big time oversteer problem

[susansdreamcar72]

good morning. just joined the site this morning hoping to find a cure for oversteer on my 1997 town car. I installed new air suspension in rear and oreilly shocks up front but I am not comfortable with handling.i'm thinking adjustable shocks could help.. any ideas? Thanks for you help. steve

[MarkIII]

Is this car new to you, or have you had it quite a while and the oversteer developed? If it is new to you, what were you driving before?

Panther-chassis cars usually plow with understeer when pushed, oversteer is not common. Is it really oversteer, or is it that the body heels over in a fast tight turn, making one think that it is out of control? It ain't a BMW 750 IL

If something really has changed, I can suggest a few things to check out:

FRONT upper control arm bushings. Each upper control arm has a front and rear bushing pressed into the ends of it. A shaft is bolted to the frame, and each end of the shaft goes through a Upper Control Arm bushing. A nut on each end of the shaft locks the bushing's center sleeve to the shaft. When the front wheel assembly goes up and down, the rubber inside the bushings twists back and forth. Eventually, over many years and miles, the rubber in the bushings wears out, and the shaft is no longer centered in the bushing. When they get really bad, then the shaft sits all the way to the outer shell of the bushing, and can really move around while driving. This can/will give odd auto-steering input to the chassis, as the whole wheel suspension assembly has its top moving around. This can make it feel like the rear end is moving around... it has happened to me. A careful check with mirror and light to look at how each end of the shaft sits in each bushing will tell a lot.

Rear anti-sway bar bushings and links. The bar bushings should be good and bar roughly centered in bushings. End links should have good bushings on them, not all squished-out or broken. A few smaller cracks are OK if it is still tight.

Rear Trailing arm pivot points. Are they tight, or loose and wobbly? Movement here can result in rear-wheel steering, never a good thing.

Locating arm on top of differential? If your car has these, the arm goes from frame rearwards to the top of diff, has bushings in each end. These usually last the life of a car, but...
This bar locates the differential, the center of the rear axle, helps prevent axle wind-up, and limits sideways movement of the rear axle assembly. Bad bushings can lead to rear axle steering.

[susansdreamcar72]

thanks for the detailed comeback mark it is appreciated. this is a garage kept car with 120,000. mostly driven by my wife but I notice the handling since I don't drive it often.school me on "panther chassis".i'm confident the front end is ok recently rebuilt but ill check sway and trailing arm.do you recommend exotic front shocks?

[Dan Szwarc]

Do all Town Cars have massive oversteer? Are you trying to return to factory or modify the factory design?

It's a Town Car, not a Miata. These cars were not designed to drive like performance cars and, physically, they probably are not capable of being designed that way. That's what happens when you make a big-ass car.

[TonyC]

Can't argue there. Bessie grabbed the road, no understeer; and the only oversteer I got was when the roads were extremely icy (which happened only once). I'm still trying to get used to Frankenstein's handling again.

---Tony

[MarkIII]

school me on "panther chassis"

History - The Panther chassis was the down-sized replacement for the biggest-ever full-size Ford/Lincoln/Mercury of the 1970s.
Ford - LTD 1979-82, renamed Crown Victoria for 1983-2011 (they came out with a non-panther intermediate car that used the LTD name in 1983, so changed names).
Mercury - 1979-82 Marquis, Renamed Grand Marquis for 1983-2011 (same issue with intermediate car).
Lincoln - 1980-83 Mark VI
Lincoln - 1980-81 Continental
Lincoln - 1982-2011 Town Car (they made an intermediate Lincoln, called it the Continental in 1982, so changed names).

Body Styles - Four door sedans always, two doors were available through early 1980s, 8 passenger Ford/Merc wagons available through 1990 model year.

The chassis - RWD, fully boxed frame front to rear, two different wheelbases, solid axle, Ford 8.8" differential, recirculating ball steering changed to rack & pinion for 2006 CV & MGM earlier I think for the TC.
Engines - 351 available early year, later as police special CV only; 302 till earlier 1990s then 4.6L SOHC. Was a forgettable 255 V8 made in the early 1980s for a couple years from a reduced-displacement 302, just about none sold of those.
Fuel delivery - Ford/Merc 1979-1982 carbed; 1983-85 CFI (Central Fuel Injection, a successful throttle-body setup); 1986-on EFI, the multiport fuel injection. CV 351 police special used variable venturi carb, even when the 302 was fuel injected.
Lincoln Mark VI 1980-83 CFI except for 1980 351 option was carbed.
Lincoln Town Car/big Continental 1980-85 CFI; 1986-on EFI.

