Whats the issues with callipers without dust seals

[Graham]

Hi all, what are the problems assosiated with using callipers without dust seals, other than corrosion and dirt ingression, what sort of protection is given, i.e. are the pistons the only part exposed to dust, or can dust get into the piston bore. Do the callipers have a wiper onto the piston to stop dust ingress like any normal hydraulic cylinder. Or do they have none.
Cheers Graham

[Alistair C]

Good Queation! Quote from the manufacturers of my calipers when I asked what the whole sealed / unsealed issue was all about.....

'All of your production type calipers use dust seals. These work well as
intended until they start degrading or are overheated, at that point
they are worse than having no seals at all. Most of your production
calipers are made from cast iron and use mild steel for the pistons all
of which are highly susceptible to rust. The main function of the dust
seals is to keep moisture and debris out of the caliper bore beyond the
sealing ring and to keep the dirty piston form going past the sealing
ring during pad changes. When the dust seals get worn, they allow
moisture to get trapped in the outer bore and rust sets in. This is
extremely prevalent in limited use vehicles such as track cars and
Sunday afternoon cars. Many racers that are required to run a stock
caliper will remove the dust seals for several reasons such as,
decreases drag on piston, keeps the seals from melting under extreme
heat, allows for early detection of seepage and aids in cooling. Our
calipers are constructed of high grade Alum. that is hard coat anodized
for additional strength and corrosion protection and the pistons are
constructed of stainless steel. Since we do not use a dust seal we
highly recommend that you clean the exposed area of the pistons before
you push them back in the bores during a pad change, this should be done
on any caliper with dust seals also. Spraying the calipers with brake
cleaner any time the wheels are off or as the calipers get dirty is also
not a bad idea for any caliper.'

Ideally for a road car you'd have dust seals. But some people here will say they are essential & calipers will not last without them. Fact is Dialynx for one have been using 'unsealed' calipers on customers cars for many years and have told me they have never come across any problems related to this fact. Clean the pistons on pushing back & change the piston seals every now & then. Easy.

Right - said my peace.....now let the arguments commence!

[Graham]

Sweet i like your style, the gauntlet is down, should bring up a good topic as these technical debates sometimes come up with ingenious solutions.
Graham