UNL1MTD Posted March 15, 2009 Share Posted March 15, 2009 I've gone through the Haynes Manual steps to adjust the parking brake a couple times and I'm left with the condition of the parking brake not working when the rear is downhill. When the front is downhill it holds exceptionally well. When the tires are off the ground and the parking brake is applied I can rotate the tires in reverse by hand by adding a fair amount of force, thats how loose it is. When I got the truck in 2007 I replaces all ebrake components (pedel springs, front cable, rear cables, all brake hardware, and brake cylinders) I'm a bit stumpted on what to try do to fix this issue and I've got state inspection coming up next month. Any ideas? Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 15, 2009 Share Posted March 15, 2009 I've gone through the Haynes Manual steps to adjust the parking brake a couple times and I'm left with the condition of the parking brake not working when the rear is downhill. When the front is downhill it holds exceptionally well. When the tires are off the ground and the parking brake is applied I can rotate the tires in reverse by hand by adding a fair amount of force, thats how loose it is. When I got the truck in 2007 I replaces all ebrake components (pedel springs, front cable, rear cables, all brake hardware, and brake cylinders) I'm a bit stumpted on what to try do to fix this issue and I've got state inspection coming up next month. Any ideas? AFAIK in VA the parking brake test was just put the tranny in D (or 1st gear) and rev the engine a bit. If it's holding downhill, you should be okay, no? Or have they changed the ebrake test? Link to comment Share on other sites More sharing options...
UNL1MTD Posted March 15, 2009 Author Share Posted March 15, 2009 I've gone through the Haynes Manual steps to adjust the parking brake a couple times and I'm left with the condition of the parking brake not working when the rear is downhill. When the front is downhill it holds exceptionally well. When the tires are off the ground and the parking brake is applied I can rotate the tires in reverse by hand by adding a fair amount of force, thats how loose it is. When I got the truck in 2007 I replaces all ebrake components (pedel springs, front cable, rear cables, all brake hardware, and brake cylinders) I'm a bit stumpted on what to try do to fix this issue and I've got state inspection coming up next month. Any ideas? AFAIK in VA the parking brake test was just put the tranny in D (or 1st gear) and rev the engine a bit. If it's holding downhill, you should be okay, no? Or have they changed the ebrake test? Well if thats the test, then it will pass. But I would like to fix it just for general safety and function. Link to comment Share on other sites More sharing options...
Eagle Posted March 15, 2009 Share Posted March 15, 2009 It's not broken. This has been discussed several times in the past. Drum brakes do not hold as well in reverse as they do going forward. It's a function of the way the shoes and levers are arranged. In the old days, they were called "servo-assisted" brakes, The idea is that the forward rotation imparted to the shoes when they contact the drums tends to cam the shoes out and jam them harder against the drums, providing better braking. The same geometry also helps the parking brake hold when the nose is pointing downhill. It does NOT work in reverse. And it will not work in reverse. If you adjust your parking brakes so you get a good hold with the tail pointing downhill, they will be adjusted so tight that the brakes will be dragging and you'll wear them out in a very short while -- and probably ruin the drums in the process. It's just one of those facts of life we have to accept and learn to live with. Basically, don't park nose-up on steel hills, and ALWAYS use PARK or leave the tranny in first or reverse when parked -- don't EVER trust the parking brake alone. Link to comment Share on other sites More sharing options...
Drahcir495 Posted March 15, 2009 Share Posted March 15, 2009 It's not broken. This has been discussed several times in the past. Well I am glad you brought it up again, because I missed all the other discussions :cheers: Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 16, 2009 Share Posted March 16, 2009 It does NOT work in reverse. And it will not work in reverse. If you adjust your parking brakes so you get a good hold with the tail pointing downhill, they will be adjusted so tight that the brakes will be dragging and you'll wear them out in a very short while -- and probably ruin the drums in the process. It's just one of those facts of life we have to accept and learn to live with. Basically, don't park nose-up on steel hills, and ALWAYS use PARK or leave the tranny in first or reverse when parked -- don't EVER trust the parking brake alone. You don't have to accept it and live with it - just junk the antiquated drum brakes and install disk brakes. Simple! :beerhead: Link to comment Share on other sites More sharing options...
