- Joined
- Jul 18, 2000
- Posts
- 1,695
- Reaction score
- 2,115
As many of you have read, I’ve been chasing an odd issue with my 10.5 14 bolt in the K10 for the past few years where it likes to purge oil after a few hours of driving on the Interstate at 75 to 85 MPH. When driven on state highways at slower speeds or off-road there has been no issues with oil purge…only at high speeds. About a year ago, I ripped it down and inspected and replaced every bearing, race, seal, and verified and driveline angles and back lash. There was no smoking gun, no signs of overheat and only found one bearing (wheel bearing) that had a loose cage. Hardly a culprit.
We took off on Desert Trip 2016 and sure enough, a few hours of Interstate driving it started belching oil again. I had a cheap Hazard Freight inferred thermometer with me where the rear diff covers between the K10 and Suburban were within a few degrees of each other (the rear axles in the K10 and Polar Bear Suburban are identical, minus the fact the Burb has an open diff). Again, proving that it is not an overheat issue in the K10. The popular opinion is there is nothing wrong with the axle at all, just a stack up of tolerances between the 4:56 thick gears, Detroit locker, heavy truck, tall tires and high road speed.
The answer would be to slow the hell down on the Interstate, which I am not going to do. I want to be able to keep up with traffic and even pass traffic but without using my James Bond oil hose squirting everybody as I pass them. Being I am sick and tired of the Detroit Locker antics of click bang!, the truck darting one direction under heavy throttle then darting the other direction when letting off I decided it was time for a selectable locker. I also wanted to go to a little wider axle housing to even up the track so I followed Mosesburbs recipe with a 70” wide (hub to hub) G-Van axle to more even up the track to the front Dana 60 at 69” wide. As a comparison to the 67” side C20 axle I’ve had in it for 20 years.
With that, a fresh rear is in process for the K10….
Hopefully, the ass wiping when the purge bottle over flows will be over now. Talk about a sticky mess all over the back of the camper and trasheroo.
This is the axle donor. A very nice and clean 1995 G-30. Not even sure why it was in the salvage yard. Originally a BBC/4L80E van too
After some power washing, which it didn’t need much as it was so clean already
The tear down began. It had a G80 4:10 carrier still up for grabs in the Classified section
After a quick call to the nice guys at ORD a new ARB RB114, ring gear bolt set, spring perches and 4:56 gear set appeared. My buddy Bill has a lot more experience with gear set ups than I so he did the fine tuning. Like a dog, I have to keep food in front of him so he can keep his eyes on the prize. See if you can find the hidden Oreo cookie. Oh, and cutting off those old spring perches were the two worst days of my life!
Truck porn!
The Quality Control team said it passed inspection
As many of you also know, I am not a fan of rear disk brake conversions. I don’t have a problem with factory rear disk axles like 2001 and later GM HD trucks but still not enough to go buy one of those axles for this swap. That said, I had to change the backing plates as the G-van axle had the later pushin type brake cables whereas my K10 requires the bolt in for easier hook up to the original brake cable set up.
The first order was to rip the backing plates off my old axle and sand blast them then weld up the shoe wear marks in the backing plates. I’ve come to notice trucks (usually manual trans rigs) have major wear marks in the backing plates whereas automatic rigs do not (the G-van's backing plates were perfect). I recently welded up the wear marks on the Polar Bear Suburban’s backing plates and found a HUGE difference in park brake performance once the shoes weren't being forced to dig into the backing plates anymore. It holds like it is drilled into the ground now. Fixing the K10’s backing plates should make a noticeable difference as well. The park brake hasn't been working as well as it used to.
Weld’er up!
After
Another thing I experimented with on the Polar Bear Burb a while ago when doing its brake job, was moving to the larger DRW wheel cylinders with the larger 1 3/16 bore (Napa 37337). The SRW wheel cylinder has a 1 1/16 bore (Napa 37290). Moving to the larger wheel cylinders also made a noticeable difference in how the Burb stops however, I wouldn’t recommend the large wheel cylinders on a lighter Blazer or truck as the rear brakes can become pretty aggressive. The DRW cylinder is on the right.
Treated the backing plates to some fresh shoes, park brake cables and cleaned up hardware. All the hardware was just replaced about a year ago
And this is how she sits at the moment until I get some work travel out of the way.
