Scary handling (Page 1/1)
treborerellim APR 20, 11:18 AM
I've own a 1987 GT. It has a five speed. It has coil overs in the rear which are fairly stiff and and it also has polyurethane cradle bushings. If every time I go around are corner if and I'm not real careful with the gas pedal the rear and wants to rotate. When it is wet it is really bad. Can anybody explain why this might be happening. The tires have very good tread.

Much appreciate any help I can get,

Bob
Darrelk APR 20, 12:04 PM
Do you know what your current state of alignment is like? When was the last time it was aligned? Run of the mill kind of alignment shops won't spend much time with our old Fieros. When I had my last 86 with coilovers, 3800 SC, etc., aligned the guy really knew Fieros and had done some racing with them. He spent about 3 hours on the alignment and the car handled like a slot car...... wet or dry.....
olejoedad APR 20, 01:17 PM
Stock front springs?
What spring rate on coilovers?
Rear sway bar?
Gall757 APR 20, 01:20 PM
+1 on alignment.....some shops don't even do the rear and call it good.

Are the tires old? They can look great but still be getting hard and slippery. Fieros love soft tires.

The other thing to look at is your motor mounts. If the engine moves when you accelerate it's no fun. You may have to jack up the motor a bit to see a tear in the rubber mounts.
cvxjet APR 20, 06:54 PM
Check your alignment; If you have a straight edge that is 4-6 feet long, put it across the sides of the rear tires and see where it points......It should point almost directly to the sidewall of the front tire.....That would mean it is close. I had very bad alignment after swapping engine/trany......

No matter what, find a good alignment shop- someone who will do a proper alignment on the car. I have a Big O chain tire store around the corner- I am friends with the manager so I can get a good alignment there- Some chain stores will not do a good or thorough job...and most will not do custom alignments.

Another thing that has been mentioned is the tires; My Van's tires still have plenty of tread, but they are 6 years old. The rubber is old and dried out....I can hardly leave a stop sign without spinning them. Inflation is also very important. Your tires should be between 28 and 32 PSI. Always carry a tire gauge and check your tire pressure at least once a month. Look at the tires more often- at least once a week, or when you are taking it for a drive. From your description, you may have bad / old / under-inflated tires on the rear, but check all four of them.
fierofool APR 20, 06:57 PM
Lift the rear of the car with a floor jack, then put stands underneath the control arms. Grasp the wheels at top and bottom to see if there's any movement. You might also take a good pry bar or 2 x 4 and place underneath the tire and try lifting up on it from the side. Have someone watch the ball joint. The car must be supported by the control arm to identify a bad ball joint.

Grasp the wheel at the 3 and 9 o'clock positions and have someone observe the tie rod end and its inboard bushing.

If you have much larger tires on the rear than on the front and the rake is heavily nose down, the rear will tend to come around more easily, so tire sizes could be a factor.

Check the mounting hardware at the top of the strut tower. I had serious problems and found the 3 nuts that hold the ring in place were loose. A total of 4 things were causing my problem. Bad ball joint, failed strut, and loose strut tower bolts and a lousy alignment. After replacing 1 piece at a time and tightening the strut tower bolts a good alignment solved the problem, in that order.

Afterthought: Bad front tie rod ends or ball joints can also impart the same reaction. As you take a turn, the geometry of the front end changes quickly, cutting more sharply into the turn. Check front components in the same manner as the rear.

[This message has been edited by fierofool (edited 04-20-2019).]

Neils88 APR 20, 07:44 PM
Double check the cradle mount bolts are properly tightened.
treborerellim APR 21, 05:41 AM
Holy smokes guys you have given me an enough to keep me busy for months. I've got a lot of things to consider. The tires and the stiff of coilover were already on my list, but the rest of the ideas I hadn't thought of. So thank you for all the ideas you have given me to check out and I'm sure one of them or a combination will straighten it all out.

Thanks, much appreciated
Bob
Darrelk APR 21, 09:38 AM
Because of the age of our cars now you don't have many out there that are like the "factory" set-up. I was lucky to have ordered a brand new 86 back in the day. I knew the guy that owned the dealership and he was a sports car fanatic as well. His dealer prep. was outstanding. I know how these cars can drive/handle if everything is working right. There are just so many variables that affect them that with this many years of wear/tear/changes that many guys just accept the...."Well, it's just an old sports car made with off the shelf economy parts" and leave it at that. Take your time....go through the basics of making sure what parts you have are "there" and in-spec and go with a good inspection by a knowledgeable alignment shop.....
Spoon APR 21, 10:43 AM
A sloppy Dog Bone along with weak motor mounts will give you a whole new outlook on life after going thru a sharp turn.

Spoon

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