Ok, here's the deal....
I have everything ready for the frame/body re-encounter scheduled for tomorrow, Saturday Jan 31. I wanted to install the brake shoes as later in the process as possible to avoid any rust or time induced "stuck effect", and since it's easier to do while the body is off, I started them today. My problem..or question actually, is that when I installed them with springs, they are "loose"and don't seem to be secured.
I haven't installed the master cylinder (the tandem under the hood), so there is no hydrolic pressure yet, so I wonder if that is why the shoes are like this?!?!?! I also wonder if the springs were installed the wrong way.....the manual has a diagram that is not very helpful on the subject......any takers?
Jorge
REAR BRAKE SHOES
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DatsunBucky
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Jorge0227-
Not being able to actually see the set-up puts me at a bit of a disadvantage, but I'll take a stab at it.
There is a horizontal spring that pulls the tops of the shoes together and another to pull the bottoms together. The bottoms of the shoes rest on a tapered adjustment post whereas the top of the shoes are pushed outward by the action of the wheel cylinder under pressure. The shoes are retracted back to "idle" position by the spring between the tops of the shoes. With the adjustment post all the way back, the shoes should not be in contact with the drum. That's why drum brakes are actually prefered by some drag racers: no hydraulic pressure = no friction.
IIRC, with no drum in place, there will normally be a little movement of the shoes, but they shouldn't fall off. If they do, something is wrong. I wouldn't worry about "time induced 'stuck effect'" If the shoes are not in contact with the drum, that won't happen. There should also be a bit of white grease (like lithium) where the shoes contact the backing plate to keep things moving freely.
If the shoes are loose at the top, then I don't know. Maybe wrong shoes. Maybe wrong wheel cylinder. Maybe the return spring (the top one) is too long. Having hydraulic fluid in the system shouldn't make any difference with that. The return spring will push the fluid back into the master cylinder when pressure on the pedal is released. So the shoes should contact the cylinder when everything is relaxed.
In sum, the springs go horizontally between holes in each of the shoes, pulling them in to a tapered post (bottom) or the wheel cylinder (top). The handbrake pulls the leading (I think) shoe, and when it contacts the drum the wheel cylinder slides until the other shoe contacts the drum. The diagram in the manual IS a little vague, but the shoe on the left is supposed to be where the spring ends are.
Bet you're gettin' anxious!
Not being able to actually see the set-up puts me at a bit of a disadvantage, but I'll take a stab at it.
There is a horizontal spring that pulls the tops of the shoes together and another to pull the bottoms together. The bottoms of the shoes rest on a tapered adjustment post whereas the top of the shoes are pushed outward by the action of the wheel cylinder under pressure. The shoes are retracted back to "idle" position by the spring between the tops of the shoes. With the adjustment post all the way back, the shoes should not be in contact with the drum. That's why drum brakes are actually prefered by some drag racers: no hydraulic pressure = no friction.
IIRC, with no drum in place, there will normally be a little movement of the shoes, but they shouldn't fall off. If they do, something is wrong. I wouldn't worry about "time induced 'stuck effect'" If the shoes are not in contact with the drum, that won't happen. There should also be a bit of white grease (like lithium) where the shoes contact the backing plate to keep things moving freely.
If the shoes are loose at the top, then I don't know. Maybe wrong shoes. Maybe wrong wheel cylinder. Maybe the return spring (the top one) is too long. Having hydraulic fluid in the system shouldn't make any difference with that. The return spring will push the fluid back into the master cylinder when pressure on the pedal is released. So the shoes should contact the cylinder when everything is relaxed.
In sum, the springs go horizontally between holes in each of the shoes, pulling them in to a tapered post (bottom) or the wheel cylinder (top). The handbrake pulls the leading (I think) shoe, and when it contacts the drum the wheel cylinder slides until the other shoe contacts the drum. The diagram in the manual IS a little vague, but the shoe on the left is supposed to be where the spring ends are.
Bet you're gettin' anxious!
Bucky
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Minh
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The spring that clamp the shoes together must go on the inside. The spring tension the shoes to collapse inward.
Visually the springs can't be are not seen once installed.
Visually the springs can't be are not seen once installed.
'69 1982cc SU
'74 1600cc VW Bug
http://www.311s.org/registry/1969/srl311-07837.html
When life hands you lemons, ask for TEQUILA AND SALT!
'74 1600cc VW Bug
http://www.311s.org/registry/1969/srl311-07837.html
When life hands you lemons, ask for TEQUILA AND SALT!
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Guest
Bucky: Thanks for the explanation.....I understand now the mechanism, and the right "place" for the shoes to contact the system..........
Mihn: I am embarrassed to say this, but I went back, and I saw the problem.......I put the springs on the front rather than the back, and it was doing exactly what you said. They were being pushed forward. Once I put them on the back, the shoes got in place perfectly!
Thanks to both, because I was able to clarify all my doubts egarding rear brakes!
Jorge
Mihn: I am embarrassed to say this, but I went back, and I saw the problem.......I put the springs on the front rather than the back, and it was doing exactly what you said. They were being pushed forward. Once I put them on the back, the shoes got in place perfectly!
Thanks to both, because I was able to clarify all my doubts egarding rear brakes!
Jorge