brake caliper cylinder/piston polish

[towbar]

This is my frist caliper job (Deutz-Fahr tractor). I cleaned the parts and need to decide if polishing the cylinder is required at all, and also if the piston is still acceptable, as I think it is.

The plated piston hasn't been polished yet, something I intend to do with 400 or 600 grit tape or just buffing. The plating faults are at the edges where the seal placed in the cylinder groove will never ride.

The cylinder wall was never plated or polished (I blasted it ligthly) so do I really need honing or polishing (it's the piston that slides against the seal and not the cylinder). If I should resurface it, what tool? It's +/- 60mm id so maybe a 3/4-2.5" honing tool (amazon), what grit stones and where can I get such stones?

The plate under the the piston is from the seal-kit I bought, what is it's exact purpose?

Thanks for any wisdom

 

[Delmer]

I'd run it. Maybe hit the piston lightly with 400 or 600 like you said. It can't hurt. Since the cylinder was blasted, I'd lightly smooth it with the same paper. Especially the seal groove. Can't say where the plate goes, seems like it should fit the caliper or pad mount some how.

 

[towbar]

I blasted lightly and never blast with crushed glass but only with natural sand. That plate goes between the business end of the piston and the pads and it's like hanging loose on pins which makes me think it could be some sort of anti-seizure device.

 

[Truck Shop]

Looks fine.

 

[1693TA]

I've seen much worse and operating fine.

 

[Delmer]

Heat shield to protect the dust seal bellows?

 

[towbar]

Heat shield to protect the dust seal bellows?

Could be! This (europid) tractor isn't going to be braking much but they were known for brake fires. That's why on US (Deutz-Allis?) models the regulatory wanted in-axle wet brakes instead of these external ones.

 

[joe--h]

The shield is supposed to be an anti squeal device. Old Girling cylinder, knock those rust spots down so they don't damage the seal going together.

Joe H

 

[towbar]

Yeh, it's a pretty tight fit, judging from what it took to pop the pistons out. Speaking of going together, the seal-kit came with an asembly grease, DOT-4 & 5.1, mentions not to use oil-baseds, no word about white or silicone grease.

 

[joe--h]

What it came with is compatible with the seals, use it.

Don't cock it going together.

Joe H

 

[towbar]

Sure thing, I was just wondering about white grease seeing that a mechanic told me to use that (not knowing that a grease pouch would be packed in the kit).

That anti-sqeak plate has a half moon cutout, I didndn't take enough pictures to show which side the cutout is supposed to go on, wheel going up/down, or ...?

 

[towbar]

Done. Amazing what 400 grit can do (couldn't get any 600). I was on my back trying to screw on the last mounting bolt but it wouldn't go easy. Finally took it out and saw the thread slightly damaged but had no 14mmx1.5 dye or tap so off I went to the blacksmith again to 'borrow'

Thanks for the help, heavywequipmenters!