Painting chassis-related components

Painting chassis-related components
General
Information on painting the cab can be found in the document Painting the cab.Information on the final painting of the vehicle's different parts can be found in the document Surface treatment at the factory.

GeneralIMPORTANT!

Scania advises against painting components consisting of soft and flexible materials, as the paint may affect the shelf life of the material. Adhesion will also be poor. For example, this applies to components made of soft plastic and hydraulic hoses made of rubber.

This document contains the prerequisites and instructions for painting the vehicle’s chassis-related components, such as the chassis, axles and rims.

Use paints that are compatible with Scania paints when painting. The paints must not affect the characteristics of the underlying original paintwork.

Scania Truck Bodybuilder 22:10-527 Issue 6 2021-09-08© Scania CV AB 2021, Sweden 1 (13)

General


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Location of radar.

Safety precautionsWARNING!

The radar cover must be protected during re-painting or anti-corrosion treatment. The vehicle's radar, located at the front and on the sides, is very sensitive to interference and must not be covered or painted over. Its functionality depends on the thickness of the radar cover and its material properties. Obstructing the radar's field of view by, for example, covering with paint or stickers risks negatively affecting the vehicle's safety functions, resulting in unwanted braking or no braking.

Note:Labels and markings on factory-fitted equipment must not be covered or painted over. This may be equipment such as e.g. fuel tanks, the compressed air tank, the air system and connectors. Mask all markings, all labels and symbols before painting.

Note:If the sticker on road speed sensor T20 is modified by e.g. being covered with paint, stickers or other items, this may result in the following undesirable consequences:• Tachograph failed to activate• 2-year check cannot be carried out

More on information road speed sensor T20 can be found in the section Road speed sensor T20.


General


Safety requirements for gas vehicles

WARNING!Gas tanks and gas systems must not be subjected to temperatures above 60°C. If the paint needs to dry at a temperature above 60°C, the gas tanks must be removed. The entire gas system must be flushed with an inert gas1 and removed.

IMPORTANT!

Work that involves opening the gas circuits must only be carried out by certified staff.

More information can be found in the document “Working on hybrid vehicles”.

1. A gas that does not react chemically with its environment.


General


Safety precautions for battery electric vehicles

WARNING!• The propulsion batteries must not be exposed to temperatures above 60°C for

longer than 2 h, as this will impair the service life.• The propulsion batteries must not be exposed to temperatures above 95°C. The

electrolyte in the cells is then turned into a gas, which means that permanent dam-age occurs and flammable gas is vented out of the batteries.


Metal chassis parts


Metal chassis partsPretreatment

1. Wash the surface with a water-based degreasing agent to rinse away any salts.2. Sand off any rust and clean the surface once again with a degreasing agent.3. Rinse clean with water using a pressure washer. The highest permitted water tem-

perature is 50°C.Avoid rinsing water over the following parts:– Parts where grease or other lubrication needs be preserved, e.g. ball bearings– Diaphragm for various functions– Wheel bearing– Electronic control units, ECU(Electronic Control Unit)– Support bearing and slide bearing for propeller shaft

4. The following parts must not be painted over and must therefore be masked:– Diaphragm for brake, air suspension and automatic clutch– Unions for filling air, lubrication, venting and drainage– Radar. More information can be found under the heading Safety precautions– Road speed sensor T20. More information can be found under the heading

Road speed sensor T20– Propeller shaft slip joint. More information can be found under the heading

Propeller shafts– Contact surfaces on rims. More information can be found under the heading

Rims– Chassis serial number in the frame


Metal chassis parts


PaintingIMPORTANT!

Do not use epoxy-based paint as a top coat as it is sensitive to UV light.

Scania chassis are powder-coated. When painting without a primer, an acrylic or pol-yurethane-based two-component paint must be used.

When painting with primer, a one-component paint can be used with a satisfactory result. Avoid air drying one-component paint as adhesion will be poor.

Follow the instructions in Scania standard STD2331.

More information can be found on the website Scania Truck Bodybuilder in the doc-ument STD2331– Surface treatment of trailers, bodyworks and chassis.


Plastic chassis parts


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External plastic parts of the chassis.


Environment

Unpainted PC/PBT plastic and PP plastic are fully recyclable. If the plastic is paint-ed, it cannot be recycled to the same extent.

The vehicle’s chassis consists partly of plastic parts.

The table below shows the chassis' plastic parts, type of plastic and the material they are composed of:

Plastic part Type of plastic MaterialsBumper Thermoplastic PC/PBT plasticLower front grille panel’s shielding netBoarding step unit casings.Front mudguardsSide skirtsBattery boxesLower front grille panels PC/PET plasticRear mudguards PP plastic (Polypropylene)Cover around tail lamps




PretreatmentPC/PBT plastic and PC/PET plastic must be painted with primer to ensure paint ad-hesion.

PP plastic requires pretreatment such as flame treatment or plasma treatment to en-sure good adhesion. Flame treatment and plasma treatment are also suitable for elas-tic surfaces. Then paint with primer to preserve the activation.

Ask your paint supplier about which type of primer is suitable for PC/PBT plastic, PC/PET plastic and PP plastic.

1. Wash the surface with a water-based degreasing agent to remove any salt and grease.

2. Remove any dirt and rough surfaces.3. Rinse clean with water using a pressure washer.4. Mask parts that must not be painted.




PaintingUse a paint that is suitable for elastic materials. Ask your paint supplier for help choosing the right paint.

Painting to repair painted plastic parts1. Paint with top coat.

Painting unpainted plastic parts1. Paint with primer.2. Paint with top coat.

If the plastic surface structure is not to be visible after painting1. Paint with primer that has a filling capacity.2. Sand the surface.3. Clean thoroughly and wipe the surface dry.4. Paint with primer.5. Paint with top coat.


Road speed sensor T20


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Road speed sensor located on gearbox.1. Road speed sensor with part number.2. Road speed sensor, illuminated with UV lamp.

Road speed sensor T20Note:The road speed sensor must not be painted over.

The name of the supplier and part number should be visible. The label with the hol-ogram should be legible. When the label is illuminated with a 365 nm UV lamp, the text, e.g. VDO, must be visible.

The road speed sensor may be located on the gearbox, rear axle or transfer gearbox depending on the vehicle specification.


Propeller shafts


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Propeller shaftsIMPORTANT!

To avoid excessive play in the propeller shaft slip joint, it is important to mask the entire splined sleeve where it meets the wiper seal, see illustration.If insufficient masking is applied, paint edges will form and chafe against the wiper seal. Paint edges will quickly wear the wiper seal as the slip joint moves backwards and forwards during operation. A worn seal will allow dirt ingress into the slip joint and grease will seep out. This leads to increased wear on the splined joint, resulting in excessive play and disintegration.


Rims


RimsWARNING!

No contact surfaces may be painted, e.g. contact surface between rim and hub or rim and wheel nut.

Always mask the rim’s contact surfaces with the wheel nuts using masking tape when painting the rims. If the contact surfaces are painted, the paint will be rubbed off when driving. This may cause the wheel nuts to loosen, potentially causing the wheels to come loose.

Ask your paint supplier for a suitable paint for aluminium rims. Scania does not rec-ommend painting highly polished rims.


U-bolts


U-boltsWARNING!

Only use pH-neutral or alkaline detergents when cleaning U-bolts.

Certain components, such as e.g. U-bolts, are very sensitive to detergent with a pH of less than 7. Acidic detergent causes hydrogen embrittlement, which can result in U-bolts breaking much earlier than expected. Always wash the vehicle with water-based products.


Documents

Painting chassis-related components