Bizarre brake breakage

[DanB98TJ]

Fred (StealthTJ) and I ran Charouleau Gap yesterday - fun trail, but a little more difficult than usual thanks to wet/sandy rocks.....

After getting through the rough stuff, it felt like I had a rear brake grabbing. We had gone through some water not too far back and I figured the brakes might be wet, so I rode them lightly for a few yards to try and dry them out. When I hit the brakes again it felt like a wheel locked up and made a strange noise. Then the pedal went to the floor. After a couple pumps and I realized I had a serious problem - it felt like the pedal was disconnected from the master cylinder.

I lifted the hood and saw that the master cylinder reservoir was nearly empty. Once I walked around the Jeep it was pretty easy to see where all the fluid went - it was running out of the right rear drum. I could also see the rear shoe retaining pin hanging loose from the backing plate.

When we got the wheel and drum off I was pretty shocked. The backing plate was severely bent and ripped loose from the mounting bolts, one of the return springs mangled, one of the shoes bent, and the front piston had blown out of the wheel cylinder. Fred and I pulled all the parts off the backing plate, hammered the metal brake line closed and dumped in some fluid so we could get my Jeep back to pavement.

I'm really baffled about what happened, and have never seen anything like this before. When Fred did his rear disc conversion he gave me all the drum brake parts, so I have everything to fix it (except a new brake line), but would really like to know what caused this and hopefully never have it happen again. There was no indication that the axle seal or wheel cylinder was leaking and caused the brake to grab. Any ideas?

Apparently Webshots is being picky again and won't let me post a pic. Here is a link to a few shots:

http://community.webshots.com/album/58905922kiWryx

[Scott Hill]

in 4 lo the backing plates are not strong enough I have seen several wrap around them selves happenes a lot if you back up in 4 lo with the ebrake on

as far as I know the only way to prevent this is disk brakes but longer ebrake cables can help they get pulled tight on full drop and if you have a locker it really works that backing plate


Scott

PS I am on my second set now and they are not 100% straight anymore.

[DanB98TJ]

Hmmm....I'm trying to remember if I may have done that about a mile earlier on the trail when we stopped to "adjust" Fred's instrument cluster. I had pulled off the trail so a Pinzgauer (or whatever those 6-wheeled things are) could get by. I probably didn't have to use the brakes again until around the time I noticed the problem, so I guess it's possible the damage had already been done by then, and the cylinder puked a piston when I was trying to figure out if a brake was grabbing. Makes about as much sense as anything else, I guess....

My big concern now is that the mounting surface on the housing is slightly tweaked on one corner. I don't THINK it will hurt anything, at least I hope not. If so I guess I'll have to sell a kidney and buy a D44 or 9".

I've added a few more photos to the Webshots album, and you can see the damage better.

[Robert J. Yates]

Dan,
I'll second what Scott told you. We have seen that quite a bit out here. Swap to disks and then you can forget about it.

[Jerry Bransford]

Originally posted by Robert J. Yates
Dan,
I'll second what Scott told you. We have seen that quite a bit out here. Swap to disks and then you can forget about it.

Robert, would you please stop reminding me of all the crap I still need to do to my TJ? Gawd it's never ending is it.

[DanB98TJ]

Yeah, I'm getting the feeling that a disc swap will be coming soon. For now I swapped on Fred's parts until the $$$$ is available...whenever that might be. As soon as the brake line arrives I can get the Jeep back on the road (figured it was worth the $15 at the dealer for a new line, just so I didn't have to screw with bending and flaring a new one).

I'm still not 100% sure if I left the e-brake on, but based on the way the holes ripped in the backing plate the damage happened going forward. I guess it could have tweaked the plate enough to cause things to bind up going forward, but I'm starting to wonder if a spring popped loose and let one of the shoes bind. Guess it doesn't matter, but it would be nice to know if it was caused by my stupidity or just a freak accident.

[Robert J. Yates]

No, it doesn't end Jerry, even when you are out of the mode of doing big mods as there is still maintenance to take care of simply due to trail wear and tear

Dan, do you have a D35? If so, the swap to disks is probably easier and cheaper than you think.

[DanB98TJ]

Yep, I'm stuck with the D35....at least until I win the Lottery. I've heard the disc conversion is pretty much a bolt-on but haven't had a chance to dig for a write-up.

[Jerry Bransford]

Does anyone like Blaine still have a pair of machined retainer plates for mounting ZJ brakes on a D44? I'm close to starting that project and would like to start by obtaining a pair. Anyone? TIA!

[Stu Olson]

Jerry, you should have grabbed a pair (or two pairs if you have spare shafts) of those about 6 months ago when Blaine still had some. I don't know if anyone else has any stashed or not.

I know that some of the folks on JU bought some....you might check there and see if someone got them and never did the project.

[Jerry Bransford]

Thanks Stu, that's what I figured. I'm in no real rush, I'll just keep my ears open for more of them being made available somewhere. I'll check on JU too, thanks.

[mrblaine]

Jerry, one of the several reasons that I quit the retainer business is that Tera now offers the whole conversion. It looks to be the same jeep parts that you get at the junkyard, only new and it also appears that they did what I was going to. That is- make a ring and just use the original Spicer retainers.

Bob should be able to hook you up.

[Jerry Bransford]

Originally posted by mrblaine
Jerry, one of the several reasons that I quit the retainer business is that Tera now offers the whole conversion. It looks to be the same jeep parts that you get at the junkyard, only new and it also appears that they did what I was going to. That is- make a ring and just use the original Spicer retainers.

Bob should be able to hook you up.

Hey that is good news, I'll check it out. I hope they'll sell everything but the disk brake assemblies, that will save me some money. hanks Blaine!

[mrblaine]

Jerry, I have a source for the retainer plates. All one piece and go for 20 dollars for the pair. Very nice quality, OEM equivalent.

I am going to grab some just to have around. Let me know if you need some. I recommend getting two pair. You need a set for spare axles if you ever get some.

[ChrisK]

Blaine,
I might be interested in another set for my spares.

Chris

[Jerry Bransford]

Thanks Blaine, I'll take you up on that... just sent you a PM. Thanks!!

[mrblaine]

I am going to see how many I can source. Right now, I don't have any but the prototype. I will let you guys know when I get them. They are ordered though. I placed a blanket order for 10 pair.

[Paradiddle]

As an FYI I called Tera and they are still waiting on their disc brake conversion kits. They do not have pricing yet and told me to call in a couple of weeks.

Jeff