How bad of an idea is this?

[crimsoneclipse]

1. Likely the heater core. Bypass or replace. 

 

2. The booster merely makes the break application easier. Possibly the master, but check the connections and lines first for leaks. Also check the fluid quantity. 

[datzenmike]

Brakes... in town the pedal goes all the way to the floor with no braking action at all????

 

Does the master cylinder have fluid in it? and does it need filling all the time? Do not drive with only the emergency brake. You've only been lucky so far, and luck always runs out.

[Bennn]

I don't keep driving when that happens I have to pull off and let it sit for a while then they'll regain pressure. The master cylinder is full now but might leak a little bit? I filled it a few months ago and it dropped to the low line about a week ago so not much leakage or seepage. I've looked over everything else and nothing seems to be leaking.

[Z-train]

That the block surface??? Looks like it's been buried in the ground for years. That's got to be cleaned up like this... 

 

Or as clean and bare metal as you can possibly get it. For the cast iron block a wire wheel on an angle grinder should do. The head is much softer aluminum and you'll have to go easier with it.

 

Use the 3m brand "ro-lok" (or similar)scotch brite disks (3" dia disks)on ur pnu angle grinder 2 prep 4 new headgasket(block) then clean with carb/choke and blue paper towels till no residue appears on cloth. Cast iron rings seat in better/faster on a "re-honed" cyl. Chrome rings accellerate long term cyl wear/taper!

NEVER,NEVER DO this.Block & heads surfaces are to be cleaned by hand ONLY.Never use powered rotary grinders/sanders.

[Bennn]

NEVER,NEVER DO this.Block & heads surfaces are to be cleaned by hand ONLY.Never use powered rotary grinders/sanders.

 

Eh didn't matter, took a razor to it cleaned off the gasket that was there and called it a day lol 

[xsdg]

I don't keep driving when that happens I have to pull off and let it sit for a while then they'll regain pressure. The master cylinder is full now but might leak a little bit? I filled it a few months ago and it dropped to the low line about a week ago so not much leakage or seepage. I've looked over everything else and nothing seems to be leaking.

 

This sounds like either a problem with the master cylinder (air, or damaged pistons), or a leak somewhere.  My guess is that city vs. highway driving doesn't make a difference, so much as how frequently/infrequently you apply the brakes.

 

First things first, though.  What color is your brake fluid?  When was the last time you bled the brakes?  When was the last time the brake system was flushed?  If your parking brake works in those cases, that suggests that the problem isn't the brake pads/discs/rotors, but the hydraulic system that actuates them.

 

Given no leaks and constant fluid level, I would start off with a really thorough brake bleed job.  _Don't forget_ that bleeding must start with the NLSV (Nissan Load Sensing Valve), which is on the inside of the passenger frame rail, directly beneath the passenger seat.  It has a bleed screw at its highest point.  After that, rear axle, then front axle.  I have had inconsistent braking happen when I had a leaky master _plus_ failed to bleed the NLSV.  I replaced the master (and made sure to bench-bleed the replacement), and bled the system in the proper order, and now the brake system works fantastic.

 

Next step if that doesn't work: bench-bleed master cylinder.  This can be done with the MC on the truck still, and will need to be followed by bleeding the system.  I would suggest doing the bench bleed, and then following it with a full brake fluid flush.  Not only will the flush get rid of old, potentially-hydrated or -contaminated brake fluid, but it'll also help to push out air that may be sitting in odd places in the system.

 

If that doesn't help, the last step is to replace the master cylinder.

[Bennn]

This sounds like either a problem with the master cylinder (air, or damaged pistons), or a leak somewhere.  My guess is that city vs. highway driving doesn't make a difference, so much as how frequently/infrequently you apply the brakes.

 

First things first, though.  What color is your brake fluid?  When was the last time you bled the brakes?  When was the last time the brake system was flushed?  If your parking brake works in those cases, that suggests that the problem isn't the brake pads/discs/rotors, but the hydraulic system that actuates them.

