Since I had difficulty finding much information on the suspensions for these cars and available upgrades, I decided to post the little bit that I was able to learn from hands on experience. Awhile back while doing a brake job I discovered that my front lower sway had broken where it attaches to the end link. Some internet searching revealed that it was semi-common for the bars from these era cars to break in this manner. I had been noticing some weird handling issues, and now I knew the cause.

I had looked into upgrades some time ago and never found a lot of definitive information, the best I can tell is that there are 5 or 6 different size sway bars ranging from 26-34mm in diameter, as well as hollow and solid variants, and that this particular style has been in use on GM FWD Full-size cars for 15-20 years. Models that I know of that are compatible include Cadillac Deville's and Fleetwood's (FWD of course), Buick Lesabre's (possibly other models), Pontiac Bonneville's, Oldsmobile 88's and 98's (I think, and possibly other models), and no Chevy's that I know of.

My particular car is a 1989 Cadillac Sedan DeVille with FE2 suspension option, which meant I had the 32mm front bar. As I mentioned, I had looked into these once before and supposedly there's a 34mm bar out there, but as far as I can tell, it was only used on GM FWD Full-size Commercial Chassis models. So things like limo's, hearse', etc, but only the FWD ones would have it. I assumed that the larger size would be an improvement and tried to find one in the past, but to no avail. Addco also lists a sway bar in their catalog, but I can't swear that it's correct to the car. While it lists the same year, make, model and engine size of my car, it also says that it's RWD. Obviously Cadillac never made a RWD car with the 4.x line of motors (unless I'm mistaken, but I've never seen one). Not being able to confirm whether it was in fact correct, I didn't want to spend that much money only to have to send it back if it was in fact the wrong one.

Anyways, back to the main issue of mine being broken and in need of replacing. I started searching local salvage yards and online sites for a 32mm bar, since that's what was stock on my car. I only found one locally, and it was in poor condition so I passed. Then I found one on ebay for $55 off a late 90's Buick Lesabre. I was very happy with it, that is until I was getting ready to start the process of swapping it out, and on a lark decided to measure it. Turned out it was in fact a 30mm bar. I didn't want to downgrade, so I went back to the internet, found another 32mm bar, this time off a late 90's Pontiac Bonneville SSEI for $50.

On a side note, since I was removing them anyways, I also ordered a new set of sway bar bushings, and I've been a huge fan of MOOG products for years now, so that's what I ordered. I was at first concerned that I had been ripped off, because when I opened the MOOG package, it said right on the bushings, RAMCOA: Made in the USA. A little web searching revealed that apparently MOOG has started outsourcing a few things, rubber bushings being one of them. So if you get a RAMCOA part in a MOOG box, it is correct. Can't say that I'm impressed with this, since I'm paying a premium price for a premium brand, I expect to get the brand I paid for, not a 3rd party brand part. Only time will tell if they'll hold up as well as I'd expect from MOOG.

So back to the main topic, I set about tearing into the car to get the sway bar out, and i can offer a few tips that at least apply to '89 Cadillac's, although I suspect the same would be true for any model using this style bar. Wheels gotta come off, (duh), remove the end links, (this would also be a good time to replace those since they're coming off anyways and are cheap, I didn't because I just did a complete overhaul of the front suspension last year, including new struts, springs, bearing plates, outer tie rods, ball joints, wheel bearings, axles, end links and control arm bushings, never expected to ever have to touch anything under there again, but wasn't expecting that bar to break either).

Next I removed the sway bar bushing brackets. These will be a little bit of a pain, since the bolts will be rusty and have probably never been removed. It's also a bit of a tight fit to get tools to the bolts, so you may have to get creative. For the bolt closest to the wheels, to break it loose I used a wrench with the box end on the nut, then hooked a second wrench onto the open end side for twice the torque, (a trick I picked up from my grandpa, but this greatly increases the odds of breaking the wrench, so I'd strongly recommend doing it only if your tools have a no questions asked lifetime warranty, for example craftsman). I used a 3/8" ratchet with a home-brew extension for extra torque (a deep well socket big enough that it slips over the handle of the ratchet and a 10" extension in the socket) to finish removing it. For the bolt further away you have a little more room to work, and can get a 1/2" ratchet in there, but it seemed harder to break loose so I used an 18" breaker bar to start, and then back to the ratchet. And if you look underneath the frame, you'll a find a hole or two where you should be able to see the threads of these bolts sticking through, and from here you can easily squirt some wd-40 or penetrating oil onto the threads to help with the rust when you remove them.

