crouse's mj Posted June 9, 2014 Share Posted June 9, 2014 I just did a front end swap from a 1990 cherokee and I put in all new calipers and the drivers side flex line. Bled the lines and everything was fine till i ran to the store and boom it took everything that the glorious 2.8 had to get back home. Any ideas? New master cylinder, calipers, pads, drivers side flex hose, rear drum brakes. Link to comment Share on other sites More sharing options...
ggcnash Posted June 9, 2014 Share Posted June 9, 2014 I just did a front end swap from a 1990 cherokee and I put in all new calipers and the drivers side flex line. Bled the lines and everything was fine till i ran to the store and boom it took everything that the glorious 2.8 had to get back home. Any ideas? New master cylinder, calipers, pads, drivers side flex hose, rear drum brakes. How long was everything fine for? Link to comment Share on other sites More sharing options...
ggcnash Posted June 9, 2014 Share Posted June 9, 2014 The reason I ask is my first thought improper installation, unless this was a sudden occurrence with previous working brakes. Link to comment Share on other sites More sharing options...
crouse's mj Posted June 9, 2014 Author Share Posted June 9, 2014 like 15 mins? but i bench bled the master and everything thing else i thing its the portioning vavle but I'm not sure. Link to comment Share on other sites More sharing options...
nitroxsteve Posted June 9, 2014 Share Posted June 9, 2014 Were both sides dragging? I would think if you went very far they would have been very hot. Link to comment Share on other sites More sharing options...
crouse's mj Posted June 9, 2014 Author Share Posted June 9, 2014 didnt go far but It was like touching a stove top. Link to comment Share on other sites More sharing options...
crouse's mj Posted June 9, 2014 Author Share Posted June 9, 2014 And yes both sides a dragging. Link to comment Share on other sites More sharing options...
Blue XJ Posted June 9, 2014 Share Posted June 9, 2014 I've had the surface on the knuckle that the pads ride on get a groove in it from the pads. They can get hung up in the groove and lock up the brakes. Odd it would happen to both sides at the same time but I guess it could. 5 minutes with a welder and a flap wheel and it's good as new. Link to comment Share on other sites More sharing options...
crouse's mj Posted June 9, 2014 Author Share Posted June 9, 2014 Yeah anything is possible with this truck. As soon as I figure out how to upload photos ill show you guys what I'm looking at. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 9, 2014 Share Posted June 9, 2014 I've had the surface on the knuckle that the pads ride on get a groove in it from the pads. They can get hung up in the groove and lock up the brakes. Odd it would happen to both sides at the same time but I guess it could. 5 minutes with a welder and a flap wheel and it's good as new. ^^ Agree. Also use a little brake grease on the notches that the pads ride on, the rear face of the pads, and the brake caliper pins on so they can slide w/o binding. Did you use "loaded" calipers with the pads already installed? If not, make sure the inboard and outboard brake bads are installed correctly as they are not interchangeable, and of course the new calipers must be installed with the bleed screw UP. Link to comment Share on other sites More sharing options...
crouse's mj Posted June 9, 2014 Author Share Posted June 9, 2014 No, everything was separate. I had to get new rotors because it ruined my last set before i realized what was going on. fast forward new calipers and rotors still the same, everything was put on right so I'm just lost right now Link to comment Share on other sites More sharing options...
nitroxsteve Posted June 9, 2014 Share Posted June 9, 2014 I would put the front up on stands and pull the front tires. Apply the brakes fully then release the pedal. Now crack the bleeder and see if it is holding pressure. If you have no pressure then we need to start looking for a mechaical reason the brakes are dragging. If you have pressure we can start looking for a hydraulic blockage or restriction. Link to comment Share on other sites More sharing options...
crouse's mj Posted June 9, 2014 Author Share Posted June 9, 2014 https://imgur.com/a/6HnS3#0 these are some pics i just took of it. Link to comment Share on other sites More sharing options...
Blue88Comanche Posted June 9, 2014 Share Posted June 9, 2014 I've had the surface on the knuckle that the pads ride on get a groove in it from the pads. They can get hung up in the groove and lock up the brakes. Odd it would happen to both sides at the same time but I guess it could. 5 minutes with a welder and a flap wheel and it's good as new. ^^ Agree. Also use a little brake grease on the notches that the pads ride on, the rear face of the pads, and the brake caliper pins on so they can slide w/o binding. Did you use "loaded" calipers with the pads already installed? If not, make sure the inboard and outboard brake bads are installed correctly as they are not interchangeable, and of course the new calipers must be installed with the bleed screw UP. yes bad things happen when a off road shops some how manage to install my brakes improperly. however in my case i had no brakes... Link to comment Share on other sites More sharing options...
Eagle Posted June 10, 2014 Share Posted June 10, 2014 No, everything was separate. I had to get new rotors because it ruined my last set before i realized what was going on. fast forward new calipers and rotors still the same, everything was put on right so I'm just lost right now I suspect that you have an incompatible mix of steering/suspension and brake parts. From my long-time work-in-progress book (copyrighted, I do NOT grant any permission to reproduce): In general, the parts to be concerned with in keeping the front brakes compatible are the steering knuckles, the hub/bearing assemblies, the rotors, and the calipers. (There is a more complete enumeration of the interrelationship of these parts in Chapter 6, Axles.) • Only two steering knuckle designs were used: 1984 through 1989, and 1990 through 2001. Left and right side knuckles are different part numbers within each group. • Three different hub/bearing units were used. The hub/bearing units are the same for both sides of the vehicle. The different years for hub/bearing assemblies were: 1984 through 1989; 1990 through mid-1999 (composite rotors); and late-1999 through 2001 (cast rotors). • Three rotor types were used: 1984 through 1989; 1990 through mid-1999 (composite); and late-1999 through 2001 (cast). • Only two caliper types were used: 1984 through 1989, and 1990 through 2001. Left and right side calipers are different part numbers within each group. If everything doesn't match ... you get issues. Link to comment Share on other sites More sharing options...
