My old 5 series still has a crap HB even after the rear discs/ drums, HB shoes & fitting kit were fitted last year .. ok as a parking brake (just) but will only hold the car idling in 'drive' if the HB is applied just before the car is brought to a halt on the service brake, but this makes for discomfort for any passengers.
Yep, I heard lots of similar stories, from owners, replacing parts of the HB system, and it being no better. The only part I replaced on mine, was the nyloc nut, because the thread had been stripped - I had to drill it off.
Well, assuming yours, is similar to the 75's HB......
There is an adjuster nut, a nyloc nut, tucked inside the lever, on a long thread. People tended to just adjust the system there, and the nut would end up tightened all the way and jammed on the bottom of the thread. Some have to be drilled, to get them off the thread.
The part that deforms/stretches, the compensator, to balance the pull on the left and right drums, is attached to the adjuster thread, by a very short cable, which hooks onto the compensator.
The two parts of the compensator itself, are linked, and allowed to swivel, by being linked by an item which looks quite similar to a 6 inch nail, with no point, and bent into a U. All of the HB, is taken through the head of the nail, and the U around a peg - The other end of the nail is restrained, but not attached. What happened, was that in use, the position of the U, would be gradually forced to move down the nail, allowing the two parts of the compensator to move apart, and needing the nyloc nut adjusted, to take up the increasing slack. The nail, was made from a very soft mild steel.
That problem, was compounded, by drivers being less inclined to use the handbrake - that causes the inside drum surface to rust, and the rust dust acts as a good lubricant. The worse they become, the more effort needed at the lever, the more the compensator tended to stretch. The stretched compensators, didn't show any obvious sign of being deformed, that was until you placed one next to a new one, then the extra length became obvious.
The fix was simple - I offered a free service, other than my costs, to exchange stretched compensators, for reshaped and reinforced compensators. I, cut the compensators apart, reshaped the U in the nail, back to where it belonged, reassembled, and welded up, including welding the open end of the U, so that could no longer move. As said, I did hundreds of these, as a mail order exchange service..
The other part of the fix, is to make regular use of the handbrake, to stop the car, to clean off, and prevent the rust in the drum. As I slow down to a gentle stop in traffic, I pull the handbrake on, a click, so it gets some use. One click will slow it, two clicks will hold it on a slope, three will hold it on any slope - or lock the rear wheels on the move. Best part is, I don't have to heave on the HB lever, to get it to work.
The manufacturer's under warranty fix, for the dealers, was to drive the car round the car park, with the HB partially applied, to clean the rust from the drum.
