I know I ain't been on here for a while but when work comes up and I'm broke I can't help but do the job and for that I'm sorry and do the best that I can. Enough of that already. what I'm in the middle of right now is changing out the whole differential on my old '79 F-150 and I'm wondering if someone would be of assistance by telling me how much slower my speedometer will be when I get this done the gear ratio that is coming out is 3:25's and what is going back in is 2:75's both rear ends are out of a 79 F-150 are both 9'' so there won't be any trouble lining them up with the bolts

 

Welcome home !!
Where is a trooper with a radar gun when you need him/her ??
If you could get one to track you at 40, MPH on your speedometer, I think you could get a pretty good idea of speed difference.
If you can't find one just take it up to the speed limit and they will appear out of nowhere.

 

I can't afford to get any tickets. but it's nice to see that you haven't lost your sense of humor hanky

 

I don't know if you had a tach in your truck, but if you did and you knew what speed you did at what rpm with the old rear you might be able to calculate the speed at the same rpm with the new rear. Did you have a tach in it?

 

it's an old custom it didn't have one from the factory and still doesn't have one because my tach is what I hear when I go to float the gears

 

it's just an old 3 speed on the column and the clutch pedal is so stiff that I can't hold it down with my left leg for very long. so when I'm stopped at a light the truck is in neutral while my right foot is on the brake pedal until I get ready to go forward and then I just use the gas pedal with engine speed and road speed. I just use the clutch when taking off and while in reverse

 

well I got the rear end in now I can't tell how far off my speedometer is. it feels like it's about right to me anyway. some one told me a long time ago that the drive gear on the end of the cable is one tooth = 6mph but that I can't tell the difference between what I had and what I have now. I have a new problem now with the rear brakes not doing their part when I had my eldest son help me bleed the brakes after I got through buttoning everything up my brake pedal did not move after taking the bleeder screw and nothing came out of it. I could be wrong about this but I think that the portioning valve on brake lines might be stuck and allowing the front brakes stop the truck only

 

Ya know your taxing my little brain with these problems on older vehicles don't ya?
If I recall correctly, you had to either depress or pull out the button on the proportioning valve when bleeding the brakes on those. Try that and see what you get.

 

I found the problem why the rear brakes ain't workin'. the master cylinder is almost completely blocked and not letting any fluid go to the rear brakes. once I get a new one installed and bled out they should work like they should. and yes Hanky I will try that little trick with the button while I'm at it just to make sure that my proportioning valve ain't bad

 

okay tried that little trick on the equalizer block and no good the rear brakes won't work changed master cylinder and replaced one of the lines due to the fact that it twisted in two when I took it apart. still the same problem. next thing I'm gonna do is replace the equalizer block and the lines going to the rear end. on the bright side of this problem is I'll never have to replace the rear brake shoes if they don't work