rear end swap

So, I am considering a different rear end. Mine makes noise due to the worn spider gears on the axle (I am pretty sure that is it). I get a clunk when I turn. Also, at some time, the RR bearing spun in the housing. I made a spacer out of wire so that the flange would clamp the outer race, but it is not a proper fix. Regardless, I think the 3.24 (I cannot remember exactly what it is, but is something close to this...) ratio is a bit short and a 3.08 is almost impossible to find for this car. I'd like something to drop the revs and there are 3.08s for tons of cars out there.
Has anyone researched this? Is there something close that can be adapted? I know it has a multi-link layout which complicates the substitution. Does anyone, offhand, know the width of the rear end flange to flange? Has anyone here tried anything like this?

Keith

You may want to take a look at the rear end from an 80's Chevy S10. The 4-wheel drive ones are just about the same width as the Buick. Two-wheel drive versions are a few inches narrower. if you wanted to go with wider rear wheels. The S10 axles are plentiful in wrecking yards and have the common 10-bolt cover. They come in a wide range of ratios and are widely supported by the aftermarket if you wished to make a ring and pinion swap. Of course, they all have pads for leaf springs, so those would need to be cut off and mounts for the four-link fabricated. They all would have the usual Chevy 5 on 4.75" bolt pattern, which isn't the end of the world. Late 60's Corvair hubs accept the same wheel bearings as the Buick if you wanted some five lug hubs to match on the front.

@gearznbeerz Thanks for the info. I unfortunately just bought a set of rims and converted the fronts over to discs, so I would have to get the flanges re-drilled for 4 on 4.25

Do you have written down what the dimensional difference is? My tires/rims required a bit of filing on the rear lip to clear and if the S10 is wider than OEM, that would be bad, I would think. I have a couple spare rear axles, so I could measure and have fab-ed some mounts. Where did you get yours done, or did you do it yourself? Do you know what the rear end ratios are?

I just did some digging and found this:
2wd 54.5"
4wd 59"
ZR2 63"

Guess I have to measure mine to see what it is, now. Every time I go onto a new car/truck forum, it is a new language that I have to learn.

As I'm sure you're aware, the rear end on our little Buicks is a real unique piece. The combination of its narrowness and its four-link suspension makes finding a suitable replacement problematic. I'm going with the 2wd S10 because I'm running a 700r4 overdrive and wanted a lower ratio...just the opposite of what you're after. I also wanted the 5 lug bolt pattern and the ability to swap to discs, so the s10 works well for me. If you want to stay with the 4 on 4.5 lug pattern you might take a look at the early 60's Chevy II or Mustang/Falcon. They all had about the same width as the Buick (give or take a 1/2") and same wheel bolt pattern. All had leaf springs, of course, and may not be an improvement over the Buick except being Ford or Chevy it would be much easier to find parts for.

@gearznbeerz49 Yes, I know it is a unique piece. So much to consider with a retrofit. I am pretty set on keeping the 4 on 4.5 pattern with the new wheels and tires and will look at the others you mention as well. Quite interested in the S10, though, if it is the right width, it will fit an OEM zexel/torsen from a camaro with the 'series 2 carrier' if I want 3.08. Like I said lots of research and learning new lingo. Down the rabbit hole I go. Do you know if the S10 is wider or narrower than the OEM?

I have a torn up 3.23 (pinion bearing)and a torn up 4.10 posi (spider gears) for the 62 plus the 3.23 that is on the car right now with its damage. I do not have an overdrive as mine is a 4sp (1:1). The 2.54:1 first gear should be plenty to launch with the 215 driving it and I really only use the transmission as a 3sp anyway with lots of skip shifting.

I understand that the 4 wheel drive s10 diffs are about 4-5 inches wider than the 2 wheel drive units like I have. That would mean that they are essentially the same width as the Buick rear, give or take a half inch or so. I imagine the axle flanges could be re-drilled with the 4 on 4.5 bolt pattern. There are a lot of cars that use that bolt pattern, so with some research and a little bit of luck you may even be able to find brake drums the right diameter and width that would work as well Good luck!

Well, that also throws a monkey wrench in it... I had not yet gotten to the brakes. The 62 skylark has 9.5 x 1.75" with a 7/8" slave. The S-10 has standard GM rear drums for a ton of cars - 9.5" x 2.0" with a 3/4" slave.
I could not find anything with 4 on 4.5 with the standard 9.5x2 rear brakes. I am certain I can make it work. Drilling a set of drums for 4 on 4.5 should not be a huge deal. Maybe I can retrofit the original 62 Buick brakes to it.
Option B is to sell my wheels and tires to someone here and get a new set of 5 lug wheels and some hubs and discs for 5 lugs for the front...

