Lower Control Arm Mount Bolt/Nuts
Thread Starter
Racer
Joined: Mar 2015
Posts: 336
Likes: 40
From: Longview WA
Lower Control Arm Mount Bolt/Nuts
I had an alignment done on my vette last Wednesday... everything was basically in check.
During a more spirited drive this weekend, I started feeling a weird sliding sensation... the tires weren't sliding, but when I accelerated the car twisted right (like the rear rears started to twist right and step out - not spinning them)
Once I let off the gas, the rear end drifted back left. (quite suddenly)
I jacked up the rear... took the tires off, checked all the torque on the suspension.
I found a torque spec list here: http://www.lbfun.com/warehouse/tech_...orqueSpecs.pdf
- I found the lower control arm mount nuts were no where near 120ft/lb torque.
Once I tightened them all (front and rear)... the issue disappeared.
P.S: My right rear wheel liner was destroyed by this apparently... the left side is showing damage/ severe wear.
Anyone else have any issues like this before from an alignment shop?
During a more spirited drive this weekend, I started feeling a weird sliding sensation... the tires weren't sliding, but when I accelerated the car twisted right (like the rear rears started to twist right and step out - not spinning them)
Once I let off the gas, the rear end drifted back left. (quite suddenly)
I jacked up the rear... took the tires off, checked all the torque on the suspension.
I found a torque spec list here: http://www.lbfun.com/warehouse/tech_...orqueSpecs.pdf
- I found the lower control arm mount nuts were no where near 120ft/lb torque.
Once I tightened them all (front and rear)... the issue disappeared.
P.S: My right rear wheel liner was destroyed by this apparently... the left side is showing damage/ severe wear.
Anyone else have any issues like this before from an alignment shop?
Melting Slicks
Joined: Aug 2004
Posts: 3,003
Likes: 89
From: Indy IN
Common issue if the guy doing the alignment doesn't properly torque the eccentric bolts, they will slip with any kind of hard cornering.
It is even more common with folks who track their car and use sticky tires. Even the stock 120 ft lbs isn't enough for those situations.
Jlaw is right, you need to take it back and have it realigned and make them pay for the damage to the inner fender liners.
What most track rats do is after you get the car back from the alignment shop is to mark he eccentrics with a strip of paint or nail polish. That way if the eccentrics slip you can go back and reset the alignment to where it was and you don't need to go back and have it realigned. Also it's easy to check to make sure they haven't slipped if you have that stripe since if it's moved at all it will be clearly visible.
It is even more common with folks who track their car and use sticky tires. Even the stock 120 ft lbs isn't enough for those situations.
Jlaw is right, you need to take it back and have it realigned and make them pay for the damage to the inner fender liners.
What most track rats do is after you get the car back from the alignment shop is to mark he eccentrics with a strip of paint or nail polish. That way if the eccentrics slip you can go back and reset the alignment to where it was and you don't need to go back and have it realigned. Also it's easy to check to make sure they haven't slipped if you have that stripe since if it's moved at all it will be clearly visible.
Drifting
Joined: May 2007
Posts: 1,544
Likes: 209
From: Huntersville, NC
the torque specs for the rear LCA's are less than the front LCA's. They are 107 for the eccentric and 70 for the nut that tightens down the rear back LCA pivot. There is no eccentric in the back of the rear LCA.
The damage you describe, what tires and wheels do you have on? I can't imagine camber alone with stock C5 or C5Z wheels/tire sizes giving rubbing. Also is the car radically lowered?
The thing I would suspect is the retaining nut on the rear suspension adjustment link (everyone here probably calls it the rear tie rod). In order to adjust rear toe or thrust angle both the tie rod end jam nut and the retaining nut have to be loosened The retaining nut is at the opposite end of the link from the tie rod ball joint end and is kinda hidden behind the exhaust pipes. It is sometimes forgotten by the alignment tech and if it gets loose, chaos ensues. both the link retaining nut and the jam nut are 44 ft-lb torque.
Also, find out what the wheel runout measurements were on the wheels. If the tech says HUH????, run don't walk from that clown. He won't last long anyway, wheel runout is a good way to sell wheels to a captive customer.
The FSM says .040" is the max runout, but if the runout of the wheel is a visible wobble, it could throw the toe measurements and the camber for that matter way off. you should be able to spin the wheel and see .020" wobble visibly and that is enough to have the toe way out of spec. Unless the wheels have hit a curb most of them have .006 or less runout. unfortunately, the FSM spec runout is boilerplate stuff and that much runout would make for a miserable drive at high speed in a Corvette. there are other things that can cause runout, like dirt between wheel and hub, and bad spindle bearings.
