BRAKES NOT WORKING CORRECTLY STILL

[22350]

I am having the worst time getting the brakes on my 1964 L320 to work correctly

 

New shoes, drums, wheel cyclinders, rebuilt master

 

To adjust I put the car on a lift.  released the parking brake cable.  Tightened the adjuster until it couldn't be tightened any more, then backed off 12 clicks

 

I am getting a "knocking" sound, which is the adjuster sliding into the end of it's floating track.  

 

Earlier I had them adjusted tighter, but that seemed to make the clunk worse.  Also the brakes would heat up and bind.  Even at the 12 click setting, the front right brake began to overheat

 

I am at a loss

[datzenmike]

Instead loosen the adjustment till wheel spins freely. Adjust tighter till the tire just rubs when spinning by hand. Step on brakes to center the shoes and check the tire just rubs when spinning by hand.

 

Grease the slider area. It should be free to adjust when the brakes are applied but once set they needn't move again. Do you have all the clips in? It shouldn't be loose.

[22350]

When I had it tighter, they would bind

[datzenmike]

WT Hell is that clunking????

 

Take the drum back off and turn the axle back and forth the same way. Does it clunk without the drum on???

[22350]

10 hours ago, datzenmike said:

WT Hell is that clunking????

 

Take the drum back off and turn the axle back and forth the same way. Does it clunk without the drum on???

No definitely in the brakes. 
 

I did another adjustment, releasing the parking brake cable and doing the 12 clicks and it appears to not do that anymore. 
 

my issue now  is the fronts binding, unless they are incredibly loose. Then they clunk, like the shoes are too loose, which they are 

[22350]

So I am pulling the wheels again and I have replacement springs, so i am going to change them in the front

 

Does the big spring go on the top of the bottom of the front wheels?

 

 

[Stoffregen Motorsports]

Are the shoes directional? If so, they may grab if installed the wrong way.

[22350]

30 minutes ago, Stoffregen Motorsports said:

Are the shoes directional? If so, they may grab if installed the wrong way.

They are on the front, but they are in correctly 

[Datsunscott]

Check the drum surface, Might need cleaning up good if they got brake fluid or crud on the inner surface.

I would check the shoes to see if they fit the drum inner circumference correctly. They may need arcing.

Also the front shoes are directional so make sure both are in correctly.

 

I normally do't turn them, just clean super good with something like purple power.

Then sand the braking surface evenly all around the inner surface with paper between approx 100 grit and 220. you want clean metal with no black staining,

I just sand them back and forth in the same direction they turn.

Check for a inner or outer ridge on the inner drum wear surface, might need turning the minimum at a good shop to remove if there is a ridge so they don't grab.

 

Put together and bleed brakes good all around. Than adjust up so cant turn by hand, then back off a couple clicks.

Then get inside and hit brakes good a couple times to help center them. Than retighten bit by bit till cant turn by hand.

Back off until you can barely turn them and repeat process.

Rarely are the drums warped enough to be a problem, if they are really out of round you will need to turn or new ones. But not likely.

 

Once you are satisfied they they have been cycled and centered a couple times tighten a click or two until they drag just enough you cant turn by hand.

Hit brakes again and check. might need to go a click or two more?

Or if dragging back off until you hear/feel  them barely just rub in one or two spots as you rotate the wheel.

Not scraping or locking up- just barely touching both sides. Do it by feel so both sides are equal.

 

I am in Fountain Valley. You can hit me up if needed. Scott

 

 

 

[Datsunscott]

Not sure if my post got in. Another thing to check!

Check the countersunk screws that hold the drums to the axle flange and front hubs.

I use a little grease or antisieze and torque tight so the drums have no movement.

I use a "hammer on it"  hand held impact when I do mine to get tight without damaging the phillips.

It drives the force down into the phillips as you torque.

My sisters honda was clunking in the front brakes- turns out the locating screws on the rotor were not tight,

It clunked even with the lugnuts torqued to proper spec. Replacing the damaged countersunk screws and torquing them fixed it.

Apparently the brakes/trans applied enough rotational force to be able to move the rotor when going from fwd to reverse at high idel

and sometimes braking.

[Datsunscott]

And might want to make sure non of the backing plates are bent while you are in there-

that all shoes sit on a flat parallel surface?

So the shoes are "straight" and the friction material is not at and angle compared to the inner drum.

A matter of good eyeballing or using a bar w/ protractor?

 

[22350]

The dust flanges definately have had their share of bending, but the plates look pretty good

 

I did have the shoes backwards on the front, but that was corrected.

 

This is the current situation:

After the shoes where put on correctly, I had all the new drums turned.  I also replaced all the springs.  The adjustment was done, by stepping on the brakes to center, then tighten.  I would alternate that process, until the wheels stopped.  I then backed off until i got light contact, and a full 1.25 rotation.

 

The shoes do not bind anymore, but the front right still seems to heat up about 20f more than the front left.  They also tend to tug right, after driving a while.

 

Here is my question:  The manual indicates that the brakes should be tightened to stop and then backed off 12 clicks.  Do I simply have the front brakes too tight?  Are they warming up, because they are just not floating enough?

