Rear axle questions

[shifty]

Not-so-quick question. After recently finding out that I was misinformed about crossmember swaps, I wanted to ask about this while I'm at it.

I am going 5-lug drums on the rear of my truck. I DO NOT WANT REAR DISC BRAKES. My rear drums on my '68 are in absolutely wonderful shape, so I would like to keep them, or as much of them as possible, but I need to know some things first.

Now, I have a complete '77 (leaf spring) 5-lug rear end with some drums that are pretty far gone at my disposal. However, it seems the axles in the '73-87 pickups are about an inch or inch and a half longer than my '68, so I'm assuming this will be a problem, and I'll need to get new drum brakes. I think the width of the actual drum on the 73-87 trucks is wider than on my '68.

To boot, I *think* I can easily go to Summit Racing 30-mins down the street and pick up new proper-length/spline 5 on 5 5-lug axles for around $100 each. BUT before I go out and waste even more money only to find that, for whatever reason, the axles I got will require different brakes or something, I wanted to ask here.

Realistically, what ARE my options? For example...

Can I take my '77 axles to a shop to have them properly cut down to the same length as my '68?

If I do that, can I use those axles with my '68 drums?

If so, what can I reuse and how - and where can I get the 5-lug drums "pie dish" part from? How do I make it work?

Is there some easier way to do this?

Curious to hear feedback. I want to keep my expense under $200. I keep finding that I'm taking advice on this forum to heart and it's cosing me money sometimes

I do get to meet some friggin cool board members during the process, though!!

[SCOTI]

I swapped in Moser axles w/a 5x5 pattern & used 71-72 drums w/my existing 68 hardware. The splines took some persuasion (read emory cloth) but that was it. About 2-bills for the axles & $25ea for the drums IIRC.

[shifty]

Originally Posted by SCOTI

I swapped in Moser axles w/a 5x5 pattern & used 71-72 drums w/my existing 68 hardware. The splines took some persuasion (read emory cloth) but that was it. About 2-bills for the axles & $25ea for the drums IIRC.

Did you install the axles in a '67-68 rear end? If so, were the axles shorter/longer than the original stock axles? If yes, which was it, and how did you compensate?

Is it cheaper (seriously, bang vs. buck) just to buy all of the brake springs and shoes and drum parts brand new? If so, where is a good place to get all this stuff?

And thanks for the input, btw.

Originally Posted by SCOTI

What didn't work out about your crossmember swap?

I didn't want to trade drilling for drilling

http://67-72chevytrucks.com/vboard/s...d.php?t=281308

So, it didn't work out. I'm sending off a note to the boardmember who was interested in buying my '68 crossmember and taking it off the forum. I'd rather just work with what I've got and go from there. Thank goodness I didn't order the ART arms yet

[wild one]

Hello from the 60-66 section!

I just completed an axle swap into my 66 to go from six lug axles to five lugs this is what I did.

I used a rear housing and axles from a 1971 C10 and used the drums, shoes, wheel cylinders, and backing plates off of my 1975 GMC C15 parts truck. The backing plates of off the newer (1973-? stuff) are offset inboard to allow for the wider shoes and drums used on the newer stuff. The backing plates/drums bolted up with no issues and work great! The only modification I had to do was slightly tweak the brake line to rear cylinder angle as the wheel cylinders are different.

Otherwise, everything fit and is working great, you gotta love the interchange-ability of these trucks.

I hope this helps,
Pete

P.S. - aren't the rear drums on all 68's six lug? If so, you would need to re-drill the drums for five lug axles and I don't think that is advise-able.
You could use drums meant for a 1971-1972 C10 if you opt to purchase five lug axles that fit you original axle.
Or, you can purchase a "late model axle" install kit from ECE, Brothers, etc.. - this will usually be a pair of axle saddles that will need to be welded onto the rear axle and an adjustable track bar kit.
If there is enough axle spline length in the newer axle shafts to allow you cut of the required amount and have the c-clip grove re-machined I don't see why you couldn't do that, just be sure that a competent machinist performs this mod for you.

[Hart_Rod]

ECE sells a kit that contains the correct length of axles that uses 71/72 drums. I think it even comes with new bearings and seals. I think the cost was a little over $319. I used the kit on my 69 Burb.

[shifty]

Thanks, guys.

Rob - did that ECE kit come with all of the brake supplies as well? (backing plates, internals, drum, etc.)

[Hart_Rod]

You can use all the brake stuff that you have. Basically pull the old axles, slip in the new ones, put on the new drums and you're 5 LUGGIN' .

[shifty]

Interesting. Hafta look into that ASAP. I kinda want the add'l 2" or so of width, and then again, I don't at the same time

(i refuse to think forward to wheel selection.)

[Hart_Rod]

I kinda like the shorter width. It allows for a deeper dished wheel.

[shifty]

That was my thought as well.

I was asking the guy who bought his truck from "junkyardjohn" about shortening axles and crap. I wanted to go shorter for more wheel width, so ... I guess this will work.

