One note,
I have found that if bleading a used (ie, not brand new) mastercyclinder,
especially and old one, it helps if you don't go all the way to the floor
when depressing the pedal to release fluid from a bleeder valve. The
reason? I may be completely wrong, but I have found and others have
agreed, that like an engine cylinder, the piston in the master
cylinder will wear into the walls of a master cylinder for the distance it
usually has to travel. This distance is *not* usually the distance to
presss the pedal to the floor. Anyway, when this wear pattern has
developed, and you start to bleed the brakes by pressing the pedal to the
floor, you start putting the piston in an area where the cylinder walls
are of a different texture then where it is seated. Sometimes this is
enough to ruin the rubber, etc on the piston and you will develop a leak
or just not have as much pressure.. Anyway, not a hard and fast rule, just
something to think about. It gets really complicated trying to get your
buddy to only press and hold the pedal a little ways, so I just usually
don't bother when doing a car... A motorcycle is a different story, since
I can to that myself.
-alfie
On Thu, 13 Jul 2000, Jon Kunkel wrote:
> I have used the same process, it is a 2 person job, as my father used to
> race cars in the 50's and 60's, I remember sitting in the race car
> pretending I was racing, and having to pump and hold the pedal down until my
> father sai to start pumping again. The important thing about doing the
> brakes this way is to have the person pumping the pedal to keep constant
> firm pedal pressure until you have opened and closed the bleeder valve.
> This process seemed to take about 1 hour to complete as I remember, and it
> was fun to do as a kid!
>
> Jon 50 3100
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
>
> ----- Original Message -----
> From: "tcape" <tcape@weblnk.net>
> To: "G. Simmons" <gls@4link.net>; <>
> Sent: Thursday, July 13, 2000 6:55 AM
> Subject: Re: [oletrucks] Brake Bleeding
>
>
> > Excellent description of the brake bleeding process, Grant! That's one to
> > print out and keep for the 'home shop manual'. Is the process you
> describe
> > a "one-person" process....or do you still need someone to pump the brakes
> > while you check the lines?
> > Thanks,
> > Tom Caperton
> > 47-2nd 3100....in Whiteville, NC
> >
> > ----- Original Message -----
> > From: G. Simmons <gls@4link.net>
> > To: <oletrucks@autox.team.net>
> > Sent: Thursday, July 13, 2000 2:05 AM
> > Subject: Re: [oletrucks] Brake Bleeding
> >
> >
> > > >My problem is I've pumped about half a gallon of brake fluid through
> > >just
> > > one wheel cylinder with the Mityvac over a couple hours and I am >still
> > > getting air through the lines.
> > >
> > > Hi Tom,
> > >
> > > It does take a long time to move all that air a few inches at a time
> from
> > an
> > > empty system. Doug's comment that there may be a leak somewhere
> strikes
> > me
> > > as a likely diagnosis if you've given it a fair chance already. I
> wonder
> > if
> > > the vacuum method draws air from the whole system rather than just the
> > line
> > > you're trying to bleed. I thought I'd tell you my method, which uses
> > > pressure from the pedal rather than vacuum from the cyllinder. This isn
> 't
> > > necessarily better, but is just another technique.
> > >
> > > The equipment required is a wrench for the bleeder valve, a short length
> > of
> > > aquarium tubing, a small jar with a lid, and a large clip of the sort
> used
> > > for documents.
> > >
> > > I punch a hole in the jar lid that will let the tube pass through but
> > still
> > > hold the jar on the tube when filled with brake fluid.
> > >
> > > I fill the bottom of the jar with 1/2 inch of clean brake fluid, then
> > screw
> > > the lid on so the tube end is submerged. The other end of the tube
> slips
> > > over the bleeder valve. Then use the clip to hold the tube to the brake
> > > line or something that will keep the jar supported. Any other way you
> > can
> > > think of to make sure the jar doesn't spill will do.
> > >
> > > Loosen the bleeder a half turn or so, then slowly depress the pedal two
> or
> > > three times and check the fluid level in the jar so you can make sure it
> > > doesn't overflow. When it gets full empty it down to 1/2 inch and
> repeat
> > > until no bubbles appear in the tube. Then tighten the bleeder and move
> on
> > > to the next wheel. The pedal will not become stiff till you're near the
> > > end.
> > >
> > > Hope these thoughts help. May just require patience.
> > >
> > > Regards,
> > >
> > > Grant S.
> > > 54 3100 (mostly all there)
> > > 54 3100 (mostly not there)
> > > 55 1st 3100 (mostly rust)
> > > Los Angeles, CA
> > >
> > >
> > > > >
> >
> >
> > oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
>
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
>
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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