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1977 Datsun 620 PU Brakes Grab


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#1 Rummie

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Posted 29 January 2010 - 05:22 PM

New Shoes, wheel cylinders, turned drums.

When I start the engine, the pedal goes towards the floor.

Bled the brakes over and over again.

Very little pedal. Very Little.

NO leaks.

Auto Trans will overcome the brakes in reverse. Must put trans into Neutral to stop truck.

Any ideas are welcomed.

Thanks

#2 datzenmike

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Posted 29 January 2010 - 07:06 PM

You need to raise each wheel and adjust the shoes in until they just start to rub. pump several times to center the shoes and check the adjustment again. Do the rest. Look here about 1/4 way down the page for drum brake adjustments how to.

Also make sure you bleed the NLSV Nissan Load Sensing Valve located on the inside of the frame rail under the passenger seat. This must be bled also.

It's perfectly normal for the pedal to drop (but only slightly) when the motor is started... even on a good system.

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#3 moparvwfreak

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Posted 29 January 2010 - 09:56 PM

You need to raise each wheel and adjust the shoes in until they just start to rub. pump several times to center the shoes and check the adjustment again. Do the rest. Look here about 1/4 way down the page for drum brake adjustments how to.

Also make sure you bleed the NLSV Nissan Load Sensing Valve located on the inside of the frame rail under the passenger seat. This must be bled also.

It's perfectly normal for the pedal to drop (but only slightly) when the motor is started... even on a good system.


yup. as he said. i have drums on my 73, which i hate, and i have to do this every so often. its a pain but when they work right, they work great.
#655321

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I have seen the way of the trunk, and it is good.

1973 Datsun 620 L20B, another 73 620 L20B, 1978 Datsun 620 KC parted

Monroe Rabbit Rescue. even VW Rabbits need love!

#4 AceOfDiamonds0

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Posted 10 April 2014 - 06:01 PM

I've searched a bit and haven't found a definite answer but I have a 77 620 and it has the NLSV. Do you bleed the NLSV after bleeding from the back to the front or do you bleed it after bleeding the back?

#5 AceOfDiamonds0

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Posted 16 April 2014 - 05:55 AM

Does anybody know?



#6 datzenmike

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Posted 16 April 2014 - 06:42 AM

I can look it up when I get off work.


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#7 AceOfDiamonds0

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Posted 27 April 2014 - 10:01 PM

So what was the verdict?



#8 ggzilla

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Posted 27 April 2014 - 10:17 PM

Bleed the NLSV after bleeding the Master cylinder, and before the weel cylinders
Here today gone tomorrow

#9 AceOfDiamonds0

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Posted 30 April 2014 - 08:21 AM

Gotcha. Thanks



#10 datzenmike

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Posted 30 April 2014 - 07:07 PM

Well FWIW the '78 FSM says...

 

Master cylinder front

Master cylinder rear..... this probably means bench bleeding the master

NLSV front

NLSV rear

Front wheels

Rear wheels

NLSV rear

NLSV center

 

I know this flies in the face of everything but it does make sense to purge air from the front first and work to the rear with solid fluid.


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