Land Rover Monthly – October 2019

126 LANDROVERMONTHLY http://www.britpart.com

Projects,repairs,modifi cationsandadvice guide

CONTRIBUTOR

TREVOR

CUTHBERT

NEEDTOKNOW

COST:£285.58TIME:6hours

DIFFICULTY:

MODELS:Defender90,110

TOOL S:Wire terminalcrimpers,

automotive test light,mult imeter,drill,

spanners, trimtool

PARTS&COSTS:Partsfr om

GwynnLewis4x4,ARBHighOutput

Compressor KitCKMA12,£226;

ARBPump-upKitarb171302,£31.38;

ARBAirGauge, ARB605,£28.20

CONTACT:GwynLewis4x4,Tel:

01938810 298,gwynlewis4x4.co. uk

WORKSAFELY:

•Wearprotective glovesandsafety

boots,pluseyeandhandprotection

whencutting,fi linganddrilling

•Dis connectthebattery(earthlead

fi rst)be fore startingwork

•Checkallwiringcarefullyandensure

correctfusesareinplace

T

HE most commonreasonfor

fi tting a permanent aircompres-

sor system to a LandRover is to

provide an air supplyto operate

an air-locking differential on one or both

of the axles. As the drivingconditions

become arduous, the drivercan switch the

compressor on by the mainswitch and

thenfl ick individualswitchesfor each of

the axle diff locks.Each switch causes a

solenoidvalve to open, admitting air pres-

sureto the differential to instantly lock up

the diff –offering full traction from both

wheels on that axle.

Manyowners have realised that in

additionto air-powering their locking dif-

ferentials, the on-boardcompressor can be

usedfor tyre infl ation aswell. And,by the

simple additionof a T-pieceat the aircom-

pressor, an air hose couplingcan befi tted,

and an air hose and infl ator carried aspart

of the tool kitfor the LandRover.

Why dooff-road drivers need afacility

for tyre infl ation? LandRover tyres ha ve a

relatively highrecommended pressure for

use on theroad ranging from perhaps 30

psi to say 46psi, depending on the load

carried in thevehicle. Whenoff-road, much

MONTHLYTECHNICAL

Fittinganon-board

aircompressor

Trevor Cuthbertexplainsthebenefi tsof having anon-board

aircompressor andshowshowto installone

lower tyre pressures, such as 15to 18 psi,

provide better grip in muddyconditions.

It is very easy to lower thetyre pressures

by letting some air out, but the problem

arises whenyou want to drive homesafely

on theroad, unless you ha ve an on-board

air compressor.

I fi nd my mobilecompressor system

useful aroundmy two yards where there

are numerousvehicles including Land

Rovers, tractors, forklift trucks, trailers and

cars, anyof which might need asoft tyre

re-infl ating. Here, an on-boardsystem is

far moreconvenient than unpacking and

connecting a portable compressor.

On-boardcompressed air hasrecrea-

tional uses, too. On acamping trip, air

mattressesare quickly andeasily infl ated,

and even infl atable boats. And there’s

always the advantage of being ableto use

air-powered tools.

I was in touch withGwyn Lewis about an

ARBcompressor for an off-roader project

that I have beenworking on, and whenI

discovered that agood pricewas onoffer,

I decidedto purchase a kitfor my working

DefenderTd5 90for tyre infl ation dutiesat

my workshop andyards.