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What were they thinking?

I have been a staunch supporter of auto engineers in general. Their jobs are not easy and often criticized. Then I tried doing the lower ball joints on my '04 Trailblazer over the weekend…

What a breeze to separate the upper and lower ball joints! It really couldn’t be easier to do. I had the entire assembly off in about 10 minutes from the time I started pushing the jack under it. Then came the gut punch. You need a special receiver cup to press out the lower ball joint. There’s really no sound reason I can see for it. There was plenty of room to allow for one of the standard 3 cups to fit. Someone purposely chose a weird design that requires a cut away cup to allow room for the arm and to engage two “wings” on either side of the arm.

I spent most of the day driving around looking for the proper GM kit adapters. Which brings me to another gripe- I specifically called your parts store asking if you had the right kit. When you say yes, please make sure you actually have one. Do not trust your computer system. I drove 40 miles round trip to find out OOOPPS, we don’t actually have one, sorry. I had to fabricate my own out of materials I had laying around. I could have spent that driving time doing it, BUT NO! Now I feel better…

Twin Turbo, Did You Encounter A Problem ?
I Guess I’m Just Not Seeing It.

Every repair I do seems to have a SNAFU - Situation Normal, All “Fouled” Up. This whole fiasco appears completely normal from where I sit.

I liked the, "It really couldn’t be easier to do."
I have found from experience that these are the toughest jobs.

Rest assured that you are not alone.
What doesn’t kill you, makes you stronger.
Can you bench press that Trailblazer, yet ?

On a more serious note, I always spend the big bucks ordering the factory manuals from Helm Inc. for all the GM vehicles I purchase. I look over each repair and am often alerted to the need for special tools.

I ordered a couple of inexpensive tools in advance that were listed in the factory manual (not Helm) for my 3.5L Intrepid that made installing a timing belt easier (actually they made it possible !). That saved me the “run around for special tools SNAFU” that you talked about. Then I only had 2 or 3 other ones to deal with.



The problem as stated above- You need a special receiver cup to press out the lower ball joint.

It is unique to the GM truck and there does not appear to be any technical reason for it.
If they had added 1/8" of material to the radius of the lower arm socket, it would allow the use of the common tool size.
Instead, it requires a unique tool, albeit a simple modification. Makes no sense unless you’re trying to capture repair revenue IMHO.

Anyway, in 3-5 business days, I will become the proud owner of a GM specific, set of receiver cups for the low, low price of $62.58. I’ll be ready for the next one.

Fortunately, you could plan ahead for your timed intervention on the belt replacement. The ball joint failed inspection and was really quite alarmingly close to a permanent dirt nap. It required immediate attention, if not sooner :wink:

There’s a techno-bable term called “engineering prerogative”. I’m not sure what it means, but I think it’s a concept that allows some engineers to rationalize designing something that they know in their gut would be near impossible for they themselves to work on. It doesn’t matter if they’re designing a coffin on wheels, (er–AUTOMOBILE!) or a Waring Blender. They are the Creator of the thing in question, & you don’t question the Creator! It’s up to us “technicians”, whether mechanics, or DIYer’s, to somehow GET 'ER DONE, & that’s what you did. Don’t be bitter; congratulate yourself. Most people would’ve given up & gone to a garage!

I guess this bears repeating. There IS a valid reason for such engineering practices. Having to use special tools and not making things too user friendly serves two purposes. First, it keeps incompetents from performing tasks they shouldn’t. Second, a major income for automotive industry is parts and service (and specialized tools). Cars are meant to be serviced and projected profits on cars over time always take this into account.
It’s an engineering balance between serving the wishes of bean counters who want to maximize profits and sales who want to advertize reliability and minimal maintenance. The few times a reliable, “maintenance free car” needs service, it “needs” to be done by the dealership.

AutoZones in my area have that set avail. as a “loan-a-tool”.

I’m not persuaded that these difficulties are intentionally designed in. Major considerations in design include ease and cost of manufacture, prevention of error through assymetry of design and differing parts to prevent the use of the incorrect part. The manufacturing and cost considerations have standardized practices that include using a single part to perform multiple functions. It also includes using instant attachments (such as the plastic push-rivets so common in body panels and assemblies) rather than screws and brackets. “Package engineering”, getting as much as possible out of as small an overall vehicle as possible, also compounds things.

