Picked up a 1970 GMC C3500 dump truck that needs some TLC

   / Picked up a 1970 GMC C3500 dump truck that needs some TLC #181  
Weird, looking at your thread is like following what i've been doing to the 69 c30 I bought a few months ago, except I ended up having to do head gaskets too. If I get ambitious i'll make a thread for it lol. Nice work, wish I had the rear tires you ended up with!
 
   / Picked up a 1970 GMC C3500 dump truck that needs some TLC #182  
Definitely looks like you had some moisture in the rear end. Those old trucks require a lot of maintenance but they're worth it.
 
   / Picked up a 1970 GMC C3500 dump truck that needs some TLC #183  
I'm trying to figure out what to do with this mess. There are no tabs or anything on the axle for me to attach this too. Perhaps they make diff cover bolts with a secondary thread that I could attach these to? Or perhaps a clip of some sort to slip under one of the diff bolts?
dana70-05.jpg
3/4" wide piece of 1/8" flat stock?
Looks like the ebrake bracket would go right under one of the bolt heads as would the breather hose bracket.

Aaron Z
 
   / Picked up a 1970 GMC C3500 dump truck that needs some TLC #184  
I'm trying to figure out what to do with this mess. There are no tabs or anything on the axle for me to attach this too. Perhaps they make diff cover bolts with a secondary thread that I could attach these to? Or perhaps a clip of some sort to slip under one of the diff bolts?

dana70-05.jpg

Buy a tubing cutter and a Flaring tool and cut and reflare the brake lines so they fit right.
 
   / Picked up a 1970 GMC C3500 dump truck that needs some TLC #185  
Buy a tubing cutter and a Flaring tool and cut and reflare the brake lines so they fit right.

Totally. Just make sure to get the double flare for brake lines. Also get a tubing bender(I have the spring type and the round block type). I redid my old Jeep when I put a new master cylinder and swinging pedals(brake/clutch) in it. It really came out clean, with everything trimmed up nice and tucked away so nothing would snag while off-roading.

NAPA or other local parts store should have tabs for securing tube on diff cover bolts at least.

Make sure the flare tool is for double flare; dont use a single flare on brake lines.
DSCN1759.jpgDSCN1762.jpg
 
   / Picked up a 1970 GMC C3500 dump truck that needs some TLC #187  
Yeah, you don't really think about brakes much until you do not have them. Last year, I was leaving a local restaurant after a meal and happy hour when the brakes on my 2003 Silverado 2500HD failed completely. That is truly scarey and I am glad that the emergency braking system on the GM trucks is as good as it is.

I made it home safely and then immediately dropped it off at the dealership. Unfortunately, they do not make brake lines for my truck any longer so the technician has to custom bend everything and that cost me $1800, but it was a very good and tidy job. Too many years of driving on extremely salty roads in the winter months had rusted out my brakelines badly.
-Stu
 
   / Picked up a 1970 GMC C3500 dump truck that needs some TLC
  • Thread Starter
#188  
Appreciate the advice on the brake lines. I'll get a double flare tool. I think I might have inherited one from my dad. I'll dig through the basement to see, before purchasing one.

Went to NAPA this morning and picked up seals, inner and outer bearings and races (one bearing set includes new races in the box).

dana70bearings-0.jpg


Also finally broke down and picked up a slide hammer. I've been in many situations in the past where I wish I had one. It made getting those seals out pretty easy.

dana70bearings-1.jpg


The old inner bearing. Pitted pretty badly.

dana70bearings-2.jpg


After getting the inner bearings out, I cleaned up the drums. The race for the inner bearings were in excellent shape, so I left those alone.

dana70bearings-3.jpg


I then attempted to remove the retaining ring that holds the outer bearing in place. After trying various tools, I finally gave up and decided just to clean and repack them as best I could.

dana70bearings-4.jpg


Next I installed the new inner bearings and seals

dana70bearings-5.jpg


Put everything back together and bleed the rear brakes.

dana70bearings-6.jpg


After that I put the wheels back on and decided to put the truck straight to work!

gmcdirthaul-1.jpg


I'm digging them white rims! :D

gmcdirthaul-2.jpg


No more surprises busting ball joints going over rough terrain.

gmcdirthaul-3.jpg


Nothing broke or blew up, but the brakes still suck. I think there is still air in the lines. Pedal is very spongy and I still don't think I'm getting much if any action from the rear brakes. I did pull those self-adjusters off and lubed them and reinstalled. I also adjusted them out as far as I could where the drums would just barely slide back on.

I might try the manual bleed method with a friend instead of the suction device as well. After hauling some more loads, I'll pull the axles again, and check the torque on the axle nuts.
 
Last edited:
   / Picked up a 1970 GMC C3500 dump truck that needs some TLC #189  
The drums look like a ridge so if they went back on it probably still had play.
Try backing up and pumping the brakes. Everytime you rock the shoes in reverse it will click one notch on the adjusters.

Time for some side boards on the bed and a paint job!
 
   / Picked up a 1970 GMC C3500 dump truck that needs some TLC #190  
Double post.
 

Tractor & Equipment Auctions

UNUSED FUTURE QUICK ATTACH MAST W/ 29" FORKS (A51248)
UNUSED FUTURE...
2012 JOHN DEERE 410K BACKHOE (A51246)
2012 JOHN DEERE...
(1) HD 24ft Free Standing Corral Panel (A51573)
(1) HD 24ft Free...
2017 Ford Explorer AWD SUV (A51694)
2017 Ford Explorer...
2012 BMW 328i Coupe (A51694)
2012 BMW 328i...
2010 Ford Edge SE SUV (A51694)
2010 Ford Edge SE...
 
Top