620 Drum Brake ??'s

[metalmonkey47]

I just got finished replacing my front shoes on my 620, replacing the hardware, and soda blasting/lubing the adjuster and now that I'm trying to adjust the brakes I've noticed that the brakes drag like a sonovabitch even with the adjuster turned literally all the way in. :confused:

 

There's not a lot more material on these shoes then the ones that came off, and on the old brakes the adjuster was out quite a big (maybe 1/2-1'') and now it's nearly in all the way and still dragging...

 

 

 

 

[Dawa]

ive read that the 620 drums have a 10lb spring to keep the shoes from dragging. do you have an fsm? maybe the fix is described in there? if not, ill go pull mine and read it and try to help you.

[metalmonkey47]

I don't see anything mentioning that specifically in the FSM. I got a spring set from Rock Auto and matches the ones that came off of the truck, so I'm not sure those are going to be an issue. I pulled the drum off while it was dragging and the shoes are fully retracted, so I'm not sure why they'd be dragging. I turned the adjuster in all the way and still they drag. Gonna go back and look it over again.

 

 

It's really time for a front disk conversion now :ninja:

[datzenmike]

Compare the shoes, all of them. They may have different lining lengths and you may have all the longs on one side, shorts on the other. If there are two different lining lengths, the shorter lengths go to the front. Also all my pictures show the shoes with one narrow end down one up. In this picture you have both narrow ends down....

 

 

The tops are squared off but the bottoms narrow down.

[Eagle_Adam]

i just did mine, when i checked the lining length they were the same.

 

Heres a pic of mine:

 

dunno if that helps

 

 

i agree with mike tho, i think your shoes are upside down

[datzenmike]

I said one is upside down. All my FSMs and 'other' shows this.

[alabama_lowlife]

I took mine apart last night. I think the end with 2 holes should be at the bottom.

[datsunaholic]

Just to add to the agreement here... the front shoe is upside-down.

[metalmonkey47]

Good call guys. That must be it.

 

I thought it was strange, and the brakes came off like that, so I put it together how they came off.

 

The passenger side works great with no complaints, so I'm not sure why the driver didn't.

 

 

 

 

My driver side wheel spins free when it's on the truck and driving and doesn't feel like it is, but is still dragging like a mofo. I can smell the burning brakes when I go a few miles down the road and that's no good on new shoes.

[ggzilla]

1. Make sure the E-brake is backed off all the way. It must be slack where it connects behind the brake drum area

 

2. Make sure the cylinder/adjuster is sliding freely

[DanielC]

Make sure the shoes are in the the right position, look at the Factory Service manual. It can be possible to put the front show in the back, put the shoes on upside down, put a shoe from the right side on the left side, with the other left side shoe.

As old as these trucks are, you cannot depend on the previous owner putting the shoes in correctly, so how it came apart, is not really a good guide.

The shoes must slide around freely. This allows the shoes to center themselves correctly. As mentioned, the adjuster must slide. When you put new shoes in, adjust them tight, and rotate the wheel forward and backwards as you tighten up the adjustment. This too slides the shoes around to center in the drum.

Sometimes you need to go for a short drive, and apply the brakes gently, to help the centering process.

The new shoes may not have the exact same curve as the inside of the drum. It sounds wrong, but sometimes you can improve this by driving with slight brake pedal pressure, it wears down the high spots on the shoes.

With new shoes, you need to adjust then a lot. As the shoe wears to match the drum the need for frequent adjustment will go away, but you still have to adjust the brakes every 3000 or less, miles, because they are not self adjusting.

[datzenmike]

1. Make sure the E-brake is backed off all the way. It must be slack where it connects behind the brake drum area

 

2. Make sure the cylinder/adjuster is sliding freely

 

Front drum. I was going to say the anti rattle springs are missing but the fronts didn't have them... learn something Datsun every day.

[mklotz70]

As said before....make sure the adjuster at the bottom is sliding freely in the backing plate. It could be that it's off to one side and stuck....causing one shoe to constantly rub. It's supposed to be able to move each time the brakes are applied.

[metalmonkey47]

Thanks guys! As always you guys give the best, most informative responses.

 

 

 

I promise, the adjuster slides nice and new! I spend 8 hours today cleaning up everything and putting it together. I had my best mechanic (monkeygirl) working on it :thumbup:

 

 

 

 

The adjusters alone were about 2 hours cleaning and polishing. They are soooooo smooth.

 

 

 

 

 

 

 

 

Tadaaaaa!! Too bad the shoes are backwards :(

 

[metalmonkey47]

By the way,,,

 

this is how the old brakes were set up...

 

For some reason there were two large springs on this side, rather then the smaller on top then I'm used to.

 

[I'm BLUE]

.. replace with disc brakes and win!

[Guest kamakazi620]

.. replace with disc brakes and win!

Or Put them on the RIGHT Way and they work just fine!!!!!!!!!

[mklotz70]

I'm glad to hear they slide well. :)

Always great to see the ladies in the shop :)

[alabama_lowlife]

This may just be due to mine being a 521, but mine has 3 springs on each side on the front. The 2 long springs that attach the shoes to each other, and then one smaller spring that attaches one of the shoes to the backing plate. You can see it in the picture that Eagle_Adam posted, it's in the bottom left corner.

[datsunaholic]

I see the small spring in the 1st pic. It's usually the first to break when folks re-use springs, though I've found all 3 broken one time or another. That small spring does the job of the anti-rattle springs in the rear.

[metalmonkey47]

Just realized this... my brake adjuster is in backwards on the drivers side, where it was dragging. Might this be the reason it's dragging regardless of adjustment and the passenger isn't?

 

 

My driver:

 

 

My passenger:

 

 

 

 

Adams:

 

[ggzilla]

Yes, that might do it.

[metalmonkey47]

Nope, that wasn't it. I switched it around, re-adjusted them and the driver side STILL DRAGS.

 

I noticed with the drum on and tire off, it turns freely, but once you apply a large enough amount of force on the drum (bolting up the tire) is when it starts to drag. I can loosen the adjuster but it feels the same regardless.

[ggzilla]

Replace the brake hose on that side.

[metalmonkey47]

I guess the only way to confirm that's it is to open the bleed screw on the wheel cylinder and see if it still drags?

 

It'll be Wednesday before I get the hose if I order it tonight, and I'd like to be sure that's my problem first, so if it's not I can keep investigating.