The Stovebolt Site Forums The Shop Area Driveline AD parking brake cable replacement

Swapping rear ends. Truck already had an open driveline installed decades ago. Replacing the current 55-64 HO33 with a different one…it’s supposedly from a 55 2nd series and has the task force style brake cable.

I have new AD cables on the way. The brakes on this rear look newish and I’d prefer not to tear them all the way down.

What does it take to replace only the cable? Does it all have to come apart?

My shop manual seems rather silent on the topic. Strangely, YouTube is as well. I’m comfortable enough with drum brakes to fee Ok about pulling them all apart and putting back together. I’d just rather not do that if it’s not necessary.

I’ve adjusted my cables before (they might be originals) but I’ve never had the rears completely torn down. My quick look at it the other evening….in the dark with a headlamp….makes me think there no short cut.

Your 51 with a 55 2nd rear axle.

Both ends of the AD and TF stranded steel cable are crimped and cannot be removed without cutting the cable.
A crimped cable stop for the inside lever of the drum and a crimped threaded rod for the yoke.
A cable can be cut at the stop, for shortening and a new stop installed (welding, crimp etc.).

For the cable housing, the attachment to the backing plate is different, AD to TF, as is the cable holder at the frame.
What were you planning to do here?

Hopefully someone who has done this before will chime in.

It is simplest to use the cables which came with the rear axle you will be using, and then modifying the the front end of the cable to fit your truck. Embrace your inner MacGyver. Paper clips, Swiss army knife, whatever it takes.

Carl's advice is good and also you can reverse his suggestion. Just use the cable setup that came with your truck and let it remain the part that connects to the front part of the brake mechanism. My rear end came from a 1969 Chevy 1/2 ton truck and I just cobbled the cables to work by first soldering the wires of the cable that connects to the brake shoe affair together (to prevent them from unwinding), cutting off the rear end of the cable and then using a screw-on cable end to mate with the 1969 setup. If it concerns you, I suppose you could solder that new cable end, also, but you don't have to. Just do get a MAPP bottle and solder the cables or at the very least wrap them tightly with 1mm diameter wire to keep them from raveling. If they do start unwinding, no joy will follow. Good luck!

I’m not married to the AD setup, but I already bought the cables thinking it would make my life easy. I more or less understand the backing plate attachment. What hooks to what inside the brake drum is a little less clear.

See the picture (from flea-bay) with the red square. Hidden is a U-shaped end of the brake lever (I didn't look up the proper name).
Here is how I do it.
Take off brake drum. Need a brake spring tool to take top springs off.
Be careful not to put a lot of force on the wheel cylinder and damage the inner seals.
Remove the 2 brake shoe retaining clips/springs.
Both hands to pull the shoes out and do a 180 to release the bottom spring tension.
The adjuster usually falls out.
You now have good access to the brake lever.
I use grips to pull the spring back and lift the cable and stop out of the U-shaped end.

Exactly what I needed, Buoymaker! Thanks!

A couple questions while I run back the parts store. My partial disassembly plan didn’t work out. I’m all the way in now.

1). See the attached pic. How do those molded sheet metal tabs work? I see how the inner fits down in the recess. Am I to bolt the together or to the lower arm that connects the two shoes?

2) Am I good to use the modern style hold down springs which are coil type, rather than the old sheet metal ones?

Nathan, It appears there are no pics for folks to see??? Can't answer question 1 without seeing what you're asking about. For question 2 - YES, you can use the brake shoe coil style hold down springs and retaining caps in place of the bent in half metal spring clips. Just did that all the way around on my '51 3100 during recent brake overhaul.

Sorry….

These are the things I’m unsure what to do with.

Well, those were used on different backing plates. 1951 through around 1955 first series as I recall. There should be two holes where screws or rivets were used to attach them to the plate. I'm not certain they will work correctly on the backing plates you have. Then in the 1960s a cable which poked into a hole and had 4 prongs on it was used.

