Lower Control Arms & Sway Bars - Upgrades

6116 Views 59 Replies 11 Participants Last post by Johnp410, 8 mo ago

Caddyshack95

Discussion Starter · Jul 26, 2021

I have been looking at Lower control arms and sway bars to try and control some of the body roll and rear end noise in my car. I have FE2 suspension (OEM) and was looking at putting beefier rear and front sway bars in the vehicle. Read on some old forum posts that a fat rear bar will likely crack the original lower control arms so now I am looking at those as well.

UMI seems to be a great place to get LCAs from... I did see that new POLY bushes will make the car ride stiff compared to the OEM rubber ones. Is this the case? I'm looking to keep the ride as squishy as possible, but remove some sway and roll in turns/corners.

Anyone have any experience with the standard UMI bars? What about the Roto joints? Would those make the car ride more smoothly compared to 2 POLY bushings? Links below to see what I am talking about. The Roto joints look really interesting, but can't find much about just a streetable car that's driven gently most of the time.

UMI Performance 3615 - UMI Boxed Lower Control Arms - GM B-Body

UMI Performance UMI Boxed Lower Control Arms - GM B-Body - 3615

www.lmperformance.com

1978-1996 GM B-Body Boxed Rear Lower Control Arms- Poly/Roto-Joint - UMI Performance Inc.

UMI’s boxed lower control arms utilize our Roto-Joint technology for a bind free performance and quiet comfortable ride quality. The

www.umiperformance.com

Also, it's been recommended that I check out BMR sway bars - their rear bar is fat and should really control the back end pretty well. Front bar is smaller, but the set would probably even the car out well (replace both).

Free Shipping on all BMR Suspension packages!

Leader in High Performance Suspension and Chassis Products For American Muscle Vehicles.

www.bmrsuspension.com

Thanks for your thoughtful advice!

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Caddylack

· #20 · Jul 29, 2021

Considering what I know about your goals, be careful with poly bushings.

If you want that soft Caddy feel, I would probably only go poly on the sway bar bushings and end links. For the rest of the suspension, rubber will be fine.

Definitely +1 on the front frame brace. No downside.

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Caddylack

· #23 · Jul 30, 2021

Caddyshack95 said:
That's where I am stuck. If I want to add a stiffer sway bar, I'm going to have to upgrade the LCA.... But the new ones all come with poly bushings.

I have a tow pack so my front bar is already 30mm and rear bar is 26mm straight from the factory.

The rubber bushings are no doubt TOAST. So how soft will they really be right now? Will I even notice a difference between new poly and old rubber? Roads here aren't glass like FL or AZ, so we do have potholes. However, I go back to age of bushings and what the difference will be real world.

Any ideas on that front?

91ss said:
I've ran with stock arms and the 1.5" HA bar most of the 91's life. Close to 200k just as a reference. It's all how you treat, or abuse the car...

It is NOT necessary to upgrade your LCA's just because you upgraded your sway bar. Like 91ss said, it's all about how you drive the car.

If you are going to be tracking the car, you need to upgrade the LCA's, as they are one of the known weak points in our suspension. For a daily driver, I would not hesitate to use a set of new OEM arms. You will be fine.

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Caddylack

· #25 · Jul 31, 2021

Caddyshack95 said:
I see on both fronts here guys. So tracking it will almost certainly cause the system to fail with a new sway bar.... No track and massive stress, the new sway bar will be fine with OEM LCA (new).

So back to a point: New (OEM) LCA will certainly improve the ride quality as they are newer and new bushings. Is it worth the sway bar upgrade? As @Caddylack and I have been discussing via PM, my car already has thicker sway bars from the factory.

ADD: @Caddylack where do you even get a new OEM LCA? I can't find anything on RockAuto or Autozone....

Definitely verify the size of the sway bars on your car, just because there has been conflicting info posted here on the forum. Harbor Freight sells a little dial caliper for like 2-3 dollars or something, and you can use that to find out the exact size.

There may not be an OEM equivalent lower out there. I will have to check. I had a really tough time finding OEM rear uppers, and ultimately went with a Dorman part number that was listed for like 77-81 Caprice or something weird like that. You will be surprised what you find on Rock Auto if you spend enough time browsing.

The bushings are the same for the uppers and lowers, and those are readily available. I would say go ahead and order the new bushings and then have Brent press them in. He might be able to box them for you, I'm not sure.

You could always just order the aftermarket lowers with the poly bushings. It won't kill you to have a couple of poly bushings, but just think of it as a spectrum. The more rubber bushings that you replace with poly, the more firm the ride will be.

Keep in mind you also have bushings on your axle housing where the uppers attach, and those are more of a pain just because the axle is obviously attached to the car.

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Caddylack

· #26 · Jul 31, 2021

This just in:

Dorman 520571 is available on Rock Auto for $36

At that price, don't even bother with getting bushings pressed.

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Caddylack

· #27 · Jul 31, 2021

Dorman 520572 are the uppers, and they cost $20

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Caddylack

· #29 · Jul 31, 2021

95wagon said:
Think you will find the housing bushes are different.
Pre metric, they all were the same but when the other 6 got largers with 14mm hardware, the diff upper didn't

So, what you're saying is that the (older) uppers will not bolt to the 94-96 axle housing bushings properly? Swapping the bushings would solve this problem?

If those Dorman uppers don't work, then that would also be news to Brent.

The lowers should be a non-issue, as they are listed for 1992 Roadmaster.

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Caddylack

· #32 · Aug 1, 2021

95wagon said:
you might have misinterpereted my post.
At one point in this susps life span all 8 bushings were interchangeble.
When they became metric in later years, the housing mounted bushing did not change.
Then 6 bushes were the same , two were not.
Look at the hardware on our cars.
The bolts in the housing bushings are smaller dia than the rest.
Can't tell you the exact year change.
All 91-96 though, 14mm in 6 postions ,smaller dia in top housing.

Haha... This just happened the other day!

I knew exactly what you meant, and we are on the same page.

Caddyshack95 said:
Thanks for the good post. Incredible find on the OEM (sorta) LCA.

So are we saying that the LCA would fit right in to my car if I decide to go that route?

I need to verify my sway bar size, which I can hopefully do soon. Yes the poly spectrum makes complete sense. That and stiffening the frame a bit as well. I would like to look at how bad the LCA bushings are... That will also sway my decision (LOL).

That lower control arm is a direct bolt-in for your car.

The upper is almost a direct bolt-in, but will require some sort of adjustment (like changing the bushings on your axle housing).

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Caddylack

· #34 · Aug 4, 2021

95wagon said:
you might have misinterpereted my post.
At one point in this susps life span all 8 bushings were interchangeble.
When they became metric in later years, the housing mounted bushing did not change.
Then 6 bushes were the same , two were not.
Look at the hardware on our cars.
The bolts in the housing bushings are smaller dia than the rest.
Can't tell you the exact year change.
All 91-96 though, 14mm in 6 postions ,smaller dia in top housing.

Wait... I just realized I had it backwards.

If the housing bushing didn't change, then that means we know the older uppers will use the correct size bolt on that end.

It's the other 6 bushings that we need to be skeptical of, given we don't know the exact year they changed.

Is that correct?

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Caddylack

· #37 · 9 mo ago

I've never been fluted. Not even once.

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