Gen 3 Alignment issues

[cothrelo]

So I have had my car at 2 high end places (the do lambos, farrari, vetts etc and neither could align my 05. They stated that they didn't have the tools to do so after specifically asking if they could do it. The last place said that a hand held computer is needed. From what I have been reading it is needed but not really? Is it really that big of a deal to align these cars? Is there something I could install to make this easier to find someone to do it?

I do have one more place lined up for this Friday that is an hour away. I asked specifcally if they had the tools to do the job and they said yes. They also stated that they have aligned vipers for track use. Hopefully they can get it done.

 

[MoparMap]

I think it comes down to how they want to align them. The service manual alignment process uses fixtures that attach to the sides of the knuckles to measure caster and require the dealer DRB III tool to read them. That being said, I don't see why the "standard" process of turning the wheels to measure camber gain and calculating caster from that isn't still viable. I've been doing my alignment in my garage for a few years now with some holes I drill in the floor to hold posts to mount strings on and a generic camber gauge. I have a DRB III now and the caster fixtures and I do think it makes a difference when the caster is set correctly, but I don't think the tools are necessarily required to do that. I had my car aligned at other shops around me prior to that and no one (even just the local Tire Rack or Big O tires or wherever) seemed to have any problems and they all gave me readouts for all the measurements. I wonder if the shops are getting too hung up on the service manual procedure.

At the assembly line they also measure alignment at various wheel travel points and adjust the steering rack and rear toe links to control bump steer. They are both adjustable with some shims. That's maybe something that's fairly difficult and not typical at most tire shops, but if you haven't adjusted your ride height I would generally say that you would likely not need to change it from wherever the factory set it to begin with.

 

[GTS Dean]

The front end is no problem for any shop. Checking and setting the rear caster angle can't be done without the knuckle adapter brackets and a magnetic digital inclinometer. If the front is in-spec, tires are confirmed good and the car is still not behaving, then the back end needs the full works.

 

[cothrelo]

Appreciate the response. That must be what it is. The car is lowered and the rear is off according to the last place I took it to. They didn't have the tools to adjust the rear. Will call the place that I am taking it to on friday and make sure they can do it.

 

[GTS Dean]

Before I got my DRB and Viper tools, I had to wing my rear alignment in the garage. If you remove the tires, free up the cam adjusters a bit at each corner, use air to get the grit out, then put a pair of 3/4, or 19mm wrenches on the cam bolt heads, you can run them through the full adjustment range - in/out together in time, (camber adjustment) or work them opposite directions (caster adjustment).

The main thing is you want to do is make sure you are starting each corner with the bolts absolutely centered in the guide slots (the cams straight up). The way the cars are designed, this should get you right about zero camber and design caster. If you want more negative camber, roll the cams in/bolts outward together in-time and this will hold caster fixed. If you have your camber set where you want it, you can move the lower ball joint forward (more positive caster) while keeping camber constant by rolling the back bolt out and the front bolt in by the same rotation amount. If you keep the front cam fixed and roll the back cam in (bolt out) you add positive caster and negative camber. On all cars past Gen 1, you will want positive rear caster - lower ball joint very slightly ahead of the upper ball joint. We are talking in the neighborhood of 1 degree positive.

If your bushings are in good shape, this process works pretty well. However, bushings wear, they begin take a set with the bolt guide tubes off-center. This makes the above process less trustworthy and requires the proper caster tools to set up correctly. The photos below illustrate the very worst caster starting situation you can imagine negative caster on both sides and unequal side-side. The handling was as nervous as a prost***te in church - requiring both hands firmly on the wheel at all times. Getting it set right made the drive an easy 1-hand experience.

 

[Stag Stopa]

Hi,

alignment with only standard equipment (plus one set of Mopar caster adapters) and enough time is possible. I do not recommend the procedure GTS Dean described, though. Every Viper is different ... Sure, the factory did a good job, but I wouldn't bet that every frame is identical and that following a mere 'visual guidance' leads to relaible results. Plus: the car in question had some serious suspension tuning - extra caution is strongly advised for my taste.
When I rebuild my Viper last year (after I got into an accident on the Autobahn) my father and me (both mechanics) did alignment (and all the other funny stuff) all by ourselves. We got the Miller adapter for the rear axle (MILLER TOOL 8996), a magnetic inclinometer and a 'standard' wheel alignment machine (nothing fancy, no lasers, just four reguar measuring heads) ... It's very important that the car stands on turntables with ALL four wheels and that the suspension is sufficently bounced a few times so it settles on a neutral height. I also have to disagree a little bit regarding indirect caster measurment at the front - our alignment machine only was able to show the actual caster, but wasn't able to calculate live adjustments (6,6° caster isn't usual for European equipment I guess)^^ We simply 'copied' the rear adapters for the front so that we could use the inclinometer there, too. The rest is (as all the people said) standard (but maybe very time consuming). Direct measurement for caster (this extreme) works best in my experience ... indirect measurement by turning the wheels can lead to the same results, but in our case it would have been way more time consuming (and with mounted bumper outright impossible).

