Drum and Disk Brakes question

[Suspect]

On my 77 Datsun, it has 4 wheel drum brakes. Everything is new, lines, master cylinder, drums, shoes, etc. I get the brakes working good and it last for about two weeks then there is no pedal. Its not loosing any fluid. I think it has to do with the brake adjusters. But anyways, is there a way to put front disk brakes on it? I've seen wild wood brake kit but thats too much money. Can I use something off an 80's nissan pickup?

[datzenmike]

Sure, if you look here:...

 

http://forum.ratsun.net/showthread.php?t=2129

 

 

...you'll find, this:...

 

http://forum.ratsun.net/showthread.php?t=154

 

There's probably more if you look.

[Llittle_Llama]

pm beebani

[Bleach]

really... NO pedal in two weeks? The brake pedal just goes to the floor?

You've got other problems. Bad master cylinder if the fluid is still full.

 

Properly adjusted they are still soft feeling brakes and need to be re-adjusted once a year. Maybe twice a year if you're picky.

 

Disc brakes just give a more firm stopping power.

 

Short answer on your disc brake swap: there is no cheap factory brakes that will bolt on. You need to buy lower control arms from a certain Datsun truck, custom upper control arms (search for those here), and brakes and spindles from a certain truck.

[Suspect]

Well, barely any pedal....

 

I just reajusted the brake adjusters again and I have brakes now. The ajusters seem to work correctly and they arn't striped. The shoes still look new so its not them wearing out in 2 weeks. I havn't bled the brakes the last two times I reajusted them. I don't mind drum brakes but its a pain to have to keep ajusting them.

[datzenmike]

The proper bleeding order for the '77 brake system is:

 

master cylinder front, master cylinder rear, load sensing valve front, right front, left front, left rear, right rear, load sensing valve rear, load sensing valve center.

 

The NLSV, Nissan Load Sensing Valve is located on the inside of the frame rail below the pass seat.

[SHADY280]

umm correction on mike, for the bleeding, as for the operating cylinders at each drum, you have to do the furthest one from the master cylinder first, so right rear, left rear, right front left front. sounds like you arent adjusting them correctly. there should be a slight to meduim drag to each one, not too tight, beacuse it will wear very heavy, and not loose either because youll have excess pedal travel. also check the spring across each adjuster and make sure its there, without that they will adjust by themselves.

[datzenmike]

umm correction on mike, for the bleeding, as for the operating cylinders at each drum, you have to do the furthest one from the master cylinder first, so right rear, left rear, right front left front.

 

The method I describe is word for word from the Nissan factory service manual. Chilton's is the same. :mellow:

[fiveNdime]

The NLSV, Nissan Load Sensing Valve is located on the inside of the frame rail below the pass seat.

 

The 521's dont have these valves right? I have bled my brakes a couple times and they seem great.

 

On that adjuster thing I know my truck was very picky on having them just right on all 4 corners. It would pull one way up front so you have to spend a little quality time with the drums after a brake job.

[datzenmike]

The 521's dont have these valves right? I have bled my brakes a couple times and they seem great.

 

On that adjuster thing I know my truck was very picky on having them just right on all 4 corners. It would pull one way up front so you have to spend a little quality time with the drums after a brake job.

 

I couldn't find one on the 521s. Up to a point, smaller wheel cylinders could be used on the back to bias stopping power to the front wheels.

[Bleach]

The method I describe is word for word from the Nissan factory service manual. Chilton's is the same. :mellow:

 

Nissan is wrong. Chilton's just copies the Nissan manual. :blink:

as for me and my house, we start with the rear right. ;)

 

Also, I think this guy's adjusters are backing off. Maybe they need cleaning or replacing.

[datzenmike]

Nissan is wrong. Chilton's just copies the Nissan manual. :blink:

 

I hear that. I have another FSM listing the Z series main bearing size the same as the L16/18. I've measured them L20B, Z20/22/24 all 6 bolt crank mains are larger than the 5 bolt, period.

[dat521gatherer]

if you suspect the adjusters just count the clicks. adjust the tire til it doesnt move and count the clicks that you back off. then the next time you check them you will have a reference of how many clicks til the tire stops moving.

 

if you dont hear any clicks you have a problem.

 

i think your bleeding the master cylinder by adjusting the wheel cylinders in and out. definitely a master cylinder prob i think. good luck.

[dat521gatherer]

any time the pedal falls to the floor and there is no leak its the master cylinder. or you've popped out a wheel cylinder which would make a mess.

[Jester]

Sorry Mike but I have to agree with the corrections. I have ALWAYS been told to start at the furthest point away from the master and work to it.

 

As for the adjusters, when your done with your next adjustment, put a "referance mark" with a sharpie or paint so you can see if they are un-adjusting themselves. If this turns out to be the case, go from there.

[datzenmike]

Sorry Mike but I have to agree with the corrections. I have ALWAYS been told to start at the furthest point away from the master and work to it.

 

 

 

O K sounds good. Both ways seem to have merit. What about the load sensor valve... back moving toward the front?

[Jester]

Kinda like first come, first served. Starting in the back. ;)

[Suspect]

I'll have to look over everything when I get a day off work. Now I have another small issue, the U-Joints. I drive so much that its hard to find time to do anything. I started driving it May 2nd and already put 8000 miles on it so far.