Rear Suspension Rebuild with Mark VIII arms

Stanley

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1997 Thunderbird 4.6L V8
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I'm looking for help. With the front suspension sorted and the hub-and-brake swap planned for next month, I'm beginning to plan the next stage of my car rebuild: the rear suspension. The rear seems to be much more of a pain than the front to put together a comprehensive package. As usual, I've found all sorts of information applying to different cars and part setups or recommending parts from businesses and people now unfortunately dead and gone. So I'm making an up-to-date thread to try and sort everything out for my particular usage case.

I'm going to post some parts and hopefully people can give me some feedback on fit (ignore prices: the listings are for part verification only). Like my hub swap thread, I plan to change this from questions to a guide once I've figured everything out.



I'll start with rear bushings. Assuming you're adding Mark VIII lower control arms, I'm not clear on how many you need. As best as I can tell, you want:

BUSHINGS
Subframe4 per side
Lower Control Arm (Mark VIII-specific)2 per side
Upper Control Arm1 per side
Spindle/Knuckle3 per side
Differential Carrier1 per side
Sway Bar1 per side

Subframe Bushings - 1 set
UHMW. Comes with new bolts. I believe only SCP does these.

Mark VIII Arm Lower Control Arm Bushings - 2 sets
Delrin. If you're swapping out your stock T-bird LCAs with Mark VIII LCAs, you then need bushings specifically made for the Mark VIII arms. I believe only SCP does these.

Upper Control Arm Bushings - 2 sets
Rubber. You don't have to use SCP here, but they'll ensure you get the right design, rather than ones that potentially don't work right (an issue on aftermarket ones, as a bad design has infiltrated the supply channel: both the correct, original design and the flawed replacement have shown up in the same packaging, under the same part numbers, from multiple brands).

(Despite the specificity on "inner", the upper UCA doesn't have any other bushing: what would be considered the outer bushing is actually in the spindle).

Spindle/Knuckle Bushings - 1 set
Polyurethane. Part number 4.3163.

Differential Carrier Bushings - 1 set
Polyurethane. Part number 4.1126.

Rear Sway Bar Bushings - 1 set
Sway bar sizes vary depending on the year and car subtype, and then there's aftermarket Addco ones which introduce even more variance. See this thread for a chart matching sway bar sizes to Energy Suspension bushing part numbers (also useful for other information).

As an aside, if you're deciding to upgrade your rear sway bar with an Addco one at this time and you're buying it new, Addco provides the correct mid-section sway bar bushings for your bar size with the bar, plus end links, so you don't need to buy them separately. General consensus is that you don't want to go more than 1 1/4" for the rear sway bar unless you're also increasing the size of the front bar.



Non-bushing bits:

Mark VIII lower control arms
Any year will do.

Mark VIII Arm Spring Perches - 1 set
Intended to allow a proper mounting of the Mark VIII arms on a non-Mark VIII car. I believe only SCP does these.

Performance Upper Control Arms - 1 set
Lighter and stronger version of the normal UCAs. I believe only SCP does these. Not necessary, but nice.

Rear Shock Mounts - 1 set
Any LX Bird needs this type. Super Coupes and the '89-91 XR7 use ARC (automatic ride control) and so require a different type. These are polyurethane; I believe only SCP does these.

Rear Coil Spring Isolator Pads - 2 sets
Part number 61709.

While badged as lower-only and specifically for Mustang Cobras, this works for our cars, and you just buy two sets instead of finding a separate upper set, since the spring diameter on our cars is same top and bottom (unlike Mustangs where it reduces at the frame).

Rear Sway Bar End Links & Bushings - 2 sets
Part number k8641.

According to SCP, any non-SC V6 and 4.6L V8 used 5/8"-wide rear end links (bushings?), while all Super Coupes and 5.0L V8 cars used 3/4"-wide end links. However, Moog only offers a single one-size-fits-all end link for 1989-1997 cars (linked above), with no dimensions given. Not sure who is right here / how this all works.



So, ignoring generic nuts, bolts, washers etc as any mechanic will have those, am I missing anything that I should be getting for a rear suspension rebuild? (I already have newish rear shocks.) Are there any better options than what I've listed in terms of quality, or something odd I may be overlooking? Is anything outright wrong? If it matters, I'm looking at a daily driver rather than a racing machine.

Thanks as always for your time.
 
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I’m a staunch the spring perch isn’t necessary believer, never ran them in my Mark LCAs

The SCP tubular UCA is a pointless bling item at best, there’s no reason whatsoever the stock ones need upgrading, they have one job and one job only and that is to keep the spindle upright, all other loads go through the lower control arm.
 
I beg to differ on that one, if you are running a lowered car the ucas from scp have better camber adjustment. Stock arms I always had negative camber, even adjusted all the way out. I run mine about halfway out and have a little positive camber so everything flattens out when I get on it. They also help with wheel hop.

As far as the list goes, some of those additional bushings you had are unnecessary if getting bushings from scp. He has the mark viii lca bushings, then spindle bushings in poly or uhmw, if you get the ucas then all bushings are covered. I think I've got everything except the subframe bushings, but that's because unfortunately my car is so rusty that if I try to remove the bolts they will just break. End links and sway bar bushings are a great idea obviously as well, other than that you have the toe compensators to replace or bypass with spacers if running the uhmw bushings

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I'm also running the poly spring cups, poly pinion bushings, pinion support brace, poly rear diff mount with Ford Racing reinforced diff cover, dss level 6 axles. I was tired of breaking stuff so I tried to build everything as strong as possible. The combination of all that plus 285s is so smooth, no wheel hop and little wheel spin, that's with around 500hp and 500tq.
 
