85lebaront2 Posted August 1, 2019 Share Posted August 1, 2019 I am in the process of doing a rear disc brake conversion for a good friend, actually you could say best friend as we have known each other since 1972, raised kids together, both pursued the same woman, and as he put it "you asked first". We also both campaigned my 1966 GT350 in autocross competition, he bought the tires and I provided the car. He has a 1995 F350, crew cab DRW truck similar to Darth, but with a Powerstroke Diesel. The kit he purchased from Circle Track Supply is pretty comprehensive and is offered in both Dana and Sterling versions, his is the Sterling which also encompasses the 1985-86 models. He purchased a used 4.10 traction-loc from Pete's Used Parts that came from the same truck a lot of Darth's interior and the Alcoa rims came from. I will be adding pictures as it goes along, but the gist of it, it uses Cadillac Eldorado calipers with parking brake provision and rear rotors from a later E series with rear disc brakes and the internal drum style parking brake. These still take the same bolt circle as the pre-1998 F series. In order to clear the inner dual rim, the rotor is mounted on an adapter installed on the inside of the hub and retained by the original wheel studs. In order to fit on the pilot on this aluminum adapter, the original hole in the rotor has to be enlarged to fit as the rotor hole is 4.9" ID and the pilot on the adapter is 5.4"+. Link to comment Share on other sites More sharing options...
Steve83 Posted August 1, 2019 Share Posted August 1, 2019 Did he or you investigate simply swapping in a later factory rear disk axle? It seems like what you're doing will be a lot more work & expense; both now, and later as the parts have to be replaced for normal wear. With a stock axle, he could simply buy direct-replacement parts. Link to comment Share on other sites More sharing options...
85lebaront2 Posted August 1, 2019 Author Share Posted August 1, 2019 Did he or you investigate simply swapping in a later factory rear disk axle? It seems like what you're doing will be a lot more work & expense; both now, and later as the parts have to be replaced for normal wear. With a stock axle, he could simply buy direct-replacement parts. Yes, and it is called "bolt circle change" the 1998 up super duty trucks use a metric bolt circle that is not compatible with the older trucks. Believe me I almost bought a complete 2000 SD rear till I found I would need two different rims, two front plus one spare and 4 rear plus one spare. Link to comment Share on other sites More sharing options...
85lebaront2 Posted August 1, 2019 Author Share Posted August 1, 2019 Yes, and it is called "bolt circle change" the 1998 up super duty trucks use a metric bolt circle that is not compatible with the older trucks. Believe me I almost bought a complete 2000 SD rear till I found I would need two different rims, two front plus one spare and 4 rear plus one spare. The kit is made by a company named EGR Performance Brakes located in Statesville NC. It seems to be a very comprehensive kit, but there have been a few issues. Here is the left side drum brake and hub, axle is upside down on my pneumatic frame lift as it sits on the pads by adding a scrap piece of 2X4 to get the pumpkin off the center and is fairly stable and at a convenient working height. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 1, 2019 Share Posted August 1, 2019 Yes, and it is called "bolt circle change" the 1998 up super duty trucks use a metric bolt circle that is not compatible with the older trucks. Believe me I almost bought a complete 2000 SD rear till I found I would need two different rims, two front plus one spare and 4 rear plus one spare. If the E350 axle was the right width, with the right spring and shock mount spacing, it might be easier. Having to cut it up and weld it back together, 100%, is easier said then done. And then there's the matter of axles made to fit.... Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 1, 2019 Share Posted August 1, 2019 If the E350 axle was the right width, with the right spring and shock mount spacing, it might be easier. Having to cut it up and weld it back together, 100%, is easier said then done. And then there's the matter of axles made to fit.... Bill - What's the reasoning behind the move to disc? I grant that Big Blue's brakes are marginal with a load on, but suspect they aren't working properly and hope that the move to the bigger '95 F350 brakes in front and hydroboost all 'round will solve that problem. Link to comment Share on other sites More sharing options...
85lebaront2 Posted August 2, 2019 Author Share Posted August 2, 2019 Bill - What's the reasoning behind the move to disc? I grant that Big Blue's brakes are marginal with a load on, but suspect they aren't working properly and hope that the move to the bigger '95 F350 brakes in front and hydroboost all 'round will solve that problem. John Gleason's truck has never had decent brakes, I think the decision maker for him was while we were working on the house in NN, and rather than get his Corvette out after backing his truck and trailer in since the restaurant we were going to closed fairly soon, I suggested he just drive Darth as I was there on the street. First corner he damn near put us both through the windshield. I told him, that's what the brakes are supposed to feel like. He's had his back to the same shop in Poquoson 4 or 5 times over brakes. Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 2, 2019 Share Posted August 2, 2019 John Gleason's truck has never had decent brakes, I think the decision maker for him was while we were working on the house in NN, and rather than get his Corvette out after backing his truck and trailer in since the restaurant we were going to closed fairly soon, I suggested he just drive Darth as I was there on the street. First corner he damn near put us both through the windshield. I told him, that's what the brakes are supposed to feel like. He's had his back to the same shop in Poquoson 4 or 5 times over brakes. You don't have hydroboost on Darth, so it is just that the brakes are working correctly? Couldn't all be the big rear brakes, right? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 2, 2019 Share Posted August 2, 2019 You don't have hydroboost on Darth, so it is just that the brakes are working correctly? Couldn't all be the big rear brakes, right? There's a LOT of friction area in a 12x3.5 drum! If they are adjusted right and not covered in diff lube or glazed they will work well. Compare that to the swept area of a pair of pads, and note only very little of THAT area is out at 6" from the axis of rotation. Higher line pressures help, so maybe a smaller master cylinder, but there's only so much you can do about the laws of physics. Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 2, 2019 Share Posted August 2, 2019 There's a LOT of friction area in a 12x3.5 drum! If they are adjusted right and not covered in diff lube or glazed they will work well. Compare that to the swept area of a pair of pads, and note only very little of THAT area is out at 6" from the axis of rotation. Higher line pressures help, so maybe a smaller master cylinder, but there's only so much you can do about the laws of physics. That's sorta why I'm asking the question. It seems to me that properly functioning drum brakes would more easily be able to stop the rotation than disc brakes just given the leverage, not to mention the swept area. Given the reports I've read on hydroboost, and the braking capability of Darth, then..... Link to comment Share on other sites More sharing options...
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