[Chuck78]

I've just read of two guys swapping a Detroit TrueTrac into their old GMC housings now, so apparently it's not an issue. I'm going to assume the outside diameter of the bearings is the same, and the inside diameter is all that was the oddball dimension on our original carriers o.d. bearing surface, therefore a modern Dana 44 kit will fit the modern limited slip differentials...



More info:

Originally Posted by D-Rat

Re: GMC guys! Dana 44 ??
Most modern D44s are 30 spline, but they did make them in the 60s with like a 19 spline. An International Scout II rear D44 would have 5 on 5.5" lug outers and drum brakes, and may possibly interchange as long as you have 30 spline shafts.

Originally Posted by Fitz

Call Currie enterprises. They have axles for your diff in 30, 31, 33, or 35 spline, small or large bearing in a 5 x 5 lug pattern. cost is 319.95 (2010 prices)

Originally Posted by fasttech

Get axles turned for a 3" pilot and outer flange diameter of 6.125" or just have some new axles built like I did. When I compared the cost of all the machine work (including 6 to 5 lug) to the cost of new ones it was only about $100 more. Got mine from Dutchman Motorsports.

And here's some great info from several people on rear disc brake swaps:

http://67-72chevytrucks.com/vboard/s...+Dana+44+axles

Apparently a Wilwood kit for Ford 9" works, Wilwood brake set 140-7139, after turning down the drum/wheel register diameter on the end of the shaft to 3" or 3.07" on a lathe. The wheel bearings and the axle tube end flange are the same as the "Big Ford" bolt pattern. I have a set of the OldeDays brackets for the Ford 9" to GM Seville/79-81 Trans Am WS6 calipers, and AWD Astro Van front 5-lug rotors. I believe they are slightly larger diameter than the Cadillac rotors, and the Cadillac rotors would work with those brackets without any bracket mods. I'll mod the brackets to get slightly larger rear rotors. I think it was 11" vs 11.2"?

Originally Posted by fasttech

Re: GMC guys! Dana 44 ??
The setup I am using works but I can't comment on the Willwood.

If you want to go the build your own route here is what you need:
* Ford 9" Bracket Kit (from Oldedays)
* Left Rear Caliper GM 79-85 (Cardone 18-4139) this one has the parking brake
* Right Rear Caliper GM 79-85 (Cardone 18-4139) this one has the parking brake
* Brake pads for GM 79-85 rear caliper
* 1978 Seville Rear Rotors (can get get slotted and drilled as option)
* Disc Brake Hose Kit (Gear Head 9828) this one is stainless
* Parking brake cable (BrakeBest BC93292) needs a little customization
* Get axles turned for a 3" pilot and outer flange diameter of 6.125" or just have some new axles built like I did. When I compared the cost of all the machine work (including 6 to 5 lug) to the cost of new ones it was only about $100 more. Got mine from Dutchman Motorsports.

Originally Posted by steinepstein

Re: GMC guys! Dana 44 ??
I also just measured the bolt dimensions on the axle housing end. They are the same as a big ford housing end. 3.5" x 2.375". You can find these dimensions on the assembly instructions document on the Wilwood website. Wilwood brake set 140-7139 should bolt right up to that housing end.
I just confirmed that the axle pilot hole will have to be turned down to fit the 140-7139 Wilwood kit, but other than that, the axle housing end and bearing on the Dana 44 is big a Ford 9" setup, awesome.

Originally Posted by dougminton

Re: GMC guys! Dana 44 ??
redrill your axles to 5x5 pattern
2 front rotors from a AWD astro van (5x5 pattern) 80$
Rear calipers from 1979 Cadillac Eldorado at rockauto170$ including core
caliper brackets from speedway motors 30$ shipped
longer wheel studs
plus hoses

Originally Posted by fasttech

I have researched the crap out of this and starting to collect the required parts for my conversion but here is what I have learned.

The Dana 44 rear ends in the 67-72 trucks have axle mounting flanges based on the Ford 9" early big bearing. So basically any disc brake kit based on the Ford 9" early big bearing will / should work. There are a bunch of disc brake kits out there but the most cost effective approach I could find is to buy the parts individually as follows:

Bracket Kit ($70) - http://shop.oldedaysclassiccarparts....&categoryId=29 You could make your own but I figured it would cost more than $70 in materials and my time to make a set.

1985 Cadillac Seville Calipers ($150 to $200) - eBay is your best bet for a reman set but these are still pricey without a core exchange. Just make sure you get the semi-loaded caliper with all the brackets etc. for the parking brake. I got lucky and found a fresh reman set that a guy needed to get rid of. You could also save a few bucks by using the front calipers off the same car if you don't need and e-brake.

1978 Cadillac Seville Rear Rotors ($60 - $120) - I am going with a 5x5 bolt pattern and these rotors come stock with a 5x5 pattern. You will have to get them re-drilled if you need a different bolt pattern. eBay is probably your best price option here as well. The price will depend on if they are cross drilled, slotted, and with or without pads included.

GM Metric Caliper Brake Hose Kit ($40 - $60) - (2) -3 15" long brake hoses; (2) 3/16" inverted flare to -3 adapters; (2) weld-on brake adapter mounts; (2) brake adapter clips; (2) 10mm x 1.5 banjo bolts; (2) 10mm to -3 banjos; (4) 10mm crush washers. Price depends on if you go with rubber or SS braided hoses.

Axle Modifications - The center pilot hub on this rear end is 3.5" and the pilot hole on the Seville rotors is 3.07" which means you will need to have the hub pilot on both axles turned down to 3". The stock bolt pattern is a 6 lug setup so if you want to change this to some other bolt pattern the axles will have to be re-drilled for that pattern. The wheel studs for the 5x5 pattern is 1/2" so those things like that need to be considered as well. This could end up being a lot of machine work so it may be a better to purchase a set of custom built axles from Dutchman or Moser. I have the axle dimensions if you are interested.

Based on my research you will spend from $450 to $550 plus the axle or rotor mods to convert the rear Dana 44 to disc brakes.