Sharps40
Old Mossy Horns
This where I'm at. Run the wheels off and when I can't Keep it up, sell it to someone who'll do her over again.
Coming up on almost 2 years of driving with Ol Bessy....had a couple panic stops here recently and it highlighted a nagging issue in the back of my mind. Id previously switched to a 1" bore master (From 1 1/8' as the system lacked pressure) with my GM power disc/drum combo but no matter the adjustment they just seemed inadaquate. Not much feel at the top of the pedal, long stroke to get to function (master pin is 20 thou off the piston, etc, etc.) and those panic stops were long ones with me and 4 other legs pushing the pedal without any tire bark.
Did a bunch of reading and rearranged a few things. Naturally, checked all the shoes and pads and looked for leaks, etc,....all was well.
Went back to my youthful methods of adjusting rear brakes, tossing aside the measuring caliper and after fitting shoes to the drums, adjust them to lock and backed off till just free......that helped but still needed 5 legs for a tire quiet panic stop and still not much feel or action at the top half of the stroke.
Went through all the checks on the 7" dual diaphragm booster (thats all that'll fit in the space available), run the pressure calculations (should easily make the 900 to 1400 lbs needed for power discs), and decided to change the ratio from power brake 5 to 1 to manual brake 7 to 1. Same, it helped, but still not a factory feel to the brakes and still needed a lot of effort for what was still a longish panic stop from 45 mph.
Did a bunch more reading and came across several articles on effeciency of levers. Seems the lever ideally needs to be at 90 degrees to the master cylinder push rod at the mid point of the stroke. Mine was set up with the top of the pedal forward and the angle reduced on application of the brake.
So, I moved the pedal pivot back and changed up the push rod length so I'm a bit over 90 to start and push thru 90 as I'm applying pressure.
Happy Joy! I can feel the brakes engaging nicely in the top third of the stroke and panic stops are one legged and a darn sight shorter than before. Even got some tire noise jumping it full panic.....still need to adjust up the right rear a bit tighter but so much more feel and brakeing power.
The original mounting point for the brake lever is the middle bolt, there was a steep angle to the much longer push rod that bacame shallower as I pressed the brake.....e.g. the brake lever was moving into a position parallel to the master push rod. Not efficient per what I was reading.
Now, the brake lever is moved toward the firewall and the angle is a bit over 90 degrees to start with and moves through 90 as I operate the brake. Best overall improvement so far to brakeing feel and performance. (Ratios on the three holes top to bottom are 7 to 1, 5.7 to 1 and 4.6 to 1 but the bottom holes require an offset push rod to keep the master pushrod straight on in the bore.)
Now only a couple more things to do.
1. Get some steel (and a buddy that can weld for me) and fab up a brake lever that hangs like this and is a bit straighter so it fits my foot and seating position within the constricted space of the pushed back fire wall.
2. Start making up door cards and arm rests so I can get the upholsterer working on it.
Yep, I was toying with tossing the big master back on and pulling out ear hairs but reading tech stuff at brake manufactures web sites paid dividends on this one.
Coming up on almost 2 years of driving with Ol Bessy....had a couple panic stops here recently and it highlighted a nagging issue in the back of my mind. Id previously switched to a 1" bore master (From 1 1/8' as the system lacked pressure) with my GM power disc/drum combo but no matter the adjustment they just seemed inadaquate. Not much feel at the top of the pedal, long stroke to get to function (master pin is 20 thou off the piston, etc, etc.) and those panic stops were long ones with me and 4 other legs pushing the pedal without any tire bark.
Did a bunch of reading and rearranged a few things. Naturally, checked all the shoes and pads and looked for leaks, etc,....all was well.
Went back to my youthful methods of adjusting rear brakes, tossing aside the measuring caliper and after fitting shoes to the drums, adjust them to lock and backed off till just free......that helped but still needed 5 legs for a tire quiet panic stop and still not much feel or action at the top half of the stroke.
Went through all the checks on the 7" dual diaphragm booster (thats all that'll fit in the space available), run the pressure calculations (should easily make the 900 to 1400 lbs needed for power discs), and decided to change the ratio from power brake 5 to 1 to manual brake 7 to 1. Same, it helped, but still not a factory feel to the brakes and still needed a lot of effort for what was still a longish panic stop from 45 mph.
Did a bunch more reading and came across several articles on effeciency of levers. Seems the lever ideally needs to be at 90 degrees to the master cylinder push rod at the mid point of the stroke. Mine was set up with the top of the pedal rearward from the master and the angle between lever and push rod reduced a lot on application of the brake.
So, I moved the pedal pivot forward toward the master, changed up the push rod length and I'm a bit over 90 degrees to start and push thru 90 degrees as I'm applying pressure.
Happy Joy! I can feel the brakes engaging nicely in the top third of the stroke and panic stops are one legged and a darn sight shorter than before. Even got some tire noise jumping it full panic.....still need to adjust up the right rear a bit tighter but so much more feel and brakeing power.
The original mounting point for the brake lever is the middle bolt, there was a steep angle to the much longer push rod that bacame shallower as I pressed the brake.....e.g. the brake lever was moving into a position parallel to the master push rod. Not efficient per what I was reading.
Now, the brake lever is moved toward the firewall and the angle is a bit over 90 degrees to start with and moves through 90 as I operate the brake. Best overall improvement so far to brakeing feel and performance. (Ratios on the three holes top to bottom are 7 to 1, 5.7 to 1 and 4.6 to 1 but the bottom holes require an offset push rod to keep the master pushrod straight on in the bore.)
Now only a couple more things to do.
1. Get some steel (and a buddy that can weld for me) and fab up a brake lever that hangs like this and is a bit straighter so it fits my foot and seating position within the constricted space of the pushed back fire wall.
2. Start making up door cards and arm rests so I can get the upholsterer working on it.
View attachment 96604
View attachment 96602
constricted foot bay with the fire wall moved closer to the seat to accomodate the V8.