I learned how shops fudge alignment - PeachParts Mercedes-Benz Forum

Junkman · #1 11-03-2015, 09:32 AM

The "heads" of the machine are mounted to the wheels. What's supposed to happen is the suspension is adjusted to get the desire,angle. Alternatively, the tech can simply bump the head mo ing it independently of the wheel, getting the desired reading only,and sending you on your way. The tech absolves himself by pointing to the print out which of course shows a perfectly aligned front end. Now you're scratching you head,wondering why your car steers like crap.

FWIW, the machine a new Hunter did call for the,spreader bar. The shop doesn't have one but the tech who autocrosses said that,he pushes out on the tires as part of his toe setting process.

I'll have to physically watch the alignment being done from now on and not rely on the final,print out. The good news is I,bought some Michlin Defender tires which are supposed to last a long time.

leathermang · #2 11-03-2015, 09:52 AM

I worked for a while in a front end alignment shop....and this ' spreader bar' is totally foreign to me.... I assume they are using that instead of rolling the tires forward to take out any ' set ' they have in the position they start at.....
I would avoid any place that used a spreader bar. The idea that it can correctly compensate for the ' play ' in the steering parts which ' toe in' is designed to compensate for.... call me very skeptical.... at the least....
When I first heard ' spreader bar' I thought they were using that name for the measurement stick used in front of the tires to check on Toe In.... The measurement bar is used twice... once before and once after rolling the tires forward...

zu! · #3 11-03-2015, 11:02 AM

My alignment shop doesn't show me any printout. Oh I'm sure they have it, but the proof of the pudding is in the eating as it were. So, the owner drives the car before and after the alignment.

It's always been perfect.

Sent from my iPhone using Tapatalk

dude99 · #4 11-03-2015, 11:14 AM

Quote:

I would avoid any place that used a spreader bar.

The Mercedes FSM specifies using one for the w123... so if they have the correct equipment I would have no problem with them using it...

vstech · #5 11-03-2015, 11:28 AM

the spreader bar is for shops that use floating suspension computer alignment...

if an old school alignment is performed under load of the suspension, and not raised up off the ground, no bar is needed.

I agree with LMG... spreader bar is a cheat, and it's results depend on the tech's knowledge for using it.

the shop I worked in drove the car, pulled into the shop on a perfectly level pit with rotator plates under the tires, and aligned the car under load.

Junkman · #6 11-03-2015, 12:27 PM

I don't recall what machine the FSM assumes in the 30 yr old instructions. The spreader bar is noted to be positioned inside the tires at the front and exerting ~30 lb of pressure outward.

The McParts alignment places don't put the effort into alignment that a competent shop will. The 1 remaining competent Indy doesn't have a machine.

leathermang · #7 11-03-2015, 01:09 PM

VStech, Thanks for that overview....we had those rotator plates up on a ramp.. so the alignment guy did not have to bend over too far...... at that shop we also balanced the tires on the car.. which I still believe in...though I do not know of any place to get that done on a car.. I assume that trucks get their tires balanced that way still (?)...

vstech · #8 11-03-2015, 01:23 PM

yeah, our place had a full depth pit... no bending over required (by the tech anyway...)

leathermang · #9 11-03-2015, 01:51 PM

Quote:

Originally Posted by vstech

yeah, our place had a full depth pit... no bending over required (by the tech anyway...)

If you have one foot or less... of topsoil....and caliche from there down... you have to go up unless you are rich.... Military installations always had that ' grease pit'...very safe and useful....

https://en.wikipedia.org/wiki/Caliche

Dan Stokes · #10 11-03-2015, 02:14 PM

To the OP - I'm afraid you just found a bad shop. No honest shop I know of would fudge the numbers. Some will try to sell you parts (ball joints are a top seller) in an effort to make more money but I have never worked in a place that willfully messed with the measurements. Really, there's no advantage unless that operator is high and just lacks to motivation to adjust the adjustments in which case the boss will toss him/her out the door. So tell the boss what you saw. If the shop condones or supports this behavior I'd:
1) Never go there again.
2) Tell everyone I know (lots of folks look to me for auto advise).
3) Report them to the Better Business Bureau. They'll make a record of it and if they get many complaints will black list the company.

Dan

BillGrissom · #11 11-03-2015, 03:14 PM

If I had a shop I could trust, I might pay the $$, otherwise I never know what they really adjusted, aka the "we don't allow customers in the shop to watch". Long ago, a K-mart must not have actually aligned my toe-in because another shop a few months later found one tie rod end had totally stripped threads. The most critical alignment is toe-in and one can do that quite accurate with a tape measure (youtube). I do so on my two 300D's and they go straight w/ hands off the wheel and the front tires wear evenly. I can resolve 1/8 turn on the tie rod adjusters so doubt a laser machine could do much better, nor would it matter. It is not too tedious w/ a helper holding the tape and much faster than driving to a shop and waiting while they maybe do nothing but take your money.

charmalu · #12 11-03-2015, 03:28 PM

I did a search on Spreader Bar and found this thread that talks about it.

Too much caster. Why? - Mercedes-Benz Forum

And this site that sells them and shows a picture how it is used.

Wheel Spreader | Specialty Products | 99918

I don`t think I have ever had an alignment that the bar was used.

Charlie

send from my pos computer

Ceristimo · #13 11-03-2015, 04:04 PM

Aaah, the beauty of alignments. Took my daily driver to an alignment place about 4 months ago, because she was pulling ever so slightly to the right.

The 2-year old tires (only used in summer, so about 8 months of wear on them) looked good with even wear though.

Tracks perfectly straight after the alignment.

I was all happy.

Inside of my tires worn bald 2 months later...

Graham · #14 11-03-2015, 05:48 PM

Quote:

Originally Posted by dude99

The Mercedes FSM specifies using one for the w123... so if they have the correct equipment I would have no problem with them using it...

Last time I had an alignment done was at Speedy Muffler here in Canada. They used a spreader bar. The Hunter machine instruction tells them to use it. They didn't have one, so made one up from some pieces of pipe and hose clamps! Crude, but seemed effective.

That was about 4 years ago. No problem with alignment or tire wear with Kumho tires I put on. They still have quite a few years life left on them.

By the way, I was able to watch them do the alignment from the waiting room that had glass wall to shop.

Zulfiqar · #15 11-04-2015, 01:25 PM

the german tools for alignment have the 5 finger prong that goes into the holes near the lug bolts, a hand wheel is then turned to lock the tool in place, I wonder if that provides a better result as it cannot be moved unless its unlocked from the wheel.

I have seen it once (long time ago) and the shop was using an optical alignment unit. that hub tool actually had a mirror on it.

I have seen a "home made" spreader bar being used on an old mazda RX7 for alignment. The old man who ran the shop and did alignments himself was pretty famous for good jobs, when I asked him about the bar he also told me its for simulating a road. his home made bar was 2 pieces of wood with a screwjack and spring in between.