Jump to content

  • Welcome to Auto Parts Forum

    Whether you are a veteran automotive parts guru or just someone looking for some quick auto parts advice, register today and start a new topic in our forum. Registration is free and you can even sign up with social network platforms such as Facebook, X, and LinkedIn. 

     

Hydraulic Suspension Bushings


Recommended Posts

rssImage-e0ef25942d3053d42bf2b2519e68a596.jpeg

If a customer mentions that they’re seeing fluid trickling from a suspension bushing, their eyes aren’t playing tricks on them. That bushing could be hydraulic.

Hydraulic suspension bushings were developed in response to customer demands for smoother, quieter and better-handling vehicles. To achieve this, sophisticated suspension components are needed. Modern suspension systems look a lot different than they used to, with multiple links used to maintain suspension geometry.

A non-hydraulic suspension bushing typically will feature a number of empty voids inside them. These voids are a product of clever engineering, and they allow for deflection/compression in a specific direction when placed under load. Hydraulic bushings fill those empty voids with a fluid. This fluid works like a hydraulic damper, while still allowing for deflection/compression when under load.

The word “hydraulic” might imply that hydraulic fluid or oil is used inside these bushings, but they typically use a glycol mixture instead. Oil or hydraulic fluid would break down the rubber inside the bushing and cause it to fail prematurely. If you’ve ever seen a radiator hose that got coated in engine oil, you know what we’re talking about.

These bushings are engineered with a certain tire and wheel combination in mind. This means increasing the tire and/or wheel sizes can throw this off, and the suspension may need to be repaired more frequently.

Hydraulic bushings are able to isolate noise, vibration and harshness (NVH) from entering the vehicle cabin more effectively than standard bushings. Hydraulic bushings can be firmer without compromising passenger comfort, leading to crisp steering response and road feel. They will deflect less under load, such as braking or hard cornering, and this means better vehicle stability.

But, all bushings eventually will wear out and need to be replaced. Hydraulic bushings may crack, rip or tear, just the same as non-hydraulic bushings will. The big giveaway is the hydraulic fluid leaking from the bushing.

Failing hydraulic bushings typically exhibit one or more of the following symptoms:

  • Clunking or knocking noises while braking or turning
  • Evidence of fluid leaks coming from the bushings
  • Unwanted suspension movement
  • Tire wear (from excessive suspension movement)
  • Increased NVH transferring into the vehicle cabin

Replacement Tips

Hydraulic bushings likely will be more expensive to replace than standard bushings. Here are a few tips and tricks to share with your customers.

Let’s start with the most important tip: Always check the OE service information. Even if your customer has performed this type of repair in the past, it’s still a good idea to check the service information to see if anything has been updated recently. They should road-test the vehicle before and after the repair.

If your customer is pressing a hydraulic bushing into or out of a suspension arm, they should be careful not to apply force directly against the rubber part of the bushing. Doing this will most likely rupture the rubber bushing, causing the hydraulic fluid to spill all over the floor. Once this happens, the bushing is ruined and must be replaced. Be sure to only apply force against the outer race or sleeve.

Modern bushings likely will feature some sort of locating mark, notch or indicator. Reference the OE service information to learn how to correctly align the bushing to the suspension arm. Doing this will allow the suspension to articulate properly. Failure to do this may cause the suspension to bind up during movement, and/or cause the bushing to wear out or fail prematurely.

It’s strongly recommended to wait to torque the fasteners down to specification until the suspension has been set to normal ride height. If the fasteners are tightened down with the vehicle in the air, the bushing will be forced to twist when the vehicle is lowered onto the ground. This means that the bushing will always be twisting at normal ride height, and this will surely lead to premature wear, tearing and/or failure.

Finally, your customer should perform a four-wheel alignment if the service information calls for it. Some suspension components may not require an alignment after service; it depends on the make, model and application.

The post

link hidden, please login to view
appeared first on
link hidden, please login to view
.

