On Wed, 6 Aug 1997 17:09:32 +0100 as@boris.umds.ac.uk (A.D.Smith) writes:
>Having finally got my carbs rebuilt after about 3 weeks off
>the road, I was driving home the other night (well OK,
>morning), when I noticed a pulsing through the pedal every
>time I applied the brakes. Fortunately, even in London,
>there's not much traffic around at 5:15am, so I got back home
>without using the brakes over much.
>
>I had a look at them the next day, to find that the pads were
>pretty worn, so slipped in a new set. This just seemed to
>make things worse, to the point that the pulsing of the
>pedal was pretty strong, and certainly not to be ignored.
>
>The other symptom is that after setting off and driving a
>couple of tens of metres, the brake pedal almost hits the
>floor the first time you need it, then bites OK on a second
>press.
>
>My diagnosis is bent disks, pushing the pistons out as the
>disk goes round, meaning that I need massive pedal travel
>to get the pads back in contact with the disk when I need
>the brakes, and causing the pulsing force on the pedal.
Your diagnosis is probably right on the button.
>Could it be anything else ? Or am I right in being resigned
>to having to pull it all apart again to put new disks on ?
Sorry, that's about the only cure that really works.
>I've done about 25K miles on the current disks, and can't
>(by eye) see any wobbling.
It would only take about .010" or less "wobble" to cause the symptoms you
describe, and .010" is pretty hard to see with the naked (or even
clothed) eye.
> Could be that some part of
>the disk is thicker than another ?
I'ts possible, but if that were the case, the problem would have been
present fron the first.
>Any clues ?
One thing that can really screw up rotors (discs) is the yahoo at the
tire store who replaces your lug nuts with a monster impact motor set for
a bout a zillion ft/lbs of torque. It can cause distortion of the rotor,
and will in many cases be permenant.
One thing you might want to try, is to replace the tire/wheel and torque
the lug nuts correctly, actually using a torque wrench. I don't have the
torque specs handy, but it will be in the neighbor hood of 40-50 lbs.
Check the manual to be sure.
Then, try the brakes again. If the problem is still there, I'm afraid a
new set of rotors is in order.
Rick Morrison
72 MGBGT
74 Midget
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