<VV> honing wheel cylinders, good used parts parts

[djtcz at comcast.net]

snipped and bottom posted 

-------------- Original message -------------- 
> From: "Andrew Golt" 
> 
> BS... Hone-ing tool at 50 paces, buddy... 
> 
> The backing plate acts as a perfect holder, like so... 
> 
> http://www.youtube.com/watch?v=f-shtKfy6u8 
> 
> 
"better" cleaning is achievable off the car, but I believe acceptable cleaning on the car is possible with diligence (and plenty of brake fluid flowing down from the master cylinder).

Around 1:00 in the video the "rubber" cup inspection shows some details that would make me hesitate to re-use it.
1 - what looks to be a pit or void in the seal OD.
2 - the sharp-when-new lip is worn flat over a very broad area.
http://www.neffp.com/images/products/brake_cup_sm.jpg
http://www.cj-jeep.com/cj2a/images/805654.jpg
At several 100 psi during a brake application I imagine the entire seal OD face is in contact with the cylinder bore, but I believe it takes many brake applications for the seal to slide enough miles to wear the OD.

I use a similar comparison when evaluating rotating seals.
A rotating seal starts life with a sharp lip.
Half way down the page this Chicago rawhide rep considers a lip worn to ~ 0.025 " wide broken in.
http://www.maintenanceresources.com/referencelibrary/seals/sealenergy.htm

So I figure a seal with a lip worn >0.125 inch has seen lots of service.


Dan Timberlake 
Westford, Massachusetts, USA 



-------------- Original message -------------- 
> From: "Andrew Golt" 
> 
> BS... Hone-ing tool at 50 paces, buddy... 
> 
> The backing plate acts as a perfect holder, like so... 
> 
> http://www.youtube.com/watch?v=f-shtKfy6u8 
> 
>