Unfortunately, many of these practices make disassembly dependant on special tooling. And in some cases things are impossible to disassembly. In many cases, such as changing the rear shocks in my tC, things are more difficult than they were many years ago (and expensive for those paying someone to do the work).

And then there’s the “fed stuff”, all those things that the design wil have to meet. In my car, crashworthiness has driven the design of the steering column to include two joints, allowing the column to fold under the passenger cabin in the event of a crash rather than push the steering wheel back. I suspect that far more of the package design is focused on crashworthiness than I realize.

The thing is, almost everyone is using pressed in ball joints now. I say almost because although every car/truck I have seen uses them, I haven’t seen every car/truck made. None of them use this funky design. I see no clearance issue driving the difference. It’s not like 1/8" more material is going to significantly impact the cost or reduce the performance of the part. They can be assembled (pressed in) using the standard tool. It’s only the removal (service aspect) of the part that is impacted.

The truly weird thing is, getting to the ball joints was easier than any other vehicle I’ve ever done this work on. It is insanely easy to do with the exception of this one tool modification that is different than everyone else’s approach.

Like I said, I’m normally skeptical of these claims but after seeing this, I’m coming around to the notion it was intentional for the reasons dagosa detailed in the second half of his post above.

next time just pay someone and stop complaining

So, you read through the entire thread and this is the best contribution you can make? If that is your solution to the problems you encounter in life, I hope you have a decent trust fund…

Engineers have very little prerogative. Engineering managers, or more correctly, engineering managers several steps above engineers, set policy in conjunction with marketing managers and dealer managers. They must provide a plan that eases manufacturing and encourages use of the dealer’s service shop. And they have to fit all these parts into smaller and smaller spaces. Whether you or I can perform a repair is not a priority for them. It’s easier to provide a tool that allows access to that particular bolt because a dealer can spend $100 on a tool he uses 1000 times. Are you going to spend $100 on a tool you use once? I first encountered this over 20 years ago trying to remove an alternator. It looked like it was a slam-dunk; it was right on top of the engine. But I either needed the exact offset wrench for this job or the patience to monkey around with it for an hour or two. I opted for cursing for a couple of hours.

Every manufacturer has had these type of design issues.

Back in the 80’s on the Chevy Monza with the V8…you had to disconnect the engine mounts and raise the vehicle up to change a couple the spark-plugs.

I’m not too sure it was intentional…as opposed to NOT really thought through. Many times the engine designers and body designers work independently until the car is assembled…then things get hammered into place to work and let the mechanic or owner figure out how to fix it if something goes wrong.

I know what you mean Mike. Times have changed. Back in the 80s, computer aided design was in its infancy. Were I worked, we still were doing a lot by hand. Today, all of the disciplines can share models between their respective design platforms. For example, the electrical designers transfer their schematics to the PCB designers and they collaborate on-line, in real time with the mechanical engineers designing the enclosures. The optical engineers can also use the mechanical models to insure their component designs will work as intended. Interference fits are automatically identified and highlighted by the software. 3D models are exported and can be viewed by anyone. Those views can be sliced or layers removed to view any inside component as it relates to the package or other components. These are really the standard tools in use today, nothing special.

It’s also very common to engage in collaborative efforts between various business entities or sub-contractors that can be located anywhere. Sharing design info is done in real-time with multiple parties viewing the same images on their computers and discussing issues related to the interaction of various components or sub-systems. Not long ago, I had to get up at 4 in the morning to have video conference calls with a design team halfway around the world and we would review system models in real time. So the idea of having an interference fit that is unrecognized until first article assembly would be surprising to me in this day and age.

On a related note, back in the 90s, I had the pleasure of working with NASA and Lockheed as a sub-contractor for some equipment to go on orbit aboard the shuttles, MIR and later the ISS. Those guys at NASA had the most comprehensive and astounding set of analysis tools I have ever seen. They were able to do very complex modeling of stresses encountered during launch and could identify exactly where to place shock isolators, their sizing and what durometer they needed to be as just one example. No company I have ever worked for could afford that level of sophistication (and I’ve worked with some BIG companies in the past).

