Brakes imblanaced across an axle MOT failure

[Bl0ndie]

Just had a joyous MOT failure, and as a competent DIYer I was hoping to fix the problems myself in order to not have to spank the entirity of my christmas budget on the car.
2011 Mitsubishi Outlander
Offside front brakes slow in rise (the MOT guy glossed over that when I asked him what that specifically means)
Nearside rear brakes almost inoperative 65%

Also have an advisory for nearside rear brake disc worn pitted or scored but not seriously weakened.

My thoughts (in ascending order of cost) are that the likely culprits could be the brake fluid has bubbles in it, the sliding pins on the calipers are sticking, and the pistons are seized and need rebuilding.

Does this process of elimination seem sensible? I'm also aware I'm fumbling in the dark as I've got no idea if I've solved the problem with flushing the brake lines. Anyone got any ideas how to self-diagnose this issue?

[littleredrooster]

I would forget the 'air bubbles' theory - there's probably less than a 5% chance it may be the culprit.

More likely is that something has seized - pins or pistons, as you already suggested; the only way to find out is to strip them and then it will become apparent.

I would suggest putting a pair of refurbed calipers on, and this should make the problem go away for at least another 10 years. I have faffed about freeing them off and rebuilding them, but the problem always seems to return after three or four years!

If the discs are less than perfect, you are going to need a pair of those also, to go with the new pads that you will be fitting.

[Krikkit]

Replace the rear brake materials, while you're in there be prepared for the calipers to have stuck pistons and sliders.

Easiest fix is to replace the calipers with sliders etc for refurbed ones, just need to bleed the brakes. Alternatively you can order pistons and seals etc and refurb a caliper yourself, depends how crusty it is as to whether that's worth the effort.

[VeeReihenmotor6]

Not sure how the braking system operates on those cars but aside from a caliper/slide pins it could be down to a regulator valve also.

[anonymous-user]

littleredrooster said:

More likely is that something has seized - pins or pistons, as you already suggested; the only way to find out is to strip them and then it will become apparent.

I would suggest putting a pair of refurbed calipers on, and this should make the problem go away for at least another 10 years. I have faffed about freeing them off and rebuilding them, but the problem always seems to return after three or four years!

If the discs are less than perfect, you are going to need a pair of those also, to go with the new pads that you will be fitting.

This will almost certainly be the culprit. I don't know what it is about Japanese cars but they seem to like having seized callipers for fun. As you say, buying refurbished callipers is a lot less hassle than rebuilding them.