On Tue, 17 Mar 2015 18:58:48 -0700, Larry Jaques
wrote:

On Tue, 17 Mar 2015 18:21:29 -0400, wrote:

On Mon, 16 Mar 2015 21:07:44 -0700, Larry Jaques
wrote:

On Mon, 16 Mar 2015 20:54:00 -0400, "Jim Wilkins"
wrote:

wrote in message
m...
On Mon, 16 Mar 2015 15:40:22 -0700, Larry Jaques
wrote:


Your 96 Ranger is newer than my Ranger, though mine has been getting
newer piece by piece.

Next question:
How do you seal the air leak along the bleeder threads when vacuum
bleeding? I didn't want to squirt on something incompatible that might
get back into the cylinder.

You don't. Vacuum bleeders are trash. Harrumph!


A neighbor was home and helped by pushing the pedal, which finally
blew out the air that was keeping it soft. My usual one-man method of
depressing the pedal with a broomstick bungee'd to the steering wheel
wasn't forceful enough to clear out bubbles.

Yeah, manually depressing the brake pedal is the cleanest, fastest,
most thorough method of properly bleeding brakes. But the pressure cap
for the master cylinder is nice, too. Have you seen them? Here's a
DIY hack job. http://tinyurl.com/m7d3s76 Just remember to refill the
master after doing each wheel. Running it dry and introducing air
into the entire line again is a real bummer. DAMHIKT when I was in a
hurry and the customer was waiting once. (just once!) We had an old
but professional universal pressure bleeder kit, but I more often
grabbed another mechanic or bodyman and had them do the pedal honors.
Ever reverse bleed a brake system? You pump the fluid into the
bleeder screw untill fluid starts to fill the master cyl - one wheel
at a time from longest line to shortest.

Which leads back to the OP's question: "How do you seal the bleeder
screw? I wouldn't consider that to be a valid method due to leaks.
And I haven't seen any bleeder screws/wheel cylinders with o-ring
seals, so they all leak when bleeding, in my long-term experience.
shrug

Reverse bleeding is the recommended way of bleeding most motorcycles,
and is the only simple and effective way to bleed twin leading shoe
brakes on many older british cars without standing them on end. As for
leaking around the threads , the question is, what does it matter? You
apply pressure to pump fluid in through the center of the bleeder
screw. It is relatively low pressure (no more than 4.5PSI is
required), so very little fluid will escape past the threads - and
being under pressure there is NO chance of air (or any other foreign
matter) entering via the threads.

Actually there is no commonly used method of bleeding brakes where
leakage past the bleeder screw threads CAN cause a problem, and the
bleeder screw seals with a tapered seat so has no need for a
troublesome deterioration prone "O" ring. The only way I can see it
being an issue is if you attempted to draw the fluid into the system
through the bleeder screws by applying a vacuum to the top of the
master - which would be a REALLY stupid way to attempt to bleed a
brake system on so many counts.