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12 Bolt Doner Swap.... Questions!

LEEREED123

LEEREED123

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I found a 77 Blazer with a dana 44 front with auto hubs and a 12 bolt rear for $300. the truck's in great shape.
I have a 91 Jimmy with quad shocks and 10 bolt front and rearwith manual hubs.
My questions are:
1. are they direct bolt ins? any welding or cutting involved?
2. will the manual hubs that i JUST put on my 10 bolt work on a 44?
3. is the 12 bolt much stronger than the 10? (It's my daughters truck and she doesn't go off road with it. but her gov loc is making noise)
4. anyone want whats left?(I KNOW...wrong forum for this question.)
 
(1) The axles are a direct swap. No welding or cutting involved.
(2) Yes the manual hubs will swap from the 10 bolt to the D44
(3) The 12 bolt is marginally stronger than a 10 bolt and not worth the swap trouble unless there are problems with the 10 bolt and the 12 bolt is good to go.
(4) You may need a different rear axle u-joint.
 
Just to elaborate a little more on point 4. I did a very similiar swap, '76 running gear (44 front and 12 bolt rear) into an '86 (both 10 bolts). You can either get a crossover u-joint or get a new driveshaft made that will accept the 12 bolt stock u-joint setup. I went the driveshaft route since I needed my extended anyway and I also wanted to run an ordinary run of the mill u-joint. The crossover one was more expensive (I believe it was 35 to 40 bucks) and they are a little harder to come by since I found not everyone stocks them.
 
T10 bolt is bad, but the 12 is good.
I've tried to find a 14 around here for quite a while, but for some reason, everyone around here wants a fortune for them!
 
bownut said:
Just to elaborate a little more on point 4. I did a very similiar swap, '76 running gear (44 front and 12 bolt rear) into an '86 (both 10 bolts). You can either get a crossover u-joint or get a new driveshaft made that will accept the 12 bolt stock u-joint setup. I went the driveshaft route since I needed my extended anyway and I also wanted to run an ordinary run of the mill u-joint. The crossover one was more expensive (I believe it was 35 to 40 bucks) and they are a little harder to come by since I found not everyone stocks them.
Click to expand...

yeah, hers has no lift, so i'd just go with a cross over. happen to know what the crossover sizes are?
 
Let me look when I get home. I actually bought one and installed it in the stock driveshaft initially when I was building my rig. But after seeing how much the yoke was coming out of the transfer case when flexing, I got an extended driveshaft made and had them put the matching 12 bolt yoke on so I could run normal u-joints. I picked it up thorugh United Auto Supply. If you don't have one of them around, pick another well know, and knowledgable, parts store that will understand what you are looking to do. Some of these cracker box parts stores are worthless when you start getting into odd applications. If it isn't totally stock, you throw them a huge curveball and get nothing but a blank stare.
 
i fyour local parts store can't help you, try a drive shaft shop, they usually have a much better understanding of these things and can look up a part # for you if they don't already stock it
 
You need a conversion u-joint . And the easiest way to deal with the brakes is to pull the 10 bolt shafts , and the 12 bolt shafts so you can unbolt the brake backing plates , take them off and tie them up , and drop the axle out from under them .

The brakes will interchange if you use the whole 9 yards off the 10 bolt . Some 12 bolts had smaller brakes . And besides your 10 bolt stuff is newer .
 
I still have it but can't find anything on it that will be of help as far as brand and part number. Best thing to do is go to a part shop, tell them you want a conversion joint and tell them what your application is. They can look up the u-joint for the 77 and get that part number and then do the same for the 91. Once they got that for mine, they went to another section which showed a conversion joint for that application. The main thing to remember is that the 77 should have an out locking clip while the 91 will have an inner locking ring. Also, the comment made about the brakes reminded me of another thing that I did to the front. I didn't remove the backing plates as mentioned. I just used a grinder to clearance where the brake caliper was hitting on the backing plate. It wasn't that much that had to be removed. I still have the axle and brakes laying in the garage and can snap a pict of what I trimmed if you want.
 
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