big66440 Posted April 19, 2011 Share Posted April 19, 2011 Thought I'd start a new thread about the topic, I've replaced my brake master cylinder,LF,RF and rear rubber brake hoses as well as my wheel cylinders on my manche, I've seen the thread that gives step by step instructions on bleeding the system with the height sensing valve and have done the following procedure using my pressure bleeder, 1. I bled the system RR,LR,RF and LF (all my steps were done with 15psi of pressure and the truck sitting level at curb height) 2.I pressurized the system opened the right front bleeder turned the ignition switch to the "on" position pressed in the brake pedal and held it with a jack handle against the seat,I then went to the RR wheel cylinder opened it and did not stop getting air bubbles, must have waited AT LEAST 45 minutes and still didn't get rid of the air,am I doing something wrong? I checked the pedal to be sure and to no surprise it was spongy. Link to comment Share on other sites More sharing options...
Eagle Posted April 19, 2011 Share Posted April 19, 2011 Two questions: 1. Why did you turn on the ignition? 2. Why did you prop the brake peddle down with a jack handle? It doesn't sound like you understand the reason for the special bleeding procedure. There's an emergency by-pass circuit to the rear brakes so that if the front brakes fail you can have full pressure to the rear rather than going through the height-sensing proportioning valve. Normally, the slider in the front junction block has that emergency circuit blocked off. The purpose of opening a front bleeder is to simulate a front brake failure and get the slider to move, opening the by-pass circuit so it can be bled. Holding the brake peddle down doesn't accomplish anything. What needs to be done is to open the front bleeder, then stomp on the brake peddle to force the slider to slide. If the brake warning light doesn't come on, you didn't stomp hard enough. And the only reason for turning on the ignition would be to see if the warning light comes on. Link to comment Share on other sites More sharing options...
big66440 Posted April 19, 2011 Author Share Posted April 19, 2011 So once I open the front bleeder and stomp the pedal I can release it right away?, do i leave the front bleeder open while the system is pressurized and I'm bleeding the rears? Link to comment Share on other sites More sharing options...
05mxdiesel Posted April 19, 2011 Share Posted April 19, 2011 When you leave one of the bleeders open in the front, all pressure gets sent to the rear, which kicks the brake light on. While all the pressure is being forced to the rear, the bypass line from the height sensoring valve will get bled. If the all the pressure is not forced forced to the rear, air will remain in the lines. I spent two hours bleeding brakes and could not get them right until I found out the proper procedure. Link to comment Share on other sites More sharing options...
duster1971 Posted April 19, 2011 Share Posted April 19, 2011 so what i am geting from this is that inorder to bleed our brakes we need to trip a safty feature? can some body please explain to me why this has to be done in detail? i guss i have never had any vehicle that required such complicated proceidure. sorry for the :hijack: :hijack: but i need to know as my rear line has a hole in it that i am going to be fixing shortly. Link to comment Share on other sites More sharing options...
big66440 Posted April 20, 2011 Author Share Posted April 20, 2011 It's a pain in the @$$,I've had my butt naked coronet outside of the garage in the driveway for almost 2 weeks and taking the bus to work :fs1: :headpop: :mad: :wall: :fs2: I think I may have even come up with some new curse words, I've tried everything I possibly can and not to be a show off but it's a bit embarrassing since I'm ASE certified on brakes Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 20, 2011 Share Posted April 20, 2011 Must be that time of the year for bloody bleeding brake problems. I've been through two freaking quarts of brake fluid since I swapped out the rear axle trying to bleed the system. Air, more air, then more air ad nauseam. Haven't even gotten past the rear wheels yet. Bleeding as I always do the old fashioned way, pump pedal, release bleed screw, pedal goes to floor, air bubbles come out, tighten bleed screw. I use a clear hose submerged in brake fluid to prevent air being sucked back in, no joy. Even tried the "Speed Bleeder" screws, same. BUT the brake pedal is firm and the braking is great as before with the old axle. Can easily lock up all four wheels as before on a panic stop and I have retained the load leveling valve. I'm seriously considering going to the dealer (something I've never done ever with the MJ) and trying a pressure bleeder. But the brakes are just fine with zero spongy pedal. I don't get it............. :dunno: Link to comment Share on other sites More sharing options...
big66440 Posted April 20, 2011 Author Share Posted April 20, 2011 I've gone through 3 quarts and I've had it!!! I have a jegs proportioning valve that was gonna go on my coronet but oh heck I'll just run it on the manche I did a quick "run through" of the system and it seems pretty easy aside from finding the distribution block right off the master without the second outlet to the rear any one know were I can buy one? I'm planning on having it done for next coming monday so I can finally start driving back to work. Link to comment Share on other sites More sharing options...