As far as the list goes, some of those additional bushings you had are unnecessary if getting bushings from scp. He has the mark viii lca bushings, then spindle bushings in poly or uhmw, if you get the ucas then all bushings are covered. I think I've got everything except the subframe bushings, but that's because unfortunately my car is so rusty that if I try to remove the bolts they will just break. End links and sway bar bushings are a great idea obviously as well, other than that you have the toe compensators to replace or bypass with spacers if running the uhmw bushings

Sorry, could you specify which entries in the list I should delete (presuming I want to go with the SCP bushings and UCAs)? I've made some edits so it might be right now, but I'd like to be sure.
 
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Sorry, could you specify which entries in the list I should delete (presuming I want to go with the SCP bushings and UCAs)?
I would use as many parts off this site as possible:https://www.energysuspensionparts.com/products/ford_thunderbird_1996
The spring centering piece can be made for $20 each, from a 3"dia aluminum disk3"tall. Drill a hole in the center, bolt it in,buy 2 spring isolators, one top one bottom of the spring. Use the money you save to buy a new set of koni shocks for the rear.(02 mustang vert with irs)
The delrin bushings are only $20 more than the guy that designed them.
 
Ouch! That price hurts. I'll be going with these.

That's way better. At the same time, whenever I see a price differential like that, I'm inclined to think the cheap one is made of saltwater taffy. But I'll do some digging.

I would use as many parts off this site as possible:https://www.energysuspensionparts.com/products/ford_thunderbird_1996
The spring centering piece can be made for $20 each, from a 3"dia aluminum disk3"tall. Drill a hole in the center, bolt it in,buy 2 spring isolators, one top one bottom of the spring. Use the money you save to buy a new set of koni shocks for the rear.(02 mustang vert with irs)
The delrin bushings are only $20 more than the guy that designed them.

I did that: you'll see all the links up top are from that site (saw them recommended over at TCCOA; I used the 97 landing page instead of the 96, but it looks at a glance to be the same parts). My issue is that, because people use different names for the same part, and because the switching to Mark VIII parts and mixing in of Mustang parts clouds the issue, I'm not clear on what if any overlap I have in my list in my first post. AdamG seemed to be implying that I could cut certain entries, but I don't know what as I'm new to all this.

I made some trims to the list based on further research, so hopefully I have it right now (and I listed out the bushings in a new table at the start).
 
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That's way better. At the same time, whenever I see a price differential like that, I'm inclined to think the cheap one is made of saltwater taffy. But I'll do some digging.
That's my tendency as well. But I ordered a set of Dorman Premium lower control arms from CARiD and they substituted an SKP for one of them and it was absolutely identical, just considerably cheaper.
 
Why not just get the Moog part from RockAuto? Regular price is $25 and they have some on closeout for $16.

I probably will. With this sort of post I'm just looking to list what I need so that I can get feedback on whether or not it's right, rather than find the listing with the best price. In this case I went through the same website for everything to keep things quick. But it's accuracy that's my main concern: I'm not sure what I have listed is right.
 
I used one of the leftover urethane bushings for the mark kit;(they also fit the cobra irs) and cut it down for the stock rear swaybar link.
From Energy suspension and prothane, you want The lca bushings, the knuckle bushings, The diff bushings, the spring isolators, and the trans support. You want new toe links.
 
I used one of the leftover urethane bushings for the mark kit;(they also fit the cobra irs) and cut it down for the stock rear swaybar link.
From Energy suspension and prothane, you want The lca bushings, the knuckle bushings, The diff bushings, the spring isolators, and the trans support. You want new toe links.

What is "the trans support"?
 
There’s a bracket bolted to the frame rails that supports the trans. Bushings at each mounting point and the trans mount in the center.
 
I just came across this long-ago post from MN12 Performance with regards to the rear sway bar here:

"SC and sport-equipped cars have a larger 3/4" endlink bushing all others used a smaller 5/8"."

I'm not having any luck matching these figures up to part listings. Does anyone have an example of parts for these two figures?
 
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I just came across this long-ago post from MN12 Performance:

"SC and sport-equipped cars have a larger 3/4" endlink bushing all others used a smaller 5/8"."

I'm not having any luck matching these figures up to part listings. Does anyone have an example of parts for these two figures?

Maybe in bushing height? SC and sport springs tend to sit a little bit higher than LX springs so they may have used longer bushings to compensate….but that is literally the first I’ve heard that and that’s pure speculation. Definitely not true if referring to bushing diameter.
 
The original Sport and sc front lca's had a larger bushing, but those went away back in the 90's.
 
Digging around some more I found these links, which are the only items that are related and have the dimensions the MN12 post mentions:


The site says that the 5/8-inch-wide rear end links "were used in all the regular V6 (non SC) and the 4.6L SOHC cars" and the 3/4-inch-wide ones were "used in all the SC V6 and the 5.0L cars".

So lacking any other info I'm assuming that's what MN12 was referring to back in the day. With SCP taking over MN12's old business it makes sense that their offerings and dimensions would match up.
 
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Ohh! I was thinking the bushings in question were the lower ones that attach to the LCA. The upper makes much more sense
 
Ohh! I was thinking the bushings in question were the lower ones that attach to the LCA. The upper makes much more sense

The interesting part is where Moog only offers a one-size-fits-all rear end link for all 1989-1997 Birds. I'm not sure how to reconcile that with the MN12/SCP info. Especially since I've already ordered the Moog part...
 
The interesting part is where Moog only offers a one-size-fits-all rear end link for all 1989-1997 Birds. I'm not sure how to reconcile that with the MN12/SCP info. Especially since I've already ordered the Moog part...

Most likely it’s just the lower bushing, the upper has always been something you get as an end link assembly if the bushing goes bad
 

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