521 brakes

[dbuzz77]

it has been 30 years since i owned a datsun so i can't remember what the brakes are like. the pedal seems to go down a long way for my liking. i bled all 4 wheels ( it was a bit spongy before) and adjusted the shoes on all 4 wheels. maybe that's just the way it is or is it the master cylinder? thanks

[vindats1]

Sure you got all of the air out? Most likely mst cylinder. Seen any leaking from the wheel cylinders? good luck, T

[nukeday]

Welcome to 1950. j/k...

 

The 521 brake system is a topic of much discussion here. Fisch had a stuck wheel cylinder (or two?) and zenndog wrote up a great 'how-to' on R&R'ing the system. Zenndog has a 320, which is an earlier truck, but most (if not all) of the brake parts interchange. MKlotz would know for sure.

 

Did you pull the drums and do a visual inspection at each wheel?

 

The brakes are not self adjusting, so they need to be kept after to function right. The emergency brake on the rear axle is also usually a problem area (the cabling, not the shoe actuator).

 

Good luck.

[fisch]

Welcome to 1950. j/k...

 

The 521 brake system is a topic of much discussion here. Fisch had a stuck wheel cylinder (or two?) and zenndog wrote up a great 'how-to' on R&R'ing the system. Zenndog has a 320, which is an earlier truck, but most (if not all) of the brake parts interchange. MKlotz would know for sure.

 

Did you pull the drums and do a visual inspection at each wheel?

 

The brakes are not self adjusting, so they need to be kept after to function right. The emergency brake on the rear axle is also usually a problem area (the cabling, not the shoe actuator).

 

Good luck.

 

Very true! Man I almost forgot about this! As I recall the system bled fine and adjusted fine, but because the rear cylinders were frozen, I had no back brakes and didn't know it!! I just thought the brakes really really sucked.

 

As was told to me, jack up the rear, spin the back tire and hit the foot brake. Did it stop?

[dbuzz77]

i adjusted each wheel till it scraped slightly when it was turned.

[mklotz70]

you can get the factory manuals at www.olddatsuns.com (free) on the tech page.

 

If the pedal travels too far before it has pressure, it's adjustment. If it travels too much after resistance(spongy) it's probably air in the line. If it gets good and firm, but you have to keep pushing harder, I'd sand paper the shoes to get any glazing of and maybe even have the drums turned too. ........wait....that's not what "I'd" do at all.............I'd put discs on it :) But, that's just me :)

[lil89ram50]

im gettin a 521, and he said he jus re did the brakes, but he still has to pump it a few times before they work.... could it jus need to be bled, or is more like wheel cylinders or master, or is this jus a normal thing? also how much does it cost total to convert to discs?? i would like to do it.

[mklotz70]

If it has to be pumped, it's adjustmet. The shoes are too far away from the drums and it takes a second pedal stroke to get them there.

[lil89ram50]

ok thanks :) so how much does it normally coes to convert to discs... this is with beebani brackets right? ot do you make the brackets? and how much are they, and what else do i need to get to get the calipers and discs and what ever else from? sorry for the q's i searched n couldnt really find much, could u show me where to look or jus tell me? lol

[dbuzz77]

as i said, i bled them to get the spongy out and i adjusted each wheel for travel.

[nukeday]

dbuzz77, what is your concern with the brakes now? Are they not stopping the truck? High pedal effort? Pumping?

[lilhustler521]

ok thanks :) so how much does it normally coes to convert to discs... this is with beebani brackets right? ot do you make the brackets? and how much are they, and what else do i need to get to get the calipers and discs and what ever else from? sorry for the q's i searched n couldnt really find much, could u show me where to look or jus tell me? lol

 

It will probably cost you about $400 if you use all new parts to convert including brackets. Another alternative is to hit the junk yard for your calipers and hoses, this will save you a pretty penny and there are tons of pathfinders in the junk yards in beatiful condition because of cash for clunkers. The rotors you will probably have to buy new because I dont think you will find a 2002 rodeo at the j/y, but they are only $30 a peice anyway. Coincedently I sell brackets to, here is a link to more info on the conversion and my brackets... http://community.ratsun.net/topic/19655-truck-cnc-aluminum-brake-brackets/

[dbuzz77]

there just seems to be a lot of pedal travel compared to what i am used to.

[mklotz70]

You'll have about 1/4-3/8" of travel before the pushrod really engages the m/c. It will go about 1/2 way down from there before it gets firm....this is because of how far it has to move the shoes before they make good contact. from there, probably another 1/2-3/4" of modulation....maybe more. With disc brakes, the pads are basically up against the rotor, so it takes very little movement for them to be engaged. Plus, all the parts are more rigid, so there's less flexing as you press hard.