Did you have the nannies turned on or off for your "spirited driving event"? Depending on the options in your car, you could have activated the TCS. It will give you a funky feeling car moves but usually will keep you on the road. When it activates it usually takes away the gas pedal response and the abs will bump an offending caliper with a little pressure.
Also be a little careful with spirited driving, you can get into an oversteer condition and that is hard to correct on a street that is crowned as most are, and the grip changes when you cross lane marker paint or the road edge. Then your donkey is in oncoming traffic. Once you get your donkey in the oncoming lane and your front in your lane, it is hard for the rear which has no grip to climb the hill and get back in your lane. C5 Corvettes are biased to understeer, but there are things you can do that will suddenly change, like lift the throttle to much at the wrong time.... then slam it back on. This is usually when the nannies are off, or they have gone on strike because they were asked to do some task they did not want to do.
The damage you describe, what tires and wheels do you have on? I can't imagine camber alone with stock C5 or C5Z wheels/tire sizes giving rubbing. Also is the car radically lowered?
The thing I would suspect is the retaining nut on the rear suspension adjustment link (everyone here probably calls it the rear tie rod). In order to adjust rear toe or thrust angle both the tie rod end jam nut and the retaining nut have to be loosened The retaining nut is at the opposite end of the link from the tie rod ball joint end and is kinda hidden behind the exhaust pipes. It is sometimes forgotten by the alignment tech and if it gets loose, chaos ensues. both the link retaining nut and the jam nut are 44 ft-lb torque.
Also, find out what the wheel runout measurements were on the wheels. If the tech says HUH????, run don't walk from that clown. He won't last long anyway, wheel runout is a good way to sell wheels to a captive customer.
The FSM says .040" is the max runout, but if the runout of the wheel is a visible wobble, it could throw the toe measurements and the camber for that matter way off. you should be able to spin the wheel and see .020" wobble visibly and that is enough to have the toe way out of spec. Unless the wheels have hit a curb most of them have .006 or less runout. unfortunately, the FSM spec runout is boilerplate stuff and that much runout would make for a miserable drive at high speed in a Corvette. there are other things that can cause runout, like dirt between wheel and hub, and bad spindle bearings.
Did you have the nannies turned on or off for your "spirited driving event"? Depending on the options in your car, you could have activated the TCS. It will give you a funky feeling car moves but usually will keep you on the road. When it activates it usually takes away the gas pedal response and the abs will bump an offending caliper with a little pressure.
Also be a little careful with spirited driving, you can get into an oversteer condition and that is hard to correct on a street that is crowned as most are, and the grip changes when you cross lane marker paint or the road edge. Then your donkey is in oncoming traffic. Once you get your donkey in the oncoming lane and your front in your lane, it is hard for the rear which has no grip to climb the hill and get back in your lane. C5 Corvettes are biased to understeer, but there are things you can do that will suddenly change, like lift the throttle to much at the wrong time.... then slam it back on. This is usually when the nannies are off, or they have gone on strike because they were asked to do some task they did not want to do.
Melting Slicks
Joined: Aug 2004
Posts: 3,003
Likes: 89
From: Indy IN
I wouldn't think that you could do damage to the inner fender liners unless the car was radically lowered.
More importantly if the car was lowered a lot you will introduce a second set of problems.
What happens if the car is lowered all the way on stock bolts, or even more with lowering bolts in the back is that you will hit the bump stops. That doesn't sound too bad until you realize that the bump stops are on the shocks. What happens is that the shocks bottom out and the shock forces go through the roof. The shocks are laid over at an angle and the forces on the shock act like a wedge, trying to push the lower control arm out away from the car. This causes the eccentrics to slip and the alignment to go to hell.
Even though the alignment guy didn't torque the bolts properly, if you were extensively lowered it wouldn't have mattered. The eccentrics will slip if you are lowered enough to smack the bump stops very hard.
Lastly it's worse when you are cornering hard since if you are lowered you will have used up almost all the travel, and a small bump at that point is all it takes to bottom out and push the alignment off.
Thread Starter
Racer
Joined: Mar 2015
Posts: 336
Likes: 40
From: Longview WA
the torque specs for the rear LCA's are less than the front LCA's. They are 107 for the eccentric and 70 for the nut that tightens down the rear back LCA pivot. There is no eccentric in the back of the rear LCA.
The damage you describe, what tires and wheels do you have on? I can't imagine camber alone with stock C5 or C5Z wheels/tire sizes giving rubbing. Also is the car radically lowered?
