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Volvo

VOLVO Brake Service and Suspension Repairs

Edited from an article by Boe Kalinoski, ImportCar Magazine, April 2003

When a Volvo is in our shop for scheduled maintenance, we take our time to check the integrity of all systems, particularly the suspension and brakes. With hard driving in the winter months taking its toll on customers’ vehicles, plus the added exposure to potholes, salt and extremely low temperatures, the undercarriage of most vehicles really get a workout. Thorough inspections in the springtime will reveal worn components and other problem areas such as bent rims, bald tires, loose ball joints, alignments that are way out of range, brake squeal, pedal pulsation caused by warped rotors and a host of other undercar problems.

Pedal pulsation can be caused by:

1. Rust build-up on the face of the hub;
2. Wheel lug nuts that are not torqued correctly;
3. Quick hard-pressure braking;
4. Brake overheating; and
5. Rear pads that are frozen in the calipers.

Whenever a rotor is replaced, it’s important that the technician sands and cleans the hub beforehand. The lug nuts must be torqued to the exact Volvo requirements using a torque stick.

Brake overheating is also a problem. Sometimes the cause can be customers who drive their cars hard in city traffic using quick, hard-pressure braking. So during your brake inspections, be sure to ask the customer under what conditions they log most of the miles on their vehicle.

In certain Volvos, I’ve noticed that the rear brake pads freeze/rust in the brake caliper, making the front take all of the braking effort and causing them to fail early. So, it’s a good practice to check the rear brakes when the vehicle is in to have the front brakes replaced. The rear pads will appear to have plenty of friction material remaining, but will be frozen and won’t move. Trying to remove frozen brake pads could be a task. I’ve made up a special tool using a slide hammer to aid in the removal. The use of special brake pad grease can also help in this area.

In general, the rear brakes tend to produce less problems, as all the weight and drive for the vehicle (on most models) is up front.

To avoid comebacks caused by pulsation and noise, I don’t recommend resurfacing the front rotors. The rear rotors, however, can be chucked up on the brake lathe and resurfaced, turning them within the specified range stamped on the rotors.

We have very good results installing slotted front rotors as well as a cross-drilled style, as the factory doesn’t offer a heavy-duty rotor. The slotted rotors that we use undergo a factory three-stage heating process that prevents warpage. They cost a few more dollars than other brands, but they are well worth it when comebacks for this problem become history.

Here are some general guidelines to keep in mind, while servicing the brakes on your customers’ Volvos:

• Change the brake fluid and bleed the system after pads and rotors have been replaced. It’s also a good idea to check and lubricate the caliper slides.
  
  
• Check the emergency brake shoes when replacing the pads. It’s necessary to pull off the caliper and rotor to service them. Look for frozen adjusters and springs that should be replaced when the shoes are being installed.
  
  
• Check the rubber flex hoses, inspect the calipers for leakage and look for frozen pistons, and repair/replace as soon as possible.
  
  
• Most technicians forget to check the ABS sensors and reluctor wheels, which are used to measure and compare rotational speeds of the tires. They can become fouled by dirt and brake carbon. This typically occurs in the front where the sensors and reluctor wheels attract a considerable amount of brake dust shed by the front pads and rotors. As accumulation of brake dust grows, heat fuses it into a carbon-like coating that reduces the minute changes in reluctance measured by the sensors. This is picked up by the vehicle’s ABS control unit as a continuous difference in rotational speeds between one or more tires - eventually exceeding the perimeter value and triggering the ABS fault light.

SUSPENSION REPAIRS
Suspension inspections can reveal problem areas that can provide profitable service opportunities for your shop. Changing worn struts, bushings and joints represent commonly required services that are also safety-related repairs.

Front-drive Volvos are designed in a simple lower control arm/strut configuration. Volvo used an integral ball joint/control arm beginning with the 1995 model year 850. The earlier version had only replacement ball joints (see photo 1).

The sway bar links have a failure problem, evidenced in a "clunk" noise that is noted in many of the vehicles that are in for routine service. During the replacement procedure, we recommend replacing both sides (see photo 2).

The front struts, with long-life gas/hydraulic cartridges and upper bearings, tend to hold up very well in the 850 models. But if the strut cartridges require replacement, the upper bearings/bushings should also be replaced at the same time.

Wheel bearings in the front-drive cars can’t be serviced, as they are sealed units. If noise or play exists in that area, the wheel bearing must be replaced with a new unit. Front wheel bearing replacement is such a smooth task without the removal of the spindle and the use of any press device.