According to both the factory service manual and a Haynes manual, you also need to disconnect the exhaust and outer tie rod ends. I skipped both these steps to see if I could save myself the hassle. Once I got the bar unbolted from everything and tried to pull it out, it only took a couple minutes to realize that the tie-rods would have to be disconnected. Once they were popped out, the tie-rods could be moved out of the way, and on whichever side you pull the bar out from, (I followed the instructions and pulled it out from the passenger side), you'll have to take the brake disc/knuckle on that side and turn it away from the bar. I'd also recommend pulling the bushing brackets and the bushings themselves off the bar, since getting it out is a tight fit even with them off.

From here it's a little bit of a puzzle, but the main trick seemed to be this: once I had it nearly all the way out, one end was up in the fender well and I couldn't get it down enough to clear the fender without potentially catching and damaging the chrome trim piece there. So I pushed the bar back in a little bit, spun it around 180°, and then it popped right out. Right away I noticed something about it though, it weighed a fraction of what the other two bars that I had bought weighed. I knew that the bar on my car was a 32mm hollow bar, since I had previously measured it, and from where it was broken I could clearly see that it was hollow. However the extreme weight difference made it clear to me that both the 30mm and 32mm bar that I had purchased were solid bars. The solid bar easily weighed twice as much as the one I pulled off my car, so I was delighted to discover that this was going to be a substantial upgrade.

Again, I don't exactly when they made the switch from hollow to solid, or if they were both used and which cars got what depended on models and options and etc., but I can say for certain that the late 90's bars I bought were both solid. (Don't quote me on this, because I bought two within a couple weeks and I don't have the paperwork in front of me, but I'll double-check to make sure I'm right), I believe the solid 30mm bar came off a '99 Buick LeSabre, and the solid 32mm bar came off a '98 Pontiac Bonneville SSEI.

Also, as I noted before, I didn't bother to remove the exhaust, since that's an even bigger PITA, and it didn't seem to cause any problems. Granted, at one point it would have been nice if the exhaust pipe was raised up an inch or two, but I got the old bar out and the new one in with it still in place. Potentially though, because when Cadillac went from the 4.5 to the 4.9 liter V8 they increased the diameter of the exhaust by a 1/2", that might make it just tight enough that it won't work without removing it. It was tight with mine, and I had it wedged against it pretty good at one point, but with a little elbow grease I was able to work it past that point both ways, but with a slightly larger exhaust pipe I don't know.

And again, at some point once I got it started in (I intentionally started with it spun around 180° since that was how I got the last section of it out), I then had to spin it back around 180°. Getting it in was definitely more of a challenge than getting it out, but I managed. One thing to watch for, if you start it in from the passenger side like I did, as it enters into position on the driver's side, there is the potential for it to catch the front-passenger side brake line near the bottom of the driver side wheel well. At this point, I had the bar tilted just right that I got it kind of wedged up against the strut on the passenger side and I had to keep tapping it with a lead hammer to push it through. I did have to push the strut forward some during this, but they have some give to them so no worries there, I just had to keep checking after each little bit of movement that it was catching the brake line on the other side. Also, it came through on top of that brake line, so once I got it far enough that it was again free, I had to carefully pry that brake line back just a little to get the bar down into proper position on the driver side.

From there it was a simple nuts and bolts process of putting everything back together. To aid the installation of the bushings, I greased the bejesus out of the bushings and also applied some to the bar itself. Once I got them started they slid all the way into position with little effort. It's possible to put them on backwards, but if you pay attention to how the old ones came off, or just look closely at how they will sit on the engine cradle, it's clear which way they go on. Make sure you torque everything, double check that you haven't missed anything, and you should probably grease the tie-rods since you had them out, (and you may as well grease the ball joints as long as you're there).

Finally I had it done, rotated the tires as long as I had it up on the hoist (I forgot to mention that, I have a car hoist at my disposal, makes working on cars a million times easier). And then took it for a test drive to see how it felt. First off and most importantly, the weird handling issues were gone, it drove like a normal car again. And second, if you get the chance to upgrade your caddy from the hollow bar to the solid bar, DO IT!!! I can't begin to tell you how much better this car drives. I haven't noticed any adverse effects to the stiffer bar, and the advantages are amazing. It stays almost perfectly flat in the corners, no matter how hard I push it. I still need to take it back onto the curvy highway near me to test high-speed cornering since it was raining that day, but in town today where it was completely dry I decided to push it harder.

On a quiet street near me there's a sharp left turn and then a sharp right turn, speed limit of 25mph. The curves aren't quite as sharp as going around a corner at an intersection, but close to it. Previously I could take the curves at 25mph no problem, start pushing 30mph though and the car didn't like it much. After the sway bar broke, I could barely make the corners at 25mph without the tires squealing, so I was backing it off to 20mph. Today I threw it into the corners at 35mph, and although I could feel some g-forces at work (it is a big-*** car afterall), it tracked perfectly, stayed almost completely flat and never heard even the slightest chirp out of the tires. I suspect I could probably take them at 40mph without much issue, but it's not an ideal place to be speeding that badly.

