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best factory suspension and brake upgrades for w body

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usetaboost

New member
I've found some of the information I am looking for, but not all of it. I know that the 9c impala fleet cars have a front strut tower brace, boxed rear trailing arms, thicker sway bars, and front brakes are 1 inch larger. WHat I haven't been able to find out is exactly what years this stuff comes off of. Some sources say only 00-03 will fit '00 cars. Others say 00-06. I'm also trying to find out if these fleet cars had better springs and struts than the gtp. A junkyard swap sticky or section would be a great addition to this website. I have a 4 day weekend coming up so I'd like to get to the junkyards and get this stuff before the weather gets bad. Thanks for the help.
 


05-08 GXP struts and springs would be nice.

They're Bilsteins and possibly rebuildable. Check for crimps on the top seal.

The bigger sways and STB are somewhat cheap still: http://www.gmpartsdirect.com/results.cfm?singlepart=1&partnumber=pk12456148

They were factory on the fleet impalas though. They came on the 00-05 Impalas.

A lot of the stuff is still interchangeable, however you might have to change a few other parts to get it to work.

For example, you can grab the 06+ impala calipers, rotors and pads. They bolt up just fine, offer the same stopping power as the F body calipers but they bolt on, are cheaper and don't have issues with clamshell failures because they're iron. Downside, they're iron. But so are your current ones. You have to use the 06+ rotors though, nothing else will work properly.

Or for an easier brake swap, just grab 00-05 Impala caliper brackets. Then buy some rotors from a 00-05 Impala, and pads. Swap the caliper brackets and install the new pads and rotors. 12" upgrade without changing brake fluid. You should probably flush it anyways though. Hoses are probably old and weak as well.

Another example is the newer cars with strut mounted sway bars can switch back to control arm mounted sway bars and then run larger sway bars. However they need to buy control arms that have the spot for sway bar end link attachment.

The only other shock that's possibly worth buying used would be the comp G struts. They seem to hold up very well.
 
IIRC GXP springs will make a 97-03 sit higher if you use the whole assembly off a GXP there are sticky threads on here and clubgp.com that talk stock diameter sways also.
 
I'll probably just do the caliper brackets and get a new rotor and pad to keep it cheap and simple. Will the spare tire still fit with the 00-05 12 in rotor and caliper bracket?
 


did the car sit much higher? Is there that much of a difference between the gtp springs and impala fleet springs? ANyone have spring rates for these?
 
If you find a 9C1 Impala at the yard grab the oil cooler setup and the trans cooler with all the lines
 
Trying to do things on the cheap and easy so here's the current list. TOday I went out to a local yard and found a 00 fleet impala. I grabbed the strut bar, tubular fender braces, caliper brackets, rotors, the newish ceramic pads that were on it, and the front sway bar. I was going to get the rearview mirror but it was already starting to seperate. Still trying to figure out the 9c cars. I don't think all the packages were the same. The car I picked stuff from had a very small rear sway bar and there was nothing special about the rear trailing arms. The 6/99 gtp I compared it to had a much larger rear bar and this car was obviously bone stock. I couldn't find the trunk spare cover so I didn't have access to the rpo's but I know it was a 9c car, most likely a taxi or something other, definitely not law enforcement. This car also had the aluminum engine crossmember. I don't know if they're really worth anything so I didn't get it. I got everything for 50 bucks.
 
Ok turns out the car I took parts off of was a 3400 car. I'm sure the strut tower bar would still work. As far as the front sway bar goes I can't tell if its bigger or not. I don't really know where to measure it to check since there's so many tweaks in it. Even if it is the same size as the one on my car now, at least I have one lying around for when it breaks. EIther the undercover fleet cars code doesn't include the gmpp goodies or they are only available on the 3800 optioned cars. I know was a fleet car for sure it was a bench seat, column shift, low option and no dome light. THought about installing the strut bar last night but it's hard to get myself to drill a hole in a 14k car lol! I suppose if I take my time and drill the holes right the first time it won't be a big deal.
 


THinking about ordering a pair of dorman rear trailing arms. Is there really anything to benefit if the stockers are still good or is this more of a peace of mind part?
 
Many of you asked about certain changes and what the effect is on GP. My 01 GP is used primarily as transportation to the airport for business travel and to the train station for the same purpose. Most of the other time my 17 year old daughter drives the car. I have owned the car since new (150,000 miles now on the 3.1 engine and the 4T65E tranny (I know, it's not a 3.8, but not an issue since I have other cars for performance) and it has to be spot on reliable due to it's dual purpose mentioned previously. Here is what has been done over the last 12.5 years, most changes since about 90,000 miles.