Please take a look at the backing plates in this auction. These are for a Cadillac but most GM vehicles of this timeframe used this type. The pieces will attach as you can see:
https://tinyurl.com/29u39v5e

I'm pretty sure those pieces around the cable go on the OUTSIDE of the backing plate.

I mistakenly assumed that because I have a later axle with the 51 park brake, that the backing plates are the same.

As I crawl under the truck to survey the current situation, it would appear that ONE of those two plates goes on the outside and presumably the other is inside.

Left with a couple choices. I think I can make work what I have…..by lopping at least one of the two ears. And figuring out a way to secure the cable so it doesn’t move around. On the 55.2 ebrake I just removed, it was just held in place by some tiny spring barbs on the collar.

Or I could swap backing plate from one axle to the other. That currently seems like a giant PITA. But I’m gonna sit down and have a beer about it.

Edit: By the way…I don’t see any way how what LMC sent could be bolted one plate inside and one outside, even on the proper backing plate. Perhaps PHak1 will weigh in. He recommended the LMC cables.

They do go on the outside. They just weren't designed for the backing plate for which the image appeared. As for inside/outside, I don't remember them that way but I changed to a 1969 rear end many years ago and so it could be the case. I remember them attaching to the backing plate with rivets or screws, nuts/bolts, something like that but on the same side (the outside). I looked in the shop manual but it showed nothing for that. I also looked through apx 2000 images I have kept (including around 60 on the braking system). No joy there, either. Sorry.

Add about a quarter cup of tomato juice to that beer. It will be as drinkable as any beer you've ever had. Old NY trick but I've seen it as far south as Chihuahua.

'47-55.1,both of the brackets belong on the outside of the backing plate. There is a felt gasket which goes between them.It keeps dirt out.

Yes, both on the outside. I thought about putting one piece inside the backing plate but it wasn't going to happen, as the smaller piece won't fit thru the hole in the backing plate. Both on the outside was how my truck came to me.

Fabricobble…..engaged.

Good deal. Glad it worked.

The parking brake cable has to be firmly attached to the backing plate.
Test that your modification works properly before reassembling other parts.
You don't want your parked truck to roll off on you.

As long as the old-style clips still have good tension, they can be reused.
A good pair of needle nose pliers to grab the end of the pin, push down on the spring clip and twist the pliers 90 degrees to line up with the slot.
Brake work can be very frustrating if you try to do it without some previous knowledge or help.
Take your time. Ask questions on this forum. Search the net for instruction videos.
I was 13 years old when I watched a mechanic (Ed) do a brake job. I was curious and he showed me things that helps me today.

It is important to make sure that the orientation of parts is correct during re-assembly.
(https://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0515.htm)

Make sure the threads on the adjuster are clean and free. They like to rust (brake dust and humidity).
Binding adjusters can be a real pistol when setting the shoes properly against the drum.

The cable sheath doesn't really have to be fixed on both ends, but it looks like your "fabricobble" will work. The only downside I see is that in order to replace a cable, you'd have to pretty much remove all the brake components from the backing plate. But how often would you need to do that?
Good job making it work.

I’m going to add some sort of shaft collar (or maybe just a good fuel injection hose clamp) to make it secure on both side of the backing plate.

Enlarging the hole was part of the process too.

I'm not a mechanical engineer but I wouldn't think GM wasted time and money to anchor both ends of the cable housing.

I’ve done drum brakes a time or two. I get along pretty well with everything but the hold down springs. I hate them.

It will be better anchored by the time I’m done with it. By the way, the anchoring of the task force design was just some flimsy little barbs that stuck out on the inside, to keep it from working out of the hole. A fair bit of movement there.

Failed to get a pic. But I drilled a small hole near the tip of the metal plate remnant. And a corresponding hole in the backing plate to receive a cotter pin. Maybe overkill but I don’t want that thing dancing around and possibly hanging on any of the working parts.

A rivet might have been better that a cotter pin. But I don’t have a pop rivet tool around here.

Sounds like a good excuse to buy another tool.

With what should I lube the cable?

White lithium grease is what most people suggest. I've used Lubriplate at times.