NEW wheel cylinders leaking

[vze28h54 at verizon.net (Chris)]

> > Did you disassemble the wheel cylinder and coat everything (internal),
> > especially the cups, with brake fluid?  Did you use wheel cylinder paste on
> > the pistons?
>No, and no.  It didn't occur to me to dismantle and apply brake fluid
>and/or any kind of paste to new wheel cylinder assemblies.  Is this a
>"need to do" or a "nice to do" step?

If the cups are "dry", that is not covered with brake fluid, they may fail 
before they have a chance to be lubricated by the brake fluid in the 
system, after installation.  I don't know if there is an industry standard 
or practice for delivering assembled items of this nature, but, in my 
opinion, unless the information that came with the cylinders indicated that 
disassembly and lubrication is necessary, then the units should be ready to 
install.  Was there something to keep the pistons from coming out while in 
the package and were the holes for the brake line and  bleeder valve 
plugged? (That is, was there something to keep brake fluid in the wheel 
cylinder while in the box?)  VW recommends that brake fluid and the paste 
be used, and that brake fluid alone be used only when the paste is 
unavailable.  Personally, I have just used brake fluid. Also, the brake 
system should have clean fluid in it before the wheel cylinder is 
installed.  You don't want any old crud (or even new crud) and sediment 
getting into your brand new cylinder.

You may never know  the cause of the problem. Could have been 1) poor 
quality part 2) improper assembly (somebody's first hour on the job)  3) 
sitting on the shelf too long, 4) a returned part that some doofus buggered 
up and took back to the store.  Maybe we have to be like Carroll Smith 
("Prepare To Win", etc).  The first thing he does when receiving an 
assembled race car is to take it completely apart and then assemble it 
himself.  He is quite frank that he doesn't trust anybody in a situation 
like that.  Maybe we have to do the same.

Chris


>Thanks,
>matt.