Category Archives: Suspension

INTERNAL REBOUND SPRING F.A.Q.s

INTERNAL REBOUND SPRING F.A.Q.s

“Why are some KYB shocks shorter than OE?”

This is due to the presence of a “rebound spring”. During the first mass production phase of a car, OE struts will often contain a rebound spring. It is at this point that the KYB aftermarket shocks are released, exactly matching this initial design.

After the initial mass production phase, some vehicle manufacturers are known to remove the rebound spring to reduce cost. This means when comparing a new OE unit with a KYB unit, there will be a noticeable distance in piston rod length- sometimes by up to 50mm. This can also be the case when comparing a KYB unit with a cheaper brand unit which does not contain a performance enhancing rebound spring.

It is worth noting the length of the piston has no effect on the ride height of the vehicle, this is determined by the height of the spring seat.

“What does a rebound spring do?”

It is a metal spring placed around the base of the piston rod inside the body of the shock absorber. The purpose of the rebound spring is to protect against potential damage from full extension of the piston rod. This also adds stability on cornering, and adds extra resistance during moments of heightened body roll, increasing comfort and safety.

The presence of the rebound spring makes it almost impossible to manually fully extend the piston rod from out of the body of the shock absorber. This is why there is a noticeable difference between units with and those without.

“When transfering the compressed coil spring and mounting kit to the new strut, the threaded stud doesn’t come through far enough”

On some applications, it is necessary to raise the axle or suspension slightly to attach the shock absorber mountings. This can be done either with a drive on ramp or by raising the lower control arm / axle so that it is not fully extended.

There are also tools on the market to assist with fitting shock absorbers that have a rebound spring. They compress the internal rebound spring sufficiently to be able to extend the piston rod to the required length to be able to thread the upper nut correctly.

TOYOTA RAV4 (Front)

TOYOTA RAV4 (Front)

When you replace the strut mount, you must check the shape of the piston rod. KYB shock absorbers 339031/32 have a flat surface and the strut mount must reflect this. These flat surfaces lock the piston rod in the installation position, allowing you to tighten or remove the nut. So, if you use the wrong strut mount, you are not able to assemble the parts correctly.

KYB shock absorbers 339031/32

DACIA Lodgy (Rear)

DACIA Lodgy (Rear)

Following a fitting test, KYB has found that this shock absorber must be fitted with the serrated surface against the car body – otherwise you may hear noise whilst driving.

Car body

Upper eye of KYB shock absorber

Fitting

Front Shock Fitment: Alfa Romeo

Step by step replacement guide for 01.11 Mito Model

With nearly 18,000 of these models on the road in the UK, the chances that your workshop will be faced
with a shock absorber replacement are fairly high. This job should take roughly one hour per side and should be undertaken following our expert instructions.

Getting started

Remove the tyre. Now release the ABS sensor cable from it’s clip, then the brake hose (see Fig 1).

Undo the clip on the left and keep it safely stored (see Fig 2).

fig3

Then undo the brake hose clip (see Fig 3).

fig33

Raise the height of the vehicle then remove the bottom two bolts from the strut (see Fig 4).

fig 4

Strut assembly

Under the bonnet, remove both windscreen wipers and the scuttle panel (see Fig 5).

fig5

Loosen the top nut and, whilst supporting the strut below, remove the nut and lift out the strut assembly (see Fig 6).

fig6

Use a good quality coil spring compressor to safely disassemble the unit.When assembling the new KYB shock absorber, coil spring, protection kit and top mount, check the end of the coil spring is aligned at the correct point on the spring seat (see Fig 7).

fig7

Gripping stuff

Ensure you tighten the top mount to the correct torque. It’s essential that you never use mole grips to steady the piston rod whilst assembling the unit – the grip can damage the smooth chrome coating on
the piston rod which will result in it not having perfect contact with the oil seal, causing premature leaking (see Fig 8).

fig8
The assembled suspension unit can now be offered up under the wheel arch and fixed in position from the top first, tightened to the correct torque. Use a small jack to support the wheel hub weight (see Fig 9).

fig9
Lower the vehicle and finish tightening the top nut to the correct torque. Then you can replace the bulk head, windscreen wipers and scuttle panel, not forgetting the small clip to the side of the bottom bracket see Fig 10).

fig10

Always fit in pairs!

