Caliper Pistons Pitting

If you mean the ‘rim of the bucket’ it is inconsequential provided it bears pretty flat on the back of the pad. They should get a smear of brake grease on re-fitting to forestall further corrosion. Brasso is pretty good for polishing the important bits! Just clean it off well as it is a fine abrasive.

 

DanielB
Yes I would fit stainless pistons. I did think they had stainless. I have in the past sanded rough bits out and uses super glue then sanded back again.
Regards & Ride Safe
Joe.

 

DanielB.
They are goners stick them in the metal skip and treat your self to some stainless.
Regards
Joe.

 

As Joe said, bin them. Pointless skimping if your going to the effort of a caliper rebuild.

 

I am curious to know how you achieved the Damascus effect......

I would agree they are now past it.

 

You should find your bits here:

https://www.triumphparts.co.uk/prod...rts/triumph-all-parts-stocked/triumph-brakes/

Personally I don’t think stainless confers any particular benefit given the service life you probably seek.

 

When doing caliper refurbs I always use red rubber grease and a nice smear of it around the outer seal where the exposed piston shows,i found as the pads wear more of the piston is proud and prone to the elements this trick has worked for me for many years.

 

It is the flowing pattern you get from twisting and working strands of steel with heat and hammers to create strength with elasticity. Found in swords and 19C shotguns.

 

I think it's the reflection of the paper/cloth the piston's are sitting on ... ?

Polish up the piston's on a cloth polishing wheel ! Those pit's will still be there but very minor ! It's the rust that's sticking proud that will cause the most issues. I did the piston's on my America and the brakes are fine ! That pitting is right on the edge of where they start working. The sealing ring is several mm's back ! So all should be fine with new pads and rubber greased as mentioned above ... ! ... ?

 

As you have overhauled the rest of the braking system and for the small nominal cost of replacement pistons replace them, it will give you peace of mind, plus 1 on the red grease.

 

I do everything you’ve said above
Just a smidgen of copper grease on the bleed screw

 

OK apologies for confusing you with misplaced humour. The photo is of Damascus shotgun barrels. You achieved a similar effect with reflected paper towel and fine buff marks.

Grease - red brake variety. A light smear on the inner fluid seal for ease of assembly but brake fluid would be my preference. Light smear to fit and seat outer dust seal but minimal as it will attract dirt. A more obvious smear on ‘bucket rim’ where it bears on the back of the pads and on the opposing fingers (or pistons as the case may be)
The calliper gallery seals need no lubricant but you can use a light dab to keep them located during assembly.

Bleed screws and calliper shell clamping bolts use copper anti seize. It resists corrosion rather than lubricates and impedes air leaking back up the thread during bleeding.

 

I myself I have never used grease I just smear them all with the brake fluid. Used this method for years and its never let me down. All the other bits like bolts and bleed nipple I apply anti seize grease or copper slip.
Regards
Joe.