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Old 05-10-2014, 10:08 PM   #1
Hiluxxulih
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No adjustment hole for rear brakes

I have a 1985 Chevy 4x2 long bed truck and there is no hole in the backing plate to adjust the brakes how do I adjust them ? I know about the backing up thing but they should have a hole there to manually adjust them shouldn't they ?
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Old 05-10-2014, 10:12 PM   #2
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Re: No adjustment hole for rear brakes

you know, I just ran into this on my 67 camaro. The driver side had the access on the backing plate. The passenger had the access on the outside of the drum. Which I found by removing the wheel. This was new to me and made it interesting because that brake was froze up. I had to push the car to rotate the drum to 6 o'colock to get to the release.

Hope it helps. Matt
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Old 05-10-2014, 10:18 PM   #3
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Re: No adjustment hole for rear brakes

I had the drum off a few weeks ago and there is no access hole in it either I am stumped .
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Old 05-10-2014, 11:46 PM   #4
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Re: No adjustment hole for rear brakes

Outside of the drum, huh?! And NO access on the '85 truck! Geeze, I've never heard of that in all my years!
My Camaro, and FRANKENTRUCK, both have the standard access on both sides, as do all my other vehicles.
Learn something new everyday,...
I'd guess Hiluxxulih will be doing a gross adjustment with the drums off and then utilizing the backup technique to complete the adjustment to the rears.
How strange,...
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Old 05-11-2014, 09:56 AM   #5
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Re: No adjustment hole for rear brakes

I thought you was hallucinatin' till I looked at mine.
No holes on mine either!

But a little quality time with a drill and files and a new plug will fix that.
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Old 05-11-2014, 09:58 AM   #6
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Re: No adjustment hole for rear brakes

Have seen this before. Clean the backing plate real good at the bottom where the slot would be located. There should be 2 scored areas, use a chisel and hammer to knock out the slot needed.
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Old 05-12-2014, 08:12 AM   #7
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Re: No adjustment hole for rear brakes

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Originally Posted by Oldriginal86 View Post
Have seen this before. Clean the backing plate real good at the bottom where the slot would be located. There should be 2 scored areas, use a chisel and hammer to knock out the slot needed.
Correct. There should be a "knock out" that needs to be knocked out and plugged with a rubber plug.

There are two because the backing plates are common and that way the same part can be used for both sides.

K
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Old 05-12-2014, 05:28 PM   #8
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Re: No adjustment hole for rear brakes

This must be an oddball truck no knockouts to be found ., maybe Canadian trucks did not have them .

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Old 05-12-2014, 06:42 PM   #9
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Re: No adjustment hole for rear brakes

What makes you think your truck is from Canada?
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Old 05-12-2014, 07:13 PM   #10
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Re: No adjustment hole for rear brakes

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What makes you think your truck is from Canada?
The Vin says its made in Canada , I was just thinking the Canadian built trucks had different backing plates for some reason the drum even says made in Canada .
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Old 05-12-2014, 07:29 PM   #11
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Re: No adjustment hole for rear brakes

Could be, but maybe just certain optioned trucks where like that or just for a couple years.
My 84 is an Alabama truck built in Flint.
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Old 05-12-2014, 07:47 PM   #12
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Re: No adjustment hole for rear brakes

Shouldn't be too confusing as its extremely common. Niether of my current trucks has the hole nor did my previous 79. The 79 was american built, both my currents are canadian built. You adjust with the drum off, then put it on and check, then re-do if needed. Or drill the hole lol.
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Old 05-12-2014, 08:15 PM   #13
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Re: No adjustment hole for rear brakes

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Shouldn't be too confusing as its extremely common. Niether of my current trucks has the hole nor did my previous 79. The 79 was american built, both my currents are canadian built. You adjust with the drum off, then put it on and check, then re-do if needed. Or drill the hole lol.
That's what I did I was just making an observation .
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Old 05-12-2014, 08:48 PM   #14
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Re: No adjustment hole for rear brakes

my truck doesn't have them either, even searched for knock outs when I just did brakes none found. I always adjust them before I put drum on so there tight then do the reverse procedure
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Old 05-12-2014, 09:50 PM   #15
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Re: No adjustment hole for rear brakes

