GM van rear axle questions

[Mwilliamshs]

I have access to a ~1993 Chevrolet G-20 or G-30 van (not sure which) that my dad is using for storage on the farm but he wants to get rid of. It's scrap to him so I can have any parts I want. I have a 1989 Ford E-150 that I'd like to put a heavier duty rear axle in. Anybody know or have a way to find out the distance between the leaf spring perches on the axle housing? What about its overall width, WMS-WMS? Thinking it should be a 14b, maybe a FF, and probably a 3.73 or 4.10 r&p. I'd love to find it's a 3.54 but I doubt I'd be so lucky, especially since it has the 4L80E and is a 15 passenger model.

Also, are these van axles of the type where a brake job requires removing axle shafts/wheel studs? Had an old Ford truck like that and HATED it.

 

[Lunchbox2]

The axle will be different between a G20 and a G30. The G20 will have a 8.5" 10-bolt and 5-lug. If it's a G30 it will have either a 9.5" 14-bolt semi-float, or a full float 10.5" 14-bolt, 8-lug. The perches measure 50" center to center, and I'm pretty sure it has a 70" wms to wms. It's been a year since I built mine, so I'm running off year-old memories. You don't have to remove axles to do a brake job on any of these axles, as far as I know...

 

[mezmochill]

I would avoid the 4:10 unless it goes well with your transmission gear ratios, engine powerband and tire size otherwise you may end up driving 65 mph at 5000 rpm.

Measurements i know not, but i know others will. Good luck.


^^^ and there they are from the man that knows his stuff.

 

[Mwilliamshs]

The axle will be different between a G20 and a G30. The G20 will have a 8.5" 10-bolt and 5-lug. If it's a G30 it will have either a 9.5" 14-bolt semi-float, or a full float 10.5" 14-bolt, 8-lug. The perches measure 50" center to center, and I'm pretty sure it has a 70" wms to wms. It's been a year since I built mine, so I'm running off year-old memories. You don't have to remove axles to do a brake job on any of these axles, as far as I know...

Was just cruising your thread thinking there might be some info there...YUP. Probably a G30 cuz I know it has 16" wheels and I'm pretty sure it's 8 lug.

I originally picked up a 14 bolt from a dually, then realized that they aren't wide enough. The spring perches were 40" center to center, and I needed 50" center to center to keep my leaf springs in the factory spot. So I sourced a G30 van with the correct full-float 14 bolt, and worked out a deal with the owner...

THANKS

 

[Lunchbox2]

Was just cruising your thread thinking there might be some info there...YUP. Probably a G30 cuz I know it has 16" wheels and I'm pretty sure it's 8 lug.



THANKS

Glad I could help!

 

[86cj]

The axle will be different between a G20 and a G30. The G20 will have a 8.5" 10-bolt and 5-lug. If it's a G30 it will have either a 9.5" 14-bolt semi-float, or a full float 10.5" 14-bolt, 8-lug. The perches measure 50" center to center, and I'm pretty sure it has a 70" wms to wms. It's been a year since I built mine, so I'm running off year-old memories. You don't have to remove axles to do a brake job on any of these axles, as far as I know...

Up until around 2003 a one ton almost always had a 10.5" full floater, on a full float axle you have to pull the axle shafts to get the drum off unless it has disk brakes which is a newer thing. A full float axle with disc brakes is better than sliced bread, I dream of discs on a full floater. One of the only ways to get a full floater in the 96 and up vans is a Duramax diesel and it has a 3:54 gear. That van could have a 4:56 with a 350 engine if it is a G30 they were not uncommon, with 4:10 common.

 

[Lunchbox2]

Up until around 2003 a one ton almost always had a 10.5" full floater, on a full float axle you have to pull the axle shafts to get the drum off unless it has disk brakes which is a newer thing. A full float axle with disc brakes is better than sliced bread, I dream of discs on a full floater. One of the only ways to get a full floater in the 96 and up vans is a Duramax diesel and it has a 3:54 gear. That van could have a 4:56 with a 350 engine if it is a G30 they were not uncommon, with 4:10 common.

I had to search for a little while to find a full floater, every G30 or express van I came across had the 9.5" semi float axle it seemed like. After searching junkyards and craigslist in neighboring towns/states for weeks, I ended up finding a full float in a '94 G30 5 minutes from my house, go figure... lol.

