Fordboy300 Posted November 23, 2018 Share Posted November 23, 2018 Hey Guys, hope everyone is having a great Thanksgiving weekend anywho I have two questions. First question is about my dads 86 f250. Okay so it has problem after my dad and I changed the rear brake shoes. It has a spongy pedal well it also had a brake booster okay today I changed the booster and re adjusted the rear brake shoes. The firmness of the brake pedal is okay but I feel like it could be better. Drove it and stepped on the brakes like a sudden brake and it stopped but not on the dime didnt even lock up the brakes or nothing. Second question is about my 86 f150 so next year I plan on changing the rear gear I was reading up on and my mechanic mentioned that I would need to change the speedometer gear drive. Is there anyone that could help me find out which one is the right one I'm gonna need when I decide to do that. Link to comment Share on other sites More sharing options...
Rembrant Posted November 23, 2018 Share Posted November 23, 2018 Second question is about my 86 f150 so next year I plan on changing the rear gear I was reading up on and my mechanic mentioned that I would need to change the speedometer gear drive. Is there anyone that could help me find out which one is the right one I'm gonna need when I decide to do that. What size tires are you running now? And are they the correct size for the truck? What is your gearing now, and what gearing are you wanting to change to? Link to comment Share on other sites More sharing options...
Ford F834 Posted November 24, 2018 Share Posted November 24, 2018 Sometimes on the brakes it takes a little while for the new pads/shoes to seat and wear to the imperfections of the rotor/drum. If the pedal firmness feels good and they are adjusted right then just try driving and braking for a bit and see if it improves. If you have spongy pedal that is usually air in the hydraulic system that needs bled out, but if you just did shoes and booster none of that should have been disturbed (did you take any lines off when you replaced the booster?). On the driven gear, this web page may help 😉 http://www.garysgaragemahal.com/speedometer-driven-gears.html Link to comment Share on other sites More sharing options...
Fordboy300 Posted November 24, 2018 Author Share Posted November 24, 2018 Second question is about my 86 f150 so next year I plan on changing the rear gear I was reading up on and my mechanic mentioned that I would need to change the speedometer gear drive. Is there anyone that could help me find out which one is the right one I'm gonna need when I decide to do that. What size tires are you running now? And are they the correct size for the truck? What is your gearing now, and what gearing are you wanting to change to? Well right I have two sets of tires. Both 15 inch wheels. P235 75R15 and P225 75R15. The original tire size for my truck is 215 75R15. My gearing now is 3.08 open differential. I'm changing to a 3.55 Limited slip. Link to comment Share on other sites More sharing options...
Fordboy300 Posted November 24, 2018 Author Share Posted November 24, 2018 Sometimes on the brakes it takes a little while for the new pads/shoes to seat and wear to the imperfections of the rotor/drum. If the pedal firmness feels good and they are adjusted right then just try driving and braking for a bit and see if it improves. If you have spongy pedal that is usually air in the hydraulic system that needs bled out, but if you just did shoes and booster none of that should have been disturbed (did you take any lines off when you replaced the booster?). On the driven gear, this web page may help 😉 http://www.garysgaragemahal.com/speedometer-driven-gears.html I believe that's what happened. It must have air in the lines somewhere. Tomorrow my dad and I will bleed the brake. I will keep you guys posted. Thanks ! Link to comment Share on other sites More sharing options...
Rembrant Posted November 24, 2018 Share Posted November 24, 2018 Well right I have two sets of tires. Both 15 inch wheels. P235 75R15 and P225 75R15. The original tire size for my truck is 215 75R15. My gearing now is 3.08 open differential. I'm changing to a 3.55 Limited slip. Ok, if your truck has a 3.08 rear diff and originally had 215 75/R15 tires specified, then it should have a 8/18 speedometer gears. That's an 8 tooth drive gear, and an 18 tooth driven gear on the speedo cable. If you install 3.55 gears and P225 75/R15 or P235 75R15 tires, you would have to install a 20 tooth driven gear on the speedo cable. https://shop.broncograveyard.com/Speedo-driven-gear-20-teeth-black/productinfo/37192E/ This is just me doing some rough math here. One of the other guys may come along and correct me. I'm not sure if a 20 tooth driven gear will work with an 8 tooth drive gear. I know there is a range of gears that work with the 8 tooth drive gear, and in some case you may have to change the drive gear to get the correct ratio. All I can say is that the math calculates a 20 tooth driven gear. Link to comment Share on other sites More sharing options...
Steve83 Posted November 24, 2018 Share Posted November 24, 2018 This caption contains Ford's instructions for correcting a speedo: https://supermotors.net/getfile/831124/thumbnail/speedocabletop.jpg Brake problems usually come from the drums, because they're the least-understood & most-neglected. Click this & read the NEXT several captions: https://supermotors.net/getfile/895328/thumbnail/brakedrum.jpg Link to comment Share on other sites More sharing options...
Fordboy300 Posted November 24, 2018 Author Share Posted November 24, 2018 This caption contains Ford's instructions for correcting a speedo: https://supermotors.net/getfile/831124/thumbnail/speedocabletop.jpg Brake problems usually come from the drums, because they're the least-understood & most-neglected. Click this & read the NEXT several captions: https://supermotors.net/getfile/895328/thumbnail/brakedrum.jpg Does it matter what transmission I have? Because I have the SROD transmission I dont plan on changing it unless it grenades itself. I drive my truck pretty hard at times ever since I hopped the 300 up. Link to comment Share on other sites More sharing options...
Ford F834 Posted November 25, 2018 Share Posted November 25, 2018 Does it matter what transmission I have? Because I have the SROD transmission I dont plan on changing it unless it grenades itself. I drive my truck pretty hard at times ever since I hopped the 300 up. The tooth count of the drive gear inside the transmission or transfer case is the other half of the ratio equation. If you get a heavier transmission it may have a different drive gear tooth count. Often you can just correct it with the corresponding driven gear for your axle ratio and tire size. Link to comment Share on other sites More sharing options...
Fordboy300 Posted November 25, 2018 Author Share Posted November 25, 2018 The tooth count of the drive gear inside the transmission or transfer case is the other half of the ratio equation. If you get a heavier transmission it may have a different drive gear tooth count. Often you can just correct it with the corresponding driven gear for your axle ratio and tire size. Hi guys, So yesterday my dad and I bled the rear brake twice and today he drove it. He said he still felt a spongy/soft pedal he says it stops but it kinda takes its time. Now I'm just assuming do you guys think it has anything to do with the power brake booster rod adjustment?? I did measure the old one to the new one (just with a engineers stick ruler) and its pretty close to old one. Link to comment Share on other sites More sharing options...
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