This an email I received from
David who is well travelled in France. He is refering to the Renault
Trafic but is equally relevent to the Boxer:
your site looking for someone selling replacement rear springs
for our ancient Eriba camping car, Whilst accepting the truth of
your relations comments regarding the rear springs, I fear
there may be an error creeping in here, the major problem with
motorhome rear springs is that the rear springs are rated to
carry a percentage of the rated load a percentage of the
time, and almost never to carry that full load just sitting
around, which is the situation with motorhomes. They are bearing
about 90% payload every day and the rear springs, over a period
of time, quite understandably sag under the load.
loading valve is an unsophisticated mechanical linkage to a
limiter, merely reducing the rear brake effort when it detects
the rear ride height is higher, and permitting more braking if
the rear ride height is lower, i.e loaded. The idea is not
to increase braking power loaded but to reduce braking when
unloaded to avoid the rear brakes locking up when braking hard
the rear axle becomes unloaded due to weight transfer. The rear
brakes make little contribution to the overall braking,
our race cars have the rear brakes almost completely backed off
to avoid them locking up and it's still very hard to lock the fronts!!
owner of the Eriba had to stand on the pedal coming
downhill he probably needs new genuine discs and proper EU-manufactured
pads from a proven manufacturer, most "motor factor"
aftermarket pads are either counterfeit or Taiwanese/Chinese
rubbish, you'd be better off with genuine Renault parts from a
dealer, regardless of cost!! You may even be able to buy better
pads to fit the Trafic caliper, if it's used on something more
exotic, from someone like Demon Tweeks. Pads and discs
aren"t "all the same"!!
heavier-duty springs do not raise the rear ride height to
a greater height than would have been the case when the vehicle
was new no harm will be done. Our Eriba, which is in France
currently, has detailed graphs on the drivers door detailing the
load valve settings, I would imagine an Eriba would have had the
load valve adjusted when the conversion was carried out, I
wouldn't be so confident about UK "back-street"
converters using used vehicles!!
the springs will restore the original loaded ride
height, for another 16 years anyway!!
great believer in the Airide rear suspension units, I've
fitted them to a Hymer, and had them on my Chevy which I've just
sold, and they work really well especially as we used to tow
fairly heavy race car trailers and this allowed the ride height
to be adjusted to correct the tail drooping down due to nose
weight. Coming down the Alps to Monza towing a 1t, 20' trailer
is a test of any braking system, and Chevys are
notoriously under-braked yet we've never had a problem with rear lock-up!!
Best of luck,
comments are very relevant, but my reason for using springs,
were, they were a lighter weight option.