The thing I would suspect is the retaining nut on the rear suspension adjustment link (everyone here probably calls it the rear tie rod). In order to adjust rear toe or thrust angle both the tie rod end jam nut and the retaining nut have to be loosened The retaining nut is at the opposite end of the link from the tie rod ball joint end and is kinda hidden behind the exhaust pipes. It is sometimes forgotten by the alignment tech and if it gets loose, chaos ensues. both the link retaining nut and the jam nut are 44 ft-lb torque.
Also, find out what the wheel runout measurements were on the wheels. If the tech says HUH????, run don't walk from that clown. He won't last long anyway, wheel runout is a good way to sell wheels to a captive customer.
The FSM says .040" is the max runout, but if the runout of the wheel is a visible wobble, it could throw the toe measurements and the camber for that matter way off. you should be able to spin the wheel and see .020" wobble visibly and that is enough to have the toe way out of spec. Unless the wheels have hit a curb most of them have .006 or less runout. unfortunately, the FSM spec runout is boilerplate stuff and that much runout would make for a miserable drive at high speed in a Corvette. there are other things that can cause runout, like dirt between wheel and hub, and bad spindle bearings.
Did you have the nannies turned on or off for your "spirited driving event"? Depending on the options in your car, you could have activated the TCS. It will give you a funky feeling car moves but usually will keep you on the road. When it activates it usually takes away the gas pedal response and the abs will bump an offending caliper with a little pressure.
Also be a little careful with spirited driving, you can get into an oversteer condition and that is hard to correct on a street that is crowned as most are, and the grip changes when you cross lane marker paint or the road edge. Then your donkey is in oncoming traffic. Once you get your donkey in the oncoming lane and your front in your lane, it is hard for the rear which has no grip to climb the hill and get back in your lane. C5 Corvettes are biased to understeer, but there are things you can do that will suddenly change, like lift the throttle to much at the wrong time.... then slam it back on. This is usually when the nannies are off, or they have gone on strike because they were asked to do some task they did not want to do.
The damage you describe, what tires and wheels do you have on? I can't imagine camber alone with stock C5 or C5Z wheels/tire sizes giving rubbing. Also is the car radically lowered?
The thing I would suspect is the retaining nut on the rear suspension adjustment link (everyone here probably calls it the rear tie rod). In order to adjust rear toe or thrust angle both the tie rod end jam nut and the retaining nut have to be loosened The retaining nut is at the opposite end of the link from the tie rod ball joint end and is kinda hidden behind the exhaust pipes. It is sometimes forgotten by the alignment tech and if it gets loose, chaos ensues. both the link retaining nut and the jam nut are 44 ft-lb torque.
Also, find out what the wheel runout measurements were on the wheels. If the tech says HUH????, run don't walk from that clown. He won't last long anyway, wheel runout is a good way to sell wheels to a captive customer.
The FSM says .040" is the max runout, but if the runout of the wheel is a visible wobble, it could throw the toe measurements and the camber for that matter way off. you should be able to spin the wheel and see .020" wobble visibly and that is enough to have the toe way out of spec. Unless the wheels have hit a curb most of them have .006 or less runout. unfortunately, the FSM spec runout is boilerplate stuff and that much runout would make for a miserable drive at high speed in a Corvette. there are other things that can cause runout, like dirt between wheel and hub, and bad spindle bearings.
Did you have the nannies turned on or off for your "spirited driving event"? Depending on the options in your car, you could have activated the TCS. It will give you a funky feeling car moves but usually will keep you on the road. When it activates it usually takes away the gas pedal response and the abs will bump an offending caliper with a little pressure.
Also be a little careful with spirited driving, you can get into an oversteer condition and that is hard to correct on a street that is crowned as most are, and the grip changes when you cross lane marker paint or the road edge. Then your donkey is in oncoming traffic. Once you get your donkey in the oncoming lane and your front in your lane, it is hard for the rear which has no grip to climb the hill and get back in your lane. C5 Corvettes are biased to understeer, but there are things you can do that will suddenly change, like lift the throttle to much at the wrong time.... then slam it back on. This is usually when the nannies are off, or they have gone on strike because they were asked to do some task they did not want to do.
I have CCWs on the car.. 18s - 275/35 front and 19 - 295/35 rear, i believe.
I think the car is lowered about 1 1/2 inches.
I was in a straight line, did not slip the tires, nor did TCS activate at all (it really wasn't WOT, as a simple blip of the throttle would result in the rear wanting to step out right, and as i let off the throttle... back to the left.)
Issue went away after torque the LCA's.
Having another shop align it today... and i'm trying to get a refund from the last shop
They claim they didn't touch anything, threw it on the rack and the alignment was good. But they are the only shop to have done my alignment twice in the past 5 months.
Grumble
