Some Jamar cylinder's had poor machining on the bores, Definitely worth
checking, When checking the bore's also check the seals, On my
first cylinder I had mis-match seals of different materials, this
prompted me to replace all my seals with good quality ones, When
both piston's are at rest they should be clear of a cross drilled
connection in the body of the master cylinder, check it isn't
obstructed, On the front of the piston seals are plastic washer's these
can stick in the bores so reduce there size slightly, I have done away
with the DOT5 Silicone fluid entirely , replacing it with the DOT 5.1
glycol based fluids, But if you do this all your seals will need
replacing including the seals in the handbrake valve and calipers,
Bleeding was as simple as putting a small funnel on top of the reservoir
filled with fluid so the master cylinder had a good head of fluid,
Undoing a caliper bleed nipple one at a time and watch the air being
expelled, The reason DOT 5 Silicone fluid is recommended is because it
is combatable with both types of rubber seals used in the Master
cylinder and Calipers/handbrake valve, If you check the archives there
is a lot of information
Regards
Ivor
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of
rob@Neils.US
Sent: 30 December 2007 00:54
Subject: Europa-List: Bleeding Jamar finger brakes
My reservoir is not pressurized.
I bleed the brakes as Craig describes but I can't get any pressure on
the second stroke unless the Jamar brakes are verticle instead or
horizontal.
I can get all the air out of the system by working the cylinders only
when verticle then pumping fluid up from the brake nipple to where the
brake line loosely connects to the clylinders until I get no bubbles the
I tighten the cylinder/line connection. Doing this makes the brakes
work well...for quite a while but when I have to bleed the system again
I have to dismount the cylinders and loosen the cylinder/line connection
allowing bubbles and brake fluid to seep out until I tighten the
connection. It's a real pain to go through all this to simply bleed the
brakes...and it makes a mess.
There's gotta be something wrong with the system that I haven't yet been
able to figure out. Maybe a leak? Maybe a piston part in backwards?
Maybe poor machining on the cylinders allowing leak-by on the return
stroke?
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