Powersteering v belt mystery.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Isaac nickerson

Full Access Member
Joined
Dec 3, 2020
Posts
128
Reaction score
107
Location
Hillsboro Oregon
First Name
Isaac
Truck Year
1977
Truck Model
K10
Engine Size
5.7 L
Hey guys I have tried about 8 different v belts for my powersteering and can not find one that fits right. I have a 350 sbc with no ac and and a manual tranny. The closest belts I found were one that had an outside circumference of 43.25 inches (part number 7425 or 15425) and one with a outside circumference of 43 and 5/8 (part number 7430 or 25-7430) the former is to tight even at the loosest setting and the latter is to loose even at the tightest something. I don't understand. Does someone have a part number or any advice for me?!?!?
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
10,179
Reaction score
14,481
Location
Right where I am
First Name
Bagoomba
Truck Year
1981, 1965
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
Engine Size
Carb'ed Vortec 350; 1972 L48 350
.
 
Last edited:

Turbo4whl

Supporting Member
Supporting Member
Joined
Oct 30, 2019
Posts
2,884
Reaction score
6,485
Location
Downingtown, PA
First Name
Wayne
Truck Year
1974
Truck Model
Jimmy
Engine Size
350
7425 belt is 7/16" wide and 42.5" around, measured from the center of the belt, not the top or outside. Try a 9430. The 9430 or is a 1/2" wide belt and it will sit higher in the pulley grove.

Are you getting the full movement of the pump? Need to loosen the bottom pivot bolt too. Some pump brackets use one of the reservoir studs in the back down low. If it does, it will have a short adjusting slot too.
 

Isaac nickerson

Full Access Member
Joined
Dec 3, 2020
Posts
128
Reaction score
107
Location
Hillsboro Oregon
First Name
Isaac
Truck Year
1977
Truck Model
K10
Engine Size
5.7 L
7425 belt is 7/16" wide and 42.5" around, measured from the center of the belt, not the top or outside. Try a 9430. The 9430 or is a 1/2" wide belt and it will sit higher in the pulley grove.

Are you getting the full movement of the pump? Need to loosen the bottom pivot bolt too. Some pump brackets use one of the reservoir studs in the back down low. If it does, it will have a short adjusting slot too.
Very helpful info. Thanks a lot.
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
10,179
Reaction score
14,481
Location
Right where I am
First Name
Bagoomba
Truck Year
1981, 1965
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s; 65-C20 with 4:57 gears and Borg Warner Overdrive
Engine Size
Carb'ed Vortec 350; 1972 L48 350
9435, 9440, 9445, 9450
 

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,461
Reaction score
4,572
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,70,48
Truck Model
Suburban k10, bonanza k10, c30 C&C, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350
Just go into a parts store that's got a bunch of belts and a belt measuring tool and just take your old one in and get a size slightly smaller if possible.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,191
Reaction score
5,093
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Pics help... you should have more than enough adjustment of that pump to adjust out a 1/2" difference in circumference. Something isn't right there. The one called out for non-A/C power steering belt on a 77 K10 with a 350 is a 15360. How are you trying to route it?
 

Isaac nickerson

Full Access Member
Joined
Dec 3, 2020
Posts
128
Reaction score
107
Location
Hillsboro Oregon
First Name
Isaac
Truck Year
1977
Truck Model
K10
Engine Size
5.7 L
Pics help... you should have more than enough adjustment of that pump to adjust out a 1/2" difference in circumference. Something isn't right there. The one called out for non-A/C power steering belt on a 77 K10 with a 350 is a 15360. How are you trying to route it?
I'm routing it around the crankshaft pulley, the fan pulley and the the powersteering pully which is the correct way. And also I should have mentioned that the motor isn't the original motor and I don't know the exact year if it so that part number doesnt work.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
4,066
Reaction score
5,914
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Still no luck... the belt 9430 was too tight...
Lots of good suggestions here belt measuring tool, yep. a piece of string yep. Measure your old belt, is it 7/16 or 1/2 wide? Hell I'll go look at mine later but first number is belt width last 3 are belt circumfrence 7335 is going to be 7/16 by 33.5 inches 7340 is going to be 34 inches. You know which belts don't work a little math will tell you which one will work.
 
Last edited:

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,191
Reaction score
5,093
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
I'm routing it around the crankshaft pulley, the fan pulley and the the powersteering pully which is the correct way. And also I should have mentioned that the motor isn't the original motor and I don't know the exact year if it so that part number doesnt work.

Yeah, you can see what the original year and application was by looking up the stamped numbers on the pad in front of the passenger side head. PICS HELP!!!! How many grooves are on your PS pulley? How many on fan pulley and crank pulley? If you have two grooves on your PS pulley, then the vehicle was probably originally an AC vehicle. You might be able to use the one I posted on the inside groove to run from the crank to the PS pulley only. The outside belt would then be the with-AC belt that is called out as 15423 and runs around crank/fan/PS.
 

75gmck25

Full Access Member
Joined
Oct 13, 2016
Posts
2,038
Reaction score
1,833
Location
Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
My 1975 350 truck with A/C uses a 15418 or 15420 belt around the crank, water pump and PS pump. Non A/C trucks and non HD cooling used a 15360 belt that only went around the crank and the PS pump.

I couldn’t get my PS belt to tighten up, and finally figured out that as I rotated the pump to tension the belt the bracket was hitting something on the block, and stopping it before the belt was tight. I took off the pump and ground some material off the bracket, and it solved the problem.

Bruce
 

Forum statistics

Threads
42,125
Posts
909,623
Members
33,618
Latest member
1975K20
Top