link hidden, please login to view

Link to comment
Share on other sites

Great Tire Deal

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • By Counterman
      link hidden, please login to viewreleased two new suspension bushing tool kits for on-vehicle R&I of single-wrap and double-wrap heavy-duty suspension bushings – Suspension Bushing Kit with Pump and Suspension Bushing Adapter Kit. Both tool kits replace worn-out, rusted and frozen heavy-duty suspension bushings faster and easier without risking heat or other damage by providing a 25-ton capacity, the company said. Each kit saves hours on each job by making quick work of Pivot and D-pin bushing R&I. OTC’s latest suspension bushing tool kits include:
      4247-FR Suspension Bushing Kit with Pump: Includes air/hydraulic pump, 25-ton hydraulic cylinder, hose with couplers, complete puller leg/plates and adapter set for double-wrap leaf springs.
      4254-FR Suspension Bushing Adapter Kit: For use with OTC service sets; 4247, 4275, 4261 or 4263 with 4106A 25-ton ram.
      OTC said each suspension bushing kit features Hendrickson rear suspensions, including Primaax EX, Comfort Air and FCCC V-Ride Pivot and D-Pin suspension bushings, and freightliner rear suspensions, including double and single-wrapped FAS II Airliner rear suspension bushings. Both also include centering adapters to align tool and bushing for clean installation. Both are available through OTC distribution partners and resellers.
      The post
      link hidden, please login to view appeared first on link hidden, please login to view.
      link hidden, please login to view
    • By Counterman
      Most active suspension systems come in many styles with fancy names like airmatic, dynamic or advanced. And, it doesn’t matter if it is a BMW, Mercedes or Jaguar, an active suspension must be able to react to three critical pieces of information.
      First, it must act on information from the ABS and stability control system. Second, it must measure body movement. Third, it must detect the extent and rate of suspension movement. With these three pieces of information, the suspension can actively adjust the compression and rebound of the shock or strut.
      Why would an engineer or automaker include this feature on a vehicle? An active dampener allows for a ride without compromise. The three inputs can be used to detect a rough road or an emergency situation where body roll could change the stability of the vehicle.
      Electronic Shocks/Struts
      Electronically adjustable shocks and struts use conventional mono-tube and twin-tube oil-filled dampeners. The rods, gas chambers and piston have the construction of passive units. Like a passive unit, they can fail if they leak, the gas escapes or the rods are bent. They can also wear out like a conventional unit as the oil inside breaks down and surfaces in the bore wear.
      link hidden, please login to view
      What makes these units unique are the valves with their variable orifices. These valves regulate the flow between the chambers on either side of the piston. The piston in some units, however, does not have any valving.
      The size of the orifices controlled by electromagnetic solenoids can control the valves very quickly. The electrical connections and solenoids are typically found outside the body and act on the valves inside the unit using magnetism. The signal to the solenoid is pulse-width modulated and varies the voltage to change the size of the orifice.
      The valves and solenoids can’t be serviced or separated from the shock or strut. If a problem is detected with the system, the valves go into a fail-safe position that is fixed, and the system becomes passive. The driver is then alerted with a message or light on the instrument cluster or message center.
      Most systems will perform a circuit check when the system wakes up. This typically involves sending a signal to fully open and close the valve. If the system detects an open, short or a voltage outside of the specifications, it will set a code. 
      Measuring Wheel Movement
      Ride-height sensors not only measure the position of the suspension, but also the rate of movement. They are supplied with a voltage of around 5 volts. The signal voltage is changed as a magnet moves past a coil. Most sensors have three wires – ground, power and signal.
      Internally, it is difficult to damage one of these sensors. Externally, however, the linkage that connects the sensor to the suspension arm can be damaged. Additionally, the connector can be damaged and cause a short or open that sets a code. If one of these sensors is replaced, it must be calibrated after it is installed.
      Ride-height sensors are sometimes called suspension-position or wheel-displacement sensors. The data from the sensor is used to measure the movement of the suspension. By knowing how far and fast the suspension is moving, the module can use the information to determine the size of the orifice in the dampener to control compression and rebound. These sensors should be calibrated if a sensor is replaced, a module is reprogrammed or if the battery dies.
      Measuring Body Movement
      Accelerometers mounted to the body measure changes in the ride. These accelerometers are typically mounted to the strut towers. These sensors output information as gravitational forces, or “G-force,” to a module. Changes in body roll due to cornering will produce lower G-force than a pothole would.
      Information from the accelerometers is coupled with data from the ride-height sensor, steering sensor and other inputs by a computer processor in a module. The module can determine if the vehicle is going around a corner or traveling down a bumpy road. With this datastream, the valving inside the dampener can be adjusted in milliseconds for the best control and ride quality.
      The accelerometers on the body differ from vehicle to vehicle. Some manufacturers mount the sensors under the headlights, on strut towers and near the taillights. More sophisticated systems use more than two accelerometers mounted in various locations.
      link hidden, please login to view Control Module
      The control module for the electronic dampeners needs more than the movement of the wheels and body to determine the correct settings for the dampeners. The module uses and shares information with the anti-lock braking system, engine control module and instrument cluster. This information is typically shared on the high-speed CAN serial data bus. On some BMW 7 Series models, the information is shared on the fiber-optic Flex Ray bus.
      With all this information, the module can do some amazing things with the adjustable dampeners. Problems like nosedive under braking, torque steer and understeer on FWD vehicles can be minimized. If the vehicle has air ride, the volume and pressure inside the air springs can also be tuned along with the valving in the dampeners to optimize ride quality and control.
      Most active suspension systems will perform a circuit check when the system wakes up. The system will send 5 to 12 volts to the actuators and ride height sensors. The system is also looking at the resistance in the circuit, and the amount of voltage dropped. If the system detects an open, short or voltage outside of the specifications, it will set a code. Next, the control module will fully open and close the valves in the struts. If the system does not detect any irregularities, the system will go into an active mode. 
      Looking for these self-diagnostic signals can be performed using a meter. You may have to use a bypass harness or back probe the connector. If the system detects any problems, the system will go into a passive mode.
      Sometimes servicing an active suspension is like rebuilding an engine with a new crankshaft and reusing the old bearings and valve springs. When a new active strut is reassembled with the old and tired spring and strut plate, the results can be less than desirable.
      Upper strut mounts and bearings can be hammered to death. The upper strut mount essentially supports the vehicle weight and counters both braking and acceleration torque. Most mounts are sandwiches of rubber, metal and bearings. Over time, the rubber can lose its ability to isolate the suspension from the body. Bearings can also seize and bind, causing the vehicle to have steering problems.
      Look up the ride height specifications and measure ride height front and rear, and on both sides of the vehicle. If ride height is less than specifications, the problem is most likely one or more weak springs that should be replaced. Springs should typically be replaced in pairs to maintain the same ride height side-to-side.
      Weak springs also are more likely to fail. The springs on many late-model vehicles are thinner to reduce weight and have an outer plastic coating to protect the metal from corrosion. If this outer coating is cracked or damaged, corrosion can form a hot spot that eats into the spring, weakens it and eventually causes the spring to break.
      The post
      link hidden, please login to view appeared first on link hidden, please login to view.
      link hidden, please login to view
    • By Counterman
      Westar Distribution LLC, a leading aftermarket supplier of engine & transmission mounts and air suspension components announces the release of 40 new Air Suspension Components, Engine & Transmission Mounts, Torque Strut Mounts, and Center Support Bushings servicing in excess of 35,000,000 vehicles in operation today in the US & Canada covering Acura, BMW, Dodge Truck, Ford Sport Utility, GMC Trucks, Honda, Hyundai, Jeep, Lexus, and Toyota vehicles. These newly released items are all in stock and ready for immediate shipment.  
      link hidden, please login to view For more information contact [email protected] or visit
      link hidden, please login to view.
      The post
      link hidden, please login to view appeared first on link hidden, please login to view.
      link hidden, please login to view
    • By Esacivic
      Hey y’all I have a 1989 Honda civic hatch and I’m looking to build up a strong suspension but I’m unsure of some quality brands for them. I’m looking for anti roll bars that are beefier then stock, full control arms all around, camber kits front and rear, sway bar. 
       
