When a person encounters trouble and needs vehicle repair & maintenance advice.....When a person has tire, wheel alignment, frame problems and such, the first tendancy of most people is to seek free answers or advice from a variety of available sources including the Internet. While such a subject is far reaching in that such problems cannot be answered so simply, our intention here is to help guide your next move. We intend to explain several subjects in a general sense, then if you require more extensive info, we offer the ebook that explains in greater depth tire wear patterns & other tire wear trouble, wheel alignment, truck suspension, power steering adjustment & leak repair, truck frame repair, hvac maintenance, truck clutch adjustment and more. |
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Wheel alignment is too often hit or miss....First, tire wear can be simply addressed or can be complex. Many wheel alignment tech's simply use a guide called something like "wheel alignment spec guidelines" to actually set your vehicle's wheel alignment by, and they set your alignment to fall somewhere within those spec guidelines. Those spec guidelines are too wide for optimal tire performance resulting in some wear which can become severe especially where a heavier vehicle is involved. |
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Steer tire condition is a big factor when doing a wheel alignmentWhen the normal person takes his/her vehicle in for an alignment, they normally do not replace the steer tires beforehand. Any wear patterns, with the possible exception of toe only wear, will continue to a certain extent and pulling or drifting in the front end that was there before the alignment will still be there because of the established wear pattern. Most people don't know or realize this fact and are dissappointed with the results they received from the wheel alignment. Alignment technicians or shops should inform the customer of this fact. This problem is very much apparent and prevelant with medium and heavy trucks. Setting camber to override any pulling or drifting on a vehicle with worn steer tires (and accomplishing that) is very much a no no, especially when cold bending a straight front axle is involved. |
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For optimal tire & handling performance on medium & heavy trucks....For optimal tire & handling performance, every setting is critical and some must be accurately set according to the type roads that you travel the most (ie two laned or multiple laned), the outer diameter of the tire installed as well as the brand and model, the type front suspension involved, and sometimes the brand and model of your vehicle. So you see, wheel alignment can't be as simple as just using a spec guideline book and setting the alignment to fall somewhere within those guidelines. Precise settings are paramount for optimal tire and handling performance. Doubling or tripling medium/heavy truck tire mileage is very common if EXACT settings of ALL wheel alignment angles are accomplished. Cars, SUVs and smaller pickup trucks benefit from exact settings too, and tire mileage increases along with better handling will be realized. |
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Handling is alignment related but....Handling is definately alignment related but also involves such things as steering gear adjustment, tightness of steering gear components, vehicle design or engineering, type of suspension and a whole host of other things. For instance, there are heavier vehicles that have rubber style shackle bushings and/or an air ride setup that developes severe roadwalk when the vehicle is either top heavy by design or by the load it is carrying, such as a large motorhome, or a truck hauling a top heavy load. |
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Unique handling problems....These handling problems can be eliminated on certain vehicles by changing the configuration of the shackle bushings and/or air ride setup. While these changes can get quite involved, the vehicles involved will settle down remarkably and safety will be greatly enhanced. |
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Correct truck, motorhome & bus suspension repair and maintenanceSuspension repair can be quite costly but a large portion of that repair can be eliminated by the type lubricant used as well as doing the proper scheduled maintenance and preventative upkeep. For instance, many people do not know or ignore the fact that you must regularly torque the U-bolts on the rear and front suspensions, and when they do perform such, they don't realize that there's a right way and a wrong way to do that seemingly simple task. |
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Proper lubrication a must....Especially where suspensions such as walking beams are in use, proper lubrication of ALL the grease zerts at intervals of every week or every other week with the PROPER lubricant will prolong the life of these suspensions dramatically. Where greasable shackles are in use, greasing every week with the PROPER lubricant will add thousands of miles to their life as will keeping the side to side slack out of some styles. All the other areas of front suspension upkeep require regular greasing with the PROPER grease. |
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Air rides and spring suspensions require maintenance tooAir rides and spring suspensions require upkeep and periodical repair also. Most spring suspensions also require regular greasing with PROPER grease at the equalizer. Air rides require regular inspection for any signs of problems such as leveling valve linkage (must not have slack) and air bag deterioration from chemicals unfriendly with the rubber compound they're made from. Air ride height must be maintained. As with all suspensions, spring and air rides' U-bolts/hanger bolts must be regularly retorqued to maintain proper alignment. |
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Frame repair knowledge importantWhile frame repair normally requires special equipment, some simple to do repairs to such things as crossmembers, bolt retightening, etc. can be accomplished by just about anyone with slight mechanical skills. Understanding the process used to straighten a frame and the appearance or characteristics of a damaged frame will certainly help anyone that comes up against such a problem. A guide such as the ebook offered will answer these questions and more. |
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Truck power steering leak repair and adjustment plus other itemsTruck power steering gear adjustment and some leak repair, steering component repair and explanation, truck clutch adjustment, user serviceable air conditioner trouble, brake and anti-skid malfunctions, driveline vibration or slack, driveline angles, engine torque curve, etc. are all something any mechanical minded person can accomplish with a little instruction and available support. This instruction is available in the ebook offered plus support can be had straight from the author through email. Neat, huh? |