These projects are never easy.

Like they say, if this were easy than everyone would do it. One of the most satisfying aspects of our hobby to me is figuring out how to make parts never intended for our cars work, and work better than the original part. I'm planning to go with four-wheel discs on my wagon eventually, and my friends tell me that I will need power boost to operate four wheel discs. As you know, there isn't room on the firewall for a vacuum booster in these cars so that's my looming puzzle. I'll go with five lugs because of the greater availability of wheel options.

New here... Good info on diff! Perhaps a sticky with list of widths that are close that we can add to as info comes to light - researching is part of the fun! Had an mgb for 8 years - rover 3.9 (buick kin - lighter than original tractor motor), tr8 5-speed, and a dana 44 posi -- from a post office jeep (1/2" narrower than oem).

Gearznbeerz49 - any details/pics on 700r conversion you would have time to share on new thread - perhaps a sticky for others - reason for not using 200r - that's the route I have been thinking about - wasn't a priority, but now with having to remove driveshaft, parts, perhaps welding due to damage, balancing - I may have to move up the calendar for improved first gear ratio/overdrive!

Regards, Tony

Tony - I went with the 700r4 from a V6 Chevy because they have a smaller diameter torque converter and bellhousing than the V8 version. D&D makes an adapter plate to bolt it up to the aluminum V8, and I was able to find one locally for a good price. The 200r and 700r4 are similar, as you know, and either one I think would be a vast improvement over the original lump. The 200r is a close ratio unit, which is helpful for drag racing because there is less RPM loss between shifts. For street use I don't think it matters. The 200r also has a slightly more aggressive overdrive at .67 vs .70 for the 700, which would hardly be noticeable. In addition to the adapter plate needed to mate to the engine, I had to cut a larger trans tunnel and fabricate and weld in a new, larger cover. since it is substantially larger than the old trans. I also fabricated a new crossmember, shortened the front half of the original driveshaft and attached a new yoke with the correct splines. How well it all works is still up in the air as I am still buttoning up all the little details of the engine rebuild before attempting its inaugural voyage. I should know how it works (or doesn't) very soon. I would be interested to hear just what happened with your driveshaft as I have concerns about my own two-piece creation.

Met Dan/son at first british car conversion meet in mid-west - probably a decade ago now - then spoke to his son several times on phone after Dan retired. His GM 10-bolt cut rears with disc brakes were/are popular with that crowd. Humm - I believe most of the Buick 3.8 V6's used the 200r (I believe smaller/lighter than 700r) during it's era and probably used BOPR bolt pattern along with smaller torque converter - I read Grand National was beefed up version (assume $ if specific) - some of the larger cars may have used that version - will have to check with D&D - more food for attempting to think! Btw, LOVE the WAGON (wagon fan in general) - bench seat? - adjustments to seats/tracks due to larger tunnel?

Dad measured the dead rear end he has under the porch. He measured 53". If he is right, the S10 at 54.5 is an inch and a half wider. This will definitely not fit under my fenders with the 7" rims and 205-65/15 tires I have. That is 3/4" per side. The tires now rubbed a bit when new and I had to file down some clearance. Bummer.

Anyone have a different number for the width? I thought I'd have it here by now, but it is in Cincy and I am in Chicago...

Keith

@gearznbeerz49. It has been said many times over that rear discs on one of these is a lot of work for little improvement, but knock yourself out.

fwiw, I love the pedal feel on my 1" manual master driving the CPP calipers (2-3/4" piston) with the stock rear drums. No power needed. If you need more power, you may want to consider one of the teves M/C with an electric pump. You may want to contact these guys:
http://www.abspowerbrake.com/
They rebuilt my Saab 900 ABS pump and provide kits as well as consult on cars/trucks that also have little to no room for a vacuum boosted system.

I just talked to Moser engineering. They can narrow a chevy 10 bolt to the 53" required.

My plan: Get a 3.08 torsen/zexel LSD from a 99+ Camaro and have it narrowed to 53" by Moser. I'll re-use the 2" GM rear drum brakes on the diff. Moser will make custom axles drilled with 4 on 4.5 and I will drill the drums to fit. This will get me to a rear diff but no way of bolting it on...

I have a contact here in Chicago that can laser cut brackets, so I will have to make some drawings of the brackets required to mount the trailing arms and cross links. Get them made and have them welded on locally. Once the housing is done, get someone to set up the backlash on the diff.  

I am guessing I'm in for $1500 or so to get this done, but in the end, it should be pretty serviceable. I may start on this over the winter for a next summer install.

Comments? Am I missing anything?