Nissan Repair: Nissan Micra 1,0 rear brakes, nissan micra, wheel cylinders

Question
QUESTION: Hi
Have a Micra 1,0 Mouse year 1994 . Left rear brake is kind of weak in braking . I have changed both rear wheel cylinders and have bled the hole system very thorughly . Still there seems to be a problem with left rear wheel braking cability . The system is without ABS . The brake amplifier on main brake cylinder is working okay . All brake fluid is new now . Brake pads on rear wheels is also okay .
No leaks , no fluid on ground from any where .
What can be the course of weak brake pressure on left rear wheel ?
kr
carsten

ANSWER: Carsten,

If the brake fluid comes out fine when the brake is bled, like the rest, then the line is not crushed or blocked.  This is the usual issue.  I have had many a car come to me with a brake line that has been damaged by rod debris or a shop that has used a lift and crushed a line.  Another issue I have found is a defective drum.  The metal is work hardened and will not allow the shoes to bite.  Switch the drums from left to right and see if the problem follows the drum.

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QUESTION: Hi
Thanks
Theres also a brake pressure regulator that works by load . Could it be this one creating low pressure ?

kr
cn

Answer
Carsten,

The proportioning valve controls pressure from front to back.  If you do not have ABS the lines are connected this way.  Therefore, there would not be a bias from left to right.  Again, if there is less pressure on that side, and you have ABS then the module would be defective.  If no ABS check for a crushed line.