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Rear drum brakes question

imiceman44

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So this is question for all the professionals that install breaks for a living can you answer this question because I am stumped here.
All my life changing brake shoes I replaced the same way they were, if both front and rear liners were same length it was no problem, but when it was short and long, I put the short one facing forward like I found it.
Now I was working on my 1996 suburban and I found one wheel with 2 long ones and one with 2 short ones.
Needless to say, that side was destroyed.
So Installed the new shoes like I know with all new hardware because someone destroyed and now I have a violent shake, actually bounce, it makes the right side bounce up and down when I brake at speeds more than 20mph.
I swapped parts from left to right including the drum, still the same thing on the right.
Afte 3 days driving a total of 100 miles t20210624_121919.jpghe short side on both wheels are down 30% and I have a lot of dust.
Did I install wrong, or is this a defective shoe lining or is there a problem with my wheel cylinders?
Thoughts please
 
How easy/hard do the drums slide on/off? Adjustment could be too tight.


Other issue is the wheel cylinders are stuck and not relaxing when the pressure is off.

Either way the shoes will drag and wear quickly.
 
The primary (short) shoe faces forward, secondary (long) shoe is at the rear.
Did you have the drums turned while they were off?
 
How easy/hard do the drums slide on/off? Adjustment could be too tight.


Other issue is the wheel cylinders are stuck and not relaxing when the pressure is off.

Either way the shoes will drag and wear quickly.
The drums come off easily but the adjustment is really close.
There is an air gap and they are not dragging if that is your question.
I just checked and the wheel cylinders are not stuck.
I am stumped.
I just got a 14bsf six lug to replace it, but I have a trip next week and I was hoping I could just fix the brakes for this trip and then change when I get back.
New axle is 4.10
Old axle is 3.73
So I need to change both front and back technically to have no problems but I guess I could not use the 4wd.
 
Since the PO installed the shoes incorrectly, you might want to check the star wheel adjuster screw - they should turn in opposite directions since rockauto indicates a left and right part.
 
Since the PO installed the shoes incorrectly, you might want to check the star wheel adjuster screw - they should turn in opposite directions since rockauto indicates a left and right part.
I did and I cleaned and greased them.
One side was completely stuck and the other was not adjusting easily.
They're marked L and R.
I released the adjustment a little bit and it's less violent now.
I also suspected the shocks since bouncing is the problem so I replaced all four. No change.
 
How easy/hard do the drums slide on/off? Adjustment could be too tight.


Other issue is the wheel cylinders are stuck and not relaxing when the pressure is off.

Either way the shoes will drag and wear quickly.
Could it be the master cylinder?
 
Stumped for the time being. :thinking:
It’s not leaking gear oil on your shoes is it? Probably just brake cleaner I see.
 
Stumped for the time being. :thinking:
It’s not leaking gear oil on your shoes is it? Probably just brake cleaner I see.
Just brake dust.
It was perfectly clean 3 days ago and the springs are orange blue green and yellow.
They are all black now
 
One thing I didn't consider, I have a similar shake but much milder when I get up to 70-75 mph, I did balance all tires and did an alignment.
It still does.
I wonder if a tire is out of round and causing this
 
what kind of wear did/do the backing plates have? If groved badly it could be hanging a shoe. got a picture of side assembled no drum
 
what kind of wear did/do the backing plates have? If groved badly it could be hanging a shoe. got a picture of side assembled no drum
You might have nailed it.
There is wear on the backing plate from the previous setup when it got destroyed.
That could explain the bouncing.
But why are both sides wearing the front lining faster than the rear?
Puzzling.
I guess I am swapping axles.
Not going to change backing plate on this 10 bolt
 
you could weld them and grind them flat if really bad, I suspects just one or 2 pads may be the culprit. The shoes wear a little fast on the leading and trailing edge, when first installed. Since no one arches shoes anymore.
If your shoes drag a little to much the front will tend to pull into the drum, only 1 spring pulling against rotation. While the rear shoe has a stronger/shorter spring pull with rotation.
I always tighten up till I can't turn the brake with wheel on. Step on brake pedal, back off several turns, step on pedal and recheck. I go back after 50-100 miles and do it again, once shoes have shaped to drum.
A grove in the front shoe pads can cause this drag too
 
you could weld them and grind them flat if really bad, I suspects just one or 2 pads may be the culprit. The shoes wear a little fast on the leading and trailing edge, when first installed. Since no one arches shoes anymore.
If your shoes drag a little to much the front will tend to pull into the drum, only 1 spring pulling against rotation. While the rear shoe has a stronger/shorter spring pull with rotation.
I always tighten up till I can't turn the brake with wheel on. Step on brake pedal, back off several turns, step on pedal and recheck. I go back after 50-100 miles and do it again, once shoes have shaped to drum.
A grove in the front shoe pads can cause this drag too
Not wasting time on this axle.
Tomorrow I am putting the 14bsf in.
 
score and I just missed it. 4.10 versions are difficult to find.
I saw it and looked at the glove box and it showed 4.10 gt5 and gov lock g80.
Exactly what I want, I popped the cover and confirmed both.
The only thing missing is the bracket to bolt the sway bar, but I can cut it off mine and weld it on.
 
My guess on why the rears were wearing so bad and hopping is, the proportioning valve is jacked up or the master cylinder is bad and the front brakes are not doing their job like they should.
 
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