Rear end advice

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.

Gussie

Junior Member
Joined
Aug 25, 2023
Posts
29
Reaction score
18
Location
Kansas
First Name
Corey
Truck Year
1986
Truck Model
K20
Engine Size
350
Hello All...looking for opinion on what I should do to my 14 bolt semi float rear-end for my resto. I have no idea about the co dition of it however the former owner said it drove well before he parked in barn for 20 years. I was planning g on changing the wheel bearing/seals and pinion seal but do u think I should do more since the rear-end is currently off the truck? I want to do on a budget but also be smart too. Thanks
 

Blue Ox

Turning Diesel Fuel Into Fun
Joined
Mar 27, 2018
Posts
4,891
Reaction score
10,838
Location
LI-NY
First Name
Derek
Truck Year
MCMLXXXV
Truck Model
K20HD
Engine Size
6.2L
Is it leaking? If it isn't I'd probably just clean it, paint it and run it. Maybe do an oil change. That way you can see what kind of shape the innards are in, and whether it has a gov-bomb or not. Just so you're prepared. BTW, they like synthetic oil.
 

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
5,976
Reaction score
9,923
Location
Washington
First Name
Todd
Truck Year
1986
Truck Model
K20
Engine Size
454
I wouldn’t do anything except new oil and paint it unless it needed it….
I guess you could do new pinion and axle seals but if it’s not leaking it might not for another 20 years.
Everyone seems to want the FF axles real bad. Unless hauling 3klbs + of payload around, regularly, the SF axle is very stout.
 

JT58

Member
Joined
Aug 1, 2023
Posts
40
Reaction score
53
Location
Naples, FL
First Name
JT
Truck Year
1987
Truck Model
V10
Engine Size
5.7
Yep, just clean around it, pop the cover off, change the fluid, new gasket, refill. I did that on my 87 and had extra work- the re-fill plug hex was stripped. Fluid was never changed in I don't know how many miles. I had to drill it out. Fluid was so bad I had to change it, clean the diff out drive it for a awhile, then change it again. No issues though, all is fine. Very stout rear diff!
 

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,463
Reaction score
4,577
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
I wouldn’t do anything except new oil and paint it unless it needed it….
I guess you could do new pinion and axle seals but if it’s not leaking it might not for another 20 years.
Everyone seems to want the FF axles real bad. Unless hauling 3klbs + of payload around, regularly, the SF axle is very stout.
I believe the main reason is the c-clips. I know I sure as hell don't want to chunk an entire wheel and axle shaft off my truck and take out the bedside and axle.
 

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
5,976
Reaction score
9,923
Location
Washington
First Name
Todd
Truck Year
1986
Truck Model
K20
Engine Size
454
I believe the main reason is the c-clips. I know I sure as hell don't want to chunk an entire wheel and axle shaft off my truck and take out the bedside and axle.
Agree, not as bulletproof as a FF axle, but I can’t think of the last time I saw a 14bolt SF blow a clip and spit an axle/wheel out.
Like never. Even when I worked for an outfit they thought anything with an 8’ bed could carry 3 cy of dirt or gravel…every day.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,192
Reaction score
5,096
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Agree, not as bulletproof as a FF axle, but I can’t think of the last time I saw a 14bolt SF blow a clip and spit an axle/wheel out.
Like never. Even when I worked for an outfit they thought anything with an 8’ bed could carry 3 cy of dirt or gravel…every day.
Its not really about blowing the clip. Its the fact that the clip is the only thing holding it in and the axle itself is riding on the bearing at the end of the axle tube. This puts a load on the middle of the axle while it is rotating, so if you have big power or are shock loading the axle, it can twist the axle in the middle. If the axle twists and breaks in the middle, it now has no retention and the half attached to the wheel will exit the axle.

I agree that the 14SF is a pretty stout axle and you don't really see this happen with them. It is fairly common to see happen in drag racing or rock crawlers with 10 bolts though.
 

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
5,976
Reaction score
9,923
Location
Washington
First Name
Todd
Truck Year
1986
Truck Model
K20
Engine Size
454
^Exactly. That was my point.
No, they aren’t as stout as a FF axle but they are very reliable and strong.
But depending on what I’m working on or building, sometimes I’m a make it bulletproof, belt and suspenders guy, but I’ve come to learn a lot of things don’t “need” to be done if they’re good enough for the application.
Tends to save a few (hundreds, thousands of tens of thousands) bucks as well.
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
3,701
Reaction score
6,694
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
I put dana 60/14FF, 13"x 3" drums, 1350 series custom shafts, nv4500, ORD shock braces, ORD 1.5 Tie Rods, Steering Box Brace Kit and a whole slew of overbuilt parts on my truck. Did I actually need any of it for a mostly daily driver? Nope! But when I do offroad, I like the fact that my stout 350 is the weak link in the chain.
 

CalSgt

Full Access Member
Joined
Oct 3, 2021
Posts
1,518
Reaction score
3,214
Location
CA
First Name
Casey
Truck Year
1980
Truck Model
Chevy K-10 Custom Deluxe
Engine Size
350
I wouldn’t do anything except new oil and paint it unless it needed it….
I guess you could do new pinion and axle seals but if it’s not leaking it might not for another 20 years.
Everyone seems to want the FF axles real bad. Unless hauling 3klbs + of payload around, regularly, the SF axle is very stout.
^^^^ This

Axle seals are a fairly straight forward but I'd leave the pinion seal alone if it isn't leaking, and R&P have good wear pattern. Pulling the carrier and pinion to replace a pinion seal can open a can of worms if you don't set pinion bearing preload correctly or don't get shims back in correctly.
 

Gussie

Junior Member
Joined
Aug 25, 2023
Posts
29
Reaction score
18
Location
Kansas
First Name
Corey
Truck Year
1986
Truck Model
K20
Engine Size
350
Well after inspection the spider gears were shot so rebuilt it. Feel good for doing and it was nice to see it all done and painted hooked back up under the frame...finally!
 

Attachments

  • 20231210_173655.jpg
    20231210_173655.jpg
    187.2 KB · Views: 18

GTX63

Full Access Member
Joined
Nov 27, 2022
Posts
743
Reaction score
3,003
Location
Tennessee
First Name
Ty
Truck Year
1985
Truck Model
K10
Engine Size
350
Speaking as someone who worked on these trucks back when they were still being sold new, I never, repeat, never saw an axle come out of a reasonably driven and maintained squarebody.
I have driven K10s with no bearing at all and the c clip did it's job.

The 10 bolt and 12 bolt semi floating axles are strong and dependable units. It the guy before you was rock climbing, mugg bogging and gear slamming then yeah, most anything like that will show abuse.

As has already been stated multiple times, if a rear end has been sitting for 20 years, it is cheap maintenance to drain the gear oil, flush the tubes and the carrier, replace the bearings and seals and then send it.
 

Forum statistics

Threads
42,137
Posts
909,900
Members
33,635
Latest member
85sqbod
Top