I just want to share with you my experience with replacing front brake caliper pistons and seals. In a nutshell if you face needing this done, it looks like new calipers are the way forward.
Certainly that is what the mechanic at PA Blanchard (ex military LR specialist) does. And I can see why, but their reason is the awkwardness of fitting the piston dust seal retainer, and time taken to clean up the old calipers.
Having ordered and had confirmed by the suppliers (Rimmer Bros) and with Blanchards that I have received the correct parts according to my vehicle details, albeit LR list it as a 110, when it is in fact a 127!
The pistons fit the calipers, but the seals DO NOT fit either. Wrong seals obviously? You would think that must be an easy fix, but I went to JSF in Norwich and none of their seal kits fit the pistons/calipers either.
Blanchard were very helpful in checking their stock items, and the piston and seals as listed, are indeed incompatible.
I am not certain what to do now, other than order new calipers. But for those, there are big differences in prices: TRW - £35, aftermarket - £44, genuine - £623 !! All plus VAT, according to Rimmer's website
Costs alone suggest that is the way forward: New pistons (in stainless steel) were £30 per caliper, caliper repair kits are reasonable at £7, but the caliper O rings (genuine) are £12 a pair. (I bought a selection box of round O rings for less than that)
Another conclusion: LR charge extortionate prices for genuine spares.
I have wasted many hours cleaning and painting the original calipers. Learn from my experience guys.
The seal to the right of the new piston is the original dust seal
The two to the left are the undersized new ones