Is there a fix for weak e-brake caused by large wheels?

[drdata]

Hey all, new member and my first post. I did read the stickies and searched, and did not find the answer I seek. Most brake upgrades seem to deal with swapping out rear drums for disks, which I believe makes for no e-brake!.

I have a '78 with 33"s, and found the e-brake was never strong enough. I recently threw down on a '72 with 35"s, and its that much worse. I do not think they will hold the truck on my angled driveway, let alone suffice as a brake in the case of an emergency.

I inspected brakes/cable, and all is working. Just not very well given the leverage of those tires.

Are there any real fixes here? I can see:

1. Return to smaller tires
2. Carry wheel chocks for parking
3. Upgrade to larger drums, but not clear what that entails wrt my current rims. The 72 has a corp 14 bolt with a custom axle that uses 1/2 brakes and standard bolt pattern.

Thanks in advance and thanks to this great site for all the good info.

Regards

[cleszkie]

I run a 14 Bolt full floater rear with the 3/4 ton drum brakes and 35" tires and the parking brake works great. I'm not sure what 1/2 brakes are (1/2 ton brakes?). If you have 1/2 ton brakes on the 14 bolt, it is an easy swap for the 3/4 ton or 1 ton drum brakes. You just need to make sure the shoes are properly adjusted to get the most out of the parking brake (parking brake peddle gets firm before it hits the floor).

Swapping to 3/4 or 1 ton drum brakes on a full floater axle is as easy as removing the backing plates from the donor axle (wheel cylinders, brake shoes, springs all connected to backing plate) and bolting them to your axle. This will result in an 8-lug set up, and your current rims (15"?) may need to be upgraded to 16" or 16.5" to clear the drum.

Other options for you to consider are 1) a line lock, or 2) a driveshaft mounted disk brake behind the transfer case.

[truckster]

I have 33s with stock brakes. My e-brake has no problem holding on any hill. I know you said you inspected it, but it sounds like something isn't right.

[drdata]

Interesting. Thanks for the info. I did mean 1/2 ton drum brakes, and I was worried that swapping to 3/4 ton would impact bolt pattern between front/rear and rim size. If I upgrade rims then I guess I need new tires. What a rat hole.

For those that say their ebrake works... I used to believe there was just something funky that I was too dumb to see when it was only on my '78, but when I observed much the same (only worse) on the '72 I started to believe its was simply the nature of large tires.

The below is true for both the 78 and 72, I:

1. Inspected and cleaned all parts, installed new spring kit. Plenty or rear pads, but not clear on nature of material (sintered or not). No grooving or noticeable marring of drum surface.

2. Everything seems to work, including adjusters. There is no free play where the cable enters the drum (lock nut is solid).

3. I adjusted the shoes so there is notable friction putting the drum back on. Used brake cleaner to remove any contamination from pads.

4. I adjusted the ebrake cable to remove slack and have additional drag when depressed two clicks. At one point I had it so tight the peddle would hardly travel half way, which I guess that eliminated some leverage advantage. So per the manual, slight drag at two clicks.

5. When jacked up and the peddle is depressed to normal usage the wheels appear frozen, as they should be.

6. I then drive down the street, take foot off gas, and apply ebrake, At best I feel a slight sensation of slowing, as noted. I tried this a few times to attempt to remove any pad glazing, but never seemed to improve much.

I wonder if a set of high-performance shoes might help? Any suggestions there?

I see folks with much larger tires and does seem odd that 35's would overwhelm the stock brake so badly.

Thanks again for your tips and suggestions.

[Critter]

My old E brake on the original 12 bolt axle held my 35s on an incline but just barely. I agree with cleszkie on the driveshaft mounted disc setup, they are a little tricky and kind of expensive but work great due to the added mechanical advantage not to mention they are just plain cool.

Also, you can get rear discs with E brakes by using older Eldorado rear calipers. Many will argue that the 76-78 Cadillac callipers are junk (I cant comment either way) but keep in mind Wilwood makes some after maket calipers as well, but $$$$$.

[watahyahknow]

with the drive axle mounted disk you do have to be carefull when changing a tire lift one of the drivewheels up and all braking dissapears

[drdata]

Again, thanks for the ideas and suggestions.

The drive shaft/xfer case brake is cool, but given others report similar tires and a much more functional e-brake I tend to suspect a malfunction rather than being under-designed for the 35" wheel size.

As the system is not that complex and seems to be mechanically working I suspect perhaps poor pads/contamination. I'd hate to use eldo e-brakes and find the same state of affairs on a new rear disk setup, for example. IOW, it not clear that eldorado ebrake/pads are any beefier than what I already have.

Does anyone have any recommendations on good performance pads that will really grab back there?

Regards