Hi Tim
The drum brake self-adjust mechanism is little changed since it first
appeared in the late 50's. In my experience it has never worked well. I've
always adjusted my rear brakes manually. The threaded star wheel that expands
to take up excessive non contact for the shoes has a spring loaded locking
feature intended to keep the adjustment from getting tighter or looser. It is
over ridden when you manually move the star wheel in the tighter direction or,
supposedly, you back up to 10-15mph then slam on the brakes sufficient to lock
the rears and burn rubber. One such violent stop will only pull the star wheel
up one click, if your system is working at all.
If your rears were many clicks too loose before you made your first
manual adjustment it may be that several more clicks after a bit of driving are
still in order. Dakota drum brakes are designed to move a little on their
mounting so as to ensure most of the shoe surface contacts the drum at all times.
Making a substantial manual adjustment may have resulted in the shoes
reorienting themselves hence a bit more adjustment can be taken. You might check that
to see.
To manually adjust, spin the tire as you insert the adjusting spoon and
begin taking up one or two clicks at a time. Generally one shoe will have a
high spot and will be the first to make a slight contact with the drum. You
can both hear the scrape and feel a very slight drag as you spin the tire. Stop
adjusting at this point. If you go farther then the brakes are dragging too
much, the shoes will quickly develop a glaze that reduces their stopping
power, you mileage will go down and your drums will become overheated, expand and
warp. You could have a complete failure of your rear brakes.
Over adjusting can be corrected but it is a clumsy operation. You have
to insert a screwdriver along with the adjusting spoon in the backing plate
adjustment slot. Push forward on the screwdriver to disengage the starwheel
lock then back off on the starwheel sufficient to eliminate the excessive drag.
If the shoes are over adjusted you cannot pull the drum off either so be
careful.
If you've never done manual drum brake adjustments it might be worth
your while to remove the wheel and drum and just look at the mechanism, make one
or two clicks adjustment with your fingers and check how the lock works.
Never step on the brakes while a drum is off. You'll receive an unpleasant
surprise.
If your rears were way out of adjustment then your parking brake
probably had to run all the way to its limit just to hold. Someone may have tried to
improve the parking brake by taking up on its cable without first ensuring
the shoe adjustment was full and correct. If this has occurred you need to back
off on your shoe adjustment, back off on the overly tight parking brake cable
adjustment then readjust the shoes correctly.
Paul Sahlin
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