Ross asked:
> Also, in case this matters, when I loosen the bolt... the wheel will spin
> freely, if I loosen it a tad more, the brakes start to catch, a little more
> and they are free again, a little more and the brakes barely catch, a little
> more freely and and little more they catch again???? Weird...
> Ross (66 MGB)
I had trouble with this too the first time I adjusted the brakes. I may
have been a professional mechanic, but I didn't grow up in the garage
like the guys I worked with. They had a genetic predisposition to
understand how a brake adjuster works, I had to look at it.
Here's the scoop: Both ends of the brake adjuster are square, but the
end on the inside is also tapered making it pyramid shaped. When this
thing is screwed in, a wider part of the pyramid is pushing against the
tapered blocks that are between the tops of the two brake shoes. This
forces the brake shoes apart compensating for wear of the brake shoes.
The reason it tightens and loosens when the adjuster is turned is that
the pyramid end of the adjuster is sometimes on an edge instead of the
flat making it bigger across until it's turned onto the flat again.
The spec is to adjust the brakes out (adjuster in) until the wheel
doesn't turn at all and then back off the adjustment two turns. "Two
turns" really means two flats which is actually half of a turn. I was
really annoyed when I found this out. Why couldn't they _say_ two
flats? Then I would have known what they meant.
So, the trick is to find a flat spot on the adjuster and then only
adjust in increments of single flat spots. A flat spot is where the
brakes get tighter when the adjuster is turned either direction. It's
better to use a wrench than a ratchet because then you can change
directions easily. The ease of turning the wheel only matters on flat
spots. Once you've got a flat spot, keep turning the wheel while
screwing in the adjuster. The wheel will get harder to turn and then
easier (as you've discovered). The easier spot is the next flat. Keep
turning in the adjuster while turning the wheel until the wheel won't
turn even on a flat spot. Just before this point, the adjuster gets
very difficult to turn past the high points. Once the wheel no longer
turns, back the adjuster back out past one flat spot to the next. The
brakes will definitely drag at this point, but this is the correct
adjustment.
BTW, my single-user brake bleeding equipment consists of whatever empty
jar is handy and the vacuum advance line. I put a wrench over the bleed
nipple, slip the vacuum line over the nipple, crack open the nipple,
stick the other end of the line in the bottle (not necessary, but less
messy) and pump the pedal five or six times. Then I leisurely saunter
over to the wheel and close the nipple. It usually only takes one pass
at this after replacing a wheel cylinder, but that's because I stick the
point of a pencil in the brake line to keep the fluid from running out
while the wheel cylinder is off. Don't use your personalized pencils
for this because it takes the paint off of them.
Denise Thorpe
thorpe@kegs.saic.com
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