By design, the caliper piston cannot be caused to move in and out of the caliper bore on an angle. There is simply not enough room for that to happen. However dirt and corrosion which would have made it necessary to replace the caliper when the brakes were realigned could have gone undetected because it isn't visible under the outer dust boot. Keep in mind too that a second possible cause for the pads now wearing on a taper are the caliper slides. When you step on the brake not only does the piston push the inner pad against the rotor, it causes the outer pad to be squeezed against the rotor as well because the entire caliper shifts in response to the pressure that the piston is exerting on the inner pad. If one of the slides is not operating correctly, it could cause the caliper to twist as the brakes get applied. The problem is, did the shop recommend replacement calipers or at the least caliper slide service when the brakes were done? What we have here I suspect is the classic problem of the shop trying to save you money when they should not have. OR. They did in fact recommend the caliper replacement or slide service, but when giving you options, for one reason or another the replacement of them was declined by you. Right now there is no way to know from our (my) perspective. If the shop didn't advise you replace the calipers, because they operate in an honest fashion and had no proof they were genuinely needed they did on fact do exactly what they should have done. As the saying goes "stuff happens" VBG. Work with them, get your car fixed and move on. JMHO.

I had a similar issue last July when my Lumina Van blew a head gasket. About the same mileage, w/ 3.4 It didn't take me long to decide to scrap it, because it's value was equal to the repair (and that's assuming the repair went precisely by the book). Anything else turn up, the repair would cost more than it's value, and what next on the horizon - who knows. The Lumina Van's engine is a bear to work on cause it's buried so deep - unless you remove it of course. Only my take, salt environment for me, so corrosion was there, brake lines etc would come due, it all adds up fast. If yours is pristine and ran in a dry environment, then maybe. I just don't have a lot of faith in that 90 deg V6, I've had 3, all problematic, only one left to go.

"What's causing the tie rods to break?" Your tie rod is not broken, else you be in a ditch somewhere with your head against the windshield. The tie rod "ties" the right side steering arm to the the left side steering arm. If this rod breaks, there is complete and immediate loss of steering control. The usual failure is for the ball joints that are on the ends of this rod to become so badly worn that one end of the rod comes off the steering arm. What I suspect is that these joints are worn and the easiest way for the technician to replace these is to put in a complete new rod with new joints already on the rod. Its easier to replace the entire assembly than to mess with trying to loosen corroded screws and clamps to remove the old joints, and he should replace all the clamps and screws when intalling a new joint anyway. Remember that shop costs are $65 or more per hour. Saving a half hour of labor will pay for some of the new parts. Yes, the alignment tech is correct. He can not perform a proper alignment if the ball joints are worn, and the tie rod ends are only part of the steering system. There are other joints. I believe that you question really is, "Why are the ball joints wearing out so quickly?"

The cost of replacing the intake manifold gaskets need not cost $750 IF you are willing to do the work yourself. If you are handy with wrenches, you can do it in one Saturday morning. The cost of the parts isn't much, but there is quite a bit of labor and that is where the shop charges are. I've done this repair in two GM 2.8 L V6 (Citation). The 3.1 L engine is similar. The intake is cast aluminum and doubles as a valley cover. These intakes also carry some water passages between the heads. These manifolds tend to loosen with time and thermal cycling. If caught in time, sometimes all that is needed is re-torquing the nuts. However, yours has been leaking for some time and In my opinion, a new set of gaskets and sealant should be installed. The oil leak has minor consequence compared to a coolant or air leak. The usual place of the oil leak is at the corners where the heads meet the block. Chevy had trouble sealing here. The intake manifold is tightened down between the heads that are angled 60 deg with each other. The intake manifold may not sit tight on the engine block (valley). Sealing to the heads is the most critical; sealing to the block depends on soft gaskets and very good sealant. Pay close attention to the corner pieces. What you need: Gasket set RTV or shop manual recommended sealant Torque wrench Repair manual Antifreeze mix for refilling can of water pump lube Engine oil for an oil change Oil Filter Optional: digital camera Camera! Why? Take pictures of the layout of everything before disasembly, so you'll have a reference when it comes time to re-asemble all the tubing and whatnot on top of engine. You'll probably need to photograph the stuff in layers as it comes off. If you are very familar with your car and have a good set of illustrations in a repair manual, you probably don't need photographs. I mention this as an aid. Drain the coolant. Some may spill into the crankcase even though it was drained. Plan on refilling with new coolant mix and a can of water pump lube. Plan on doing an oil and filter change. Taking the manifold off isn't hard. The difficult part is removing all the stuff on top of the manifold, and putting it back at the end. Remove all the nuts holding the manifold in place. if it is stuck in place, some tapping with a rubber mallet should loosen it. I suspect yours is already loose. Since it is cast of aluminum, you should be able to lift it without a hoist. Clean the gasket surfaces - follow the installation instruction in the manual. One recommendation: If the installation calls for RTV type sealant, do not use any old kind of RTV. It should be rated as "not harmful to catalytic converters" and it should be of the highest *hot oil* resistant RTV you can find. Repair manuals usually will recommend a sealenat type. Many corner leaks in these GM V-6s are due to the RTV washing out. When you begin to tighten the manifold, you will discover the problem - creep. I did mine slowly going through the bolt pattern multiple times, and it took about 10 trips through the pattern before the manifold snugged up. I waited for a period that was less than the set time of the RTV and went through the bolt pattern once more - yep, it had loosened. (Once the RTV sets, further disturbance may cause the RTV to loose adhesion.) Change the engine oil and filter before starting the engine. This is done to drain out any foreign fluids that may have dribbled down into the engine when the manifold was removed. Wait the recommended setting time for the sealant before refilling the coolant system and starting the engine. (The sealant around the coolant passageways may be different to that of the valley. Judge accordingly.) After this gasket replacement, I had no more problems in this area. About oil and electrical contacts: An oil film is death on power electrical contacts. If oil got inside the solenoid, that is a problem. How do I know this is bad? I worked in an industry for 38 years that made elecrical contactors, relays, pushbuttons, and circuit breakers. Most power contacts are designed to operate "dry". There does exist a class of devices having contacts submerged in oil, but these are always buried in oil and not exposed to the atmosphere. If you do not wish to tackle this repair yourself, at least you will understand what is generating the shop labor.