Alignment question

Messages
588
Location
Chicago, IL
Since alignments are in the threads lately, something I've been wondering about... how do the technicians mount the sensor things onto the wheels? How do they know the sensor is true to the wheel?
 
Messages
5,731
Location
Tn.
What is the rule of thumb if there is one on when do we grease the front end fittings, like at each oil change, every 90 days, whats the new consensus now days???????????????
 
Messages
8,576
Location
Ohio
Originally Posted By: CourierDriver
Originally Posted By: mechtech2
courier - "if there is one on"? What is on?
when do u grease the front end
I think at every oil change. Usually you lube the suspension at oil change time.
 
Messages
1,834
Location
Southeast Louisiana
I hear different stuff about lubing the suspension. I used to hit it every oil change when I was changing at 3,000 miles. My mechanic commented that I had a sensitive trigger finger with the grease gun. On the new ball joints and tie rod ends on my Dodge, it said on the packaging that Moog recommends greasing every 2500 miles, so thats what I do. Only a few squirts every 2500 miles.
 
Messages
8,711
Location
Nothern USA
May want to actually look at them. If the grease bags are still full, maybe they can wait. We know modern oils are vastly superior to 20 years ago. What about greases? Or is that why so many pivot points are not sealed?
 
Messages
155
Location
Oklahoma
When they first pull the car up on the rack, the sensors are then mounted on the wheels. Then all 4 wheels are raised off the rack with built-in air over hydraulic jacks, and each sensor is calibrated one at a time by the tech spinning the wheels while the sensors and computers measure runout of both the wheel and how well the sensors are mounted. Then the jacks are lowered and the car sits on plates that move freely on ball bearings so there is no suspension binding and the car sits as it would going down the road. (Ideally, the driver's seat is loaded with weights that simulate the driver's weight to be as close to reality as possible, though few techs do this.) Some newer alignment racks don't use the jack system and instead the wheel sensors are mounted, and they compensate by driving the car forward a couple feet while on the rack itself.
 
Last edited:
Messages
1,025
Location
New Zealand
Thanks for writing that up - the first part makes sense.
Originally Posted By: Ike_Clanton
Some newer alignment racks don't use the jack system and instead the wheel sensors are mounted, and they compensate by driving the car forward a couple feet while on the rack itself.
Surely the compliance of the suspension while moving the car would invalidate any possible compensation?
 
Messages
22,721
Location
CA
Originally Posted By: Kiwi_ME
Thanks for writing that up - the first part makes sense.
Originally Posted By: Ike_Clanton
Some newer alignment racks don't use the jack system and instead the wheel sensors are mounted, and they compensate by driving the car forward a couple feet while on the rack itself.
Surely the compliance of the suspension while moving the car would invalidate any possible compensation?
All of the newer John Bean Company (JBC) and Hunter systems will instruct the technician to roll the vehicle back and forth several times before clocking the rear wheels. Some of the Hunter systems also has the technician "bounce" the suspension as well, IIRC.
 
Messages
155
Location
Oklahoma
Originally Posted By: Kiwi_ME
Thanks for writing that up - the first part makes sense. Surely the compliance of the suspension while moving the car would invalidate any possible compensation?
I honestly don't know, but I had the same questions. I have only used Hunter systems with the jacks. Regardless of the system used, an alignment is only as good as the technician performing it, and there are a LOT of really bad alignments being done out there. "Set the toe and let 'er go..."
 
Messages
155
Location
Oklahoma
Originally Posted By: The Critic
Some of the Hunter systems also has the technician "bounce" the suspension as well, IIRC.
You ALWAYS bounce the car, always.
 
Messages
22,721
Location
CA
Originally Posted By: Ike_Clanton
Originally Posted By: The Critic
Some of the Hunter systems also has the technician "bounce" the suspension as well, IIRC.
You ALWAYS bounce the car, always.
I don't remember the JBC systems asking the technician to do that. As for setting toe and go, that is about all you can adjust on many late-model cars.
 
Messages
155
Location
Oklahoma
The system may not ask the tech to do it, but you do it to ensure the suspension is completely settled on the slip plates of the rack, especially so on old, tired racks with slip plates that aren't very slippy anymore. And as for modern cars having only front toe adjustments, well, I guess I'd counter with the fact that very few cars these days still run a beam rear axle, meaning the ones using IRS at LEAST also have a rear toe setting, too. Even some rear beam axles can be shifted in their mounts to equalize rear toe (but not adjust rear toe numbers individually.) Equally wrong is still better than inequally wrong when it comes to the rear alignment of most any vehicle.
 
Messages
22,721
Location
CA
Originally Posted By: Ike_Clanton
And as for modern cars having only front toe adjustments, well, I guess I'd counter with the fact that very few cars these days still run a beam rear axle, meaning the ones using IRS at LEAST also have a rear toe setting, too. Even some rear beam axles can be shifted in their mounts to equalize rear toe (but not adjust rear toe numbers individually.) Equally wrong is still better than inequally wrong when it comes to the rear alignment of most any vehicle.
Sorry, what I meant to say was that toe is the only adjustment you have on a lot of vehicles. Of course, more and more cars have adjustable rear toe these days. Perhaps "set toe and go" isn't the correct term to use to describe what I meant to say.
 
Messages
39,806
Location
Pottstown, PA
I find that alignment in general has been over complicated like the rest of the systems in the rolling fleet. I really don't see where a 4 wheel or "Trust angle" alignment ever needed to be developed if the engineers just hadn't bothered to tell anyone that it was there. Better yet, just not have it there to begin with. Leave it to some wizbang Euro alloy shop to spend the coin on. I took my daughter's old Taurus in for an alignment (I know the shop well), I figured the standard $59.95 front wheel job. Get the bill for $89.95 4WA and the rear adjustments were frozen. The charge was for the added labor of hanging the sensors and reading it. The average consumer sees absolutely no benefit (my opinion) from these advanced suspensions technologies and supporting them over simpler and proven designs. So what if you can't pull .0002 more g's in a turn (or whatever). Camber was a nice additional adjustment to the standard strut front end. It meant that you didn't have to trade it in if you ever got the slightest of front end damage.
 
Messages
155
Location
Oklahoma
I guess I'd agree with you to the extent than many drivers probably can't (or simply won't) notice the difference when their steering wheel is straight versus actually having their car put into proper alignment. I fault the alignment shops charging different prices on being greedy on something that should be done on EVERY alignment: adjusting everything that's adjustable to proper specs. Even some light to moderate work getting frozen pieces moving again is to be expected and should be included in the price. It is a disservice to the customer if a tech neglects to make proper adjustments if they are already "pretty close" or "good enough." Do it right or don't do it at all.
 
Top