm

Good point, appreciate the insight guys.

DrJ wrote:My bad.

Although the forum members could supply ride height dimensions of individual cars and possibly save him some time.  Thing is, you would need to determine the static deflection of both front and rear springs and that number varies with the spring rate.  So if I am thinking clearly on this a 500 lb sprung corner weight will compress a 100#/" spring 5".  The same weight will compress a 200#/" spring 2 1/2".  You end up with different ride heights.  Now with a coilover rear you would be able to spin the lower shock body spring saddle up and down to reestablish the ride height (within the limits of adjustable travel) but it gets more complicated up front.  Adjusting the lower shock body spring saddle there will affect ride height as well as the LCA which usually wants to be level with the ground as well as the outer tie rod ends.  Disturbing that relationship would, I believe, open up the possibility for bump steer.  

MC247

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Re: Front end suspension - A frames

Post by MC247 on Tue Feb 07, 2017 12:24 pm

Yeah, there in lies the issue. This car is actually just the frame sitting on stands in the shop, we are literally starting at the very beginning of building the kit and this weekend, we're putting on the new upper and lower control arms, new manual rack and pinion steering rack etc etc. My question this morning is around what QA1 coilovers to go with on the front, considering I might need to adjust once the car is actually on its wheels with full weight. OR do something less expensive, get the car built then rip out the old front suspension and replace with decent coilovers from someone like viking or QA1 once we have the full weight of the car figured out...Although from talking with QA1, I was advised that IF the front end weight of the car is below 1300 lbs, the 300 to 400lb rated single adjustable coilover will be ideal.....still thinking....

aronhk_md wrote:Coil Spring Specialties is a US company with a superb reputation.  Measure your car as it sits to the fender lip, give them the sprung weight on the corner.....then tell them what height you want to add or subtract from where your fender lip sits.....as well as what spring rate you WANT to have and send them your old spring.  

They'll test it, do the calculations, and VOILA!  A box will show up at your door.  From every dealing I've heard of with these folks they are spot on.  And coil springs are what they do.

MC247

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