mjeff87 Posted January 16, 2007 Share Posted January 16, 2007 Rounding out my wrenchfest on the MJ this weekend, getting it ready for safety inspection....pulled the rear drums off to inspect and found both sides had snapped the adjuster cables :oops: Image Not Found Replaced the cables and tidyed things up. Here's a reference pic for the rear drum assemblies for search purposes: Image Not Found Jeff Link to comment Share on other sites More sharing options...
pingpong Posted January 17, 2007 Share Posted January 17, 2007 I had the same thing happen on a XJ yrs ago... but some how the wire got inbetween the shoe and the drum.... it sucked.. so I sold the jeep, it would have costed more to fix then the jeep was worth to me Link to comment Share on other sites More sharing options...
aemsee Posted January 17, 2007 Share Posted January 17, 2007 Sorry to tell you this, but you have two secondary shoes on that side. The front shoe ( primary) should be an inch or so shorter in lining material. Check the other side, it probably has both short shoes on it. Link to comment Share on other sites More sharing options...
Kenosha Warrior Posted January 17, 2007 Share Posted January 17, 2007 I had the same thing happen on a XJ yrs ago... but some how the wire got inbetween the shoe and the drum.... it sucked.. so I sold the jeep, it would have costed more to fix then the jeep was worth to me how was it not worth fixing, in between the drum and shoe, elaborate please? Link to comment Share on other sites More sharing options...
mjeff87 Posted January 17, 2007 Author Share Posted January 17, 2007 Sorry to tell you this, but you have two secondary shoes on that side. The front shoe ( primary) should be an inch or so shorter in lining material. Check the other side, it probably has both short shoes on it. Really? I put them on about 2 years ago (shows you how much I drive it, huh? ;)) The secondary shoe on that side (passenger) looked visably thicker than the front shoe....the other side, the shoes were about the same thickness :dunno: I'll hafta check them out, again... Thanks, Jeff Link to comment Share on other sites More sharing options...
aemsee Posted January 17, 2007 Share Posted January 17, 2007 It isn't the thickness. It is the length of the lining material. The theory being is that the rear brakes on our trucks are dual action braking. As the front shoe contacts the moving drum it is forced down and back in to the rear shoe which is pressed against the drum at the bottom and the top (wheel Cyl pressure). The shorter material on the primary is supposed to help keep the shoes from locking up prematurly. Of course the reality is that the rears don't do all that much anyway and you can run with the shoes on wrong for two years with no problems :D :cheers: Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 17, 2007 Share Posted January 17, 2007 Hey Jeff; MJ rear drums are a major PITA maintainance-wise. And even if they're right, they don't stop worth a damn. More better to convert to disks. Sure you have thought about it, it's well worth it. Just my 4 cents (inflation.......) Don Link to comment Share on other sites More sharing options...
CWLONGSHOT Posted January 17, 2007 Share Posted January 17, 2007 Hey Jeff; MJ rear drums are a major PITA maintainance-wise. And even if they're right, they don't stop worth a damn. More better to convert to disks. Sure you have thought about it, it's well worth it. Just my 4 cents (inflation.......) Don the brakes are NOT the issue!! Its the funtionality of the rear prop valve!! When its working fine its OK but the trouble is unless you have some weight in the bed you do not get much bias to the rear. I ran with full bias to front AND rear for some time. (NO rear prop valve)The brakes where MUCH BETTER than even before. As a rule of thumb, you lead with the little shoe and the star likes it big. Meaning the adjuster star is nearest the rear shoe were the little cable is. CW Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 17, 2007 Share Posted January 17, 2007 Rounding out my wrenchfest on the MJ this weekend, getting it ready for safety inspection....pulled the rear drums off to inspect and found both sides had snapped the adjuster cables I believe the brakes are the issue (will not use an exclamation point). I was replying to Jeff's original problem. W. rear disks you do not have to deal with rotted out adjuster cables, frozen star wheels, etc. etc. etc. And if the rear prop valve was working properly before converting to disks, it will work just fine after too. The F/R brake bias does not change (IF the prop valve was working and adj. right before), unless you lift the rear, then you increase the length of the linkage arm to match the distance as the lift. Link to comment Share on other sites More sharing options...
ejndssn Posted January 17, 2007 Share Posted January 17, 2007 Hey CW educate me a bit here was the rear prop valve taken out of the loop so that full bias can be applied to the front & rear brakes simultaneously :dunno: Link to comment Share on other sites More sharing options...
mjeff87 Posted January 17, 2007 Author Share Posted January 17, 2007 I ditched the prop valve a couple years ago. Funny thing is I didn't notice any loss in braking performance....I had no idea the cables had snapped. I was just doing my usual go-over on it before I took it in to get an inspection sticker, that's how I discovered the broken cables.... THe OEM brakes work "good" in my opinion, if you keep them serviced, but I'm stepping up to 33" tires in the near future, and I have my doubts as to whether they'll keep me from dying. I have a set of D44a disc assemblies that I was going to install on my new D44 axle once I get it underneath. Jeff Link to comment Share on other sites More sharing options...
