Peter Zaborski wrote:
> I assume the article you are referring to is the one on bench bleeding
> the MC (http://www.vtr.org/maintain/brake-bench-bleeding.html).
> In any event,
> > Subject: brake master cyl
> > Hello Peter,
> > I just found out about your article...search it in the net.
> > Anyway, my problem is that...
> > My wheels or brake pads get stuck to the drums after say an hour
> > drive.> >
> > Why is this so....
> > Actually---we didn't do the procedure you did,
> > We bled the whole system after installing the MC.
> > Now he's saying that maybe it's the hydrovac unit which is at fault...
> > Please enlighten...
> > Thank you very much.
> > Albert S.O. Luyon
> > University of the PHilippines
Excellent article on bench bleeding .... there are some master
cylinders that can also be bench bled by pluging the fluid ports. This
leaves a small bubble at the port, but will still work fluid all the way
through the cylinder. When doing it this way, you bleed it untill you
can no longer move the piston....
Any way, on to the question ... I am no brake expert, but one situation
I have run into on an american car ...
Some brake master cylinders have a "return valve" in them (clutch MC's
never have this). This valve can get dirty & restrict the return flow
of fluid to the MC, causing the exact problem described when driving in
town with frequent stops.
I would have to wonder if the original problem may have been something
like this; it sounds like the valve may have never been cleaned or
changed (they do not come in repair kits).
When the MC was changed, if it was not bench bled, but rather the entire
system bled, you could easily still have a lot of air in the lines from
the MC that has not yet made it to the wheel cylinders.
Another possibility can be a dragging parking brake, but in this case,
it sounds like that has been ruled out.
Just a guess. It is very difficult and typically not wise to try to
diagnose brake problems without having the car to work on. It is far to
important of a system to do any guessing. Good Luck....
Tom Strange, Classic Autosports Ltd., Appleton, Wi. 920-733-5013