Well, I think I've written way more than I needed to, but hopefully some of the information was useful. And if anyone has questions about it, I'll help if I can. And once I get a chance to try out some higher speed corners I'll post an update. BTW, it should be noted that I don't run stock tires on the car, so with normal tires I probably wouldn't be able to corner as hard with it. I'm running one size wider than stock, (and I may go another size wider when I need to replace those), and I found a company that makes an H-rated tire (rated for 130mph), with a 1" wide whitewall. And yes, these Caddy's will run that fast no problem, just don't ask me how I know. ;-) I also run a higher PSI in the tires than stock. I think the stock setting is 32psi, but I run at 37psi, the max regular pressure for the tires I have on the car. So all of that combined means the tires are stiffer than stock, and allow for better handling, cornering, and fuel economy, and being a little wider just gives me a little more grip.

 

I may just look at the late 90's SSEI in the local picK n pull now. Thinking of grabbing the Eaton M90 off it anyway.
Thanks for the info. Did you look into a rear bar upgrade at all?

 

My '89 Cadillac Deville has ~140K on the odometer. The left front anti-sway bar end rusted&broke about 1/2 way up the end, no longer attached to the A-arm - right side is still attached but looks worn. Is this part (sway bar end) easily replaced? do I need to replace both ends to be safe? Do I need to have the front-end wheels aligned post sway bar end replacement?

also, on another note, the heater core seems to be leaking as I can smell
anti-freeze smell when heater is on. No puddle on passenger floor board - Im told that the leak is probably behind the carpet near the firewall - is this a big job due to the engine is transverse mounted and belts/hoses etc need to be removed to gain access to heater core?

thanks for your advice,

 

I haven't spent much time looking into the rear bar, but I need to since it's about as thick as a pencil. I need to completely overhaul my rear suspension yet anyways (both factory air shocks have failed over the last 8 months) so I will see what I can find then and post whatever I learn about it.

 

End links should be a piece of cake, emphasis on the "should" part of that statement. Honestly though, even with one broke and most likely a ton of rust all over them, you should be able to get them out no problem. If they seem stuck, hitting on them with a hammer and grabbing them with a vise grips and twisting, pulling, yanking, etc. should get them out pretty quickly. Fortunately due to the fact that there's a rubber bushing between every metal part, nothing should really be rusted together. And yes, I would replace both sides, but I think when you buy them, they only come as a pair anyways. No alignment should be necessary, the end links do not normally affect the alignment (except of course when one is broken and thus not functioning, but replacing it should correct that). If you unbolt the strut from the steering knuckle, or replace a tie-rod end, then yes you would need to have the car realigned because those are the points which are adjustable.

Not sure if the heater core is a PITA on these cars or not, never pulled one. I've done them on other cars, (in fact I need to replace the one in my mom's Subaru in the next couple weeks) but I'm not sure on GM full-size FWD cars. I have factory shop manuals for several years of Cadillacs and a Haynes manual so I can look it up tomorrow and reply with whatever I find out. If you're lucky, it'll be as easy as the first one I did (my Sunbird GT) that one could be removed by reaching under the dash and removing some fasteners, unhooking the hoses in the engine compartment and pulling the whole thing down and out. If you're not lucky, it'll be like my mom's subaru, which entails dropping the steering column, gutting almost the entire front of the cabin, disconnecting parts from the AC and probably lots of cursing. Anyways, I'll let you know what I find out about it, although from what I know off the top of my head, there shouldn't be too much trouble from the engine compartment side of it, the hoses are fairly accessible and should only need to be removed, then the heater core can be pulled out from the inside of the car. Just not sure what needs to be done on the inside to get to it.

 

OK, my curiosity was peaked, and since I didn't immediately know the answer to the question, my desire to know the answer over-rode my desire to go to bed and get some sleep. I pulled out the shop manual for the closest year I have ('90, which should have a cooling system that's 99% identical to the one in the '89) and found that the heater core isn't too bad to replace. If you're comfortable with tools, and have a good selection of tools and are reasonably patient, I'd say go for it. For the engine compartment side, it's as I suspected, just disconnect the two hoses going through the firewall to the heater core, should be between the middle and passenger side of the engine compartment, the two hoses right on top of one another.

Inside the car, it's apparently right behind the glove box behind some sort of cover. It's been awhile since I've had a glove box out for anything so I don't know exactly what it looks like back there, but there is a ton of wiring and duct work, but not so bad that you can't work back there. Anyways, remove the glove box, not hard but you need to remove the top cover of the dashboard if I remember correctly (lots of fasteners hidden under covers, behinds air vents, etc), seems to me that there's a couple fasteners for the glove box hiding under there. And if the glove box in your car has never been removed, there will probably be some sort of sticky thing holding the top of it in place. I can only assume that this was put there to absorb noise?, vibrations?, cooties? With all fasteners removed, the glove box should be noticeably loose, but probably won't just pull out easily because of this still being stuck on there, it will require a little effort to pull it out, at least mine did when I removed it to add some accessories back there for my aftermarket stereo deck. Also remove the plastic panel/sound insulation underneath the dash on that side. You'll need to disconnect some vacuum lines, electrical connectors and some sort of actuator arm from the "programmer" that's attached to the cover. I assume this will just look like some sore of electrical box with lots of stuff connected to it. The box itself stays put, you'll need to the remove the cover and pull that down and out with the programmer still attached to it. From there, remove whatever fasteners are holding the heater core to the firewall, then pull it down and out from behind the dash.

