Blacktop Posted August 8, 2019 Author Share Posted August 8, 2019 Let's see if this answers the question. Both the studs for the master cylinder/hydroboost interface and the firewall/hydroboost interface are 3/8-16. The measurements are "raw", meaning that they may 2.400" and 3.200", but they are what I got by measuring outside/outside of the studs with my dial calipers and subtracting the measured diameter of a stud. Apologies for the really bad image, doing this on my phone as I'm not near my pc. This is the '98 mustang mounting plate. It is not flat and angles the booster down toward the pedal which may help it to align with the pedal pin. I may remove the bolts and weld up the holes before redrilling to the pcd to match my removed vac booster. Link to comment Share on other sites More sharing options...
Blacktop Posted August 8, 2019 Author Share Posted August 8, 2019 Apologies for the really bad image, doing this on my phone as I'm not near my pc. This is the '98 mustang mounting plate. It is not flat and angles the booster down toward the pedal which may help it to align with the pedal pin. I may remove the bolts and weld up the holes before redrilling to the pcd to match my removed vac booster. You can see from the side how it angles the booster down... Sorry, the site keeps flipping some pics 90 degrees. Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 8, 2019 Share Posted August 8, 2019 You can see from the side how it angles the booster down... Sorry, the site keeps flipping some pics 90 degrees. I see what you mean. The plate on my unit is flat, with no angle. Should be easy enough to make out of plate. But, I don't see a good way of getting the nut off on mine. I took off the snap ring, but don't have a socket big enough for that nut. And my adjustable wrench can't get around the studs. I'm assuming you tried a thread pitch gauge to discover the thread pitch. My metric one doesn't do anything but 1/2 mm steps, so wouldn't do 1.6 mm. However, everything on my unit that I've measured is SAE, so might that nut be? 1.6mm is really close to 16 turns/inch, which is a favourite for our nuts. Link to comment Share on other sites More sharing options...
kramttocs Posted August 8, 2019 Share Posted August 8, 2019 I see what you mean. The plate on my unit is flat, with no angle. Should be easy enough to make out of plate. But, I don't see a good way of getting the nut off on mine. I took off the snap ring, but don't have a socket big enough for that nut. And my adjustable wrench can't get around the studs. I'm assuming you tried a thread pitch gauge to discover the thread pitch. My metric one doesn't do anything but 1/2 mm steps, so wouldn't do 1.6 mm. However, everything on my unit that I've measured is SAE, so might that nut be? 1.6mm is really close to 16 turns/inch, which is a favourite for our nuts. Possibly Dorman AutoGrade 1.625-16 Inch Thread Spindle Nut? Part # 615-128 Line: DOR at O'Reillys. Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 8, 2019 Share Posted August 8, 2019 Possibly Dorman AutoGrade 1.625-16 Inch Thread Spindle Nut? Part # 615-128 Line: DOR at O'Reillys. That might be it! I get 1.628" on the little bit of threads that protrude from the nut. Link to comment Share on other sites More sharing options...
Blacktop Posted August 8, 2019 Author Share Posted August 8, 2019 Possibly Dorman AutoGrade 1.625-16 Inch Thread Spindle Nut? Part # 615-128 Line: DOR at O'Reillys. Yeah, that looks like it. I'll see if I can find one over here in the UK😟 Link to comment Share on other sites More sharing options...
Blacktop Posted August 8, 2019 Author Share Posted August 8, 2019 Yeah, that looks like it. I'll see if I can find one over here in the UK😟 Found one on rockauto so at least if I cannot find one here, I can at least order from there👍 Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 8, 2019 Share Posted August 8, 2019 Found one on rockauto so at least if I cannot find one here, I can at least order from there👍 Keep us posted. Link to comment Share on other sites More sharing options...
Blacktop Posted August 9, 2019 Author Share Posted August 9, 2019 Keep us posted. Thinking I will remove the bolts from the mustang mounting plate, weld on a flat plate that has the bolt pattern of my existing booster and then bolt it straight on. Seems the simplest solution. Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 9, 2019 Share Posted August 9, 2019 Thinking I will remove the bolts from the mustang mounting plate, weld on a flat plate that has the bolt pattern of my existing booster and then bolt it straight on. Seems the simplest solution. Ok, I'm as thick as two planks, but humour me. You have the Mustang's plate off, right? Why wouldn't you just make a new plate? Or, maybe I'm thinking how I'd do it given the machines I have. So, if you don't have the machinery to do that, perhaps that's why? Link to comment Share on other sites More sharing options...
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