Rear Brakes Locking up 85 720

[datzenmike]

Yup, that the NLSV.

 

 

 

 

[Stoffregen Motorsports]

Then what's the thing Thomas showed? Different valve for different years or models?

[datzenmike]

 

N.L.S.V. Nissan load sensing valve. I described how it functions on an earlier post. Have never seen a Datsun/Nissan proportioning valve that I know of. Pressure differential switches on dual circuit brakes are often called a proportioning valve. I think Nissan builds in the bias between front and rear circuits either in the design of the master cylinder and/or the size of the rear wheel cylinders.

[Sephakrid]

7 hours ago, Thomas Perkins said:

Never had a problem with mine.Never ever bled it.I say it is your emergency brake cable locking up.Take it off and check out the end piece.Had my 720 for 29 years with 391,000 miles on it.Only people that had this problem will know. this.This was about 15 years ago when this happened.It will get worse in time.

 

 

Currently going through that right now. The rears aren't locking up, but sometimes the passenger side cable doesn't fully release which causes some drag when initially releasing the parking brake. It also sticks more on cold mornings!

Edited January 7 by Sephakrid
Spelling error!

[datzenmike]

The best thing for e brakes is to use them constantly, keeps them shiny and rust free. Pull and release the brake a couple of dozen times.

[IZRL]

Good Ol' Autozone. I've had a few instances recently with online Autozone showing the correct photo for the part that I need. But what I get is not what is pictured. The part numbers are correct but the item is different than pictured. These brake drums just arrived and they don't have these threaded holes. This is the picture on Autozone's website. It took some serious pressure to remove the old drums even with the fact I used bolts in the bolt holes to pry them apart. Just looking for a second opinion on either just going with the hole-less drums, or looking elsewhere for the ones with the holes. I'm leaning towards looking for the ones with the holes. thanks

 

[datzenmike]

Drill and tap them. And do 4 of them.

[Thomas Perkins]

On 1/6/2024 at 9:07 PM, datzenmike said:

The best thing for e brakes is to use them constantly, keeps them shiny and rust free. Pull and release the brake a couple of dozen times.

I use mine everytime I park it.Habit I guess.

[Thomas Perkins]

4 hours ago, IZRL said:

Good Ol' Autozone. I've had a few instances recently with online Autozone showing the correct photo for the part that I need. But what I get is not what is pictured. The part numbers are correct but the item is different than pictured. These brake drums just arrived and they don't have these threaded holes. This is the picture on Autozone's website. It took some serious pressure to remove the old drums even with the fact I used bolts in the bolt holes to pry them apart. Just looking for a second opinion on either just going with the hole-less drums, or looking elsewhere for the ones with the holes. I'm leaning towards looking for the ones with the holes. thanks

 

Rock Auto parts has the drums with the two holes in it.

 

[Thomas Perkins]

On 1/6/2024 at 9:00 PM, Sephakrid said:

 

Currently going through that right now. The rears aren't locking up, but sometimes the passenger side cable doesn't fully release which causes some drag when initially releasing the parking brake. It also sticks more on cold mornings!

Pull it out and see if the end going into the drum is rusted out like mine was.May cause it to not release.Mine was rusted real bad.

[Sephakrid]

This is a little bit off topic, but does anyone know if the rear drum brakes on the 720 have primary and secondary shoes? The FSM only gives one dimension for the lining (width, thickness, length) and there doesn't seem to be any difference when I visually inspected the shoes earlier this month.

[datzenmike]

Leading and trailing shoes depend only on the placement of the linings on the shoes. Some are all the same and there is no way to put them on incorrectly. Others are glued on closer to the top or bottom and definitely need the shoes oriented.

[Stoffregen Motorsports]

On 1/6/2024 at 3:12 PM, datzenmike said:

 

N.L.S.V. Nissan load sensing valve. I described how it functions on an earlier post. Have never seen a Datsun/Nissan proportioning valve that I know of. Pressure differential switches on dual circuit brakes are often called a proportioning valve. I think Nissan builds in the bias between front and rear circuits either in the design of the master cylinder and/or the size of the rear wheel cylinders.

Ok, so now I'm confused. The little brass one I showed the pic of. Is that not an LSV?

[IZRL]

3 hours ago, Stoffregen Motorsports said:

Ok, so now I'm confused. The little brass one I showed the pic of. Is that not an LSV?

The brass piece you posted is just a fancy "T" connector hose that the two brake lines attach to. Rock Auto just mistakenly sent me this hose. I needed a different one. What year truck did you take that picture from?

[Thomas Perkins]

5 hours ago, IZRL said:

The brass piece you posted is just a fancy "T" connector hose that the two brake lines attach to. Rock Auto just mistakenly sent me this hose. I needed a different one. What year truck did you take that picture from?

85 720 4X4.I never touched it before.

[Thomas Perkins]

26 minutes ago, Thomas Perkins said:

85 720 4X4.I never touched it before.It is what came on the truck when they made it.They are showing many different types.Part number in picture is 46400.

 

Edited January 11 by Thomas Perkins

[Thomas Perkins]

Just now, Thomas Perkins said:

 

 

Just now, Thomas Perkins said:

 

 

3 minutes ago, Thomas Perkins said:

85 720 4X4.I never touched it before.I have adjusted the emergency brake cable as you see in the picture.I use it everytime I park it.