KYB advises that you check the wheel alignment after the shock absorber is fitted to the vehicle and that shock absorbers and coil springs are always fitted in pairs.

VW Golf lV, Bora, Jetta IV; AUDI A3, SEAT Leon, Toledo; SKODA Octavia Front Suspension

VW Golf lV, Bora, Jetta IV; AUDI A3, SEAT Leon, Toledo; SKODA Octavia Front Suspension

Fitting video showing correct fitment of shock absorbers and coil springs to the front of:
Audi A3 2WD (09.96-05.03)
Seat Leon (11.99-06.06)
Seat Toledo II (04.99-05.06)
Volkswagen Golf IV 2WD, Variant (08.97-06.06)
Volkswagen Bora, Variant (10.98-09.05)
Volkswagen Jetta IV (10.98-09.05)
Skoda Octavia, Combi (09.96-06.04)

AUDI, SEAT, SKODA, VW – Front Suspension

AUDI, SEAT, SKODA, VW – Front Suspension

Video to show correct fitment of shock absorbers to FRONT of:

AUDI A3/A3 Sportback (05.03-)
SEAT Leon II (05.05-)
Alhambra II (06.10-);
Altea/Altea XL (03.04-)
Toledo III (04.04-05.09)

KYB – Inside Suspension

KYB – Inside Suspension

 

Showing how suspension is working inside the car, and which part is doing the hardest work during each manoeuvre.

Types of Coil Spring

Cylindrical

A cylindrical spring normally consists of end coils, transition coils and spring coils. A cylindrical spring can be designed to provide a linear rate, or equally designed to give a progressive spring rate by varying the pitch. One advantage with cylindrical springs is that they can be automatically handled easily during production.

Cylindrical Spring

Cylindrical springs can also, in the axial direction, be bent in shape. This variant can be of interest when the designer needs to compensate for lateral forces influencing the shock absorber.

axial

Conical

The conical spring is normally chosen when there is limited space for the springs in a suspension system. This type has today mostly open ends and sometimes one pig tail end. The spring can be designed with either linear or progressive spring rate. Should the designer wish to achieve a linear rate, this is achieved by changing the pitch in accordance with the spring diameter to hold the spring rate constant throughout the deflection. The designer would increase the pitch as the spring diameter increases.

Conical Spring

Mini-block

A real mini-block spring design has coil diameters adjusted so that most of the coils fit inside each other when the spring is compressed to a short length, hence the name mini-block.

This design solution can reduce the bloc length close to two times the material diameter. The advantage is the very small bloc length of the spring hence space is saved. This can be of value in the rear of a car when, for example, a flat loading area is required.

It is important to note that the fitting of the coils inside each other is controlled by the diameter of the coils, and is not dependant on the type of material used (tapered or parallel).  For this design, tapered material is sometimes used which gives a weight saving benefit, but against this is the increased risk of premature end coil failure:  A more detailed explanation of this is available from our technical brochure.

Mini-bloc springs can be designed to have progressive or linear load and deflection characteristics, and this can be achieved through the use of either tapered or parallel wire.  They often have a linear rate however since the reduced material diameter compensates for the reduction in the springs external diameter.

For this design Kilen always use parallel wire; fulfilling the mini-bloc requirements and achieving the load and deflection characteristics whilst ensuring springs that are not prone to premature end coil failure.

Mini-block Spring
Kilen produce the World’s largest range of coil springs for the automotive aftermarket
The Complete Spring Supplier

What is a judder damper?

As a technology and development partner to the world’s leading vehicle manufacturers, LuK –  a brand of Schaeffler Automotive Aftermarket – is well equipped to provide innovative solutions to the problems encountered by engine designers in the quest for ever lower emission levels and fuel consumption.

One such problem can be a ‘judder’ from the drive train, which is caused by what engineers call ‘excitation’. Whilst not a major functionality issue, excitation can cause vibration and noises that may affect the comfort and drivability of the vehicle.