I drilled my adjustment holes in my new drums...
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Old 05-12-2014, 11:15 PM   #16
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Re: No adjustment hole for rear brakes

Same thing on my 76 Julius when I did the brakes last summer. The really odd part was there were adjustment slots on the TOP side like the backing plates were used from another application and just flipped hpside down. I couldn't back off the adjusters to remove the badly worn shoes and had to break the pins and pull the whole assembly off with springs flying. Was something like 4 hours to do the whole job including the stuck wheel cylinder lines.
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Old 05-13-2014, 11:27 AM   #17
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Re: No adjustment hole for rear brakes

No adjuster access in the backing plate or drum face is not that uncommon in the industry. You need one of these shoe adjuster gauges where you flip it one way to gauge the drum then flip it around to adjust the shoe up to that dimension. This works great but if your drum has a wear lip on the edge you’ll never get them adjusted correctly. I use this tool even on vehicles with an adjuster screw access hole just to get the shoes adjusted up close to the drum then I do a few clicks of the start to run them a bit tighter. I find the tool usually gets you right on the money.

As mentioned above, most of the older 1/2 ton trucks without access in the backing plate have a knock out in the drum to punch out for adjusting however, if the truck has received a set of China's finest aftermarket brake drums in its life they probably do not have the knock out provision.

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Old 05-13-2014, 01:33 PM   #18
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Re: No adjustment hole for rear brakes

its a real bummer when you discover that the wheel is frozen due to rust and you need to release the brake to even get the drum off. then you discover no adjustment hole to release it.

got er done and home but decided to not invest any money in the old front drums and ordered power disc kit.

matt
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Old 05-15-2014, 09:38 AM   #19
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Re: No adjustment hole for rear brakes

Has anyone checked their drums to make sure the "knock Out" is there?
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Old 11-25-2016, 11:37 AM   #20
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Re: No adjustment hole for rear brakes

When I had a flat earlier this year I decided to check the drums on the rear of my '80 C-10. I looked on the back for an adjustment hole so I could back off the self adjuster, nothing.
I was beginning to think it was just my truck, until I read this thread, so now I know what to look for. Thankfully if there is a knock out in the drum itself it should still be there, looks to be the original drum.

Thanks again for all the info, save me alot of cussing trying to get the damn things off.
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Old 11-25-2016, 12:22 PM   #21
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Re: No adjustment hole for rear brakes

Are the two recessed rectangles I can see at the bottom of the backing plate not the knockouts? I've always seen oval ones, but it looks like there is something there????

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Old 11-25-2016, 07:45 PM   #22
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Re: No adjustment hole for rear brakes

My 78,C-10 had the adjustment holes in the drums.
When I got the new drums to put on it---No knockouts on them at all!
Had to make my own holes.
No knockouts in the backing plates either.
I don't understand the reason for this.Some have them and some don't?
Mike.
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Old 11-26-2016, 12:47 PM   #23
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Re: No adjustment hole for rear brakes

I was wondering if it is Canadian built truck only thing not having adjustment holes .
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Old 11-27-2016, 08:49 AM   #24
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Re: No adjustment hole for rear brakes

I think it has something to do with the brakes being automatically adjusted as you drive, but that dont make any sense though as most rear drums do that anyways if I remember correctly
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Old 10-18-2018, 01:04 PM   #25
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Re: No adjustment hole for rear brakes

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Originally Posted by Keith Seymore View Post
Correct. There should be a "knock out" that needs to be knocked out and plugged with a rubber plug.

There are two because the backing plates are common and that way the same part can be used for both sides.

K
I have a '76 Chevy G-20 van, same deal. There is an indentation where the slot should be, but it doesn't look like a knock-out to me, looks like part one continuous piece of metal. These have never been touched. 33K original miles. Van sat in the guys back yard for 40 years with a bent axle.
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