Notices
GM Drivetrain & Suspension Chassis | Transmission| Driveshaft | Gears/Rear End/Differential | Traction Aids

GM 9.5" 8 Lug to 6 Lug Conversion

Thread Tools
 
Search this Thread
 
Old 06-04-2019, 01:36 AM
  #21  
Custm2500's Rude Friend
iTrader: (17)
 
1FastBrick's Avatar
 
Join Date: Apr 2007
Location: JunkYard
Posts: 14,326
Received 761 Likes on 630 Posts
Default

I used a superior 5565 shafts on Pat's rear end and turned the OD of the Axle Flange down about 1/8 inch to work.

On Julien's truck, the Superiors were not available any more so I purchased Motive Brand equivalent. I believe they were part number 1541

The cost of new Vs junk yard was nearly the same so it only made sense to get new ones. The New units where much nicer.

Again I didn't do it the way Axis T6 listed in this thread.

I tried several axle companies an No One would make me a custom set of axles. They said there was no off the shelf Blank available.

We looked into having the 8 lug axle modified and there would be nothing left of the hub center. Also they would have to weld in a few slugs to get a good pattern and again it was not cost effective.

I even offered to Pay Mark Williams to modify there heat treating equipment so they could make custom Heat treated axles specifically for this application. I even Offered to buy a batch of 10 Pairs and they still wouldnt bite.

FWIW Dorman does not make axles. They just re-sell other brands under their label and packaging.

I do remember the actual length being listed wrong, but I don't remember what they measure Vs. what they were listed at. I do remember calling and talking to them about it though since every Manufacture listed the same Length for that application.
Old 06-04-2019, 01:56 AM
  #22  
Registered User
 
Snatchtrick's Avatar
 
Join Date: Jun 2019
Posts: 14
Received 1 Like on 1 Post
Default

Originally Posted by 1FastBrick
I used a superior 5565 shafts on Pat's rear end and turned the OD of the Axle Flange down about 1/8 inch to work.

On Julien's truck, the Superiors were not available any more so I purchased Motive Brand equivalent. I believe they were part number 1541

The cost of new Vs junk yard was nearly the same so it only made sense to get new ones. The New units where much nicer.

Again I didn't do it the way Axis T6 listed in this thread.

I tried several axle companies an No One would make me a custom set of axles. They said there was no off the shelf Blank available.

We looked into having the 8 lug axle modified and there would be nothing left of the hub center. Also they would have to weld in a few slugs to get a good pattern and again it was not cost effective.

I even offered to Pay Mark Williams to modify there heat treating equipment so they could make custom Heat treated axles specifically for this application. I even Offered to buy a batch of 10 Pairs and they still wouldnt bite.

FWIW Dorman does not make axles. They just re-sell other brands under their label and packaging.

I do remember the actual length being listed wrong, but I don't remember what they measure Vs. what they were listed at. I do remember calling and talking to them about it though since every Manufacture listed the same Length for that application.
So it sounds like I have to make the junkyard shafts that I have work. I was worried there wouldn't be any company that would be able to make this shaft for me. I agree there wouldn't be enough left of the pilot if I tried modifying the 8 lug shafts from the eBay axle.

Here's my thought and I only see one problem with it. 1st grind down the beveled edge on the back side of the hub flange so that the seal won't rub. I don't think 1/8" is going to make a difference where the carrier bearing sits (not sure if that even matters) or where the outer axle bearings sit. That solves one problem

Then I'll have a 1/8" spacer cut to the 6 x 5.5" bolt pattern with the accompanying 3.088" pilot for centering the rotor. I'll then have it welded to the hub which is pretty much redundant. This leaves a concern though. The press in stud has a smooth section for centering the rotor and with the spacer in that would cause the rotor to sit against the threads which have some play. This would get my rotor sitting correctly within the caliper.

I think I know where I can get longer studs if I don't have enough thread for the lug nuts. It's just the concern of the rotor not fitting as tightly with riding on the thread portion of the stud instead of the thicker smooth portion.

I don't see any other solution at this point. Other than use the 8 lugs and buy 8 lug rims and carry two spares. But I'd have to buy new rotors and these AC Delco ones cost me $60 each. This is a mess. $1200 for an AXN axle is looking appealing at this point. Here's to hoping someone can make me a shaft. Also I meant to say Dutchman not Dorman. Thanks for the help Fast Brick.
Old 06-04-2019, 02:09 AM
  #23  
Registered User
 
Snatchtrick's Avatar
 
Join Date: Jun 2019
Posts: 14
Received 1 Like on 1 Post
Default

Originally Posted by 1FastBrick
I used a superior 5565 shafts on Pat's rear end and turned the OD of the Axle Flange down about 1/8 inch to work.