There are three types of ‘excitation’ that are the root cause of judder: ‘facing excitation’ which exists between two surfaces (such as the drive plate and clutch cover or flywheel), ‘geometrical excitation’ caused by rotational anomalies such as gearbox to flywheel misalignment, and ‘modulation excitation’ which is brought about by relevant movement between components (i.e. excessive crankshaft end float).


Solving the issue

A team of LuK engineers looked long and hard at all of these factors and came up with a solution that honours Schaeffler’s history of creative innovation. They call it the ‘judder damper’, and you will find it incorporated into the design of some the very latest clutch discs when specified by the vehicle manufacturer.

Essentially, the clutch disc has been enhanced by the inclusion of a centrally mounted weighted and sprung damping mechanism which provides an effective barrier that absorbs and eliminates drivetrain vibrations caused by excitation. The ‘judder damper’ system works by adding a mass damper to the drive plate. The increased damper mass rotates due to inertia and changes the force required to turn it via a diaphragm spring and friction ring combination. This effect is entirely independent of any excitation torque and always provides the optimum level of damping required. What’s more, thousands of hours of development and testing have proved the key benefits of the system.

Many vehicles have already been equipped with a judder damper as original fitment and, as you would expect, LuK is ready to deliver this very latest technology direct to the aftermarket as a RepSet® repair solution.

Adding up the key features of the Judder Damper

– Elimination of pedal vibration +
– Significant reduction in cabin noise +
– Reduction in vibration levels to the drive train of more than 60%
= Increased driving comfort

Double Clutch Repair Kit for the Renault Vehicles

LuK has developed its latest new repair solution for double clutch systems with the RepSet® 2CT for Renault vehicles fitted with the DC4 six-speed transmission.

The new product will be able to assist independent garages to repair dry double clutch systems on Renault Mégane III and Scénic III models powered by K9K engines. As wear can also be expected in engagement systems, a LuK RepSet® 2CT includes not only guide sleeve, snap rings and fastening screws, but also lever actuators/engagement lever and engagement bearings.

Worn mounting kits – characteristics and visual signs

Have you ever replaced a shock absorber and put the old suspension mounting kit back on? If you were brave enough to admit it, you will be pleased to know you are not the only person!

Just like a shock absorber, a suspension mounting kit is pushed and pulled 1,500 times every mile – over the course of 50,000 miles that means this small but important component has moved 75 million times. Imagine how that amount of work will deteriorate the components in the mounting.

Suspension mounting kits optimise suspension and steering performance by:

a) Acting as a pivot for the steering mechanism, providing a smooth steering response;
b) Reducing squeaks, rattles and vibration noise.
Worn mountings have an adverse effect on ride control and safety. Mount wear depends on the type of travel, driving characteristics and the individual vehicle, however a good guideline is that if the struts are worn out, the mounts will probably be worn out too. Strut mounts should therefore be replaced every time you replace struts.

Characteristics of a worn mounting kit

* Clunking noises
* Vibration
* Loose or stiff steering
* Poor alignment
* Tyre wear
Visual signs of a worn mounting kit

* Cracked and/or sagging rubber
* Corrosio
* Deformed or bent parts
* Pitted rubber

Suspension mounting kits improve vehicle handling, ride control, alignment, braking and steering. They should be replaced every time you replace a vehicle’s shock absorbers.


Garage and sales training

KYB UK – a leading supplier of shock absorbers, coil springs and suspension mounting kits – provides valuable technical training for its garage customers. The company’s training
programme for technicians advises them on what to look out for when checking for worn shock absorbers and springs on a car

Sue Clough, Customer Service Manager, KYB UK, says: “Our training programme helps garages to look for physical signs of wear on shocks and springs, as well as the symptoms they would feel driving a vehicle. Training sessions are normally held at an individual garage customer’s premises or given to a group of garages at a
central location.

“In addition we supply visual aids, including leaflets and point-of-sale material which garages can use to explain to motorists the importance of checking shocks and springs as they are safety critical components. Their replacement also represents a great sales opportunity for our independent garage customers.”