Navara brake imbalance

ploughbynight

This forum has gotten me out of sizable holes before, here goes again!
I have a 06 Navara with 110,000km only.
Just failed the DOE/MOT last remaining issue (after 2 retests) is teh rear brake imbalance. It was at 60% now its down to 50%. Drums are clean and functioning to the eye. Can anybody shed some light on what might cause such an imbalance. Pads are ok.
Ta.

Slideways

Is it just footbrake or has the parkbrake got an imbalance too? Have you got the readings? If you have throw them up.

Initial thoughts would be a sticking wheel cylinder or glazed shoes.

ploughbynight

Parking brake is 240KGF 393KGF 39%
Service Brake is 265KGF 529KGF 50% FAIL
Shoes look ok

Slideways

Both readings are out. Are the shoes correctly adjusted? If they are and the drum has no lip or scores I would be looking for shoes. They may have gone hard. Often times the reason for this is because they haven't been working I.e. Faulty slave cylinder

ploughbynight

I will try shoes and see how we go. There was a small leak from a pipe for a while. We didnt touch any of teh cylinders. Ta for now at least.

Irish Steve

Not on a navara, but had a scenario a while back where one of the two plungers in the slave cylinder seized in the bore, had to use a VERY big hammer to get it to move, and once it did, it worked perfectly, though for safety, the entire slave cylinder was changed out. Might be worth a check

navara man

ploughbynight wrote: »

This forum has gotten me out of sizable holes before, here goes again!
I have a 06 Navara with 110,000km only.
Just failed the DOE/MOT last remaining issue (after 2 retests) is teh rear brake imbalance. It was at 60% now its down to 50%. Drums are clean and functioning to the eye. Can anybody shed some light on what might cause such an imbalance. Pads are ok.
Ta.

Nissan navara should ever have rear brake tested on (brake roller) for a doe/mot .because it has limited slip differential and it even on rsa tester manual .............would put a link if I know how ...just google "tester manual lgv rsa" go to page 34 service brake performance notes 12

ploughbynight

Tried new shoes and no difference. Will now argue the toss with test centre. I have tried to stick navara to the road at speed, both empty and with 500kg in back. I don't find it pulling to either side.

Slideways

Slowly pull up the handbrake and note if both wheels lock up at the same time.

There is no point arguing the toss with the test station, it either passes on the rollers or it doesn't

ploughbynight

The handbrake is ok and within tolerance...Has the Navara a peculiar hydraulic regulator for the rear brakes?

CJhaughey

ploughbynight wrote: »

The handbrake is ok and within tolerance...Has the Navara a peculiar hydraulic regulator for the rear brakes?

Most cars have some kind of brake proportioning valve to distribute braking forces evenly between the front and rear brakes, these can give trouble in my experience.
Also have you checked the Load sensing valve on the rear axle?

hi5

Try bleeding them, could be an air bubble at a high point on the weaker side.