Here's the deal ... I have a '77 rear end. everything was leaf springs or something, and axle is wider. So I can either stay stock and be less wide with better gearing (3.73) and replace 5-lug and shim for pinion, if required, or I can go wider with the '77 rear, have worse gearing (3.08), hafta shave off the leaf spring mounts and shock mounts, get new diagonal mounts for trailing arms, fit and weld them on, then repaint, etc.

I think it's smarter to go with what I've got.

[shifty]

PS - Rob, you're too quick tonight, bud.

Hey, are you moving out to AZ permanent, or you coming back to FL at some point?

[Hart_Rod]

My orders are up in Aug 09, so I'll be heading somewhere else, but not quite sure where............

[SCOTI]

Originally Posted by shifty

Here's the deal ... I have a '77 rear end. everything was leaf springs or something, and axle is wider. So I can either stay stock and be less wide with better gearing (3.73) and replace 5-lug and shim for pinion, if required, or I can go wider with the '77 rear, have worse gearing (3.08), hafta shave off the leaf spring mounts and shock mounts, get new diagonal mounts for trailing arms, fit and weld them on, then repaint, etc.

I think it's smarter to go with what I've got.

Seems like alot of extra work for "worse" gearing.

Do the 5-lug axle swap from ECE (or Moser) & use standard of the shelf 71-72 rear drums w/your existing 'pre-71' rear-end & brake hardware.

[shifty]

Sounds good, thanks SCOTI.

I went ahead and tore down the '77ish rearend today so I could drain it and store it.

It has a locking diff. I counted 34 splines on the larger gear (i know nothing about rear diff gearing). Not sure what the gear ratio is, if you can figure it out from the 34-spline info or not. Went ahead and yanked out the axles, but thought it was important to open one up and check it out before tearing into mine.

Is a locking diff pretty much standard on these trucks? How much does a locking diff in good shape go for?

[SCOTI]

Ring gear teeth divided by pinion gear teeth = ratio.

[Hart_Rod]

Count the teeth on the ring gear and then the teeth on the pinion gear. Divide ring gear number by pinion gear number and that's your gear ratio. I think the numbers may be stamped on the ring gear also. Mine had 11:41 = 3.73.

[shifty]

I talked to Robb (from TN) on the phone earlier, he told me about the numbers deal on the inside. I'm not good with rear diffs, so when you say "pinion gear", there were two gears at the top and bottom of the pinion bar that goes through the diff. Is it either/or? I gotta open it up again tomorrow, so I'll check it out while I'm at it. If it's geared @ 3.4x or higher, I'll probably swap it for my existing gear on my axle - assuming I can swap the diff from a '77 into a '68 and still use my '68 axles. Dunno if there are spline differences.

[shifty]

PS - I'm learning stuff I never expected I was gonna, and way deeper than I thought I would be getting.

After finding out that my '68 crossmember had some possible issues, I might still be converting to '77 crossmember after all

If I didn't have drama in my real life, all of this would definitely make up for it

[SCOTI]

Originally Posted by shifty

I talked to Robb (from TN) on the phone earlier, he told me about the numbers deal on the inside. I'm not good with rear diffs, so when you say "pinion gear", there were two gears at the top and bottom of the pinion bar that goes through the diff. Is it either/or? I gotta open it up again tomorrow, so I'll check it out while I'm at it. If it's geared @ 3.4x or higher, I'll probably swap it for my existing gear on my axle - assuming I can swap the diff from a '77 into a '68 and still use my '68 axles. Dunno if there are spline differences.

Ring gear is the big 8+" diameter gear. Pinion is the the gear @ the opposite end of the pinion shaft (what the drive shaft connects to).

[Brad]

I'm considering doing this exact same thing in the future and still debating it.

[shifty]

Originally Posted by SCOTI

Ring gear is the big 8+" diameter gear. Pinion is the the gear @ the opposite end of the pinion shaft (what the drive shaft connects to).

Damn, that joker is waaaay in there. But fortunately I took a couple pictures earlier, so I am gonna break out the camera right now and look at em.

[shifty]

ok, no dice

[SCOTI]

Look for numbers stamped into the ring gear. 41:11 = 3.73's (41/11). The pinion gear is tucked way back there but can be seen from the bottom. A dab off of a white crayon or gease-pen marks one teeth well enough to rotate things & count as it spins.

[shifty]

How tough is it to remove, clean up, reinstall a rear end? I never wanted to touch one in the past because I watched on TV all the hassles some "professional" went through trying to get the right lash on the gears. Looked like a serious pain in the ass.

Any rebuilding suggested or required when swapping these things over?

ECE has replacement 5-lug axles for $279. I think I could get away with getting new axles, new 5-lug drums, and reusing the '68 drum backing plate and internals (shoes, etc.).

[caminokid]

I gutted a 77 for my truck. I havent done the swap yet. Are you saying that the axles are too long for the 67 to 72 rear end cases? I was planning taking the axles, backing plates and drums and using them for mine.