MJCARENA Posted June 10, 2014 Share Posted June 10, 2014 Are you sure the Master Cylinder is the correct one, if it is then you might have the same problem I had. I had a problem when I went to the dual booster upgrade. My problem was the push rod from the booster was not adjusted correctly and was not letting the piston in the Master completely move back to unblock the hole to relieve the pressure to the calipers. Then the heat generated from the dragging brakes expanded the brake fluid in the calipers and made the problem worse, almost could not move. By loosening the nuts that hold the Master onto the booster, the brakes would release. Had to measure the push rod length and the piston hole depth that the rod goes into and adjusted the rod to the correct length by turning the adjuster on the tip. No more problems after that. Link to comment Share on other sites More sharing options...
johnnyc Posted June 10, 2014 Share Posted June 10, 2014 I agree with Eagle. I found this out the hard way many years ago. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 10, 2014 Share Posted June 10, 2014 There is really no reason to purchase the wrong brake parts (or any other part); all you need is the correct parts catalog for your MJ. These are available for free online download online in lots of places (two are linked below). Just look up your year, whether 2WD or 4WD, and order them using the Chrysler or AMC factory part numbers. Most every online vendor allows searching for parts using the manufacturer's part numbers. In rare cases your will need to know your build date. For example the front brake rotors for the 2WD models were changed on Feb. 10, 1992. If you depend on some parts drone to look up part numbers for you, that's asking for trouble. https://onedrive.live.com/?cid=c40904cfda278a46&id=C40904CFDA278A46!115 http://www.jeep4x4center.com/knowledge-base/ Link to comment Share on other sites More sharing options...
Jeep Driver Posted June 10, 2014 Share Posted June 10, 2014 https://imgur.com/a/6HnS3#0 these are some pics i just took of it. Your pics are not helpful. Here, the shinny portion, where the pads ride. Over time the pads will make indentions in the slides, if so, it will need to be resurfaced as this pic shows. Otherwise the pad will not release from the rotor. Link to comment Share on other sites More sharing options...
crouse's mj Posted June 10, 2014 Author Share Posted June 10, 2014 MJCARENA its the original brake booster but that booster is bad. I took for a run around the block and had to pull the pedal back up after applying it and everything was good. Getting a new one tomorrow. Eagle thanks for your concern, but I changed everything out to fit my new front end plus when you pay 40 bucks for a new to you front end its best just to go through it and get new items. I did go back through and made sure its the right stuff. Jeep Driver i'll put better ones up tomorrow. Did you just take a grinder to that? Link to comment Share on other sites More sharing options...
Jeep Driver Posted June 10, 2014 Share Posted June 10, 2014 MJCARENA its the original brake booster but that booster is bad. I took for a run around the block and had to pull the pedal back up after applying it and everything was good. Getting a new one tomorrow. Eagle thanks for your concern, but I changed everything out to fit my new front end plus when you pay 40 bucks for a new to you front end its best just to go through it and get new items. I did go back through and made sure its the right stuff. Jeep Driver i'll put better ones up tomorrow. Did you just take a grinder to that? No, you build up the metal with weld, then resurface. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 10, 2014 Share Posted June 10, 2014 Yes, this is a pretty common problem with the front disk brakes on our trucks. I have Ford Explorer disks on the rear, and they have a stainless steel "cap" that snaps across the caliper bracket track the calipers ride on. When you replace the pads, these caps are included and are replaced too. So building back up the worn metal on the bracket track is never necessary. Why AMC then Chrysler engineers didn't do this I'll never understand. And no, these clips don't fit the front Jeep calipers unfortunately. Occasionally Ford did something better. Link to comment Share on other sites More sharing options...
Eagle Posted June 10, 2014 Share Posted June 10, 2014 Eagle thanks for your concern, but I changed everything out to fit my new front end plus when you pay 40 bucks for a new to you front end its best just to go through it and get new items. I did go back through and made sure its the right stuff. But the new axle is a 1990, going into an earlier chassis. Did you buy ALL the parts to be compatible with the 1990 knuckles? That's where it starts. You can't mix and match any of the components. Link to comment Share on other sites More sharing options...
crouse's mj Posted June 10, 2014 Author Share Posted June 10, 2014 Yes it's all the same.I posted some more pics up on imgur but this mobile version won't let me link it. But the photo is where the pads are almost touching is when I pressed the brake pedal and the didn't release. Link to comment Share on other sites More sharing options...
crouse's mj Posted June 10, 2014 Author Share Posted June 10, 2014 https://imgur.com/a/6HnS3#6 It was the front proportioning vavle! finally found it. The drum brake photos is where the po had put the back plates on backwards so the emergency cable was facing the rear and had a hell of a time trying figure out why nothing worked on those. Broke the axle down which was a good thing because it looked liked motor oil in the housing. The pin in that valve is seized up so I might just have to find a new one. Thanks for all the help guys. I'll let you know whats going on tomorrow night when the booster comes in and everything is back on. Link to comment Share on other sites More sharing options...
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