1970 K2500 needs new rear axle

[Robert555]

Hi. My 1970 GMC 3/4 ton 4WD pickup has a 4.10 Dana 60 rear axle that has significant damage to one of the spindles, so I need to replace it.

I know the 2WD rear axles are different, but what exactly is the difference between the 2WD and 4WD rear axles on this truck?

I'm also thinking about maybe upgrading the rear axle to a later model 14 bolt. Exactly what years and model trucks should I be looking for to do this?

I'm a welder so I don't mind fabricating spring perches, etc. if I have to, but does anything just bolt in?

I don't really care one way or the other about disk brakes. What is REALLY important to me are good parking brakes. Is there any difference in holding power of the disk brake rear end parking brakes vs. the ones on drum brakes?

Thanks for any help!

[Stocker]

Welcome! I am still running an Eaton HO52 in my '72 K20. Unless you have a good one lying around, you probably won't want to swap to one of those. About the only input I have is..... I am pretty sure drum brakes will hold (as a parking brake) better than discs. Many disc brakes use a small drum as a parking brake. Full-size drums should hold better. IMO, that's the only advantage drums have over discs.

[57taskforce]

73+ 1 ton 14 bolt srw is a bolt in minus moving a shock mount. All other 14 bolts will need perches moved and shock mounts as well.

[davepl]

Yes. A disc brake rear end has one of two setups:

- A mechanism for grabbing the disc via the caliper, ala Cadillac, but they don't hold well
- A drum inside the rotor hat

I prefer the little drum inside the hat, but it's a lot less surface area being grabbed than by drum brakes.

Unless you're going to road-course the thing or tow in the mountains, I can't think of any reason I'd mess up a good system to do rear discs. I've generally regretted it when I've done it, and now run drum/disc in most vehicles.

My C2500 has the D60 as well, I'm also curious as to what the difference is 2WD to 4WD.

[57taskforce]

Originally Posted by davepl

Yes. A disc brake rear end has one of two setups:

- A mechanism for grabbing the disc via the caliper, ala Cadillac, but they don't hold well
- A drum inside the rotor hat

I prefer the little drum inside the hat, but it's a lot less surface area being grabbed than by drum brakes.

Unless you're going to road-course the thing or tow in the mountains, I can't think of any reason I'd mess up a good system to do rear discs. I've generally regretted it when I've done it, and now run drum/disc in most vehicles.

My C2500 has the D60 as well, I'm also curious as to what the difference is 2WD to 4WD.

2 wheel leaf spring trucks use different perch locations for one thing.

[jerry moss]

let me check with a buddy of mine to make sure he still wants the one i have. if he doesn't want it, i'll make you a hell of a deal on it. i'm only a couple hours from you so you can come pick it up. it came out of a 71 GMC 2500 4x4. P.M. our phone number and i'll let you know if he doesn't want it.

[special-K]

There ya go. Moss Man to the rescue! I hope it works out.

[Robert555]

Originally Posted by 57taskforce

73+ 1 ton 14 bolt srw is a bolt in minus moving a shock mount. All other 14 bolts will need perches moved and shock mounts as well.

1-ton 1973 to what year?

Thanks very much!

[Robert555]

Originally Posted by jerry moss

let me check with a buddy of mine to make sure he still wants the one i have. if he doesn't want it, i'll make you a hell of a deal on it. i'm only a couple hours from you so you can come pick it up. it came out of a 71 GMC 2500 4x4. P.M. our phone number and i'll let you know if he doesn't want it.

Thanks, let me know. However I'm really leaning towards the 14-bolt at this point though. I've had this truck for 30 years and it's a little light-duty for what I use it for. I've pulled the eyes off the front shocks twice. It needs a little beefing up.

[GASoline71]

Originally Posted by Robert555

1-ton 1973 to what year?

Thanks very much!

I would say to the early 1990's. You want the beefier 8-lug full floating or even a semi-floating rear axle with the 14" ring gear. Bomb-proof.

The even later model version of the 14 bolt is a lighter duty 9.5" ring gear axle that was under 1/2 tons is only a 6-lug and significantly weaker than the 8-lug version.

Gary

[Robert555]

Originally Posted by GASoline71

I would say to the early 1990's. You want the beefier 8-lug full floating or even a semi-floating rear axle with the 14" ring gear. Bomb-proof.

The even later model version of the 14 bolt is a lighter duty 9.5" ring gear axle that was under 1/2 tons is only a 6-lug and significantly weaker than the 8-lug version.

Gary

My truck is a K2500 and is 8-lug, so we're only talking full floating here.

I've learned there is a major difference in drum brakes of 14-bolt rear axles. Some of them slide off the studs which is the same on my Dana 60, and some require the axles and hubs to be removed? I am only interested in the kind that allows the drum to slide off the studs (I don't want to deal with removing the axle and hubs just to check the brakes).

What year 1-ton trucks have the style of rear brake drums that just slide off the studs?

Thanks!

[GASoline71]

That would be the semi-floater without hubs out back. It uses regular drums like any other non floating rear end. I had one under a 1991 3/4 ton Suburban.

Gary

[Bigdav160]

How bad is the spindle? They make speedi sleeves for that. Otherwise it could probably be welded and ground back down.