car failed nct/mot advice needed

[japimport]

my friends car failed its nct/mot,it failed on rear brake imbalance, i dont know what this means,is this expensive to fix,or could you do it yourself,thanks for your help

 

[wemorgan]

Sounds like one rear brake is working OK and the other not.

I'd start by checking-adjusting-replacing each brake.

 

[para alpha]

my friends car failed its nct/mot,it failed on rear brake imbalance, i dont know what this means,is this expensive to fix,or could you do it yourself,thanks for your help

You didn't mention if the imbalance was if the front or rear brakes?

 

[hitenhirani]

You didn't mention if the imbalance was if the front or rear brakes?

my friends car failed its nct/mot,it failed on rear brake imbalance, i dont know what this means,is this expensive to fix,or could you do it yourself,thanks for your help

the rear.

 

[grober]

the equation is :-

(Higher brake effort - Lower brake effort) x 100 / Higher brake effort = % imbalance

I think the limit is 25% but the regs keep changing so don't quote me. Action required depends on the nature of the rear brakes ---- disc/caliper only, drum/shoes only, or a disc/drum combination like Mercedes. May also depend on whether the imbalance showed up with normal braking or application of the handbrake only? Could be down to poor adjustment but more likely a seized caliper, leaking cylinder or worn shoes or pads.
http://www.ukmot.com/index.asp

would be useful to know the make and model of car--mercedes or other?

 

[para alpha]

the rear.

thanks for the correction?

 

[AllanE]

25% last time I had an MoT.
There's two 'versions' of imbalance - the 25% load and the speed they apply - I remember the tester asking me to apply the brakes slowly so he could see the two lines of LEDs increasing at a similar rate.