Tom,
Yep, that's what I read but I wasn't sure of the exact process. Thanks.
Mike
----- Original Message -----
From: "Thomas Walter" <twalter@austin.rr.com>
To: "datsunmike" <datsunmike@nyc.rr.com>
Cc: "Fergus OFarrell" <FOFarrell@qtww.com>;
<datsun-roadsters@autox.team.net>
Sent: Friday, August 31, 2001 9:15 AM
Subject: Re: bellhousing "window"/ bench bleeding (no, not me)
> [How to BENCH BLEED the Master Cylinder. Done when installing
> a NEW or REBUILT Master cylinder that doesn't already have
> Brake Fluid in it].
>
>
> Mike,
>
> I had some OLD brake lines that I was tossing out. I just off the
> threaded fitting and a few inches of metal line.
>
> I'd bend the lines back so the whole thing looks like a "J".
> Put the top of the "J" down into the reservoir, then thread the
> fitting into the bottom of the brake master cylinder. Ditto for
> both front and rear reservoirs on tandem brakes.
>
> Fill the reservoir with Castrol GT/LMA Brake Fluid (my favorite),
> and push in the push rod a few times. You only have to overcome
> spring force, so pretty easy to do this when the brake master cylinder
> is up on the bench. Keep this up until you do not see any more air
> bubbles coming up from the lines.
>
> I use my bench vise, with two thick soft (pine) boards to
> protect the aluminum brake cylinder from the jaws of the vise.
>
> Viola... master is now "bench bleed" which makes it FASTER to bleed
> the brake system. Disconnect the metal lines, and use an absorbent rag
> when go to put the brake master cylinder back into the car. Keep it in
> place until everything is bolted up to prevent getting brake fluid
> on the car.
>
> Tighten the fittings by hand. Yes, messy with brake fluid. Once you
> have the fitting all the way down (keep wiggling it when starting)
> then use your 7/16" flare nut wrench to "snug it" home.
>
> TRIVIA:
> Brake line fittings are 3/8x 24tpi FINE Thread. Common size for
> an american car. Lines are cheap, so you can buy a 12" long line...
> cut it (tubing cutter is the proper tool, but a fine tooth hacksaw
> blade used slowly will cut it.) Two six inch long "bench bleeding
> tools are formed. I used the letter "J" to describe the shape of the
> metal line, a "G" or "C" might give you a better idea.
>
> BRAKE MASTER CYLINDER SHIMS: You know those funny shims between the
> brake master cylinder and firewall: They are there for a reason!
> The original master cylinders used a fixed pushrod length. There
> needs to be some free play in the pushrod to master cylinder. Not
> much, maybe only 1/32" of an inch. With such a heavy return spring
> on the pedal, it is hard to notice the free play. Reach up there, and
> you should be able to "wiggle" the brake master cylinder push rod.
> OK? My hands are too large to fit, but just so you have the idea.
>
> What happens if there is no free play in the pushrod? It slides back
> into the brake master cylinder. As the pistons in the Brake Master
> Cylinder slide forward, first thing they do is cover the reservoir
> inlet holes. Remember the fluid has to move from and to the reservoir.
> So when you cover the return hole, the rear lines will maintain much
> higher brake pressure. This will leave the rear wheels dragging, or
> even locked up. Adjusting them may seem to solve the problem, but
> it returns. So check that pushrod clearance. On roadsters is was
> adjusted by shims. On the later 510/240Z Nissan used an adjustable
> pushrod. I'd swipe them off those old METRIC master cylinders, and
> retrofit them into my Roadster SAE FINE thread master cylinders. Hence
> an adjustable pushrod, and no shims to mess with.
>
> Too many words this morning. Sorry for being so verbose.
>
> Cheers,
>
> Tom Walter -no roadster-
> Austin, TX -Datsun 510 & Toyota Land Cruisers-
>
>
> datsunmike wrote:
>
> > I have a book that describes how to bleed a master but I can't remember
> > which one and I have many :(
> >
> > The holes aren't plugged, rather lines are run from them back into the
> > reservoirs.
> >
> > Mike
> >
> > ----- Original Message -----
> > From: "Fergus OFarrell" <FOFarrell@qtww.com>
> > To: <datsun-roadsters@autox.team.net>
> > Sent: Thursday, August 30, 2001 8:39 PM
> > Subject: bellhousing "window"/ bench bleeding (no, not me)
> >
> >
> >
> >>Um, folks, I was not so appalled by the picture of the bellhousing
window,
> >>because my '82 1800cc Subaru had a nicely molded bellhousing window just
> >>like that, with the timing marks underneath. (okay, it had smoother
edges)
> >>You also could use a screwdriver to turn the engine using the flywheel
> >>
> > teeth
> >
> >>thru this window. It had a nice little contoured rubber plug for it.
> >>
> > Okay,
> >
> >>so maybe the boxer style (flat 4) motor was never capable of
> >>
> > cafe-spraying,
> >
> >>flywheel-shattering torque outbursts, but a better water-cooled flat 4
> >>
> > than
> >
> >>vw's attempt.
> >>Roadster content: my trans tunnel is now completely covered in
alum-faced
> >>sound deadener, with alum-taped edges; looking "Apollo reflective".
> >>When you 'bench bleed' a master/cyl, what do you put in the brake line
> >>holes? Corks? Or nothing? Won't it just drain out the bottom?
> >>Fergus O, 69 2000 in bits
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