You're right on the brakes, I swapped to discs as soon as I got the axle to the house, and wasn't even thinking about the drum brakes when the question was asked. I was like yeah, calipers pop right off....haha The rotors/drums mount on the back side of the hub, I remember having to drive out the studs and driving them back in through the rotors. So you'd have to pull the axle, to get to the nut holding the hub on, in order to pull the drums off. Wasn't even thinking about that... It's not that bad to remove them though.

I originally wanted to go with 4.56's in mine, but could only find those in CUCV trucks, and I couldn't use those axles because the rear wasn't wide enough. In the G-van's with a full floater they only offered 3.42, 3.73, or 4.10's for a gear ratio, I lucked out and got the 4.10's. It saved money just having to match the front vs. gearing both axles to 4.56, and they seem to work pretty good with the 700r4 and 35's. I just dropped a yukon grizzly in mine, swapped to discs, and re-packed the bearings in the hubs. If I go to 37's I'll drop in 5.13's though, a little more grunt would be nice....

 

[Mwilliamshs]

I don't think I'll make the 8.8 to 14b swap. Considering the cost of driveshaft mods, parking brake cables, and limited gear availability, I think I'd be better off finding an EB Ford with a C6 and pulling both the axle and driveshaft for a bolt-in swap. Can grab the speedo drive gear too for a seamless trade. Dana 60s offer as high as 3.31s which would be nice but even the more common 3.54s ain't bad. This is a 2wd road tripper without OD so the closer to OE 3.08s the better.

 

[DRLexpress]

Can I wake this older thread up? I have a 2004 Express 2500 and I picked up a 14 bolt out of a 2000 Express 3500. No matter how much you read you will always learn more when you get the parts home, like the early Express( my axle) up till 2002 had 68.5" wms-wms then in 2003 went back to the 70" wms-wms of the older G series vans. The factory made up the difference with backspacing on the wheels. It must have had to do with matching the front suspension which was completely changed in 2003. I did not want to, but I will have to live with 3/4" wheel spacers.

Now my question. Has any one come up with a good way to run e-brake on a disc conversion? I've read the old caddy calipers don't work well. I am thinking of giving up and just using a hydraulic lock (think line lock for drag racing except mechanical) in the rear circuit. Step on brake pedal, pull knob, let off pedal. To release push in knob. Thoughts?

Doug

 

[Mat Mobile]

Can I wake this older thread up? I have a 2004 Express 2500 and I picked up a 14 bolt out of a 2000 Express 3500. No matter how much you read you will always learn more when you get the parts home, like the early Express( my axle) up till 2002 had 68.5" wms-wms then in 2003 went back to the 70" wms-wms of the older G series vans. The factory made up the difference with backspacing on the wheels. It must have had to do with matching the front suspension which was completely changed in 2003. I did not want to, but I will have to live with 3/4" wheel spacers.

Now my question. Has any one come up with a good way to run e-brake on a disc conversion? I've read the old caddy calipers don't work well. I am thinking of giving up and just using a hydraulic lock (think line lock for drag racing except mechanical) in the rear circuit. Step on brake pedal, pull knob, let off pedal. To release push in knob. Thoughts?

Doug

Great question! I asked on the Q&A of the Ruff Stuff 14 Bolt Disc Brake Brackets (C&C Hubs On An SRW Axle) (my vehicle).

 

[DRLexpress]

You mean you asked on Ruff Stuffs website? If so let me know what you find out. The trouble I am having is their kit (and most all others I have found) only work on the old style 14 bolt. Mine is the new style, the drum comes off without removing the hub.

Doug

 

[Mat Mobile]

You mean you asked on Ruff Stuffs website? If so let me know what you find out. The trouble I am having is their kit (and most all others I have found) only work on the old style 14 bolt. Mine is the new style, the drum comes off without removing the hub.

Doug

Yes. But my question hasn't appeared yet (and the link in my post above is not what I wanted... ). I'll let you know even if it's not exactly what you need it might give you an idea.

 

[Len.Barron]

01-06 Suburban 2500 rear axle would have been a better selection if you wanted a 14bolt...disc brake, full float, internal drums for parking brake built in. You would have to move the spring perches though.

 

[DRLexpress]

01-06 Suburban 2500 rear axle would have been a better selection if you wanted a 14bolt...disc brake, full float, internal drums for parking brake built in. You would have to move the spring perches though.

I looked at that and the P/U but the wms-wms on the van is wider. Now that I think about it, the Suburban that I looked at was not that new so maybe I did miss out. Live and learn.

Thanks
Doug

 

[Len.Barron]

Wilwood makes some mechanical parking brake calipers, I haven't ever checked if they have ones that work with the rotor thickness you'll be running but it's worth a look.