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Dana 44 Front Disc Brake Swap - 4-Wheel & Off-Road Magazine

If you already own or are thinking of buying an older 4x4 with a drum-brake Dana 44 up front-and that encompasses a lot of very desirable rigs-then don't touch that dial.

131 9803 Dana 44 Front Disc Swap axles With Drum And Disc Brakes Photo 35116032

This is mainly a drum-to-disc-swap article, and we'll get to that. But even if you're not a disc brake fan, sooner or later you'll probably want to upgrade or swap some Dana 44 parts. Or maybe you'll snap an axleshaft or a U-joint.

When any of the above happens, you may have a close encounter with the all-44s-are-alike myth. Of course, it's pretty common knowledge that Ford 44s are different from GM 44s, which are different from Dodge 44s, which are different from Scout 44s. But we're talking specifically about the widespread misconception that all '78-and-older, open-knuckle General Motors Dana 44s-1/2-tons and 3/4-tons-are basically identical inboard of the steering knuckles. Of course, wheel hubs (six or eight lugs), brake parts (drum or disc), gear ratios, and maybe a spring pad or a shock mount here or there may differ. But according to the myth, axlehousing dimensions, axleshafts, U-joints, and steering knuckles should be the same. And swapping later-model Dana 44 disc brakes onto an earlier open-knuckle drum brake axle should be a slam-dunk-easy deal.

Wrong-on both the interchangeability and the swapping-ease counts. We asked Joel Snider and Joe Shaff of Stage West 4-Wheel Drive to show us why and what you can do to achieve the swaps you want. And while we're concentrating on GM 44s, it's a good bet that many of the issues apply to Dodges and Fords as well.

PhotosView Slideshow 131 9803 02 o+131 9803 dana 44 front disc swap+disc brake sparks You have two choices for swapping front disc brakes onto your drum-brake Dana 44: Find a donor 44 that matches yours and use the needed parts, or swap in a whole different axle. Swapping the entire axle is usually the fastest, least-hassle option. But maybe you like to play detective or gamble a little, or have just put super gears and an ARB in your drum-brake axle and would rather not do it again. In that case, the key words are donor that matches. Contrary to the myth, GM used three different versions of the open-knuckle Dana 44 from 1969 through 1972, one for early 1969, one from mid-1969 to 1971, and one for 1972. According to specs on paper, some '73-and-up 44 parts (all had disc brakes) should fit onto some '72-and-down 44s. But unless you check the stamped numbers on the axle tube and do some legwork (we'll explain later), you may not know your swap is in trouble until you're deep inside. Disassembly and appearance of parts are very similar. Joe Shaff of Stage West 4-Wheel Drive removes the spindle to allow the axleshaft to slip out. Donor disc brake components from the steering knuckle out, including the axle's outer (or stub) shaft, should replace drum components. If you had broken an axle U-joint or an axleshaft, this is how you'd reach it for repair. And you might encounter some of the same interchangeability problems. Here's the first sign of swap trouble: '69-'72 Dana 44s (right) use smaller U-joints than the '73-'78s (earlier 1.063-inch-diameter caps; later 1.188-inch). Also note the difference in stub-shaft length and in the size of spindle shoulders (arrows). Spicer doesn't make an axle U-joint with two different cap sizes, and no one we talked with thought it was a good idea to use such a U-joint, even if it could be found or custom made. Still want to swap some parts? Then get familiar with this illo, find the numbers on your axle, and make good friends with your Dana parts distributor. The build-date code (1) tells you if the disc brake 44 on your '72 is original. It reads from left to right: month, day, last digit of year (e.g., a '72 has a 2 stamped in it), shift that built it, and production line. But the critical number is the bill of material or part number (2). These seven digits allow someone with the big Dana-Spicer spec books to find axleshaft dimensions, spline size and count, U-joint specs, and more. Why not slip in the whole later axleshaft assembly? All GM 44s are alike, right? Wrong. Compare the early '69 Blazer 44 axleshaft length (upper) to the '74 disc brake donor (lower). GM ran only two versions of the 44 from 1973 through 1978 and their axleshaft lengths match most '69-'72s (but not the Blazer's). Note the differences between the '69 spindle (above, right) and the '74 (above, left), especially in the shoulder where they fit into the steering knuckle. The spindles bolt on, but there's no way these are interchangeable since the seal designs are different. Steering knuckles differed from early (above, top) to later (above, bottom) types. The spindle bolt pattern is identical, but other differences can make for small swapping nightmares. For example, the tie-rod holes are different depending upon whether they are top- or bottom-loaded. Using the bill of material number, you can find part numbers in the Dana book for practically every axle component between the steering knuckles. That includes spindles, bearings, seals, most (but not all) knuckles, differential gears, cases, and bearings. But the number doesn't indicate whether the axles had drum brakes or discs. Those were added later by GM. According to GM parts sources, front 44 discs were made standard in 1971, and we know that all '73-and-up 44s have discs. The '73-and-up 44 axleshafts (above, top) are beefier than earlier ones, tempting some to swap them into '72-and-earlier housings. But does it work? The way we read the axleshaft specs in the Dana book indicates this might work with '70-'72 44s with bills of material 603170, 603351, and 603352. You'd probably need to swap everything from the knuckle out, too. We haven't actually done the swap, so you must check it out for yourself. This is just an example of how to track down the info. If you find a '72-or-older donor with discs, you still have to compare bill of material numbers and double-check components for fit. Besides, older disc brake 44s are scarce compared to the '73-and-up 44 shown. And you'll still have the thinner axleshafts and small U-joints. Like we said, unless you just enjoy the challenge, do yourself a favor: Find a complete later disc brake axle and swap it in. Here, Joel Snider at Stage West 4-Wheel Drive checks the distance between spring pads. The '69 and '74 44 distances were within a quarter of an inch-not enough difference to create a problem. You'll need jackstands and a floor jack to lower the old axle after you've unbolted the front driveshaft, steering drag link, shocks, brake lines, and spring U-bolts. If you don't need to tear into the diff, this is a lot less hassle than swapping in donor parts. If you have to swap gears, replace inner axle seals, or otherwise rebuild the new swap-in, then you've still saved yourself the time and aggravation (or fun, depending on your perspective) involved in trying to swap newer disc parts onto an older 44. The '74-and-newer disc brake axle had a sway bar, while our '69 Blazer did not. We kept the bar and used the later U-bolt plates. The '74's brake calipers were old and crusty, so we sprung for rebuilt ones with new semimetallic pads. Shaff cautions to check the rotors on any swap-in before you buy to be sure there's enough metal left when the brake shop turns and trues them. You will almost always need to purchase new brake lines to fit the calipers. Shaff and Snider point out that the master cylinder and proportioning valve almost always have to be upgraded in drum-to-disc brake swaps. Discs sometimes require different pressure and volume than drums to work properly.

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