I know it sounds mostly simple, but you're working in a very tight space so I'm sure it will take some time, patience and will be frustrating. But it's definitely doable, just depends on your amount of experience and comfort-level with working on cars.

 

Haha ya pencil sounds about right. I guess they never intended these cars to be carving corners but something a bit better would be nice.
I just replaced both of my rear shocks. I was going to do away with the air but Napa had a good price on them so I kept it. Im glad I did since its nice to have with passengers in the back. Especially when I have a trunk load of tools to go parts hunting in pick n pull. Gotta grab the caddy parts when I can, we are in a big retirement area around here so most of these cars are still hiding in garages with weekly trips to church and the supermarket, very few in the wreckers. Plus it has a huge trunk to haul home all the things I probably didnt need but bought anyway. Lol!

Back to the rear sway bar I havent had a chance to look yet either but am wondering about the Bonneville bar. I have SSEI rear springs in mine which actually helped a little over the soft ride springs it came with. Also debating trying the ssei front springs when I do struts to see if it helps.

 

For the hell of it I started digging around the internet looking for info on the rear bar and I may have found something useful. I looked up the sway bar bushings for the rear bar on rockauto (one of my favorite sites) and they list a 13mm set and an 18mm set for my '89 deVille. I can't imagine what the 13mm would do, other than to create the appearance of a sway bar. And I know mine has the 18mm (when I originally checked mine with a calipers I measured 19mm, but didn't take in to account the ac***ulated rust, dirt, undercoating and who knows what else was probably stuck to it).

I then looked up the same parts for random cars on the same platform, in this case the '97 Pontiac Bonneville SSEI, '95 Olds 88 w/ supercharged 3.8, and '98 Buick LeSabre w/ standard 3.8 and they listed the 18mm set, and a 22m set. So there is for certain, at least one bar larger than what is currently on our Caddy's. I assume the 22mm is for the upgraded suspension option, most likely the FE2 option at that point (since I don't think they had an FE3 option on any of the cars built on this platform). And I assume any car that came optioned with the supercharged 3.8 V6 probably got the upgraded suspension automatically, though the suspension option could probably have been selected by itself if the buyer wanted.

No idea yet whether the bars are solid or hollow, but since through my own experiences I found that the 32mm front bar on my '89 was hollow, and the replacement 32mm bar I bought from a late 90's car was solid, I would optimistically say that there could also be that improvement alone by going with just a newer 18mm bar, let alone the larger 22mm one.

And for what it's worth, I know for a fact the supercharged 3.8 V6 came standard in the Bonneville SSEI, and was an option on some Oldsmobiles that are on the same platform (depending on the year I believe these can include 88's, 98's, LSS's, Toronado's and Regency's). Buick also had the motor available on some models, but I don't know if they ever used it in any of the models built on the same platform, (also depends on year, but I think they include, mid-80's to early-90's Riviera's and early 90's to late 90's or early 2000's LeSabre's). Hopefully some of this will be useful, and whenever I get around to actually making the swap on my car, I'll post the info.

 

Thats good to know, I was thinking I should have checked the bar on the SSEI in the wrecker when I was there but I forgot until I was halfway home. Haha!
Too many projects on the go, the caddy keeps getting put off since its used as a daily driver most of the time. I'll have to remember to measure some bars next time. I'd like to upgrade mine when I do my exhaust. I keep putting that off as well because im still debating trying to come up with a true dual set up for it. If that doesnt work out I'm thinking a low restriction 3" single with a dual outlet muffler. Not sure how the 4.9 will respond to 3" single or 2.25" duals but I guess i'll learn the hard way. I'll just be nice and unbolt my stock stainless exhaust instead of cutting it off just in case.

 

One other thing I just noticed, when I clicked on the part number for the 22mm sway bar bushings, it brought up the list of vehicles the part specifically interchanges to, and it listed '92 and '93 Cadillac Deville's, Fleetwood's, and the '93 Sixty Special. So perhaps the last couple years of that body style got the 22mm rear bar instead of the 18mm one? Because when I click on the part number for the 18mm bar, the only Cadillac's listed were from '85-'90. And by my math, this apparently means that '91 Cadillac's didn't have a rear sway bar. ;-)