[dbuzz77]

i'm gonna try that e brake trick on the rears and i didn't know the shoes would re-center if you pumped the brakes while adjusting. it's crappy out here so i don't feel like doing it today.

[mklotz70]

That bottom adjuster slides in the backing plate....if it moves at all, they need re-centered. Plus, as you move the shoes apart, their circumference changes, they'll re-center more accurately.

 

I typically adjust until I get some rubbing, but not dragging. I press the brake pedal hard to re-center things. I tend to find no rubbing when I go back and spin the wheel. Also....I do it with the wheel bolted on with all four lug nuts....just to make sure there's no chance the drum warps slightly. By putting the wheel/tire on, I get more leverage when turning it and a much better idea of just how much drag the car will feel. If you do it with just the drum on, you have zero leverage and it will be hard to turn with even the smallest amount of rubbing.

 

I think in the manual, they say to crank the adjust down until it won't move, then back it off "X" number of clicks. By cranking it down hard, that is mechanically centering it. I don't ever seem to find it works out to the same clicks as the manual calls for. I like to creep up on it.

 

 

I hope you don't mind that I copy this here from the pm I sent....I kept looking at the above post wondering where I said that....then I remembered the pm :) Anyway....for clarity...this is what I sent in the pm so everyone knows what the Ebrake reference is.

 

 

"One thing you might try......

 

It's okay for the shoes to rub a bit. I adjust them, then push the brake pedal to get them to recenter the shoes, then adjust them again. If you pull the Ebrake, then apply the foot brake(may have to pump once) and the distance the pedal needs pushed is less, then the adjustment in in the rear. Release the Ebrake and readjust.

 

I'd personally upgrade to a dual resevoir m/c for safety reasons. If you the upgrade, you can put an m/c in with a bigger bore and you'll have less pedal travel."

[dbuzz77]

the e brake trick didn't prove anything, but i still might adj each wheel. i take it from all this conversation that the master cyls don't go very often, it's usually other stuff.

[mklotz70]

Usually, if it's the m/c, the pedal will go down slowly while pressing on it hard. If it does go down slowly, it can be a leak inside the m/c...or it might be coming out by the pushrod. If it was a dual reservoir m/c, there's at least one more prob it could have, but it's not. If there was no change in the pedal travel with the ebrake applied, then that would tell me the fronts need the adjustment. By applying the ebrake, you eliminated the travel of the rears. It should have felt better if the rears had the adjustment issue.

 

Just how close is it getting to the floor? The pedal on a drum setup can go through 3/4's of it's travel, which seems like a lot if you're used to driving with discs. If you can stop the rig quickly without it pulling or locking up one wheel before the others....it's probably just fine.

[dbuzz77]

that's what i was wondering about, i haven't driven a totally drum setup for years. when i adjusted the rears, the e brake worked better. i think i will still adj them using the centering method you gave me to make the clearance tighter.

[raggmann]

I don't want to hijack the thread but........

for the guys with 521's, what are you doing for bake cables?

I've got bad rear cables on both sides and any truck over 10years old needs to be inspected here before we can get plates. They only have to be inspected after a transfer of ownership so once I get plates I'm good.

I'm curious if the 74-79 620 cables are the same?

Does anyone have part numbers for the521's or do you get them custom built, or what do you do?

How does one go about getting the cables? Are they available NOS or ?

 

Thanks in advance,

Ragg

[mklotz70]

I'm nearly 100% positive the 620 cables will not fit correctly. For the factory part #'s, you can download the entire parts manual at olddatsuns.com

[dbuzz77]

a big difference after adjusting, 2 wheel were too loose.

[mklotz70]

Glad you got it taken cars of.

[pwrcat4000]

I don't want to hijack the thread but........

for the guys with 521's, what are you doing for bake cables?

I've got bad rear cables on both sides and any truck over 10years old needs to be inspected here before we can get plates. They only have to be inspected after a transfer of ownership so once I get plates I'm good.

I'm curious if the 74-79 620 cables are the same?

Does anyone have part numbers for the521's or do you get them custom built, or what do you do?

How does one go about getting the cables? Are they available NOS or ?

 

Thanks in advance,

Ragg

Me too cables are frozen in the casings so bas it broke the Right side cable in the back would be really nice to have ebrake with std transmission

[raggmann]

I managed to order cables from my local Nissan dealer.

They got them right from Japan and were cheap in my opinion.