       
      any and all help is appreciated thank you
    • A-premium Auto Parts:5% OFF with Code GM5.
    • By Counterman
      KYB said it has developed an environmentally friendly hydraulic fluid for shock absorbers.
      The newly developed SustainaLubeliminates the environmental risks associated with petroleum, according to KYB. The  
      Full release to the market is planned for 2026.
      The new fluid contributes to carbon neutrality by switching from petroleum-derived base oil to naturally derived base oil. It absorbs CO2 from the atmosphere during cultivation of the plants used for the base-oil raw materials, also reducing CO2 emissions during transportation, according to KYB.  
      SustainaLub is biodegradable up to 60% or more according to the Eco Mark certification standard (OECD301). The base-oil and additive formulation is recyclable, reducing environmental issues in the long term, KYB noted.
      “As a specialized global manufacturer of hydraulic equipment, KYB has long been involved in maintaining and improving the safety and comfort of automobiles,” the company said in a news release. “Using that experience, we are striving to achieve environmental balance without compromising performance or reliability. Not only does SustainaLub improve maneuverability and stability by applying it to the various damping force valves that we already offer, but it also improves the feel of the product by applying friction-control technology, for example KYB Prosmooth shock absorbers.”
      Replacing petroleum-based oil in KYB shock absorbers with this new hydraulic fluid will save up to 15.6 million liters of oil per year, according to KYB.
      Tested in Japan
      All new KYB products undergo reliability evaluation at the KYB Development Center in Japan.
      “Thorough performance and quality evaluation involves both bench tests and actual vehicle testing on our state-of-the-art test track,” KYB said. “This in-house design of a hydraulic oil recipe is unique to a manufacturer specializing in shock absorbers.”
      The KYB team participating in the All Japan Rally Championship JN-2 class introduced SustainaLub to their vehicles from Round 6 onwards They analyzed and verified the performance and durability in the harsh race environment, KYB noted.  
      In addition, SustainaLub was trialed in the vehicle used in the Lexus ROV (Recreational off-Highway Vehicle) Concept customer-experience program. It was used for Lexus’s first ROV equipped with a hydrogen engine. The data accumulated also contributes to technology development for future practical applications, and work toward the realization of a carbon-neutral society.
      “KYB plans to ultimately apply the technology to all hydraulic products involved in realizing a sustainable mobility society,” the company said. “As a specialized manufacturer of hydraulic equipment, KYB has long been working to improve the ride comfort and handling stability of automobiles. Based on this experience, KYB will continue to pursue advances in performance and reliability while keeping environmental impact at the forefront of development.”
      The post
      link hidden, please login to view appeared first on link hidden, please login to view.
      link hidden, please login to view

×
  • Create New...