flint54 Posted April 20, 2011 Share Posted April 20, 2011 When I did my rear axle upgrade I went through a LOT of fluid before the system satisfied me. I also had to replace two questionable lines that _might_ have allowed air into the system. After standard bleed, and opening the RF bleeder, the bypass line bleeding worked but took far longer than I expected. Had to keep a pan under RF to catch fluid also. I also use a line in a clear bottle of fluid, but I keep the bleeder open so I can push the pedal while looking under the vehicle at the bottle (one man job). I have to wonder if it is possible for a compromised seal between reservoir and MC to permit a continual but small air intrusion? Link to comment Share on other sites More sharing options...
Eagle Posted April 20, 2011 Share Posted April 20, 2011 so what i am geting from this is that inorder to bleed our brakes we need to trip a safty feature? can some body please explain to me why this has to be done in detail? I explained why in the second post in this thread. You have to trip the shuttle valve in order to open the port to the bypass line to the rear wheels. I've gone through 3 quarts and I've had it!!! I have a jegs proportioning valve that was gonna go on my coronet but oh heck I'll just run it on the manche I did a quick "run through" of the system and it seems pretty easy aside from finding the distribution block right off the master without the second outlet to the rear any one know were I can buy one? Just plug it. The thread is 1/2" SAE (fine). The shortest bolt I could find with that thread was 1" -- I cut it down until the head almost contacted the valve body when the bolt bottomed out, then I put an O-ring on it, added a "dollop" of RTV to ensure a good seal, let the RTV set up and screwed it in. Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 20, 2011 Share Posted April 20, 2011 I also had to replace two questionable lines that _might_ have allowed air into the system. All I did was rework some of the lines going over the axle and did not break any of the load leveling valve lines. If a fitting was allowing air in, wouldn't it also allow fluid out? I would think so. I'm not losing any fluid. I have to wonder if it is possible for a compromised seal between reservoir and MC to permit a continual but small air intrusion? Thought about that too, but I never touched the master and didn't allow it to drain dry. :dunno: The brakes are good, but all that air isn't "right", so it bugs me. Another thing: after I put everything back together, I tried to gravity bleed the rear wheels as I usually do for a few hours, and no fluid came out. Not trying to hijack, but maybe we have a common problem(s). Link to comment Share on other sites More sharing options...
91coMANche Posted April 20, 2011 Share Posted April 20, 2011 Glad I got my 96 XJ proportioning valve ready to go in so I can bleed the truck like a normal vehicle :) Link to comment Share on other sites More sharing options...
acfortier Posted April 20, 2011 Share Posted April 20, 2011 Glad I got my 96 XJ proportioning valve ready to go in so I can bleed the truck like a normal vehicle :) +1 to that. Going to get around it tomorrow. On another note, after bleeding my system TWICE the correct way, my brakes are still way weaker than any other car/truck I've driven. Makes me wonder if I bled them correctly... Link to comment Share on other sites More sharing options...
big66440 Posted April 21, 2011 Author Share Posted April 21, 2011 Just plug it. The thread is 1/2" SAE (fine). The shortest bolt I could find with that thread was 1" -- I cut it down until the head almost contacted the valve body when the bolt bottomed out, then I put an O-ring on it, added a "dollop" of RTV to ensure a good seal, let the RTV set up and screwed it in. does that work for the rear t fitting as well? Link to comment Share on other sites More sharing options...
big66440 Posted April 21, 2011 Author Share Posted April 21, 2011 Sorry I tried to simply copy and paste your reply Link to comment Share on other sites More sharing options...
91coMANche Posted April 22, 2011 Share Posted April 22, 2011 If you guys just installed new wheel cylinders or calipers you won't be able to gravity bleed them. Gravity bleeding only works when there is enough fluid in the system to start pulling from the master cylinder. if you're getting no fluid then you need a pedal bleed. If you haven't replaced your master cylinder then you better get that next along with the booster. Those parts do go bad and on 20 year old trucks they are already worn. Link to comment Share on other sites More sharing options...
