OBA
The Sanden compressor
I always liked the idea of an on-board air compressor to re-inflate tires
right on the trail without having to borrow someone else's or to wait
to get to the gas station, just for emergency or why not!
just for fun, but the cost of an electric compressor is scary and putted me off.
I didn't have and I didn't want to spend a lot of money for one of those...
Since only women use AC - and since there's never been AC on my Defender anyway!
-
I thought of using an AC compressor for my OBA project; a Sanden AC compressor.
An engine driven compressor could be installed in the factory location without too much work,
saving useful room in the tub
(not to mention in the cab, where the smaller ARB compressor lived already, and I decided to leave it alone working the lockable diffs).
I located a 7 pistons/8 cfm Sanden compressor (model SD708) in a nearby yard
out of a Renault Laguna? for 30€ and I brang it home.
To say the truth I did buy 2 of them, only to find out one was seized.
If you're after a used compressor, remember to check the electric clutch by hooking it up to a battery and seeing that it engages/disengages properly,
or by turning the front plate with a spanner or by hand,
so you can choose a good one.
I bought the manifold, hoses, filters, plugs etc at an hardware shop
(all the small bit alone costed much more than the compressor itself!).
The intake filter is a very cheap plastic filter for a lawnmoyer I think.
I firstly bought a bracket from Equipe which I later exchanged with Alfredo for an original bracket for 300 Tdi.
I went to an aircon place and got the proper AC hoses with crimped fittings with the right thread
from a garage for a few Euros,
so they can handle the heat and pressure generated by the Sanden
and discharged through the
discharge port,
marked with
D on the cylinder head.
From there, the compressed air goes through a coalescing filter,
through a one way valve and arrives to a manifold on which I screwed a safety valve,
an air manifold and an air coupler.
I cutted the other hose at the shortest possible lenght in order to make it compact and
putted a fitting in it,
and screwed the intake filter to the fitting.
The
suction port is marked with
S and works at low pressure so it isn't crucial.
Wiring: my compressor has only one wire for the power, it means it's already earthed through its body.
Make sure the wiring is insulated and cannot short, and put a fuse.
My setup is currently tankless although I did find a cool, light aluminium tank of a MB lorry;
as everything is always a work in progress I will fit it one day.
Also it has no pressure switch yet.
I changed the seal with a brand new one, and bored the discharge hole to a bigger diameter.
I swapped the original and too long recharge plugs with shorter plugs so I can unbolt the head
with a spanner if/when needed,
and I bought a brand new drive belt (Britpart, part #ERR2215).
On idle, it happily pumps enough air to fill my 285/75-16 SSRs with no sweat and very quickly!
Useful link with infos (in French):
