R50 pathfinder / terrano no rear brakes

[Kieran the mechanic]

1997 r50 no rear brakes. I have fitted new shoes. new wheel cylinders. new master cylinder, abs is working. My master cylinder has the proportioning valve built in. Rear brakes very sad and can't pass brake test. any ideas or possible faults known? Thanks

[Mike W.]

Are the brakes adjusted correctly? Can you bleed the rear brakes? Assuming not a couple of things come to mind, brake hoses can fail by expanding internally and not allowing fluid to pass thru. So a bad hose is a possibility. And ABS can prevent bleeding. Sometimes you have to actuate the valves electrically inside the ABS unit, but sometimes you can get fluid movement by getting one side of the vehicle on pavement, the other on dirt and hitting the brakes hard. That will cause the ABS to activate and possibly allow fluid thru.

[VStar650CL]

Do you have a load-sensing valve on the rear axle? If so, that needs to be bled before you bleed the wheels. If you just bleed the wheels the LSV will usually have trapped air that kills pressure to the rears.

[Kieran the mechanic]

No load sensing valve it's built in to master cylinder

[mdmellott]

Does the ABS warning light come on when the ignition switch is turned to On and then turn off when you start the car? If it doesn't turn on initially, the ABS warning light bulb might be blown, or its fuse or circuit may be faulty. If that is the case, perform the self-diagnosis check outlined on page BR-46 through BR-48 of the FSM to see is there is a fault code, or codes, indicated for your ABS system. https://www.nicoclub.com/service-manual ... 7%2Fbr.pdf

[Kieran the mechanic]

The Abs light works as you say.

[Kieran the mechanic]

Are the brakes adjusted correctly? Can you bleed the rear brakes? Assuming not a couple of things come to mind, brake hoses can fail by expanding internally and not allowing fluid to pass thru. So a bad hose is a possibility. And ABS can prevent bleeding. Sometimes you have to actuate the valves electrically inside the ABS unit, but sometimes you can get fluid movement by getting one side of the vehicle on pavement, the other on dirt and hitting the brakes hard. That will cause the ABS to activate and possibly allow fluid thru.

I have steel lines and can bleed up good. I have tried abs on wet grass and it seems to do what it should... I have tried the bleed sequence on the Abs unit but no change

[mdmellott]

New shoes, wheel and master cylinders, brake system fluid lines bled okay, and ABS system works but you have no rear braking action happening which contradicts being able to say the ABS system works if you have no rear braking action. I assume you mean the braking action is weak and that you cannot lock up the brakes at speed even when you slam on the brake pedal. All I can think is what Mike W. already asked. Did you adjust the brakes shoes properly after you put the brake drum and wheels back on when you were finished installing the new shoes? What exactly is not happening when you apply the brakes?

[Kieran the mechanic]

I cannot past brake test. The gauge on the brake machine barely moves. Yes brakes weak.. All braking is coming from the front unless I have the shoes wound up so tight that I cannot turn the wheels, then I end up with a little bit more efficiency but excessive imbalance.

I may try another suppliers cylinders. Out of ideas..

[mdmellott]

Got it. Roller brake testing is not a routine inspection requirement for vehicles in the USA, as it is in Europe and Australia, except for heavy commercial trucks and buses. I would venture to guess that many vehicles in the USA would not be allowed on the road if roller brake testing was performed during our periodic registration inspections every 2 to 4 years.

I wish you the best of luck tracking down the faulty component. Do you think it could perhaps be worn out brake drums or oil contaminated brake shoes?

[Mike W.]

Have you tried pressure bleeding the system? Disassembled the rear brakes to make sure everything is correct and moves freely? I'm still thinking that the problem lies in the ABS unit and you may have to manually activate it during the bleed process to get all the air out.

[Kieran the mechanic]

Yea I have back bleed and pressure bleed, manual activation by the sequence in the the service manual?

[Kieran the mechanic]

Got it. Roller brake testing is not a routine inspection requirement for vehicles in the USA, as it is in Europe and Australia, except for heavy commercial trucks and buses. I would venture to guess that many vehicles in the USA would not be allowed on the road if roller brake testing was performed during our periodic registration inspections every 2 to 4 years.

I wish you the best of luck tracking down the faulty component. Do you think it could perhaps be worn out brake drums or oil contaminated brake shoes?

Our inspection here in NZ is 6 monthly for all trucks trailers. And all cars pre 2000 is 6 monthly and yearly 2000+ its a right pain/money making scheme

I have ordered new drums and wheel cylinders if this has no success I'll be replacing the abs unit.

[Mike W.]

Our inspection here in NZ is 6 monthly for all trucks trailers. And all cars pre 2000 is 6 monthly and yearly 2000+ its a right pain/money making scheme

Wow, that's extreme. Light trucks like the R50, not just heavy trucks like we often refer to as 18 wheelers? Wow.

Here in the US (which of course does you no good) many states have emissions inspections every year or two, and some, mostly back east, have safety inspections every year or two. Here in California where I am we have a very tight emissions inspection every two years, but no safety. Good luck with it.