Next up will be some frame clean up, cutting off some old exhaust brackets that are easy to get to with the axle out of the way then roll the axle under the truck to set up the pinion angle and burn in the spring perches. After that, comes the new shock layout and ARB compressor mounting. That’s it for now….
We took off on Desert Trip 2016 and sure enough, a few hours of Interstate driving it started belching oil again. I had a cheap Hazard Freight inferred thermometer with me where the rear diff covers between the K10 and Suburban were within a few degrees of each other (the rear axles in the K10 and Polar Bear Suburban are identical, minus the fact the Burb has an open diff). Again, proving that it is not an overheat issue in the K10. The popular opinion is there is nothing wrong with the axle at all, just a stack up of tolerances between the 4:56 thick gears, Detroit locker, heavy truck, tall tires and high road speed.
The answer would be to slow the hell down on the Interstate, which I am not going to do. I want to be able to keep up with traffic and even pass traffic but without using my James Bond oil hose squirting everybody as I pass them. Being I am sick and tired of the Detroit Locker antics of click bang!, the truck darting one direction under heavy throttle then darting the other direction when letting off I decided it was time for a selectable locker. I also wanted to go to a little wider axle housing to even up the track so I followed Mosesburbs recipe with a 70” wide (hub to hub) G-Van axle to more even up the track to the front Dana 60 at 69” wide. As a comparison to the 67” side C20 axle I’ve had in it for 20 years.
With that, a fresh rear is in process for the K10….
Hopefully, the ass wiping when the purge bottle over flows will be over now. Talk about a sticky mess all over the back of the camper and trasheroo.
This is the axle donor. A very nice and clean 1995 G-30. Not even sure why it was in the salvage yard. Originally a BBC/4L80E van too
After some power washing, which it didn’t need much as it was so clean already
The tear down began. It had a G80 4:10 carrier still up for grabs in the Classified section
After a quick call to the nice guys at ORD a new ARB RB114, ring gear bolt set, spring perches and 4:56 gear set appeared. My buddy Bill has a lot more experience with gear set ups than I so he did the fine tuning. Like a dog, I have to keep food in front of him so he can keep his eyes on the prize. See if you can find the hidden Oreo cookie. Oh, and cutting off those old spring perches were the two worst days of my life!
Truck porn!
The Quality Control team said it passed inspection
As many of you also know, I am not a fan of rear disk brake conversions. I don’t have a problem with factory rear disk axles like 2001 and later GM HD trucks but still not enough to go buy one of those axles for this swap. That said, I had to change the backing plates as the G-van axle had the later pushin type brake cables whereas my K10 requires the bolt in for easier hook up to the original brake cable set up.
The first order was to rip the backing plates off my old axle and sand blast them then weld up the shoe wear marks in the backing plates. I’ve come to notice trucks (usually manual trans rigs) have major wear marks in the backing plates whereas automatic rigs do not (the G-van's backing plates were perfect). I recently welded up the wear marks on the Polar Bear Suburban’s backing plates and found a HUGE difference in park brake performance once the shoes weren't being forced to dig into the backing plates anymore. It holds like it is drilled into the ground now. Fixing the K10’s backing plates should make a noticeable difference as well. The park brake hasn't been working as well as it used to.
Weld’er up!
After
Another thing I experimented with on the Polar Bear Burb a while ago when doing its brake job, was moving to the larger DRW wheel cylinders with the larger 1 3/16 bore (Napa 37337). The SRW wheel cylinder has a 1 1/16 bore (Napa 37290). Moving to the larger wheel cylinders also made a noticeable difference in how the Burb stops however, I wouldn’t recommend the large wheel cylinders on a lighter Blazer or truck as the rear brakes can become pretty aggressive. The DRW cylinder is on the right.
Treated the backing plates to some fresh shoes, park brake cables and cleaned up hardware. All the hardware was just replaced about a year ago
And this is how she sits at the moment until I get some work travel out of the way.
Next up will be some frame clean up, cutting off some old exhaust brackets that are easy to get to with the axle out of the way then roll the axle under the truck to set up the pinion angle and burn in the spring perches. After that, comes the new shock layout and ARB compressor mounting. That’s it for now….
who knows what it was inside that finally let go and un plug its self.
