rear brakes not working

[yochase]

I have had my 74 620 for about a year now i just put a new brake master cylinder in it and i no longer have any rear brakes. mind that i have bled the air out of them very well (about a quart of new fluid). i am thinking they are just out of adjustment but the adjuster is like nothing i have worked on before. any help or ideas would be great. thanks

[jastrunk97]

Bench bleed and all? your 74 shouldn't have the NLSV

[yochase]

yes i did bench bleed. what is NLSV?

[jesusno2]

It's a load sensing valve on the passenger side frame rail that all the brake lines T into. It needs to be vacuum bleed for best results. Yea ya need to adjust the rear brakes their not self adjusting. It is possible that you may not have a NLSV but i think that was 73 model, but it may have continued into early 74 models.

[yochase]

thanks i will try and vacuum bleed it. the strange part is they worked fine before the old master died. it doesn't make any sense. also i have kind of a dumb question, it shouldn't affect the regular brakes if my ebrake has been removed would it?

[Suspect]

my 77 has that NLSV or brake proportioning valve valve but my 73 and 74's dont have it.  Keep in mind that the brake adjuster will break if they are froze up and you force them to move and I have no idea where you can even buy new ones.

[yochase]

i spent all day trying to bleed some air out of it with a vacuum and it will start to stiffen up then just vanish and sink to the floor again, i am going to pull the rear drums off tomorrow and check things out i don't know what could be wrong i just did drums hard ware and wheel cylinders in the rear maybe a month ago and everything ran fine till last Wednesday.

[jimmy dale]

morning my 78 and the 73 we just got both have the NLSV valve I had minimal brakes also in just the rear I even adjusted the brakes tight and still had none when I stepped on it

on the passenger side in line with the brake lines mine is just behind the door about 3 inches it might be there bleed the front and work towards the back then rebleed each wheel 

 

when I had the wheels off  and stepped on the brake the back did move when I applied my hands and squeeze it the other side moved so it was confusing  be very careful when adjusting the rear brake adjusters I lost one of the little clips and had to go to ford and special order them took 2 months to get

we just picked up a 3 yesterday if you need any pics I will be under it today and will take video  just to log it

I put my vids on YouTube J Hubert /  

  here is a short video makes it easier to find them I will try to get it on this afternoon to atleast show the bottom and clips and or bleeder NLSV valve

[yochase]

Thanks for all the good info. I am going to pressure bleed it tonight with the hopes that it will gett all the ait out.

[yochase]

So I got alot of pedal back with the pressure bleading but it is still squishy. I am starting to suspect my new master is no good. What masters can I use that are a better design? With little to no fabrication.

[datzenmike]

Try for an original Nissan part. Or one made in Japan.... beware the original master may have been collected from junk yards and rebuilt in China or where ever with crap internal parts. Nissan on the outside and crap on the inside.

[wickedminded420]

You can still get the adjusters at the nissan dealership considering i got mine there about three months back :D

[jimmy dale]

OK well I bled it out in order 3 times the 78 with nlsv valve

master F  R

RIGHT FRONT

LF

LR

RR

NLSV REAR

NLSV MIDDLE

ADJUSTED THE REAR UP TO STOP THENBACK IT OFF STILL HEAR IT kinda hitting

and still have no rear brakes it does push the break out but with no power I can hold it in with my hand and the other shoe pushes out.

new adjusters  new shoes  and no air in the system  what is next just stumped

[jimmy dale]

oh and when it is pumped the fluid in the rear or front bottle on master keeps breathing goes up when peddle is pumped and then goes back down

bad master?

[420n620]

oh and when it is pumped the fluid in the rear or front bottle on master keeps breathing goes up when peddle is pumped and then goes back down

bad master.  

the rear plunger seal is bad in the masters but you know that now.  ;)

[jimmy dale]

yes as it had me and you stumped thanks for coming up and helping me with it 

I had movement in the rear just had no pressure so the master needed a little fixen

got good brakes now after 3 masters and a good friend's help

[yochase]

Update! I went with a 240z master and disk brakes in the front much better.