Eagle Posted March 16, 2009 Share Posted March 16, 2009 It does NOT work in reverse. And it will not work in reverse. If you adjust your parking brakes so you get a good hold with the tail pointing downhill, they will be adjusted so tight that the brakes will be dragging and you'll wear them out in a very short while -- and probably ruin the drums in the process. It's just one of those facts of life we have to accept and learn to live with. Basically, don't park nose-up on steel hills, and ALWAYS use PARK or leave the tranny in first or reverse when parked -- don't EVER trust the parking brake alone. You don't have to accept it and live with it - just junk the antiquated drum brakes and install disk brakes. Simple! :beerhead: Probably two-thirds of the people who convert to rear discs don't even bother to hook up the parking brake, so I'm going to stay with my dinosaur attitude that there's no overriding reason or need to put rear disk brakes on a Jeep. Disc brakes are great for aircraft and racing vehicles, but for me it's just not worth the dollars or effort to make the conversion. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 16, 2009 Share Posted March 16, 2009 Probably two-thirds of the people who convert to rear discs don't even bother to hook up the parking brake, so I'm going to stay with my dinosaur attitude that there's no overriding reason or need to put rear disk brakes on a Jeep. Disc brakes are great for aircraft and racing vehicles, but for me it's just not worth the dollars or effort to make the conversion. I don't know where you got the two-thirds statistic from, but my ebrake works great! Maybe you should convert your front disks to drums too to complete the dinosaur mate. I just don't get it........ Link to comment Share on other sites More sharing options...
jaekl Posted March 16, 2009 Share Posted March 16, 2009 You must make sure the cables are moving freely. Then continue to adjust until you have just enough to hold for reverse. You will still have to push all the way down to get full braking but they won't rub when off. Drum brakes can have a leading and a trailing shoe. Our brakes are symetrical so there is always one leading shoe for either direction. Some shoe sets have shorter harder lining on the leading shoe, but every set I've bought in my years have been unmarked and identical. Therefore they should work in both directions but it is so easy to have slippage in reverse. I don't know why. Perhaps the parking brake leverage prevents the leading shoe to dig in. As far as drum verus disc brakes, I see drums as the the better design. (if it weren't for the fade) Think about it. Disc require much higher forces which require beefier components, bigger piston - more fluid displacement - higher capacity master cylinder. Drums use the rotation of the drum to increase braking force (leading shoe) and springs to pull the shoes off the friction surfaces. Ther must be a limit as to how much performance can be developed with drum brakes which necessitate the move to discs. Drums are a carry over from wagon days with a block on the wheel and could be done with mechanical leverage. There are mechanical disc brakes on smaller equipment, hydraulics are required to get the higher forces required to get the better performance. This is contrary to good design but seems to be the necessary approach. Of course heat dissipation is a good thing. Link to comment Share on other sites More sharing options...
jtdesigns Posted March 16, 2009 Share Posted March 16, 2009 Disc brakes are way more easier to service though. I have rear disc's on my Rodeo and I'd much rather mess with them instead of messing with all the springs, pins, strings, and cables found in drums, plus just the fact of having to adjust drums makes them more of a PITA. Even though the Rodeos parking brake is a drum type, I've never had to adjust my parking brake before. Link to comment Share on other sites More sharing options...
Eagle Posted March 16, 2009 Share Posted March 16, 2009 Drum brakes can have a leading and a trailing shoe. Our brakes are symetrical so there is always one leading shoe for either direction. Some shoe sets have shorter harder lining on the leading shoe, but every set I've bought in my years have been unmarked and identical. Therefore they should work in both directions but it is so easy to have slippage in reverse. I don't know why. Perhaps the parking brake leverage prevents the leading shoe to dig in. XJ and MJ brakes are NOT symmetrical. The shoe sets include two long shoes and two short shoes. Specifically, the metal shoes themselves are the same, but two have longer strips of lining than the other two. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 16, 2009 Share Posted March 16, 2009 :agree: w. JT above. And if periodic adjustments are not made to the shoes, drum brake performance deteriorites rapidly. Using Eagle's statistic, I'm sure two-thirds of the junk still running around with drum brakes have ZERO maintainance until they fail, or lose braking force so badly the owners are forced to perform maintainance. With disk brakes, replace the pads (and/or rotors if necessary), adjust the ebrake, then forget about 'em, except for eyeballing the pads once in a while for wear. Disk brake performance stays relatively consistent. I'm all for continuing tradition and love old technology otherwise I would not be driving an MJ. :D But not when it comes to brakes. :cheers: Link to comment Share on other sites More sharing options...
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