datsun-roadsters
[Top] [All Lists]

Re: Update on roadster in Philly with locking brakes...

To: David Datsun <datsun_dave@yahoo.com>
Subject: Re: Update on roadster in Philly with locking brakes...
From: "John F Sandhoff" <sandhoff@csus.edu>
Date: Thu, 13 Sep 2001 11:15:31 -0700
Concerning your locking brakes, you wrote:
Advice> ...adjust the new brake master cylinder just installed.

Your comment> We looked at the brake master cylinder; I don't think
> you can adjust the rod underneath.

It does sound like the master cylinder. As far as adjustment, YES you
can adjust it but not the way you think! There are shims that go between
the firewall and the cylinder mounting flange, these space it 'away' from
the pedal/shaft assembly. To gain free play you add shims. Check to
see if there's any free play in the push rod - if it's in full contact (no
play at all) with the cylinder piston, it's too tight. Do you have the return
spring on the pedal (this was discussed in an unrelated thread)? It goes
between the pedal where it pins to the rod, and under the front of the dash.

It is also possible that the brand new master cylinder is bad. It happens.
If you're brave, go on another test drive, take with you a piece of plastic
hose, a small catch container, and a pipe wrench. When the brakes lock
up, see if there's pressure in the system by bleeding off a little fluid
at the fitting on the side of the M/C. The rear brake circuit is the front
fitting (smaller reservoir). Try one circuit; if that doesn't work try the 
other.
If bleeding off pressure does NOT get you going them there's a problem
at a wheel: jack up each wheel and see which one's stuck (use a good
jack - floor jack, bottle jack, scissors jack but NOT the 'tower' jack that
came with the car and slides into the side lift holes!)

Figure out where the problem is and then what parts you need. If you
don't you may spend a lot of $$$ throwing new parts at the wrong problem
(I dare say those calipers you replaced are probably OK).

-- John
     John F Sandhoff   sandhoff@csus.edu   Sacramento, CA

<Prev in Thread] Current Thread [Next in Thread>