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Old 04-21-2017, 10:42 AM   #1
Carystone72
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1970 four wheel drum breaks.

I have a 1970 k10 I just did the drums all around and was wondering if they are self adjusting, the truck pulls hard left when I hit the brakes, I replaced axle seals, brake cylinders, hardware and shoes and I thought I had it adjusted correctly. Anything helps thanks.
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Old 04-21-2017, 10:45 AM   #2
BILT4ME
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Re: 1970 four wheel drum breaks.

When you were in there doing the brakes, did you see if there were self adjusters on the shoes? If so, there is an arm that covers the star wheel. They adjust when backing up.

Also, you should adjust the brakes up tight, then back them off 12 clicks (I think) on each wheel. This will set them properly from the get-go. This also makes them even from the start.

Do you have a FSM? If not, get one. They're on here electronically for free.
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Old 04-21-2017, 11:39 AM   #3
demian5
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Re: 1970 four wheel drum breaks.

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Originally Posted by Carystone72 View Post
The truck pulls hard left when I hit the brakes.
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If you are sure you adjusted everything properly and rechecked, then:
  • Check tire air pressures that they are even.
  • Look for a bad steering or suspension part.
  • Understand that drum brakes suck and this is part of having them
  • Make sure you don't have a partially plugged brake hose on one of the fronts.

Put truck in air and have someone press brakes at different pressures (and hold) and go to each wheel and spin (put truck in neutral). The one that isn't grabbing as well will become obvious. The different pedal pressures and hold will help determine if its a restricted hose as the fluid will eventually actuate the brakes, but it takes longer.
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Old 04-21-2017, 12:33 PM   #4
toolboxchev
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Re: 1970 four wheel drum breaks.

Do not give up in frustration on your original setup. I have had the drums on my 70 for over 11 years with a loose front end.

Just go through the brakes again making sure all is working properly. Mine stop so good a stupid kid ran into my rear bumper totaling his Honda.

So do they work???? It is one of the easier systems on these old rigs to rebuild or repair, Its all mechanical.
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Old 04-21-2017, 01:35 PM   #5
weq92f
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Re: 1970 four wheel drum breaks.

I have to agree that you system should work fine once adjusted.

Manual adjust drum brakes..
Assuming all up top and hoses are good... Pull off the drum and manually adjust the shoes out so that the drum fits over the shoes, but barely. When wheel is on continue the adjustment through the slot in the drum with a big screwdriver or adjusting tool. Adjust tighter until the wheel still rolls 'freely' but with a ~small amount~ of drag. Even if the drag initially is uneven and sounds completely wrong. Get both sides front and rear to this point and then go drive it. Mash it pretty good to seat everything. Repeat the adjustments until if feels right, drive for a few days and adjust again.

Hth,

-klb
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Old 04-21-2017, 03:17 PM   #6
LongBox
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Re: 1970 four wheel drum breaks.

Keep at it. Manual drum brakes can and do stop these old trucks, and in a straight line to boot. While I cannot deny the advantages of disk brakes, good drum brakes will do the job.
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Old 04-21-2017, 11:02 PM   #7
saxart
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Re: 1970 four wheel drum breaks.

Quote:
Originally Posted by Carystone72 View Post
I have a 1970 k10 I just did the drums all around and was wondering if they are self adjusting, the truck pulls hard left when I hit the brakes, I replaced axle seals, brake cylinders, hardware and shoes and I thought I had it adjusted correctly. Anything helps thanks.
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Did you replace the self-adjusters? If so, they are side-specific, so make sure you have them on the proper side of the vehicle. (Also confirm that you don't have two that belong on the same side)

Secondly, don't accept "good enough" with these brakes. There seems to be some level of hate for drum brakes around here, but if they're working correctly, there's no reason you can't have a great driving (and stopping!) vehicle.
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