On Julien's truck, the Superiors were not available any more so I purchased Motive Brand equivalent. I believe they were part number 1541
FastBrick, here's something I'm curious about. https://www.summitracing.com/parts/yga-21625/

I remember finding it way cheaper somewhere else. I've seen it on 3 different sites, all have a 6 lug in the picture but list as an 8 lug in the description. This is what I need though with the 33.31" length. Maybe I'll luck out and they actually are 6 lug.
Old 06-04-2019, 02:28 AM
  #24  
Custm2500's Rude Friend
iTrader: (17)
 
1FastBrick's Avatar
 
Join Date: Apr 2007
Location: JunkYard
Posts: 14,326
Received 761 Likes on 630 Posts
Default

Originally Posted by Snatchtrick
FastBrick, here's something I'm curious about. https://www.summitracing.com/parts/yga-21625/

I remember finding it way cheaper somewhere else. I've seen it on 3 different sites, all have a 6 lug in the picture but list as an 8 lug in the description. This is what I need though with the 33.31" length. Maybe I'll luck out and they actually are 6 lug.
The picture is generic. They will be 8 lug.

I went back and looked and I bought Motive 15521928 from Summit. https://www.summitracing.com/parts/mgr-15521928
1541H is the axle alloy used not a part number. The length listed is not correct. I do remember that.

Your best bet would be to have someone cut a shim similar to a thin wheel spacer to take up the difference you need between the axle flange and the brake rotor.
Old 06-04-2019, 02:40 AM
  #25  
Registered User
 
Snatchtrick's Avatar
 
Join Date: Jun 2019
Posts: 14
Received 1 Like on 1 Post
Default

Originally Posted by 1FastBrick
The picture is generic. They will be 8 lug.

I went back and looked and I bought Motive 15521928 from Summit. https://www.summitracing.com/parts/mgr-15521928
1541H is the axle alloy used not a part number.

Your best bet would be to have someone cut a shim similar to a thin wheel spacer to take up the difference you need between the axle flange and the brake rotor.
Gotcha. It still seems sketchy to me. Too many variables that could go wrong when it comes to where the bearings ride and worrying about the seal getting eaten up. I'm hoping Dutchman can just give me a stock blank for the eBay axle (2000 2500LD 14 Bolt 9.5 8 lug). The pilot logically should solid unlike the stock axles, thus allowing it to be turned down from 4.64" to 3.088". Then turn down the flange diameter to 6 x 5.5. Then drill the 6 x 5.5 bolt pattern.

I feel like this is not a crazy request of a custom axle manufacturing company since I saw in another thread that someone had them modify the pilot to the 8 lug size on a GMT 400 Z71 F44 and had the 8 lug rotors redrilled to 6.

Here's the thread. https://www.gmfullsize.com/threads/1...s-help.304047/

And the quoted text from axisT6 in the GMFS post:

Originally Posted by axisT6
You can use the 99+ 8 lug 14SF. This one has the larger tubes, axles, brakes, and wheel bearings as compared to the AXN 14SF which is found in the vtec max trucks and suvs.

This version is also much cheaper.

Here is what you do.

1. Buy the axle.
2. Call Dutchman and tell them you need replacement axle shafts for an 88-98 Z71 14SF with a modified pilot such that it centers the larger 8 lug rotor and your 6 lug wheels.
3. Drill 8 lug rotors for the 6 lug pattern.

The end result is a STRONG 6 lug axle at cost near or less what it would be just to purchase an AXN. The plus is you get bigger shafts, wheel bearings, tubes, brakes, and parking brake.
It's crazy no one could make you these shafts. I'm hoping I can convince someone at Dutchman because it seems easy in theory. Just take the pilot diameter down and the hub flange diameter down. Then drill the 6 lug pattern. As long as that pilot is all flat patch of metal (can't tell because of label cover). If they can't I'll just buy an 8 lug blank and have someone do it for me locally. Should just need a lathe.

Thanks for all your help and info. I'd like to reserve the spacer option as a last ditch option due to the sketchiness level, mainly from the seal rubbing because I assume the shaft has some play to go in and out being c-clip.

Last edited by 1FastBrick; 06-04-2019 at 05:03 PM. Reason: Fixed the Quote
Old 06-04-2019, 04:22 PM
  #26  
Registered User
 
Snatchtrick's Avatar
 
Join Date: Jun 2019
Posts: 14
Received 1 Like on 1 Post
Default

Originally Posted by 1FastBrick
The picture is generic. They will be 8 lug.

I went back and looked and I bought Motive 15521928 from Summit. https://www.summitracing.com/parts/mgr-15521928
1541H is the axle alloy used not a part number. The length listed is not correct. I do remember that.

Your best bet would be to have someone cut a shim similar to a thin wheel spacer to take up the difference you need between the axle flange and the brake rotor.

