Dana 18 Parking Brake questions

[dauntless89]

Alright, so I'm getting geared up for a serious overhaul after this four-wheeling season ends and one of the things I plan to address is the marginally-functional parking brake.

I have the stock D18 drum parking brake, with a newer cable. , I've taken it all apart and rebuilt it, I've tried adjusting it a half-dozen different times, and no matter what or how I do it it won't hold the adjustment. It'll work "better" (not ideally) for about a hundred miles or so and then go back to normal. Normal means I can usually trust it to hold the rig on pretty much flat terrain, if I pull the lever out as hard as i possibly can. When I go to re-adjust it, it is either too tight and drags, or it's too loose and doesn't work worth a damn. Huge PITA. It's not oil-soaked, the rear shaft seal isn't seeping and the shoes are new.

I've read about disc-brake conversions. I've read about a swap to rear drums that have the parking brake hardware in them. With everything else I'm doing, I'm not terribly inclined to add either of these to the list. I've read about various line-lock mods. I'd prefer to keep it mechanical and isolated from the brake hydraulics. York on-board air is on the list, and I'm toying with the idea of hooking up a pneumatic cylinder to the actuator lever, controlled by a toggle valve and regulator. If the dust seal in the cylinder can hold up to the under-Jeep elements, it should work pretty damn well. And if not, I'm out no more than $30 for an air cylinder and my time hooking it up. The intended use here is short-term stops with the engine running (constant supply of air pressure).

Doing research, I read someone claiming:

...any regular use of the system as a parking brake generally causes the rear output seal to seep oil...

Can anyone substantiate this?

At this point, I'm extremely skeptical. D18s have a reputation for being leaky, but is that the brake's fault for sure? If the brake works so unevenly as to push the output shaft out of concentricity with the seal, to the point of causing it to seep or wear prematurely, I would say a bad seal is the least of your problems. But that was just my first thought and there could be something completely different going on.

Bear in mind I have no idea what this guy's professional experience may or may not be. It's also the only thing that pops up when I Google search the subject. And of course I don't want to spend resources on anything more than futile efforts to re-adjust it, until I can either blow the claim off as bunk or acknowledge it as a documented truth.

Any thoughts? Thanks fellas.

 

[BajaEdition]

Welcome to early CJ5 syndrome
I run 2 D 18s with Parking brakes as such, now I do not have the problem you seem to be having but I do know I adjust them about once a year or so. Seems they are always needing to be adjusted, I would look at the entire system and see if it were all stock and find out if there is something else that is causeing the problem as every hundred miles is extreme. If it weps that bed you have t case problems
oh, remember that t case and the tranny share fliud so it could be leaking from between the 2 also, just go under and take a long look is my suggestion.

 

[dauntless89]

Welcome to early CJ5 syndrome
I run 2 D 18s with Parking brakes as such, now I do not have the problem you seem to be having but I do know I adjust them about once a year or so. Seems they are always needing to be adjusted, I would look at the entire system and see if it were all stock and find out if there is something else that is causeing the problem as every hundred miles is extreme. If it weps that bed you have t case problems
oh, remember that t case and the tranny share fliud so it could be leaking from between the 2 also, just go under and take a long look is my suggestion.

There's some seepage from the PTO cover, but nothing significant (just enough to darken the metal) and it's not getting into the brake. Bone dry in there. It's not literally 100 miles either, but I can't hardly set the brake 3 or 4 times without it losing adjustment. And, heaven forbid, if I forget to release it before taking off, it screws it WAY up.

Everything appears to be in good shape. Nothing looks hillbilly hacked or welded or ground up. Shoes are new last year. Drum surface is smooth.

Come to think of it, if anyone has pictures of the attachment point between the cable sheath and the crossmember, that would be appreciated. It looks like the sheath is pointing the wrong way, the cable's coming out of it at a fairly sharp angle, somewhere between 20 and 30 degrees, but it's bolted down in the most direct way possible.

 

[tarry99]

There's some seepage from the PTO cover, but nothing significant (just enough to darken the metal) and it's not getting into the brake. Bone dry in there. It's not literally 100 miles either, but I can't hardly set the brake 3 or 4 times without it losing adjustment. And, heaven forbid, if I forget to release it before taking off, it screws it WAY up.

Everything appears to be in good shape. Nothing looks hillbilly hacked or welded or ground up. Shoes are new last year. Drum surface is smooth.

Come to think of it, if anyone has pictures of the attachment point between the cable sheath and the crossmember, that would be appreciated. It looks like the sheath is pointing the wrong way, the cable's coming out of it at a fairly sharp angle, somewhere between 20 and 30 degrees, but it's bolted down in the most direct way possible.

You missed the most important part of making that rear drum E brake attached to the D-18 work correctly...............You need to arch the new shoes to a drum that is concentric IE; round and freshly cut .......otherwise you only have partial contact and therefore partial holding ability and as it wears it is always out of adjustment.

