You can get an assortment of shims form Vicky Brit or Moss. Buy about 10
with 7 in the very thin range (2-3 each of the 3 smallest sizes). Perhaps
your right caliper has frozen up a bit or the pads have become contaminated
with brake fluid or oil causing it to be ineffective. Your left caliper
would be stopping the car which would make it overheat which could cause
your rotor to warp. Unless you would like to buy another rotor for the left
side, I would investigate the right caliper now. Check for uneven pad
thickness and/or wear at an ange to the pad backing. In general, I consider
it an unsafe practice to work on the suspension in stages. Doing brakes one
side at a time is a definite no no in my book. Take the time to prepare for
the job and do it all at once. This also allows you to compare side to side
for diagnostics and reduces the possiblity of waisting time and parts. If
you don't know how to properly shim the bearing, why replace it? You may
just damage the new one too. I don't remember anyone saying that the bearing
was bad, just not properly shimmed which you still haven't checked.
When I'm shimming the bearings I pick up a few extra thin shimms for
testing. With the car jacked up, wheel off ground, spin the wheel and see
how freely it spins. Remove the wheel, castlated nut etc and remove all the
shims. Now reassemble. You don't have to torque it to 70 for this test. Now
try to rotate the hub. It will most likely bind and not want to turn. You
dont have enough shimms in there. Now disassemble and insert all of the
shims you have(they go between the spacer cone and the bearing. Reassemble
and turn the hub. It should turn freely but you will notice that if you
firmly grab the rotor like you would a steering wheel at 9 and 3 o'clock and
pull/push, rock the rotor back and forth that there is a bit of play or
wobble. You have too many shims inserted. Somewhere in the middle is a happy
medium where the hub spins freely with little wobble. That's your goal. It
is probably easiest to find this point starting with not enough shimms. Add
very thin shimms one at a time and retest until it spins freely. Note the
shims you are using. Add another thin shim and see if the rotor spins more
freely without introducing wobble (if so repeat with another shim) or
introduces a wobble with out decreasing rotational resistance. When you get
to the point where you introduce some wobble or do not detect a reduction in
rotational friction, go back to your previous setting. You may replace a few
of the thinner shims with one larger of the same size to conserve the small
ones for testing the other side. Retest with proper torque and reassemble.
When a bearing goes bad you can usually hear it when you drive, feel it when
you grab the wheel and shake and see it when you take the bearing out and
look at it.
Chris Reichle
creichle@nsc.msmail.miami.edu
----------
From: mgs-owner
To: 'mg'
Subject: Modulation Gone! Now what?
Date: Thursday, August 21, 1997 8:46AM
Thanks to all those who gave me suggestions, I replaced the left front
rotor as a matter of course even though it seemed true, I replaced the
left front bearings and will do the right ones tonight (even though they
seem good). The modulation is gone and my brake pedal is even firmer
than before and tightens up sooner than it used to. The brake wobble
must have been putting reverse pressure in the brake lines.
Here's the problem, The left front hub was even hotter than with the bad
bearings, After driving to work I notice that I had grease all over the
front rim, very hot melted grease, I used High temp disc brake grease,
and torqued to the specified torque of 70 LBS. , is this maybe too
tight? I left the original shim in place as I have no were to buy new
ones right away and after reading the haynes manual, still did not
really understand how to check end float.
Any ideas? BTW the right hub is still cool to the touch. And I don't
have any brake drag to over heat that hub.
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