Update: Called up Dutchman and have them modifying the pilot diameter down from 4.620" to 3.086", hub flange diameter down from 7 7/8" to 7.5", and bolt pattern from 8 x 6.5 to 6 x 5.5 on a stock 99-07 14 Bolt 9.5; 33 Spline; 33 5/16" Length; Dutchman PN#SR306.

After talking around (Thanks FastBrick) , modifying the stock 8 lug shaft that came with would be cost prohibitive and there would be nothing left of the pilot after shaving it down due to it's hollow center. Didn't like the option of the spacer btw hub and rotor either.

So $450 including shipping for some custom axle shafts. It was the only option and just happy Dutchman was able to help me out. Thanks for everyone's help. It was much appreciated.

Last edited by Snatchtrick; 06-05-2019 at 06:23 PM.
The following users liked this post:
AndyRay (06-05-2021)
Old 06-04-2019, 04:53 PM
  #27  
Custm2500's Rude Friend
iTrader: (17)
 
1FastBrick's Avatar
 
Join Date: Apr 2007
Location: JunkYard
Posts: 14,326
Received 761 Likes on 630 Posts
Default

Originally Posted by Snatchtrick
Update: Called up Dutchman and have them modifying the pilot diameter down from 4.620" to 3.086", hub flange diameter down from 7 7/8" to 7.5", and bolt pattern from 8 x 6.5 to 6 x 5.5 on a stock 99-07 14 Bolt 9.5; 33 Spline; 33 5/16" Length; Dutchman PN#SR306.

After talking around (Thanks FastBrick) , modifying the stock 8 lug shaft that came with would be cost prohibitive and there would be nothing left of the pilot after shaving it down due to it's hollow center. Didn't like the option of the spacer btw hub and rotor either.

So $300 plus shipping for some custom axle shafts. It was the only option and just happy Dutchman was able to help me out. Thanks for everyone's help. It was much appreciated.
That's Cool that dutchman can do it. Be curious how they look when the come in.
Old 06-06-2019, 12:14 AM
  #28  
Teching In
 
LSrBEST's Avatar
 
Join Date: Apr 2017
Posts: 46
Received 2 Likes on 2 Posts
Default

Why not a quick cut on each of the axle tubes and some welding? Seams like that would have been faster and more affordable. I'd imagine you could find a few people up to that task for $450 if your not capable of welding it your self. **** I think my saw would take a perfect 1/8" each cut maybe a 1/32nd more but if properly fit up and welded that's perfect. Either way glad to see you figured it out.
Old 06-06-2019, 12:41 AM
  #29  
Registered User
 
Snatchtrick's Avatar
 
Join Date: Jun 2019
Posts: 14
Received 1 Like on 1 Post
Default

I considered the welding option. But I tend to shy away from welding things that see a high rotational torque load. Also if I had a 220V welder I would have definitely just gone the 88-98 GMT 400 route and welded new spring perches and possibly shock mounts.

Unfortunately I only have a Hobart 140 Handler that is a 110V welder only capable of 1/4" in two passes. Plus I presume the housing is cast and I have no oxycetaline torches to heat it before welding.

I went this route with the GMT 800 axle in hopes I could just bolt and go. I think the 33 5/16" is just a less common length. Shafts will ship in a week, excited to be done with this.

Also a heads up, my axle has no fill plug on the cover or on top of the housing. It does have a drain plug at 5 o'clock position of the housing. Couldn't find an inexpensive cover with a plug and don't have a drill and tap set.

I mention this because my Lube Locker Gasket was off on the bolt holes by this drain plug. (They refunded me). Apparently there was a change in the housing to add this drain plug.

Not wanting to tap cover or buy a fluid pump, I decided to do this. I took a hand pump for spraying weeds, bought some clear hose (think it was 3/8), took sprayer nozzle off and attached hose to plastic pickup tube.

Eventually I will get a 3/8 PEX valve, but my local Lowes didn't have one. I'll just wrap some rubber hose around the hose for a tight seal in the drain plug. Fill it, pull the hose and put in plug. Just a heads up if anyone else has this problem and wants a quick easy fix.
Old 06-07-2019, 10:39 PM
  #30  
Teching In
 
LSrBEST's Avatar
 
Join Date: Apr 2017
Posts: 46
Received 2 Likes on 2 Posts
Default

It's quite a bit more work too.. Depending on ones amount of available time it may cost less in the end to take the route you have vs the extra work of cutting welding. I've burned my own *** trying to be cheap.. Looking back there's a few times where I should have just spent the money and moved on.. Glad you got it nailed down & Glad I read this last night. Local CL add has 2 brand new axles for sale 6 lug. So I asked for the length. Waiting for the response, $75 each. Got my fingers crossed as I'm converting a 14 bolt myself.


Quick Reply: GM 9.5" 8 Lug to 6 Lug Conversion



All times are GMT -5. The time now is 12:36 PM.