Brakes: The day I picked the car up from the dealership, I came home and removed the OEM brake pads and installed Performance Friction Carbon Metallic pads at all 4 wheels. These pads provide excellent initial bite with stock rotors, have no brake dust, and last forever, BUT have a tendency to wear the rotors faster and do not work great until there is some heat in the pads. At 50,000 miles on the car, at the first brake change, I installed Drilled and slotted rotors which help somewhat with initial brake bite and help dramatically with braking in torrential rain when the rotors are saturated. I recently installed Bigger front brakes on my 94 Mustang GT convertible with Cobra front brakes (went from 11 inch vented front rotors and single piston caliper to 13 inch vented, dual piston front caliber, and a Cobra master cylinder) and Hemi front brakes on my 2008 Chrysler 300 Limited ( went from 12 inch vented rotors and single piston caliber to 13.6 inch vented Drilled/slotted rotors with dual piston calibers-the brake pad is HUGH). These 2 brake upgrades provided impressive improvements in the braking performance of both cars. At the next GP brake change, I am going with the F body brake upgrade-98-02 calipers and brackets-with performance friction pads, 2001 12 inch Impala/Camaro front rotors, and stainless steel braided front lines. Tapping the brackets for the 14mmX2MM GP bolts is easy for me, using stainless steel lines from the W body store (comes with the correct F body Banjo bolts) and the Camaro brake pad is larger than the Impala pad.

Sway Bars: I broke a front sway bar endlink a few years ago and went with the GMPP front and rear bars (AKA Police). Not sure if gmpartsdirect still offers them but I got mine on close out for $100 for the 2 bars and the GM strut braces (which I did not use). I had a 2004 Impala LS 3.8 which I installed the strut tower braces from the W-body store with the adjustable heim end links. I prefer these struts braces since you can put pressure on the bars by turning the whole bar-these braces really improve chassis flex and stops the car body from creaking. I removed those strut tower braces and installed them on my 01 GP in 2006 when I sold the Impala (Modified them slightly to fit the 3.1 engine). Dorman sway bars and others are solid bars and pretty cheap.

Trailing Arms: Replaced the 3/4 box OEM trailing arms a few years ago with the GMPP solid trailing arms which I believe are no longer offered. They were $36 and do make the rear feel more solid and the car actually rides better plus they are MUCH stronger than the OEM ones. Again, the aftermarket offers pretty inexpensive ones as well.

Struts/springs: Had the OEM ones until about 70,000 miles and changed to KYB GR-2's with the stock springs. Frankly, I was extremely disappointed with them since they are suppose to be 10% stiffer than stock. I found them to be way to soft, hurt the ride, degraded the handling, and a downgrade from Delco Struts. Just very recently, after much research, I installed 2003 Impala Police smart struts-Monroe Sensatrac strut and springs-OEM approved-on the 01 GP. Holy smokes!!! The Police Struts have transformed the ride and handling of the car. These are the struts/springs that should have come on GT/GTP's when the car was new. Interestingly, the car rides very well. A little stiff but NOT harsh at all. They are great! One downside though is that they do ride about 1-2 inches higher than stock springs/struts but that is no issue for my GP.

Lower Control Arms: I replaced both lower control arms at about 90,000 miles with GM stock units. I am planning on changing them again at about 170,000 miles and will definitely go with the 2003 Impala Police versions of the lower control arms since they are dirt cheap (rock auto), are stronger than the OEM arms, and have slightly stiffer bushings. My experience has taught me that whenever possible go with the Police versions of parts-They are MUCH better than stock.

Hope this helps!
 
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Sways can be found on a Monte Carlo 00+, a lot of 00+ Impalas.
Use poly bushings and endlinks on the sways.
STB: Impala and Regal
F body brakes are two piston and larger, great upgrade on the cheap. These days Advance and many other places include the brackets when you buy a caliper. A different mounting bolt and sleeve or drill/tapping and you'd be all set.
Rear brakes honestly I wouldn't bother they make such a small difference most wouldn't notice.
Struts and springs, no doubt an area where improvement can be had
Tires/rims..something like an 245/45/18 seems to work very well on these cars. Especially if you don't cheap out on the tires.
 
I failed to mention that like Billboost37 mentioned above that I use poly mounting and end link swaybar bushings on the front bar and poly mounting bushings for the rear bar. Also, Tires are critical for maximizing braking and handling! Cheapo tires are a waste. I currently use 225/55/16 ZR Cooper RS3-A Ultra High Performance all season tires, tread wear 500/traction AA which can be had for about $100 each-deal! they ride great, are quiet, and should last for decent miles. Rockauto sells the 98-02 F Body brakes-Powerstop-with brackets/caliper bolts, NOT the caliper bracket bolts, powder coated red, for $60 each. I used the Powerstop Red powder coated Chrysler Hemi brakes-caliper/brackets-for my conversion mentioned above. They look great!
 
I thought about getting new police quick struts. Do the springs really raise the car that much? Is there any way you could get a measurement from the ground to the top of the fender so I can compare them to mine? My car has low miles so it should be a good comparison to stock ride height.
 
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