C/30 rear wheels locked up, no fluid

[phillip24fan]

So I'm starting to work on my grandpas '70 C/30 dually that has been sitting for years so I can get it running again.

Front wheels spin freely when jacked up in the air. I then jacked up the rear axle into the air and neither side will spin or budge at all. The brake pedal goes all the way to the floor with no resistance.

I even had the truck idling, (rear axle airborne sitting on jack stands) and the engine would stall every time I tried to put it into 1st and make the wheels spin. That's how stuck they are!

Here's a pic of the master cylinder when I took the cap off. The empty part is for the rear brakes correct? If so, why would the rear wheels be frozen when there is no brake fluid being fed to them?




I'm not very familiar with brakes so any help is much appreciated. Does it look like I need a new master cylinder? Or should I just try bleeding the rear with fresh fluid? I was planning to pull the wheels off tomorrow and bang on stuff and see if the drums will break loose and spin free as my first step.

Thanks!
-Phillip

[68wannabe]

The drums might just be the problem. I had one of mine tighten up, making it pretty much impossible to turn the tire without a lot of force. There's a small gear looking piece at the very bottom of the drum, that will turn both ways. One way to loosen the brake and the other way to tighten it. If it's not a brake, I would take off the rear differential cover and check the gears in there.

[jocko]

Recommend pull the drums and see what's really going on. Both rears locked may indicate a parking brake stuck or something like that.

[RedRoad]

Had a similar problem once, and could not turn the drum so that the access hole to the adjuster would line up. I cut the rear soft line as close as I could to the "T" and pressurized fluid came out. The line was swollen and would not allow the fluid to return causing them to lock up. A few taps to the drum and it loosened up enough to line up the hole to the adjuster.

If that fails, unbolt the wheel cylinder, giant nut, disconnect the parking brake cables and drill out the shoe retaining nails and pull the whole assembly off

[yuccales]

Get a dead blow hammer and beat (within reason) on the backing plates, shoes might be rusted to the drums. Good luck, and welcome to the forum.

[phillip24fan]

Picked up a dead blow hammer today. I'll get over to the grandparents garage tomorrow and see what happens. Thanks for the advice so far!

[phillip24fan]

Got the drums off today after a lot of elbow grease, beating, and prying. The shoes were really stuck to the drums.. I didn't realize I had to pull the axle shafts out to access the drums. Seems like a kinda crazy design.

I removed the bleeder screws and no fluid came out.



So what are my next steps? What should I look at replacing?

I went to Advanced Auto Parts and got prices on some parts. $55 for a master cylinder, $75 for shoes, $10 for a hardware kit that includes all the springs. Should I look at getting all those parts? What about the rubber brake hoses?

From this picture of the drum, can anyone tell if its too worn? Does it need to be machined?



Also, can anyone ID the axle I have?


Sorry for so many noob questions. Just trying to learn as much as I can!

[jocko]

rubber brake hoses - yes
if the brake shop will turn the drums - turn the drums, how they look doesn't matter, the new surface will be correct and concentric - all that matters is if they are thick enough, and the brake shop will measure and tell you if they can be saved.
you appear to need a wheel cylinder also if you found that trickle inside the drum

when they get to that stage, it's best to replace everything. Sometimes wheel cylinders and drums can be saved, but pretty much everything else should be replaced.

[phillip24fan]

Fluid in the picture was PB Blaster trying to free the drums. I don't think its the best stuff for brake shoes but I'm replacing them so I wasn't worried.

Curious though why the rear brake lines are dry...

[SS Tim]

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[MARKDTN]

Why replace the shoes? Looks like plenty of life left and depending on how old they are may have better linings than today.

[phillip24fan]

Originally Posted by MARKDTN

Why replace the shoes? Looks like plenty of life left and depending on how old they are may have better linings than today.

If you notice in the picture, the edges of the shoes got chipped from me trying to pry the drums off them. Are they still fine to use? I don't mind spending a little extra while I have everything off to get new shoes, unless they really aren't needed.

[CrewCab59]

Yes ,the shoes need to be replaced , they are oil soaked and will only cause problems like grabbing , lack of braking.

[Aruba1]

Unless there are cracks in the shoes going through the rivets I personally would not change them. Get you some new cylinders, hoses, hub seals and master cylinder and she will back as new. Clean the shoes and drums really well and sand them with some course grid. Ideally you can get the drums turned but if you can't, don't sweat it. When i replaced my wheel cylinders I think they were like $10 or $17 a pop, you can't beat that.

[Ironangel]

Originally Posted by CrewCab59

Yes ,the shoes need to be replaced , they are oil soaked and will only cause problems like grabbing , lack of braking.

"What he said" ...Once the linings get fluid soaked, they're toast...

[michael bustamante]

now that everythings off, casn you spin the rearend? im just wondering if the locked up brakes were the problem or if theres something else locking up the rear end

[phillip24fan]

Thank you for all the help so far! I'll be getting all new parts, including shoes.

What is a ballpark cost for having two drums turned? And do chain stores do that, like napa, or do I need to find a specialty machine shop/brake place?

Michael I still need to check that the rear end spins. But hey if it doesn't, I'll be getting a lesson from you guys in differentials!

[phillip24fan]

My grandparents (who own the truck which I'll be inheriting) have $200 to spend fixing the brakes. Anything above I'll pay for. Guessing I'll be right around that or a little over.

Where do you suggest buying the parts at the best price? I was gonna use Advanced Auto Parts, or are there websites with better prices? It's comforting to be able to walk in with the part to ensure I get the right things.

[CrewCab59]

I buy all my Timken bearings and seals from auto zone .

[RedRoad]

Rock auto was pretty good on brake parts. Even Amazon (prime free shipping) was good on parts too

[Stocker]

Follow the brake lines to see where they go; it's possible the rear reservoir (your empty one) goes to the front brakes. That's how it is on my '72 K20 (with front discs). Not sure about your '70 C30.

I believe the rear diff is an Eaton, which on a C30 should be an HO72. Can you post a front view pic of it?

[JJR]

If you do decide to get the parts from Advance be sure to order them on-line for in-store pickup. Right now they have 15% off on-line orders over $50. This is what I do if I need the part right now and can't wait for a possible cheaper option (RockAuto, Amazon, or EBay).

[phillip24fan]

What are you guys thoughts on replacing vs rebuilding the MC? I'm leaning toward rebuilding to save money.

[Aruba1]

The only way to tell is to open the MC, hone it and check the smoothness of the bore is. If it's smooth all the way then rebuilding it is just fine. If it has significant imperfections due to moisture build up, replace it! When I rebuild my brakes, I re-used the pads/shoes, installed new wheel cylinders, new hoses and new master cylinder. I only replace what is broken but when it comes to brake system I rather save money elsewhere and buy those items new. Usually when a vehicle has been parked for a long time and has brake issues, from my experience the bore of the wheel/master cylinders are bad anyways and I am not going to take chances of having no brakes when driving/pulling around. Like I said before, if you no stress crack on your shoes, clean them well and sand them just enough to remove the hard glaze. I rather have one of them fail then having failure of not able to pump fluid, at least with the brake shoes I will still have stopping power. That is just me though :-).

[MARKDTN]

Originally Posted by phillip24fan

What are you guys thoughts on replacing vs rebuilding the MC? I'm leaning toward rebuilding to save money.

I would replace. They are not that much.