The rear suspension is equipped with a semi-independent design. The unit combines the advantages of an independent semi-trailing suspension and a beam axle. The rear suspension is also designed to provide passive rear steering that is made possible by flexible rubber bushings that allow the rear axle to shift slightly as cornering loads increase.

Some bushings in the suspension could be replaced with a urethane-type, if they are available for the application (see photo 3). The increase in service life and durability will also enhance cornering and handling stability.

RWD VOLVO SUSPENSION
In rear-wheel-drive 240, 700 and 900 Series Volvos, the MacPherson strut-type suspension is used. The suspension consists of a vertically mounted strut and coil spring assembly. The lower end of the strut assembly is mounted to a ball joint, which is bolted to the lower control arm. To check the ball joints for wear, have the vehicle resting on wheels. Using a large pair of pliers, squeeze down on the joint. The maximum axial play permitted is 0.12 (3.0 mm) and the maximum radial play is 0.02 (0.5 mm). Check the rubber boots; if they are torn or damaged in any way, replace them.

1. To replace the ball joints, raise the vehicle and support it safely.
   
   
2. I’ve found that the job is easier on the 700 and 900 Series, when the bolt that holds the anti-roll bar link to the control arm is removed.
   
   
3. Remove the cotter pin, nut and washer for the ball joint stud.
   
   
4. Pull the control arm from the ball joint using a suitable puller.
   
   
5. Remove the bolt holding the ball joint to the spring strut.
   
   
6. Press the control arm downward and remove the ball joint.

The sway bar, also called the anti-roll bar or stabilizer bar, serves to control the sideways roll of the body during cornering. While the bar itself rarely fails, the links and bushings around it are prone to wear. If the bar is not rigidly mounted to the vehicle, it cannot do its job properly. Sway bars of different diameters can stiffen or soften the roll characteristics of the vehicle. Bushings are easily replaced and well worth the effort in terms of restoring proper cornering.

The control arm strut, also called the radius rod or strut rod, serves to locate the lower control arm and prevent fore-and-aft movement. The rods rarely fail, but the rubber bushings on each end are prone to fatigue and wear, and need to be replaced after a few years.

1. Loosen the rod-to-body bolt, but don’t remove it.
2. Remove the nut at the control arm. This is sometimes easier said than done as the control arm bolt can be very tight.
3. Once the front nut is loosened, the back mount may be removed and the rod placed on a work bench.

If the bushings need to be replaced, press them free of their mounts and install the new ones. If you’re using urethane bushings, coat them with a lubricant or some other kind of petroleum grease. Reinstall the rod, attaching the rear bolt first. Make sure that the front bushings seat properly in the control arm and that the front nut draws tight against its washer.

All 240 and some 700 Series Volvos use a solid rear suspension. The solid axle is suspended from the frame member by a pair of support arms and uses a pair of double-acting shocks. A pair of torque rods control the tracking and lateral movements of the rear axle in relation to the vehicle. A rear stabilizer bar, attached to both rear support arms, is also present on certain models.

On the 240 rear axle, we’ve done quite a few trailing arm bushing replacements. Volvo offers a tool to remove and install the bushings, making the repair profitable.

Some of the Volvo 700 and 900 Series are equipped with multi-link suspension systems, which independently suspend each rear wheel, allowing for improved ride and road handling, and for each wheel to be aligned separately. The only failure we’ve seen is the upper carrier housing bushing, as it’s made from rubber and has a plastic housing that cracks over a period of time. Volvo offers a tool to cut the repair time in half, with no need to remove the complete center housing and use the hydraulic press.

Multi-link suspensions require alignment any time the suspension components are disassembled. When aligning, start at the rear first setting up the camber, then the toe. Caster is fixed by the design of the suspension and cannot be changed, except by replacement of damaged parts.

During your inspection procedures, don’t forget to look for bent rims or out-of-round tires, as they could be causing vibration problems that lead to customer complaints.  Check the vehicle’s wheel alignment if any of the following conditions exist: Tires are unevenly worn; The vehicle is not stable on the highway; or Handling seems uneven in spirited driving.

If an alignment problem is suspected, first check for improper tire inflation and other possible causes including worn suspension or steering components, accident damage or even unmatched tires. As you know, it’s important to replace any worn or damaged components that you uncover, before the wheels can be properly aligned.

During your alignment procedures, note that overloading of the vehicle or sagging rear springs will affect caster. If the rear of the vehicle is lower than normal, the caster becomes more positive.

Anytime a customer’s Volvo is in for service, check the integrity of the brake and suspension systems. A short test drive is an ideal way to check brake performance, as well as determine how the vehicle steers, handles and rides. By performing these checks, you can ensure the smooth and safe-running operation of their Volvos and boost customer satisfaction levels to new heights.

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