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Now Some Things About Wheel Alignment |
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We'll start with toeToe, or more exactly put, total toe and individual toe is one of the, if not the, most critical setting on your vehicle. I say that ONLY because toe has the ability to immediately wear tires rapidly while other settings are relatively slower to show. Individual toe comes into play only on independent front suspensions. Independent suspensions have essentually two tie rods which are adjustable individually. They must be adjusted equally to acheive correct total toe or problems will surface such as faster wear on one tire or even uneven turns (left vs right) etc. Total toe can best be described as the sum total of the amount of toe present on each individual steer tire. Vehicles with solid front axles do not have individual toe setting capabilities as does independent front suspensions, but instead total toe exclusively is used. Optimal toe settings for radial tires is a small fraction of an inch (or mm or degree) unlike bias ply tires. Wheel alignment spec guidelines found in many books etc. will give a toe range that takes in bias ply tires as well as radial tires. Setting toe to fall somewhere inside these guidelines is a common mistake. Things like Ackerman effect causes toe to change during turns only and are necessary for stability and tire scrub prevention during turns, especially sharp turns. Plenty more concerning toe can be said but that is the purpose of the book-to explain further. |
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CamberCamber is the amount of lean on each tire sideways. If the bottom of the tire is inboard in relation to the vehicle, the camber amount is called positive. If the bottom of the tire is outboard, camber amount is called negative. Camber is important to help keep the vehicle straight in the road against the natural tendency of the road to be lower toward the right shoulder and higher toward the center. Many stupid people of late says camber's role is not to hold the vehicle against this crowning effect of roadways, these people only show their sheer stupidity towards the mechanics of wheel alignment. Right hand edge tire wear (and right hand drifting or pulling) is a direct effect of camber being inadequate. |
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CasterOne of the most misunderstood alignment angles is caster. Caster is a straight down the road setting in reality. It largely looses it's effect when the wheels are turned from straight ahead. Vehicles with standard steering must have a rather low amount of positive caster to enable the driver to turn the steering wheel from a steer ahead position smoothly instead of jerking the steering wheel. Power steering poses the opposite because some resistance is necessary to prevent oversteer. Therefore, positive caster is a steering stabilizer at steer ahead only. Negative caster will cause the tendency to shimmy along with tricky steering. Excessively positive caster can also promote shimmy to a certain extent but most noteably causes overly stiff steering and some road wander at times, depending on the actual setting. Cross caster (the amount of difference in caster from one wheel to the other on the same axle) can promote drifting toward the side with the lesser amount of caster when the cross caster amount exceeds 0.05 degrees. While this fact can be detrimental to some vehicles especially when the lower caster amount is on the right side, it can be a plus on larger vehicles when the side with the lower caster amount is on the left and camber fails to fully hold the vehicle up in the road against the road crown. Specific cross caster amounts will actually hold the vehicle straight preventing the right hand edge wear that slowly becomes a problem with a drifting to the right vehicle. More on this subject is available in the ebook. |
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Ackerman effect, SAI/IA, Steer axle setback, Scrub radiusWhile each of these cause their own effects (and problems if improper) they also affect other things like Ackerman effect effects toe and steer axle setback can effect SAI/IA , etc. (See Also: Glossary). These examples of steer axle angles are too complicated to explain here and must be explained in the context where individual angles are discussed such as in the ebook where they can be broken down per specific circumstances etc. |
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Rear axle thrust angles, toe, camber and casterBefore you gasp and exclaim "caster in the rear" we want to share a story from Jerry Hastings. "Some years ago we had a newer truck in the shop with a severe transmission rattle and severe rear axle bounce. We determined the transmission rattle was coming from the driveline angles. We couldn't bring the angles down adequately because the rear axles were at approx. 6-6.5 degrees angle. In the absence of angled spacer blocks that had lower angles, we removed the original blocks and sent them to the machine shop where they reduced the angle by about 2 degrees. We reinstalled the machined blocks, set the driveline angles. and adjusted the air bags to specs. Low and behold the transmission rattle AND the bounce were gone. I sat down to study why the bounce also dissappeared and since I was also an alignment technician, I decided we lowered caster in the rear. I began practicing lowering caster in the rear where it was too high and a bounce was present-it worked almost everytime. Some trucks even handled better. Yes there's caster in the rear of most any rear wheel drive vehicle, not as an alignment setting but usually for driveline angle reasons".
Rear thrust angles really should be adjustable on every vehicle. Thrust angles should be at or as near zero as possible and NEVER used to offset something like a drift in the front end (the drift should be addressed at the steer axle). Toe and camber on the rear is not adjustable on rear wheel driven vehicles but are on most front wheel drive cars. Cold bending the axle (axle housing) to correct toe and camber on the rear is necessary for rear wheel driven vehicles. Fortunately rear toe and camber is not often a problem except when caused by some sort of trauma. Bent axle shafts are a common byproduct of trauma which causes toe and camber problems on the rear axle of rear wheel driven vehicles . Complete explanation of these angles and adjusting methods, etc. is included in the ebook. |
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