pinion angle shims on the front?

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.

colonel mustard

Full Access Member
Joined
Apr 4, 2018
Posts
187
Reaction score
155
Location
louisville ky
First Name
steven
Truck Year
1981
Truck Model
k5 blazer
Engine Size
350
Good morning yall.

I recently moved the front axle 1 1/2" forward on my k5. the pinion is level with the ground and is creating a stupid crazy pinion angle. I would love to put like a 4* shim up there. I have never used shims in the front before and want to know if it is "safe"

I have a set of DIY4X shims that actually bolt into the leaf packs. thanks in advance
 

hirschdalechevy

Full Access Member
Joined
Mar 8, 2011
Posts
726
Reaction score
517
Location
norcal
First Name
rich
Truck Year
1977
Truck Model
k-30
Engine Size
454
I would just get new center pins , run them through your shims and spring pack and you are good to go, 4* shims are not that much imo.
 

TubeTruck

I'm from Boston. Deal with it.
Joined
Sep 4, 2019
Posts
1,439
Reaction score
2,180
Location
East TN
First Name
Denis
Truck Year
1978
Truck Model
Suburban K10
Engine Size
LQ9
If they bolt to the leaf packs and there is a pin on the bottom for the perch then I would say they are safe.
 

dvdswan

Full Access Member
Joined
Mar 11, 2014
Posts
2,366
Reaction score
2,035
Location
Port Orchard, WA
First Name
Dave
Truck Year
1978
Truck Model
K10
Engine Size
350
Your knuckles should be between 6-8* negative. This way you have proper steering return and don't have the dreaded "death wobble".
 

idahovette

Full Access Member
Joined
Aug 7, 2016
Posts
7,244
Reaction score
15,808
Location
Weiser Idaho
First Name
Perry
Truck Year
1975-1979
Truck Model
K20-K10
Engine Size
350
Your knuckles should be between 6-8* negative. This way you have proper steering return and don't have the dreaded "death wobble".
Not in my world, you need positive caster for a good wheel return and it also helps stability when driving. Almost all cars and trucks spec some degree of positive caster.
 

dvdswan

Full Access Member
Joined
Mar 11, 2014
Posts
2,366
Reaction score
2,035
Location
Port Orchard, WA
First Name
Dave
Truck Year
1978
Truck Model
K10
Engine Size
350
Not in my world, you need positive caster for a good wheel return and it also helps stability when driving. Almost all cars and trucks spec some degree of positive caster.


I got it backwards then. Thank you for the correction.
 

idahovette

Full Access Member
Joined
Aug 7, 2016
Posts
7,244
Reaction score
15,808
Location
Weiser Idaho
First Name
Perry
Truck Year
1975-1979
Truck Model
K20-K10
Engine Size
350
I got it backwards then. Thank you for the correction.
But when you shim for caster ,you screw up the pinion angle!!! Damned if you do, damned if you don't. Usually I'm just damned!!!
 

dvdswan

Full Access Member
Joined
Mar 11, 2014
Posts
2,366
Reaction score
2,035
Location
Port Orchard, WA
First Name
Dave
Truck Year
1978
Truck Model
K10
Engine Size
350
But when you shim for caster ,you screw up the pinion angle!!! Damned if you do, damned if you don't. Usually I'm just damned!!!


You can cut and turn the knuckles. That's what I did for mine.
 

idahovette

Full Access Member
Joined
Aug 7, 2016
Posts
7,244
Reaction score
15,808
Location
Weiser Idaho
First Name
Perry
Truck Year
1975-1979
Truck Model
K20-K10
Engine Size
350
I've heard of guys drilling the welds and pulling the tubes out and turning them. Either way lots of work and a margin for error
 

Bennyt

Full Access Member
Joined
May 17, 2019
Posts
1,193
Reaction score
1,844
Location
Surprise
First Name
Ben
Truck Year
1977
Truck Model
C10
Engine Size
350
Good morning yall.

I recently moved the front axle 1 1/2" forward on my k5. the pinion is level with the ground and is creating a stupid crazy pinion angle. I would love to put like a 4* shim up there. I have never used shims in the front before and want to know if it is "safe"

I have a set of DIY4X shims that actually bolt into the leaf packs. thanks in advance


How did you move the axle forward? Just moving it forward the pinion angle shouldn't have changed??? The front axle typically has a CV joint driveshaft to compensate for the angles anyway. On my K5 I moved the front axle forward 1" and raised the transfer case and had zero issues with handling, vibration etc. from the front. In the rear I used a nice Tom Woods shaft with CV's.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,415
Reaction score
28,216
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Some lift springs come with shims already bolted to the pack. I think with larger tires, a little more caster is beneficial. So when shims are added to point the pinion up a few degrees, you kill two birds with one stone.
 

idahovette

Full Access Member
Joined
Aug 7, 2016
Posts
7,244
Reaction score
15,808
Location
Weiser Idaho
First Name
Perry
Truck Year
1975-1979
Truck Model
K20-K10
Engine Size
350
When the pinion goes up the caster decreases(negative) in the front axle.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,415
Reaction score
28,216
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
When the pinion goes up the caster decreases(negative) in the front axle.

You said it wrong. You should have said "you are wrong and backwards" in response to my post, lol.
 

colonel mustard

Full Access Member
Joined
Apr 4, 2018
Posts
187
Reaction score
155
Location
louisville ky
First Name
steven
Truck Year
1981
Truck Model
k5 blazer
Engine Size
350
How did you move the axle forward? Just moving it forward the pinion angle shouldn't have changed??? The front axle typically has a CV joint driveshaft to compensate for the angles anyway. On my K5 I moved the front axle forward 1" and raised the transfer case and had zero issues with handling, vibration etc. from the front. In the rear I used a nice Tom Woods shaft with CV's.


thanks for the questions. I used ORD axle relocation plates. It was very easy and ill post pics shortly. moving the axle does indeed change your pinion angle as the axle follows the apex of the arch in the springs. every degree matters and moving it 1 1/2" forward changed my pinion angle another 2 degrees.
I am familiar with double cardon and all of that. nor am I concerned about caster as I would cut the knuckles and reweld if I had to. as of now the truck handles great, I just didn't like the degree which the pinion sat at.

after ordering my new drive shaft though, Tom Woods had said that his driveshaft are built for that and much more at (if I remember right 28 degree operating angle) im way under that so im not worried about this anymore
 

Forum statistics

Threads
44,092
Posts
949,149
Members
36,175
Latest member
HeeHaw_1980C10
Top