Anyways. All I wanted to say: there is no need for a DRB3 nor premium workshops ... I don't disrespect the folks there, but a Viper is (in a good way) downright stupid and honest - you need time, no image! Pay for oldschool mechanics and not VW-idiots (sorry, but I worked long enough on their 'products' and learned the hard way that there is no [mental] difference between VW, Audi, Lambo, Porsche and I never trust shops that work on too much different shiny premium stuff at the same place). Other workshops that may assist and also use much direct caster measurement should be the Merc-people ...

One last thought (and once again experience): the shop manual is VERY specific and explicit in terms of the so called design height ... I don't want to scare you, but depending on what coilovers you use there is a real chance that OEM specs simply can't be adjusted to 100% anymore. Both front knuckles on my car were broken (plus cracked steering rack and bend sway bar links) and I only found out that one control arm was also bend (though undamaged looking) when the OEM front caster wasn't in adjustable range ... Wheel alignment is one of the best ways to determine if crash repair was done right or not


Best regards and good luck,
Kevin

 

[GTS Dean]

Kevin,

Kudos to you for working through the process following every detailed step. In the instance of heavy crash damage repair, that is absolutely the only way to be certain everything is right. I have done all this myself as well on my car. With rubber bushings, the ballast, ride height adjustment and torque procedure is very important. It is extremely tedious, but extremely rewarding to know it is perfect! Measuring and adjusting bump steer is something I have done numerous times on my car. Not easy. Corner weighting too. When I finally got rid of all my rubber bits and went to monoball/urethane pivots, most of the tedium became unnecessary.

I have seen numerous cars that have made curb contact that still have straight frames, but the alignment cams are seriously out of kilter. Most times, the easiest thing to do is adjust things so they are not obviously flawed like my photos above and send them to a good alignment shop to do the grunt work. I'm not in the business, but have helped a lot of friends sort out their obvious problems.

 

[Stag Stopa]

Thanks Dean,

and props to you, too ;-) I'm glad you aren't offended by my post (that wouldn't have been the indend). Yeah, as you said - time is the important factor here. And wow - I also considered the monoball conversion back in the day but went with the stock option instead (I was glad to get my hands on NOS hardware and my car isn't for trackdays anyway) - nonetheless you've got me a little bit envious Same goes for bumb steer adjustment: 'normal alignment' was interesting enough, thanks - I just went with the two shims under the rack that are stock ... I doubt that I would be able to make out the difference or even call it necessary (as said: no time attacks planned)

And yes - the cam/cas bolts tend to snap whenever just a portion of force crosses the path of the rims. I'm certain that correctly torqued down bolts on a 'working' alignment should to the job for 'normal' use just fine ... but should I ever consider taking my Viper regulary to race tracks or do alignments with different setups more often - I would go for a 'fixed shim' setup (like the comp coupes had) immediately ;-)
On the other hand I like to tell myself (please correct me if I'm mistaken here) that these 'weak points' in the suspension serve a higher purpose ... maybe it's false but snapping cam bolts and thus deforming suspensions absorb some energy from the impact, right? Whenever I blamed the 'weak suspension parts' I corrected myself by saying: 'Maybe that's why your frame is still straight and your diff stayed alright?'
Phew, I love Mopar for building cars like the Viper but at the same time I hate them for not being able to provide even basic supply of everyday spare parts ... Most of you guys know it even better than me: The Viper is such an simple (and great!) car and everything is just about right - with just a little bit more support from Mopar it could be around the streets and tracks for so much longer! I can't understand why such an awesome (real) halo car

 

[GTS Dean]

I'm pretty certain that a bit of extra compliance, or "give" is engineered into the suspension so that road debris/potholes/lane departures don't transmit full shock loads into the frame. They want things to shear away or collapse/deform predictably to protect the occupants.

My car has seen progressively less roadway time vs track time over the years, so I've built & tuned the car for consistency of setup and higher suspension and braking loads. With a nearly 28 year old Viper - when I need parts, I have to plan for weeks or even months of potential delay time.

 

[GTS Dean]

I was checking on some alignment recommendations I had made to an owner on another site a little bit ago and I had a lightbulb moment I thought I would share here. This all assumes that there is no frame damage or twist - or else you'll be endlessly chasing your tail.

Most shops can calculate the rear thr u st angle and wheelbase difference L/R. These are indirect indicators of caster imbalance. Assuming you have the caster/camber/toe equal on both sides at the front, then with toe set to zero on both rears, if one side has a shorter wheelbase - it means that side has more positive caster (lower ball joint further ahead).

I still think it's a good idea to baseline your camber by centering both cams on a corner, then rolling the bolts out in time to get it set. Next set toe to zero and measure wheelbase difference and thr u st angle.

The Gen 1 and Gen 2 cars have 96.2" design wheelbases. I'm pretty sure the G3-G5 went several inches longer - maybe 4"? To lengthen wheelbase with camber fixed, you have to pull the wishbone rear inward and the front out by equal amounts. Then reset to zero toe and check readings again. With the ideal wheelbase measured relative to correct and balanced front front spindles, the rears should come in without much trouble. This does not give you an actual angle, but could keep you from having squirrely behavior at the back.

 

[Beardy]

Edited to correct myself...

Without the necessary fixtures I guess that one can at least ensure that the angle of the spring damper assembly at the rear should be kept the same on both sides...