 

Given no leaks and constant fluid level, I would start off with a really thorough brake bleed job.  _Don't forget_ that bleeding must start with the NLSV (Nissan Load Sensing Valve), which is on the inside of the passenger frame rail, directly beneath the passenger seat.  It has a bleed screw at its highest point.  After that, rear axle, then front axle.  I have had inconsistent braking happen when I had a leaky master _plus_ failed to bleed the NLSV.  I replaced the master (and made sure to bench-bleed the replacement), and bled the system in the proper order, and now the brake system works fantastic.

 

Next step if that doesn't work: bench-bleed master cylinder.  This can be done with the MC on the truck still, and will need to be followed by bleeding the system.  I would suggest doing the bench bleed, and then following it with a full brake fluid flush.  Not only will the flush get rid of old, potentially-hydrated or -contaminated brake fluid, but it'll also help to push out air that may be sitting in odd places in the system.

 

If that doesn't help, the last step is to replace the master cylinder.

 

Awesome info! Thank you! Will be doing it this weekend! I want to do it this week but i'm working literally 18 hours a day all week. but again thanks! will update how it goes!

[Bennn]

Soooo I pulled my dash to replace my "Leaky" heater core. and it wasn't the heater core... So I don't know if this has ever happened to anyone else before but.. My transfer case is leaking into my speedo cable and running up the cable to behind the dash which is causing a leak onto the driver side floorboard. Would NOT have ever guessed that one. So now I'm just gonna take it to a shop and get a new speedo thingy for the transfer case. lol but I did solder up my wiring harness and all that works now so thats awesome! 

[Bennn]

Sooo my truck will not idle. Under throttle it does fine and motor is solid sounding. It sounds like it misfires a little at low idle then just shuts off. I've checked my vacuum lines and all looks well there. It was really random. Drove home next day won't idle. Any ideas? I'm thinking it has something to do with the carb but I'm not 100% so any ideas would be great. i adjusted the idle screw and it seemed to idle fine then started driving came up to a light and started idling at 3k rpm. I readjusted it and it sorta idles at 1500 only when the clutch is in. When the clutch is disengaged it won't idle. It tries and then just dies. 

[Bennn]

Anybody got any input kinda clueless on this one. Think it's carb related? 

[flatcat19]

Yeah. Buy a new Weber and never worry about a stock carb again. 

[Justin Berni]

Yeah. Buy a new Weber and never worry about a stock carb again.

 

YES.

I was questioning my new truck, slapped a weber on, and now I'm in love.

[xsdg]

Idles at 1500-3000RPM with the feedback carb sounds like a vacuum leak.

 

That said, the whole clutch thing is weird.  So, you're saying that it idles fine while you're holding the clutch pedal in, and then stalls when you pull your foot off the clutch pedal?

 

Anyway, from the symptoms, I would take a close look for vacuum leaks near the two vacuum switches that are just aft of the windshield washer reservoir.  The ECU uses those to determine whether the truck is idling or at full throttle or what.

 

Another thing to check is the anti-dieseling solenoid.  If the wire for that is flaky, that could cause issues.  Someone else mentioned that it only controls fuel to the idle circuit, so if you have your foot on the gas, the anti-dieseling solenoid isn't going to do so much.  But that should still cause the engine to die any time you have your foot off the gas, at speed or not.

[DatsunKing2014]

Ok guys im new to this but I have a question I have a 1981 datsun 720 p its king cab 4x4 with the z22 engine. I cracked the cylinder head im pretty sure. But im wanting to know if I can put a ka24de engine and tranny in the truck will they swap someone help I miss my truck

[flatcat19]

Ok guys im new to this but I have a question I have a 1981 datsun 720 p its king cab 4x4 with the z22 engine. I cracked the cylinder head im pretty sure. But im wanting to know if I can put a ka24de engine and tranny in the truck will they swap someone help I miss my truck

 

You already started a thread about that. Go back to your thread and read the replies. 

[datzenmike]

Ok guys im new to this but I have a question I have a 1981 datsun 720 p its king cab 4x4 with the z22 engine. I cracked the cylinder head im pretty sure. But im wanting to know if I can put a ka24de engine and tranny in the truck will they swap someone help I miss my truck

 

 

You already started a thread about that. Go back to your thread and read the replies. 

 

This is also bennn's post about his problems. Answers to your problems will confuse everything. As stated, you have a post. Use it.