Dayco belts are gm approved.
The correct Dayco Belts are;
403 and 455-Altenator-15570
403 - P.S. - 15450
403 - A.C. - 15234
4 kinds of belts, The top one is the standard Napa or Gates belt style. This would be the 7425.
The 2nd one down is the Dayco Belt, Top Cog# 15570. Notice the extra fabric belts throughout the Dayco.
The 3rd and forth are used, a NAPA/Gates 7000 seriesand then a Gates 5000 series belt.
The 5000 belt is as good as a Dayco, but Gates won't give me the correct sizes. They insist their 7000 series is good enough.
The top is the Gates 7000 series belt
after 3-4 months.
Stretch, slip then burn. The bottom is a NAPA Belt after several years.
This belt is still good because it doesn't
stretch. It doesn't stretch because of the extra fabric belts throughout it's construction
The top NAPA belts isn't strong enough,
the bottom is.
These are not GMC Belts,(check nums).
Typical Gates/NAPA belt on a 100 amp altenator. These 100ampers need full fabric belts. See 1st photo for belt numbers.
The belts are available at most autoparts places:
AC Belt GM-9433670, Dayco 15605, NAPA
Alternator GM-405600 , Dayco 15570, NAPA 25-14483
power steer GM-9433640, Dayco 15440, NAPA 25-11303
And you can cross these belts at a PEP boys or an Auto Zone.J.R.
The belts are available at most autoparts places. We should
be using 11mm belts. Gates Co. has discontinued their 11 mm belt
product line and has substitured a 9.5 MM product line which is too
I measured them with a 10 mm wrench and 11mm wrench. The 10 mm did not fit and the 11 did. (Phil Swanson technique) This means they all passed the 11mm (7/16") test. The packages all said 11mm wide on them.
I checked both Kelly-Springfield and Goodyear. The story is exactly the same on both brands. If fact they use exactly the same part numbering system. This makes sense sinse since they are both owned by Goodyear. If you get a belt in either K-S or Goodyear that starts in 15, it is a 11mm wide belt. If you get a belt belt that starts in 17 it is a 13mm belt. The digits following the 15 are the length in milimeters.
|BELTS 455 cc||GM||DAYCO||* NAPA||GOODYEAR||* GATES||KELLY
|POWER STEERING(3/8" X 42")||943640||25-11433||15466||7450||15450
|(7/16" X 42")||9433742||7450||401-7450
|AC 7/16" X 62"||9433776||25-15733||15634||7619|
|BELTS 403 cc||GM||DAYCO||* NAPA||GOODYEAR||* GATES||KELLY
|POWER STEERING (3/8" X 42")||9433640||15440||25-11303||15466||7450||15450
|(7/16" X 42")||9433742|
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