Millions of these Panther chassis cars were sold, may be the longest-running automotive chassis in volume production ever, 33 years. Around here, just about every PD had the Crown Vic as their car, now towns/cities with enough $$ use the Chevy Tahoe (those without enough $$ use some rather sorry unmentionable vehicles that run over one curb and its out of service). Just about every limo around here was a TC, or stretched TC, most have gone to SUVs with the discontinue of the TC.

Ford got its $$$$ out of the Panther chassis, that's for sure. They did only minor updates over the years, like rack and pinion steering, rear discs, etc. They were known for being durable rebuildable cars, with trunks that could hold many bodies

i'm confident the front end is ok recently rebuilt

Good troubleshooting would not assume that. Still worth checking out the upper control arm bushings. Even if they were replaced, if the person replacing them did not understand the importance of tightening the shaft nuts ONLY when each wheel assembly is at usual ride height, the new bushings may have torn with use.

do you recommend exotic front shocks?

No.

I think an issue that we can not determine via internet, is, is there really a problem? Or are you used to some flat-handling car that you may toss around as your daily driver, and are uncomfortable with the way the TC responds in like-use?
Panther-chassis cars are not known for oversteer, in the true use of the term "oversteer". Very few cars actually had oversteer, as it can be quite dangerous... Rear-engined cars can be prone to it, example the 1961-63? Corvair early design that had the swing axles with only one pivot creating massive rear camber change on jounce/rebound, coupled with weight in rear. Many FWD cars, at least the earlier ones with a manual trans, could be made to oversteer by quickly letting off the gas in a tight turn, and could be used to handling advantage by the proper driver and conditions, to the unschooled, not so much.

Could you share with us what your daily driver is?

[susansdreamcar72]

I drove it to Houston and back to san Antonio and the proper term might be" touchy".my daily drivers in this order are 2016 chev2500,2002 chev2500,88GMC K-1500,1977 international scout.all these junks are a pleasure to drive.im stuck on front shocks or the adjustable steering box but my ears are open.in the mean time I'm checking control bushings front and rear. thanks steve

[joeyq80]

I've owned 4 Town Car's ranging from '92-'97 and have put MANY miles on all of them. With that experience, I can confidently say that if the front end, tires, and power steering pump / gear are in proper condition there shouldn't be a serious over steer condition present. With that said, these are large luxury automobiles that were designed for effortless cruising down the interstate - not for daily trials through slalom courses. Since you mention that you've replaced the shocks, and the air springs - we'll assume that they can be ruled out. Please note - the air springs adjust automatically based on load so there's no benefit to adding air shocks. Also, on '95-'97 models there is a steering sensitivity adjustment on the dash - does moving the lever between low and high produce any noticeable effort in steering dampening?

You should check the following items:

Front suspension -Upper / lower ball joints, Upper / lower control arm bushings, idler arm (if you have 100K miles or more I can tell you that you probably need to O/H the entire front end)

Steering- Have the EVO valve checked - this valve modulates the output of the pump based on the need for assist and the level of the air springs. IS there excessive free play in the steering gear, tie rods, pitman arm or steering shaft? many times loose steering is caused by a worn steering gear.

Also, you should have the car aligned by a reputable front end person. Having caster, camber or toe that's out of spec WILL cause the steering to be squirrely.

[JimA]

I've owned 4 Town Car's ranging from '92-'97 and have put MANY miles on all of them. With that experience, I can confidently say that if the front end, tires, and power steering pump / gear are in proper condition there shouldn't be a serious over steer condition present. With that said, these are large luxury automobiles that were designed for effortless cruising down the interstate - not for daily trials through slalom courses. Since you mention that you've replaced the shocks, and the air springs - we'll assume that they can be ruled out. Please note - the air springs adjust automatically based on load so there's no benefit to adding air shocks. Also, on '95-'97 models there is a steering sensitivity adjustment on the dash - does moving the lever between low and high produce any noticeable effort in steering dampening?

You should check the following items:

Front suspension -Upper / lower ball joints, Upper / lower control arm bushings, idler arm (if you have 100K miles or more I can tell you that you probably need to O/H the entire front end)

Steering- Have the EVO valve checked - this valve modulates the output of the pump based on the need for assist and the level of the air springs. IS there excessive free play in the steering gear, tie rods, pitman arm or steering shaft? many times loose steering is caused by a worn steering gear.

Also, you should have the car aligned by a reputable front end person. Having caster, camber or toe that's out of spec WILL cause the steering to be squirrely.

Good post!!! Covered the bases.