Frank Wyatt Posted February 21, 2019 Share Posted February 21, 2019 Mystery partially solved. I've confirmed that I have the Dana 70 rear end. I gathered that by the tag info as well as the axle tube diameter. The diameter for the 70 is published as 3-1/2" (mine measured 3-9/16 - lots of rust?). The diameter for a D60 is 3-1/8". The diameter for a 70HD is 4". I'm seriously debating putting disc brakes on the rear end. Seems pretty easy and not expensive. Upside is that they brake better, are more reliable and if only replacing pads - can be maintained without pulling the axle. The kits are readily available, or you can piece it together yourself and just buy the mounting bracket. Downside is that if I want a mechanical parking brake, it adds $150+ to the cost (the calipers come from mid 70s era Cadillac Eldorado. There is still one mystery on my mind. The differential casting should have a model number on it, which I would assume to be "70", but it appears to be "NC". Any thoughts? I also realized that there appears to be another metal tag at the very top of the differential. I'll have to wait until the next time I drop the spare tire to check that one out. Per the Dana manual, it is saying that the rear end on my truck only got put on chassis models. I really need to get my hands on the build sheet. FWIW, doing all that work to convert your rear drum brakes to disc is a lot of work for little if any benefit. Especially using an after market kit. Your rear brakes do contribute to your stopping ability, but you would never be able to notice the difference between the rear drum brakes from rear disc brakes if your factory brakes are working correctly. If it were me, I would make sure your brakes shoes have adequate friction material, if not replace them with a quality set of shoes. Also do not forget about the springs and replace ALL of your brake hardware with brand new and lubricate all the contact points. Once that is done, adjust your new brake shoes correctly and they will be reliable for many years. Another thing I like to do is while I'm in there I always replace my wheel cylinders. As inexpensive as they are, it just makes sense to me, but that's if it was me doing it. Link to comment Share on other sites More sharing options...
Ford F834 Posted February 21, 2019 Share Posted February 21, 2019 FWIW, doing all that work to convert your rear drum brakes to disc is a lot of work for little if any benefit. Especially using an after market kit. Your rear brakes do contribute to your stopping ability, but you would never be able to notice the difference between the rear drum brakes from rear disc brakes if your factory brakes are working correctly. If it were me, I would make sure your brakes shoes have adequate friction material, if not replace them with a quality set of shoes. Also do not forget about the springs and replace ALL of your brake hardware with brand new and lubricate all the contact points. Once that is done, adjust your new brake shoes correctly and they will be reliable for many years. Another thing I like to do is while I'm in there I always replace my wheel cylinders. As inexpensive as they are, it just makes sense to me, but that's if it was me doing it. The late Econoline disc brake Dana axles have slip-over rotors. That rotor is actually the one used in the conversion kits. However I have to agree with white knight. Disc conversion is not “all that” compared to properly serviced rear drums. If you want better performance convert to hydroboost. My interest in rear disc has more to do with ease of service and inspection than it does performance. If anything I was more looking forward to improved parking brake performance via secondary mechanical calipers. However, the parts I wanted added up to over a grand vs. around $125 to service what I have. Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 21, 2019 Share Posted February 21, 2019 The late Econoline disc brake Dana axles have slip-over rotors. That rotor is actually the one used in the conversion kits. However I have to agree with white knight. Disc conversion is not “all that” compared to properly serviced rear drums. If you want better performance convert to hydroboost. My interest in rear disc has more to do with ease of service and inspection than it does performance. If anything I was more looking forward to improved parking brake performance via secondary mechanical calipers. However, the parts I wanted added up to over a grand vs. around $125 to service what I have. I'm following this and thought I'd chime in. Big Blue, with his 10 1/4" Sterling, has a parking brakes that WORK. It doesn't take much pedal at all and the rears will NOT turn. In fact, it is hard to bring them on w/o having the rears lock. However, overall I'm not impressed with the brakes, so am doing as Jonathan suggested - going to hydroboost. Everything I've read says that makes a dramatic difference. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted February 21, 2019 Share Posted February 21, 2019 I'm following this and thought I'd chime in. Big Blue, with his 10 1/4" Sterling, has a parking brakes that WORK. It doesn't take much pedal at all and the rears will NOT turn. In fact, it is hard to bring them on w/o having the rears lock. However, overall I'm not impressed with the brakes, so am doing as Jonathan suggested - going to hydroboost. Everything I've read says that makes a dramatic difference. Gary, The regular 10.25 drum brake rear doesn't seem to have any problems with a parking brake. Converting from drum to disc is where the problem lies. The only problems I've had with mine are the pinion yoke loosening (early, short spline) and the hub seals. Updated (Scott type) seal within a seal seem to have solved the problem of gear oil getting into the drums. Discs would certainly make brake service easier and eliminate any adjustment of the primary braking system. But again, "not all that" IMO Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 21, 2019 Share Posted February 21, 2019 Gary, The regular 10.25 drum brake rear doesn't seem to have any problems with a parking brake. Converting from drum to disc is where the problem lies. The only problems I've had with mine are the pinion yoke loosening (early, short spline) and the hub seals. Updated (Scott type) seal within a seal seem to have solved the problem of gear oil getting into the drums. Discs would certainly make brake service easier and eliminate any adjustment of the primary braking system. But again, "not all that" IMO Jim - Thanks for the clarification. My misunderstanding. Link to comment Share on other sites More sharing options...
85lebaront2 Posted February 21, 2019 Share Posted February 21, 2019 I'm following this and thought I'd chime in. Big Blue, with his 10 1/4" Sterling, has a parking brakes that WORK. It doesn't take much pedal at all and the rears will NOT turn. In fact, it is hard to bring them on w/o having the rears lock. However, overall I'm not impressed with the brakes, so am doing as Jonathan suggested - going to hydroboost. Everything I've read says that makes a dramatic difference. When I installed the later housing in Darth (apparently a 1993 or early 1994) I found that instead of the 2 1/2" wide shoes on the rear brakes that came on the 1986 DRW trucks, it had 3 1/2" wide shoes which really increased the rear braking, yet generally will not lock up on hard braking. I had already installed the 1990 booster so I could use the later master cylinder with the extra port for the speed control "dump" switch. This is also where my old fashioned hydraulic trailer brake controller is plumbed in. This part is in the same vein as Jonathan's cost vs effectiveness, to even begin to approach the smoothness and ease of balance this has, an all electronic one is in the $$$$$ range. This is also one of the big reasons I do not want a newer truck, 1986 was the last year with no ABS of any kind. Link to comment Share on other sites More sharing options...
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