 

[Thomas Perkins]

1 hour ago, Thomas Perkins said:

II found a cool site explaining and  how to test it.It says the valve controls the brake pressure on front and back brakes.It doesn't say anything about just one rear locking up..It says the front brakes start stopping first then back brakes will start stopping.It has all the part numbers to the parts.It has other Nissan and Datsun cars too.It may not be the valve,maybe the rear brake cable.Never know,could be bad  brake master cylinder.These valves were 296 bucks when you could get them.Part number should be stamped on it.These are the 4 types of 4x4 valves.From 79 to  and after 85 8/11.I will look and see if I can see the part number on mine.

 

Edited January 11 by Thomas Perkins

[IZRL]

3 hours ago, Thomas Perkins said:

85 720 4X4.I never touched it before.

I was replying to Stroffegen's question. I believe what you posted is a proportioning valve.

Even tho my brake problem completely went away. I was still wondering where this NSLV part was. Well I'm here to report that my truck officially doesn't have one, neither does it have a proportioning valve. I had already followed all the brake lines from the front of the truck to the rear a few times. But there was about a 1 foot section next to the gas tank that I couldn't see. So today I followed the lines again but this time I moved the electrical wires that were blocking my view out of the way and nada, no NSLV.

 

[datzenmike]

Of course it doesn't it's from the Middle East!!!!! They probably didn't have them.

 

I have yet to see a proportioning valve on a Datsun. It's my belief that the front/rear bias is simply designed into the braking system. Probably the master cylinder and rear wheel cylinder size and design. Don't forget these have a front and a rear braking circuit. Simple enough to somehow have the rear less effective than the fronts.

[Stoffregen Motorsports]

10 hours ago, IZRL said:

I was replying to Stroffegen's question. I believe what you posted is a proportioning valve.

Even tho my brake problem completely went away. I was still wondering where this NSLV part was. Well I'm here to report that my truck officially doesn't have one, neither does it have a proportioning valve. I had already followed all the brake lines from the front of the truck to the rear a few times. But there was about a 1 foot section next to the gas tank that I couldn't see. So today I followed the lines again but this time I moved the electrical wires that were blocking my view out of the way and nada, no NSLV.

 

I got it from a google search for Nissan 720 LSV.

10 hours ago, datzenmike said:

Of course it doesn't it's from the Middle East!!!!! They probably didn't have them.

 

I have yet to see a proportioning valve on a Datsun. It's my belief that the front/rear bias is simply designed into the braking system. Probably the master cylinder and rear wheel cylinder size and design. Don't forget these have a front and a rear braking circuit. Simple enough to somehow have the rear less effective than the fronts.

Overseas Land Crusiers come equipped with an LSV, but they are more upscale than a pickup.

[IZRL]

13 hours ago, datzenmike said:

Of course it doesn't it's from the Middle East!!!!! They probably didn't have them.

 

I have yet to see a proportioning valve on a Datsun. It's my belief that the front/rear bias is simply designed into the braking system. Probably the master cylinder and rear wheel cylinder size and design. Don't forget these have a front and a rear braking circuit. Simple enough to somehow have the rear less effective than the fronts.

That could be it. Although aside from not having the NSLV, everything else in the brake system seems to be the same as the diagram posted by Thomas above (excluding part # 46400 proportioning valve).

On 1/8/2024 at 6:29 PM, datzenmike said:

Drill and tap them. And do 4 of them.

If it'll help anyone else.

 

There are 2 drum part numbers at Autozone that supposedly say are compatible with the 85 720 4x4. Part #s 3599 and 3584. Part # 3599 doesn't have the threaded holes and the website says they fit trucks built up to 03/85. The year of production on mine is 1984, which is why I chose these first. They also have a smaller diameter than the 3584s at 290mm. I should've measured mine before I ordered them, I trusted the year, rookie mistake.

 

Part # 3584 has the threaded holes and website says its for trucks built after 04/85. They are also a hair larger diameter at 295mm. What I did notice is that on both parts there is an inner rim that has a smaller diameter than the ones currently on my truck. I don't think this will make a difference tho. The shoes are just going to sit slightly closer together than before.

 

Edit: I just remembered that the rear end that came on my truck is not the same as the 85 rear ends that came on the 85 US trucks. Mine came with 4.62 gear ratio. Not sure if there's a difference in just the gears or the whole rear end?

 

 

Edited January 11 by IZRL

[datzenmike]

43206-T6000 11'82-03'85 does not include Heavy Duty and Cab/Chassis with dual rear wheels.

43206-80W10 04'85 and on.

 

I can't find any differences in the actual brake shoes or any of the other brake parts after 11'82 so the droms and shoes should be compatible. perhaps the threaded hole is what it is.

 

 

[IZRL]

Brake hose question:  im replacing all brake hoses. The front left and right hoses didn't have copper washers on the truck. which I thought was odd as they're similar to banjo fittings. Rock auto has some with and some without washers on their site. I didn't notice this when i ordered the hoses for some reason. So are they supposed to have washers?

[datzenmike]

From 11 '82 they did. 46237-A4600. You need two per side.