Eagle Posted April 22, 2011 Share Posted April 22, 2011 You can also buy a vacuum (suction) bleeder. JC Whitney sells them, and I think I've seen them more recently in Auto Zone. IIRC the name is MityMite or something like that. Yeah - http://www.mityvac.com/pages/products_hvpo.asp Link to comment Share on other sites More sharing options...
big66440 Posted April 22, 2011 Author Share Posted April 22, 2011 Ok finally bypassed the valve this afternoon with a jegs part number 555-63020 (amazingly easy by the way) and plugged the port on the distribution block but now I don't have ANY fluid to the rear wheels.I am a bit bummed but relieved at the same time since at this point it can only be either or the brake line from the distribution block to the rear wheels or the distribution block itself I've already back tracked the "clog" and it can only lead to these 2,I'm headed to the junkyard and will be replacing the distribution block with an XJ prop valve,what year XJ valves interchange with an 89 MJ? Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 22, 2011 Share Posted April 22, 2011 Ok finally bypassed the valve this afternoon with a jegs part number 555-63020 (amazingly easy by the way) and plugged the port on the distribution block but now I don't have ANY fluid to the rear wheels.I am a bit bummed but relieved at the same time since at this point it can only be either or the brake line from the distribution block to the rear wheels or the distribution block itself I've already back tracked the "clog" and it can only lead to these 2,I'm headed to the junkyard and will be replacing the distribution block with an XJ prop valve,what year XJ valves interchange with an 89 MJ? You bypassed the stock load leveling (proportioning) valve with a Jegs adj. proportioning valve and now have no fluid to the rear brakes. And are now looking to replace the existing MJ distribution block with an XJ prop valve? You only need one prop valve for the rear brakes (the Jegs) and should retain the MJ distro block. Sounds like you plugged the supply port on the distro block when you should have plugged the return line. And where is the suspected "clog"? I haven't done this (eliminate the load leveling valve), nor ever plan to unless it goes belly-up (then I'll replace it w. a Toyota load leveling valve or similar). There are several writeups detailing how to do this load leveling valve elimination correctly, perhaps Eagle will chime in here again. Link to comment Share on other sites More sharing options...
Eagle Posted April 22, 2011 Share Posted April 22, 2011 Ok finally bypassed the valve this afternoon with a jegs part number 555-63020 (amazingly easy by the way) and plugged the port on the distribution block but now I don't have ANY fluid to the rear wheels. As noted, you do NOT need an XJ proportioning valve if you have the Jegs. Which port of the MJ distribution block did you plug? The one you need to plug is the large one toward the front on the BOTTOM of the metering block. The one you retain is the port in the "nose" of the metering block. Link to comment Share on other sites More sharing options...
big66440 Posted April 22, 2011 Author Share Posted April 22, 2011 guess I plugged the wrong one :hmm: Link to comment Share on other sites More sharing options...
Eagle Posted April 23, 2011 Share Posted April 23, 2011 guess I plugged the wrong one :hmm: Pete has a photo of how to fix that ... Link to comment Share on other sites More sharing options...
91coMANche Posted April 23, 2011 Share Posted April 23, 2011 Ok finally bypassed the valve this afternoon with a jegs part number 555-63020 (amazingly easy by the way) and plugged the port on the distribution block but now I don't have ANY fluid to the rear wheels. As noted, you do NOT need an XJ proportioning valve if you have the Jegs. Which port of the MJ distribution block did you plug? The one you need to plug is the large one toward the front on the BOTTOM of the metering block. The one you retain is the port in the "nose" of the metering block. I recently installed my XJ valve and the only line that didn't bolt up was the far front port line. I cut that line off at the old block. Was that not the bypass to the rear? Link to comment Share on other sites More sharing options...
big66440 Posted April 23, 2011 Author Share Posted April 23, 2011 OK so the distribution block off the master cylinder on Mj's does NOT work as a proportioning valve right? I'm thinking I can route the "feed" line from the master to my Jegs proportioning with a fitting and bending a line to it right? Link to comment Share on other sites More sharing options...
Eagle Posted April 24, 2011 Share Posted April 24, 2011 OK so the distribution block off the master cylinder on Mj's does NOT work as a proportioning valve right? I'm thinking I can route the "feed" line from the master to my Jegs proportioning with a fitting and bending a line to it right? Correct. The MJ front "thingie" is a distribution block and it also has the slider to actuate the brake warning light. It is NOT a proportioning valve. Plug the outlet on the front bottom. That was the emergency bypass for the rear height sensing valve. The outlet from the "nose" is the normal feed to the rear brakes. Run a line from that to your new proportioning valve, then from the new proportioning valve directly to the flex hose at the rear axle. Link to comment Share on other sites More sharing options...
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