I’ve said this a number of times before on this board- Cars are designed to be built as cheaply as possible. Servicing provisions are secondary. But when they make a conscious decision to make something unique compared to everyone else, it must be for a reason. I’ve had those kind of requests from marketing in the past. In those cases, it’s been done to make it hard for competitors to compete in your “socket”. This appears to be no different…

It seems that every time I do a repair and sometimes with just regular PM, I end up asking this very question. Last month, I was trying to unclog the AC drain on my wife’s Honda. The compressed air only worked for a few minutes.

One trick I had used in the past on other vehicles, was to remove the blower motor and reach through the duct into the evap compartment and clean it out. However, on this Honda, 97 Accord, the evaporator must be removed before you can remove the blower motor. That means sucking down the freon, breaking two seals and all the headaches associated with that. Only a few minor changes in design would have made all that unnecessary, it actually looked like someone went out of their way to make this harder.

I will still drive my Nissan PU to the plant if the engineer who decided to enclose the oil filter in a nest of coolant hoses, wiring bundles and PS hard lines will replace the filter for me.

GM does seem to be the worse for this though.

As an engineer in another, but related industry, I think I can shed some light on this.

Sometimes ease and cost of manufacture becomes the most important thing. In the case of a ball joint, the probable replacement is way outside the warranty timeframe, so the difficulty in replacement becomes a non-issue for the design team management.

I agree. I also feel that financially, the engineers are many times NOT given a free reign in working outside of available off the shelf parts.

An SUV based upon a sedan means you now must integrate two systems with different design intent, often using techniques that make repair more specialized to the dealer, both in tools and knowledge. More often than not, manufacturing costs are given priority over customer convenience.How many times have you tried out a car and wondered, what idiot decided to put this knob or component here ? It’s as though it were designed by committee whose members refuse to speak to each other with the bottom line cost having the final say.

Toyota with all it’s vast resources still makes a Yaris that seems intentially designed to turn off a number of buyers when with but a few tweaks, it could be among the best in class. Must have had these old Tercel seats still left over that they had to use. Makes you wonder what thought process goes on under the hood as well.

CapriRacer, I Always Value Your Comments. This Is Interesting. Let’s Discuss This.

"In the case of a ball joint, the probable replacement is way outside the warranty timeframe, . . . "

What’s an example of probable replacement that is inside the warranty period ? Doesn’t the manufacturer do everything within reason to make all parts last through the warranty ?

Are the decisions partly a function of cost of possible warranty replacement of certain items ?

Some manufacturers have even been in a situation where they’ve replaced all the ball joints in certain models, even recalled them.

In TwinTurbo’s case the repair wasn’t that difficult, it was just the pesky special tool needed for one repair. Most dealers have an assortment of any special tools needed for something like ball joints. The cost of one tool used hundreds of times is relatively small.


Consider, too, whether or not the actual dealer will replace just the joint. A lot of parts now won’t be fixed, but just replaced outright. So the whole lower arm may be replaced. It may seem wasteful - and I think it is - but when it comes to time involved, it can be a lot quicker. If they just replace the whole arm, they may also want to replace the bushings. Once it’s apart…just do it all.

I can’t say for certain this applies in this case, but I do know dealers are headed this way. I can say that VW is doing this a lot. Rear bearings aren’t fixed - the hub is replaced with a new hub, bearings installed and greased. I guess a phone call could answer the question…I just haven’t made that call.


I think starting in the early 60’s, Chrysler had a ball joint (there were 2 styles, actually) that had non generic threads that screwed into a similarly threaded hole in the control arm:,3523.html+chrysler+screw+in+ball+joints&cd=1&hl=en&ct=clnk&gl=us&

If you look closely at one of the bigger ball joint images in the above web page, you can make out the threads.

Her’s web pages with pictures of the special service sockets for these ball joints:

OK, so they made 2 special service octagonal sockets with really oddball dimensions (1 59/64"!), when, seemingly, they could just have made the ball joint the shape of a generic hex socket. You could usually R&R these joints with a regular socket or huge adjustable wrench, except if they were bonded in real tight.

So I agree with the posters who say that this practice is done to keep the service dept busy.