Mariposa Mike
Well-Known Member
I have an issue with rear brakes on my 66 Charger with 10 inch drums. I posted some of the problem after highjacking a thread with what I thought were similar issues but that has changed. As the car is new to me (one year) I don't know what someone else may have done in the past. I have a FSM manual so some of the brake questions will be related to differences in the manual pictures of the rear drums/springs. Also yes I have read the post begun in 2022 on dragging brakes and some of the problems there are similar but not exactly what I have encountered. So here goes:
Since buying the car I've seen that the front brakes have been serviced more recently that the rear and the system has been converted to a dual master cylinder and Dot 5. The fronts are not dragging but I've been dealing with dragging and overheating rear brakes since buying the car. Recently the right rear began to leak and I found the cylinder pistons frozen so replaced both rear cylinders. The other side was frozen as well. In doing so I also found that the return springs are the same length. The FSM shows one short and one long. Put everything together and drove a few miles only to find the rears smoking. After cooling down the brakes were not dragging. When posting questions about this it was suggested the master cylinder may not be relieving pressure due to the rod coming out of the booster being too long. Backed off the M/C mounting bolts about 1/4 inch and was able a couple times to get the pressure relieved but other times it was still dragging. Bought a new spring kit and it comes with the one longer and one shorter return spring.
So now I'm thinking maybe one or two problems. Weak return springs and maybe wrong springs. But....looking at the FSM FRONT brakes pictures the primary return spring is in two different locations/holes on the left and right. I'm also needing to pull the rear drums again and look at my setup because I don't recall holes on the shoes for the upper/shorter return spring. Might be there. Assuming it is I can make the change with the new kit but would like to know what the car came with because I might need different shoes as well. I've determined that the yellow spring is for the secondary shoe and that was reversed on my car with a slightly shorter reddish color spring in the lower hole. That spring did not seem to have a much tension as the yellow.
I do not believe the springs are the only issue but after reading the above referenced post on brake dragging/lining I have more to look at and the overheating might have compromised the bonded lining. Which brings me to one more request on opinions for bonded vs riveted. My plan is to rebuild with the spring kit and shoes if needed, test and if still dragging (expected) go to the master cylinder removal and measuring of the brake rod. Any additional thoughts or experience with this issue appreciated. I'm sure hoping the adjustment of the brake rod is doable without removing the unit and replacing the rod. Getting too old and decrepit to lay under the dash.
Since buying the car I've seen that the front brakes have been serviced more recently that the rear and the system has been converted to a dual master cylinder and Dot 5. The fronts are not dragging but I've been dealing with dragging and overheating rear brakes since buying the car. Recently the right rear began to leak and I found the cylinder pistons frozen so replaced both rear cylinders. The other side was frozen as well. In doing so I also found that the return springs are the same length. The FSM shows one short and one long. Put everything together and drove a few miles only to find the rears smoking. After cooling down the brakes were not dragging. When posting questions about this it was suggested the master cylinder may not be relieving pressure due to the rod coming out of the booster being too long. Backed off the M/C mounting bolts about 1/4 inch and was able a couple times to get the pressure relieved but other times it was still dragging. Bought a new spring kit and it comes with the one longer and one shorter return spring.
So now I'm thinking maybe one or two problems. Weak return springs and maybe wrong springs. But....looking at the FSM FRONT brakes pictures the primary return spring is in two different locations/holes on the left and right. I'm also needing to pull the rear drums again and look at my setup because I don't recall holes on the shoes for the upper/shorter return spring. Might be there. Assuming it is I can make the change with the new kit but would like to know what the car came with because I might need different shoes as well. I've determined that the yellow spring is for the secondary shoe and that was reversed on my car with a slightly shorter reddish color spring in the lower hole. That spring did not seem to have a much tension as the yellow.
I do not believe the springs are the only issue but after reading the above referenced post on brake dragging/lining I have more to look at and the overheating might have compromised the bonded lining. Which brings me to one more request on opinions for bonded vs riveted. My plan is to rebuild with the spring kit and shoes if needed, test and if still dragging (expected) go to the master cylinder removal and measuring of the brake rod. Any additional thoughts or experience with this issue appreciated. I'm sure hoping the adjustment of the brake rod is doable without removing the unit and replacing the rod. Getting too old and decrepit to lay under the dash.
