Tech Tip: Honda Suspension System Diagnosis and Service – UnderhoodService
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Tech Tip: Honda Suspension System Diagnosis and Service

Like most vehicles, the suspension system on a Honda or Acura will give its owner many miles of trouble-free service. But with the amount of miles these cars deliver, it’s only a matter of time before they will need some type of repair. And unlike some of the other systems on the car, the suspension may not provide a clear indication to the driver that a problem exists. It’s really up to the technician to identify problems while routine or related service is being performed.

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By Bob Dowie, Import Specialist Contributor

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Like most vehicles, the suspension system on a Honda or Acura will give its owner many miles of trouble-free service. But with the amount of miles these cars deliver, it’s only a matter of time before they will need some type of repair. And unlike some of the other systems on the car, the suspension may not provide a clear indication to the driver that a problem exists. It’s really up to the technician to identify problems while routine or related service is being performed.

GROANING, SQUEAKING NOISES
The most common symptom that will prompt customers to bring in their Hondas for suspension work will be noise. It could be described as anything from a groaning or squeaking to a knocking or rattling. Groaning is usually caused by a tight ball joint or tie-rod end. Diagnosis shouldn’t be a problem. Using your mechanic’s stethoscope, with an assistant pushing on the car, it should be easy to find the offending part.

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Another common problem you’ll see on Accords and some Civics is broken front springs. Normally, you’d think this problem would result in obvious ride height issues, but since the springs tend to break at the lower coils, that isn’t the case with these cars. The problem usually shows up as noise caused by the broken pieces rubbing against each other as the spring is worked. Again, diagnosis shouldn’t be a problem, requiring no more than a good visual inspection.

If a broken spring is found, some decisions need to be made. Should the springs be replaced in pairs, and the struts be replaced at the same time? It will depend on the mileage of the car, and the condition of the struts. If it’s a high-mileage car or there are any signs that the struts are leaking, now is the time to replace them. If it’s decided that the struts should be replaced, it also makes sense to replace both springs at the same time. This is especially true if aftermarket springs are being installed. Not only are they generally sold in pairs, but it’s a good idea to replace both to maintain balance.

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RATTLING, KNOCKING NOISES
If the noise appears to be coming from the rear, don’t overlook the ball joints as a possible cause. Common on the older Accords, a knocking noise will be the only warning the driver will get before this joint fails. Like most suspension problems, this is an easy diagnosis. Simply grab the wheel at the top and bottom and check for movement. Nothing tricky, you just have to remember to do it. If the joint needs to be replaced, it is serviced with the arm.

STEERING SYSTEM
Hondas have no tolerance for the wrong power steering fluid. If you suspect the fluid has been contaminated, a thorough flush of the system and refill with the proper fluid is in order. This procedure has been reported to help a wide variety of problems and is certainly worth a shot before replacing expensive racks and pumps. If you’re confronted with what seems to be air in the system that won’t bleed out, suspect that the front seal on the pump is sucking air. The seal is available, but with a high-mileage car, a rebuilt unit may be a better way to deal with it.

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If you’re working on an older Accord that has no steering assist, see if it’s equipped with the steering relief valve that’s incorporated with the speedometer drive on the transmission. This valve limits the assist as the speed increases. If it fails, there will be no assist at any speed. To diagnose, simply clamp off one of the hoses and see if the assist returns. On the later-model, air bag-equipped cars, use caution when removing the steering shaft from the rack. If the steering wheel isn’t secured, and allowed to turn past the limits of the clock spring switch, that will be the end of the switch. You’ll be faced with an SRS light, and an unhappy customer and boss.

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STRUT REPLACEMENT
If you’re reading this, you should have no problem identifying struts that are in need of replacement. Any leakage should have been noted during your visual inspection, with anything more than a slight stain indicating that replacement is required. Usually, all it takes is a good push on the car to determine if the struts are doing a good job of dampening the action of the spring. Borderline cases will be harder to pick up. Whenever a customer asks that you check them, you should inquire why he asked.

TIRE-RELATED PROBLEMS
Handling complaints can vary, but most come down to “the car doesn’t go straight.” It may wander, making the driver feel as if he’s working too hard to keep it on the road. It could be that it pulls in one direction, or maybe it doesn’t feel right to the driver when changing lanes.

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It doesn’t matter whether we’re looking at a Civic or the sporty S2000, the only thing connecting the vehicle to the road are the tires – so look there first. Check both their condition and the pressure. Don’t overlook tire sizing; it takes minutes to measure the circumference. Anything more than an 1/8th of an inch of difference will cause a pulling problem.

Other tire conditions that will have you checking the suspension will be cupping and uneven wear. Cupping, usually found on the rear of the car, is the result of the tire “bouncing” on the road. Struts were always blamed for this condition in the past. But recently we’ve been seeing this condition on vehicles that don’t have any suspension problems. I suspect it’s a combination of tire balance problems along with soft suspensions.

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There is no reason that suspension and steering work shouldn’t be a profitable part of your business. You just have to keep in mind that every car that goes on a lift should get a good undercar visual safety inspection. I’m sure we all try to do that, but sometimes we need a reminder. Having a good customer’s car coming in on the hook with a broken ball joint is not the reminder we want.

THE PERFORMANCE ANGLE …
You can’t be in the business of repairing import cars without noticing the popularity of Hondas among performance enthusiasts. The most popular of the modifications performed are suspension related. Tuners are all looking to lower the car and increase the handling characteristics. Not too many years ago, the common practice was to cut the springs, upgrade the shocks and, if available, install stiffer (anti-) sway bars. The results were often less than expected, with poor ride quality and even worse tire wear.

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That’s not the case today. The compact performance market has shown that it’s here to stay and has attracted strong companies that produce high-quality, well-engineered parts that deliver what the customers expect, and that we should have no problem installing.

The current preferred method to lower the car is via the use of a “coil over kit.” These kits include an adjustable collar that slides over the strut housing incorporating an adjustable spring seat. Also included is a shorter, and usually stiffer, spring. The ride height is adjusted by moving the spring seat up or down the collar as required. This adjustability provides the owner with the option of being able to choose the ride height desired for certain conditions.

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If the springs are stiffened, it only makes sense that an upgrade of the dampers (also known as shock absorbers) will be required. It’s their job to control the action of the spring, so it’s no surprise that units designed to handle soft stock springs won’t be up to the task as the rate is increased. The shocks also serve an important function in controlling how weight is transferred as the car corners.

A good way to increase the effective spring rate without adversely impacting the ride quality is to upgrade the sway bars. When cornering, the bar acts as a torsion bar, but has no affect on the spring rate when both tires contact a bump. Usually combined with a shock upgrade, this strategy will provide an increase in cornering power without the harshness associated with the stiffer springs.

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