Author Topic: HELP!!!!! 73 C30 dually brakes  (Read 14836 times)

Offline pfouts1001

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HELP!!!!! 73 C30 dually brakes
« on: March 18, 2007, 03:00:00 PM »
Anybody here know details on brake rotors used on '73 2wd dually trucks??  I have a '73 C30 2wd dually cab and chassis dump that i need to get front rotors for.  Truck has 13 X 2-1/2" rear drums. All of the parts stores i have checked with refer me to a single wheel type rotor with no extended hub.  They give no option for dual wheels on these trucks.  I have the original build sheet for the truck which lists the dual rear wheel pkg, so i know the truck is not a put together deal.

I have tried rotors for a 74, which looked right (its kinda hard to tell since the rotors on the truck have been turned a million times and are pretty well trashed) but these rotors rub the dust shield and dust shield bolts.

My question is has anyone dealt with this problem, and if so how.  I am wondering if the rotors have been discontinued, or if it really should use the same as the 74 and this spindle has had a spun bearing at some point in time which has messed up some of the dimensions.  If anyone can help, please let me know.  


Offline Fast68

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Re: HELP!!!!! 73 C30 dually brakes
« Reply #1 on: March 19, 2007, 09:53:00 PM »
dsame 73-up

can use 71 72 ones too

same deal

different calipers 71 72 than 73-up though

parts stores are stupid like this alot

they shouldnt rub anything if they do then something else is wrong

13x3.5" rears were on all dual rear wheel, it is the 1 ton brake size




good luck

Edited by: Fast68 at: 3/19/07 8:59 pm

Offline pfouts1001

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got it figured out.... kinda
« Reply #2 on: March 20, 2007, 12:48:00 AM »
Went through the whole deal with several parts stores and 2 dealerships.  The parts stores returned nothing... one of which is a guy who can find anything and knew of issues for this particular year and model.  I talked with a parts guy at a dealership who has been there forever.  I told him i was looking for rotors for a 73 1 ton... and before i could add anymore he says.... don't tell me, you've got dual rear wheels.  Turns out 73 is a $#*() year for duallys only, and turns out the only supplier for the rotors is GM at $243 a piece if the dealership knows where to look in the catalog.  The other dealer i talked to confirmed that it was different but showed that the rotor was discontinued by GM. GM changed the rotor design slightly for 74 as it remained until the model was discontinued

The parts guy at the dealership was really helpful though.  He confirmed that the truck should have 13 X 2-1/2 rear drums, as it does.  He also was very helpful in confirming compatibility with later model front spindles as I think thats what i am going to do.  Found a parts truck this afternoon for $200 that will work.  Heck at that price I can get spindles with calipers and rotors, and still have enough money to buy new pads for less than the price of one rotor.

Just though i would post the solution for anybody else that may run into this problem.


Offline Blazin

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Re: got it figured out.... kinda
« Reply #3 on: March 20, 2007, 06:45:00 AM »
Years back I used to do all a guys work that had a 73 C20, 292, 3 speed with low, 4:56 rear with limited slip. I had to do wheel bearing rotors pads etc. I bought all the stuff and tore it apart. Nothing fit. went back to NAPA matched up the parts to the old stuff. Turned out it took C30 parts. A while later I had to do the rear brakes. They were also 13"x2" 1 ton stuff. His grandfather bought the truck brand new. He remebers his grandfather ordered the truck so he must have specified the heavy stuff on the C20 is all we could figure. I borrowed the truck one time when mine was down to move a 24' Check Mate, with a SB Chevy, I hardley knew it was behind me.

Some people are like Slinkies. Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs

Offline VileZambonie

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Re: got it figured out.... kinda
« Reply #4 on: March 20, 2007, 04:46:00 PM »
I checked all of my parts vendors and all of the #'s interchanged. I can't post them here but I crossed them with Autozone and they match also. So either you are dealing with numbnuts or something is not installed correctly.

click here

Edited by: VileZambonie  at: 3/20/07 3:47 pm
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline pfouts1001

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Re: got it figured out.... kinda
« Reply #5 on: March 22, 2007, 11:32:00 AM »
Zambonie,

Thankks for the help, but this is the same problem i ran into.  The parts which you found, and that autozone lists are for one ton single wheel only.  The assembly shown in the picture you posted is a single rear wheel assy.  The rotors on this truck are completely different, as they use an extended hub rotor for the offset dually rim.  The bearings and everything else are the same.

I found a parts truck couple days ago.  86' one ton dually crewcab with a blown up diesel less than a mile from me for $200.  Gonna swap spindles and calipers to get into the later, larger wedge style calipers.  This way in the future i know i can get parts.  Plus the salvage yards want $45 a piece for just spindles.  I can buy the truck, get the parts i need and at $180/ton for scrap, i can make money on the deal.

73 C30 350/SM465 Dump
77 K10 350/350
02 2500HD 4X4 CC D/A


Offline VileZambonie

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Re: got it figured out.... kinda
« Reply #6 on: March 22, 2007, 03:17:00 PM »
I came up with two different GM #'s maybe you can have them cross reference them at your parts store and look at them.

With Dual Rear Wheels 15635678 or
30 Series 6260806  

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              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline VileZambonie

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Re: got it figured out.... kinda
« Reply #7 on: March 22, 2007, 03:21:00 PM »
Also I looked them up on my ACME account and it lists them for Wagner

Front Disc Brake Rotor
WAG ­ BD60442 71-73      
w/DUAL REAR WHEELS

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                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline pfouts1001

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Re: got it figured out.... kinda
« Reply #8 on: March 23, 2007, 01:06:00 AM »
Thanks for the help zambonie

73 C30 350/SM465 Dump
77 K10 350/350
02 2500HD 4X4 CC D/A