 

Also, the suspension is still in bad shape.  Could the slop in this be causing the problems?

 

 

[datzenmike]

Fronts do all the braking so they definitely warm up. Run as is for a few hundred to let them bed in some

 

Pulling to the right...

 

Worn king pin(s)

Left front drum or linings contaminated

If the 320 has tension rods check the right side for worn bushings.

Check right front bearing pre load.

Left rear grabbing harder than the right rear?

 

 

 

 

 

 

[Stoffregen Motorsports]

Out of the frying pan and into the fire.

 

Fixing one problem reveals another.

[difrangia]

Try to look on the humorous side; Automotive 'Whack-A-Mole' !!

 

'The Ghost in the Works'.

[banzai510(hainz)]

On 3/8/2023 at 4:07 PM, 22350 said:

knocking" sound, which is the adjuster sliding into the end of it's floating track

Mine was causing ,y brakes to heat up. . I flipped them around and put the weak spring in the inside.

 

if the adjust moves by hand in the slot it should be harder.. drive backwards and FWD and it should self center

 

The early trucks isnt the brake lamp switch on the firewall???

 

bleed it better?  Im not a very early truck guy so Iam guessing

[bilzbobaggins]

Rebuilt master.  Did you get the freeplay adjustment correct?

[difrangia]

16 hours ago, bilzbobaggins said:

Rebuilt master.  Did you get the freeplay adjustment correct?

 

Good point, as if the master piston doesn't return to the position that it is designed to in relation to the tiny bleed-back hole in the top of the master bore, the pressure is not released in the lines possibly preventing some of the shoes from fully returning to their rest position. Also be sure that the hole is not obstructed by debris or corrosion being careful to not enlarge the size of the hole. Piston needs to return to that park position when master is on the bench and not be prevented from returning there by the operating rod after installation on the firewall.

Edited April 7, 2023 by difrangia

[bilzbobaggins]

11 hours ago, difrangia said:

 

Good point, as if the master piston doesn't return to the position that it is designed to in relation to the tiny bleed-back hole in the top of the master bore, the pressure is not released in the lines possibly preventing some of the shoes from fully returning to their rest position. Also be sure that the hole is not obstructed by debris or corrosion being careful to not enlarge the size of the hole. Piston needs to return to that park position when master is on the bench and not be prevented from returning there by the operating rod after installation on the firewall.

Thank you for explaining it.  I have a hard time getting my thoughts into words.

[22350]

On 4/7/2023 at 5:39 AM, difrangia said:

 

Good point, as if the master piston doesn't return to the position that it is designed to in relation to the tiny bleed-back hole in the top of the master bore, the pressure is not released in the lines possibly preventing some of the shoes from fully returning to their rest position. Also be sure that the hole is not obstructed by debris or corrosion being careful to not enlarge the size of the hole. Piston needs to return to that park position when master is on the bench and not be prevented from returning there by the operating rod after installation on the firewall.

The master is rebuilt.  We also pulled the splash shield from the reservoir and confirmed we are getting the little squirt out of the hole.  There is slight play in the petal to pin, so no continued pressure on the master.

 

Wheel cyclinders new 

drums new and turned once.

springs new

brake lines new

brake hoses new

 

The latest effort was to turn the adjustment all the way tight, intermitantly centering the shoes.... Then backing off the 12 clicks per the manual.  I noticed that in one wheel the adjuster was resting slightly forward, and the shoe was touching a bit more, but not anything that would cause issues.

 

Still getting a clunk intermittantly.  We are pretty sure it is the adjuster sliding to the end of it's travel slot.

 

The rest of the suspension is shit, but but i am pretty sure that this clunk is in the brakes.

 

[datzenmike]

Need more or all the shims in the sliding adjuster.

 

12 clicks never meant much sense to me. Try adjusting till it just barely rubs when turning. This will minimize any slack at the adjuster. If the adjuster is clunking this will cause wear in that sliding area.

[22350]

On 4/6/2023 at 7:28 PM, bilzbobaggins said:

Rebuilt master.  Did you get the freeplay adjustment correct?

yep

[22350]

On 4/11/2023 at 6:34 PM, datzenmike said:

Need more or all the shims in the sliding adjuster.

 

12 clicks never meant much sense to me. Try adjusting till it just barely rubs when turning. This will minimize any slack at the adjuster. If the adjuster is clunking this will cause wear in that sliding area.

I only have the two clip parts. No shims

[datzenmike]

 On most or all? Datsuns of late 60's and 70's there are at least three parts to the slider. (the 510 uses 4, the 710 uses 3 and 4 depending if Tokico or Nabco) It's very snug when installed.

 

Meant to ask... on the one's I'm familiar with the clips are curved and have to be driven in under tension

[22350]

10 hours ago, datzenmike said:

 On most or all? Datsuns of late 60's and 70's there are at least three parts to the slider. (the 510 uses 4, the 710 uses 3 and 4 depending if Tokico or Nabco) It's very snug when installed.

 

Meant to ask... on the one's I'm familiar with the clips are curved and have to be driven in under tension

None of mine have any shims.  Just the clips.  Are the kits available?