Eagle Posted January 17, 2007 Share Posted January 17, 2007 There's nothing wrong with the rear drum brakes on the MJ. As CW has postulated, a large part of the problem is the proportioning valve. Another part of the problem is the single diaphragm brake booster. Changing over to rear discs won't correct either of those problems. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 17, 2007 Share Posted January 17, 2007 X2 on the D44 w. disks Jeff. I just think decent brakes on your rig rank as the #1 priority. The 9" MJ drums the factory deemed okay are now antiquated and inadequate - period, even if you faithfully perform regular preventive maintainance. Lifts and larger tires just compound the problem. All the great upgrades you have paid for in $$ and sweat go away quickly if you can not stop in a panic situation, plus somebody most likely gets hurt. I learned the hard way, so if I seem to be BIG on brakes, please excuse the occasional rants. Any brake upgrade done right is IMHO the best way to protect yourself, your rig, and others. Okay, I be done now............. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 17, 2007 Share Posted January 17, 2007 There's nothing wrong with the rear drum brakes on the MJ. As CW has postulated, a large part of the problem is the proportioning valve. Another part of the problem is the single diaphragm brake booster. Changing over to rear discs won't correct either of those problems Well Eagle, the only thing I agree on the above is losing the single diaphram booster. More junk AMC/Mopar equipped our trucks with. Obviously they corrected this in 1995 with the XJs, too late for our trucks. And the prop valve works just fine w. rear disks IF it's functional and adjusted according to the FSM. If not functional, or beyond adjustment, dump it and put in an aftermarket prop valve. Link to comment Share on other sites More sharing options...
Eagle Posted January 17, 2007 Share Posted January 17, 2007 The reality is that in a pickup, running empty, the front brakes do probably 65% to 75% of the work. That's WHY they have a load-sensing proportioning valve in there. Until mine blew out (the arm had been disconnected by a previous owner), the rear brakes on my '88 locked up before the fronts in any kind of quasi-panic situation, or when the pavement was at all wet or slippery. Mind you, I'm an olde pharte who grew up before we had proportioning valves, so it wasn't a big deal to me but for many people it would be ... unnerving. "Upgrading" the brakes (and since my XJs all have 10" rear drums I'm still not conceding that discs in any way represent an upgrade) would only make that problem worse. You'll need a functional and properly adjusted proportioning valve with rear discs much more than you ever did with drums. No matter how you slice it and dice it, you can't fight physics. Most of the weight is on the front wheels. They do most of the work, and the proportion shifts even more to the front in a panic stop scenario. However, that's just one olde pharte's opinion. YMMV. Link to comment Share on other sites More sharing options...
CWLONGSHOT Posted January 17, 2007 Share Posted January 17, 2007 I completely agree with Eagle. I do like the idea of rear discs or discs all around. The factory braking system will work if you just add rear discs it will work it will not work anywhere as well as it could. Like Eagle said you need a better prop valve and as you suggested a better booster, one intended on utalizing discs at all corners. Eagle did a nice write up complete with pics of where and how to connect the lines. Likely a good search will turn it up. But as memory serves, you need to plug one line and move the rear line to the "nose" port in the factory distrobution block near the booster on the inner fender. One theing, if you do this... CHECK YOU LINES VERY CAREFULLY!!! Bettre yet, RUN NEW LINES!!! Just like Eagle mine blew out when I opened the rear prop valve and depressed the brakes. Imagion if I had loaded up the MJ and took off....I hit a good bump at the same time as depressing the brakes. POOP, would have gone the lines and CW would be in the ditch with a banged up MJ. After you run the lines this way, the same amount of fluid will go to the back as the front. You should have a harder pedal with much better brakes. just be aware, if you don't have weight in the bed the rear tires will lock up first. I did not find this in any way dangerous. Every one of the pick ups I have owned had the rear brakes lock up first in a panic stop. A better way to go is to add a XJ prop valve and a '95+ XJ brake booster and call it done. Thats my 2 cents. CW Link to comment Share on other sites More sharing options...
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