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Topic: Kid went to live with mom,left 521,for a
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driftindatsun
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Joined: 01 December 2003
Location: United States
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bullet Topic: Kid went to live with mom,left 521,for a
    Posted: 03 January 2004 at 2:50am
Lil Tom went back to Davis,to stay with his mom for the rest of the school year,with instructions for me to look into his brake-problem.Seems that every now and then, When you come to a complete stop,and try to take off again-you cant! the left-rear wheel is locked up. In order to un-lock it,I had to back up,and *POP* it released.I drove around ALL DAY today with no problems,and just when I was about to park it,it happened again!Same remedy-backed up,and it released.I checked the E-brake cables thinking one was frozen,but they checked out ok.   I"ll tear into it tomorrow,and see what could be wrong,anyone out here ever had this problem?anything I should check that might be over-looked?    Tom S.
72 521,(2)69 521(2),66 520 82 720 4x4,and a few more....
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datsunaholic
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bullet Posted: 03 January 2004 at 8:29pm
I've had that problem many, many times.

It was always a broken return spring.

They aren't very strong, and you CANNOT re-use them. But some folks try.

Actually, now that I think about it I had one that did that because the brakes were way out of adjustment and nearly worn through. But that was once. Have had the broken spring thing 3 times on trucks right when I aquired them.
'64 320
'68 520
'72 521 V6
'74,75,79 620s
'76,78 4X4
'76 KC
'72 510 Wgn
'78 B210
'78,81 510 Wgn
2X '78 510 Coupes
'83 720 KC

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lowpsi
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Joined: 13 October 2003
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bullet Posted: 06 January 2004 at 11:07pm

what is the return spring?

sorry dumb question

is it one inside the drum?

mine does that too ... thanks

also any one sell new drums?

 
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datsunaholic
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bullet Posted: 07 January 2004 at 12:24pm
I think you can still get drums at Kragen. I just use the 620 ones, 520/320/521 ones are NLA but are so close it doesn't matter. Front/rear are the same, it's the inner hardware (springs, shoes, and cylinders) that's different.

And yes, the return springs are the ones inside the drum that stretch between the shoes. On the front, the return springs also act as holddown springs but the rear has actual holddown springs in addition to the return springs.
'64 320
'68 520
'72 521 V6
'74,75,79 620s
'76,78 4X4
'76 KC
'72 510 Wgn
'78 B210
'78,81 510 Wgn
2X '78 510 Coupes
'83 720 KC

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earwig
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Joined: 09 December 2002
Location: United States
Posts: 857
bullet Posted: 08 January 2004 at 3:59pm
i had broken springs on both sides when i went through my rear breaks. i used 720 drums when i replaced mine. i noticed that the 720 ones had been balanced. (i.e. the little weights riveted no them) Napa has really nice "new" wheel cylinders. they are $40 and come with the "V" that the line and bleeder go onto machined out of brass. after much frustration i decided that i'll never try rebuilding aluninium cylinders again!
red'76,620regularcab,longbed L20B,Supertrap,3"shackle4"body 31X10.5X15 chrome pathfinder rims,2tube front,1tube rear bumper,720 5speed&transfercase,Blaster coil,Pertronics ingitor dizzy,WeberDGV,K&N
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lowpsi
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bullet Posted: 08 January 2004 at 10:15pm

on my 620 the 720 drums work ok?

what year?

and does it use the same shoes and springs?

 
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Bleach
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Joined: 04 December 2002
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bullet Posted: 09 January 2004 at 10:06am

Originally posted by datsunaholic

Front/rear (drums) are the same, it's the inner hardware (springs, shoes, and cylinders) that's different.

LowPSI: Sounds like 1980-85 720 drums will be fine to use. But make sure to buy the 620 shoes for your truck as mentioned above. Front shoes are different only for the lack of the parking brake attachments. (I think)
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datsunaholic
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bullet Posted: 09 January 2004 at 12:59pm
Shoes are the same size but mounting system is different. Rear shoes have provision for parking brake AND holes for hold-down springs, the fronts are held on only by the return springs.

I bought a set of '68 520 front shoes and compared them to a set of '77 620 fronts. They were IDENTICAL. Rears likewise. The drums were different by a tad but not enough to cause problems.
'64 320
'68 520
'72 521 V6
'74,75,79 620s
'76,78 4X4
'76 KC
'72 510 Wgn
'78 B210
'78,81 510 Wgn
2X '78 510 Coupes
'83 720 KC

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