 

[dauntless89]

apparently nobody around here does shoe arcing anymore. I asked about it at Les Schwab last time i was in there and the tech laughed at me. "just replace the drum. cheaper and easier." same basic story everywhere else i've bothered to ask. quite frankly I'm not willing to shell out what it would cost to

I mocked it up when I replaced them and it was really close... *maybe* a .005" gap between the shoe and drum in the center of the shoe. the drum surface is smooth and round/concentric (to the yoke) to within .003"

in my opinion, if this setup can't take that amount of tolerance, it does not belong on a 45-year-old jeep.

now, another question. The haynes/FSM specifies to turn the star wheels back out 7 notches from "contacting" the drum. how much contact and how are we measuring this? a slight drag? lock up the rear shaft? tried it both ways and a couple ways in between with little luck.

 

[mtnwhlr]

now, another question. The haynes/FSM specifies to turn the star wheels back out 7 notches from "contacting" the drum. how much contact and how are we measuring this? a slight drag? lock up the rear shaft? tried it both ways and a couple ways in between with little luck.

The way I have always done it is tighten while spinning the wheel until it lockes the wheel then loosen untill you have a slight drag.

 

[tarry99]

apparently nobody around here does shoe arcing anymore. I asked about it at Les Schwab last time i was in there and the tech laughed at me. "just replace the drum. cheaper and easier." same basic story everywhere else i've bothered to ask. quite frankly I'm not willing to shell out what it would cost to

I mocked it up when I replaced them and it was really close... *maybe* a .005" gap between the shoe and drum in the center of the shoe. the drum surface is smooth and round/concentric (to the yoke) to within .003"

in my opinion, if this setup can't take that amount of tolerance, it does not belong on a 45-year-old jeep.

now, another question. The haynes/FSM specifies to turn the star wheels back out 7 notches from "contacting" the drum. how much contact and how are we measuring this? a slight drag? lock up the rear shaft? tried it both ways and a couple ways in between with little luck.

Dauntless Buick 225 V6 ,
Herm the Overdrive guy is in Washington also...........he can rebuild your setup including arching the shoes & cutting the drum for I think $75 bucks exchange. Maybe less in your case with new parts?
The drive shaft E-Brake actually works quite well in my opinion......
E-brake drum brakes in the rear don't hold very either on a hill. .........disc's do a good job either way.

 

[dauntless89]

i'm sure it would work well if it worked at all. putting a brake ahead of the gear reduction in the axles gives the brake more leverage over the tires, it's a good idea.

i'm just growing very tired of mine not working seemingly "no matter what." there's obviously something not right with it. I'm also not enthusiastic about spending $75 on a parking brake that may or may not have an inherent design flaw, which brings me back to my main concern: whether or not "normal use" will actually, for real cause the shaft seal to fail prematurely. has anyone else heard this or know anything about why it might?

unless someone can confirm this with specifics, i'm leaning towards calling BS on the claim. there's enough of these D18s out there and they've been around long enough that if it was an issue i'd expect it to be documented somewhere. i've also not spent the last 40 years working on these transfer cases. if my assumptions are wrong, i'd love to be corrected

 

[tarry99]

i'm sure it would work well if it worked at all. putting a brake ahead of the gear reduction in the axles gives the brake more leverage over the tires, it's a good idea.

i'm just growing very tired of mine not working seemingly "no matter what." there's obviously something not right with it. I'm also not enthusiastic about spending $75 on a parking brake that may or may not have an inherent design flaw, which brings me back to my main concern: whether or not "normal use" will actually, for real cause the shaft seal to fail prematurely. has anyone else heard this or know anything about why it might?

unless someone can confirm this with specifics, i'm leaning towards calling BS on the claim. there's enough of these D18s out there and they've been around long enough that if it was an issue i'd expect it to be documented somewhere. i've also not spent the last 40 years working on these transfer cases. if my assumptions are wrong, i'd love to be corrected

Dauntless Buick 225 V6 ,

I'm with Baja I have used them and seen them used for years just for the holding & mechanical advantage of being able to grab the drive line and locking up all 4 wheels from one location........Now big tires will obviously put a big strain on that little 8-9 inch drum........I have not seen anything I like better short of maybe a 12v Line Lock or a similar mechanical locking devise. As far as getting after the seal.........I would say that perhaps the seal surface area or the bearing or a worn drive line that vibrates would be more apt to cause a seal failure than the e-brake in good condition.
As far as the design of the Dana 18 or 20 check out Novaks website......for what they do in such a compact area it's a pretty amazing piece of engineering.

There are a few small parts in the E-Brake including the adjusting ring and the shoe posts that do wear out.....get a hold of Herm's Overdrives, he'll fix you up.