TheBirdistheWord Posted March 2, 2017 Report Share Posted March 2, 2017 I have searched a bunch, and it seems the only definitive answer I can find is "keep at it, its a bitch to bleed these brakes" here are the details: Replaced ALL lines except the hard lines coming from the prop valve to the calipers/junction box. Reman front calipers, new rotors, and pads as well as converting everything in the rear to disks and it got the same treatment. Started with a japanese 15/16 unit that I bought as a rebuilt unit, very clean exterior but I didnt take it apart to inspect, so the seals blew from some light rust biuld up on the interior despite having it sealed during storage. So, now I have an autozone reman unit, cleaned, inspected, and reassembled before installation. bench bleed done on the car, gravity bleeding hasnt yielded any reseults whatsoever, continuous bubbles forever. I should mention I have verified there are absolutely NO leaks. I ran through a big jug a fluid trying to do it this way. I then tried a vaccuum bleeder, same thing, continuous bubbles forever, even after determining I in fact was having a leak at the bleeder screw which has been accomodated for. Against what most of my reading suggested I then tried the pump method with a helper. The air is seemingly all gone, solid stream of fluid out of each line and I even re bled the M/C just to be sure. The pedel will hold pressure if pumped, but wont maintain it after releasing, only way to get brake function is to pump it. So I thought the autozone master was DOA despite cleaning it prior to installation. I bought another, took the guts out and drill honed a Japanese housing and shoved the autozone guts into the japanese housing. Everything seemed to line up and seal proper, but the new housing with reman guts is giving me the EXACT same behavior as the autozone housing PLEASE any input is much appreciated! I need this to pass a salvage title inspection to receive my registration. This is my Daily, please help! Quote Link to comment
flatcat19 Posted March 2, 2017 Report Share Posted March 2, 2017 Leak at one of the calipers or wheel cylinder? Rear brakes loose? Quote Link to comment
TheBirdistheWord Posted March 2, 2017 Author Report Share Posted March 2, 2017 Leak at one of the calipers or wheel cylinder? Rear brakes loose? if there was, wouldnt it be impossible to hold the pressure when pumped? Also, how would I get a completely air free line if this were the case? Quote Link to comment
Doctor510 Posted March 2, 2017 Report Share Posted March 2, 2017 Bleed the master cylinder first Quote Link to comment
flatcat19 Posted March 2, 2017 Report Share Posted March 2, 2017 Master, RR, LR, RF, LF. Bleed into a bottle with a clear tube attached to bleeder. Normally... Pump and holds, adjustment out. Holds then fades, leak/air. 1 Quote Link to comment
TheBirdistheWord Posted March 2, 2017 Author Report Share Posted March 2, 2017 Bleed the master cylinder first I did, I bled again for safe measure and repeated entire bleed process. all lines are full Master, RR, LR, RF, LF. Bleed into a bottle with a clear tube attached to bleeder. Normally... Pump and holds, adjustment out. Holds then fades, leak/air. that is how ive done it, sent just over a quater gallon of fluid through the system in this way. when you say adjustment out, do you mean the M/C plunger may not be pushed in all of the way? I am pretty far out on the rod adjustment, ill try max length and see if I can get any different behavior Quote Link to comment
flatcat19 Posted March 2, 2017 Report Share Posted March 2, 2017 Drums or pedal pushrod. Inspect wheel cylinders and calipers for leaks. Quote Link to comment
TheBirdistheWord Posted March 2, 2017 Author Report Share Posted March 2, 2017 Drums or pedal pushrod. Inspect wheel cylinders and calipers for leaks. I just converted the entire system to 280ZX brakes. Ive gone around a few times and wiped everything and felt around all of the new hose connection down to verify the seal. will triple check. Quote Link to comment
datzenmike Posted March 2, 2017 Report Share Posted March 2, 2017 The masters are aluminum so they don't rust. Internal metal parts only contact the bore by a rubber seal. If rebuilt then the rebuilder is suspect or it wasn't rebuilt or cheap pars used in a Nissan casting. If a Chinese knock off always best to take apart to look for machining metal chips and debris. (twenty yen an hour workers don't care) JDM are much better quality. As to requiring multiple pumps to build up brake pressure, are the flex lines soft? They can swell under pressure. Watch all four while an assistant pumps them up. Are the calipers swapped side to side? The bleeders will be at the bottom instead of the top to let the air out. Are the emergency brake cables connected and are they backed off for bleeding? Seals are best at containing pressure from inside. Air doesn't usually get in but if there is enough suction it may. Quote Link to comment
flatcat19 Posted March 2, 2017 Report Share Posted March 2, 2017 15/16" master...Do you still have drums in the rear? And a proper proportioning valve? Quote Link to comment
datzenmike Posted March 2, 2017 Report Share Posted March 2, 2017 Said all converted over to zx brakes. Quote Link to comment
flatcat19 Posted March 2, 2017 Report Share Posted March 2, 2017 I read that. Just making sure rear discs are part of this or not. Quote Link to comment
TheBirdistheWord Posted March 3, 2017 Author Report Share Posted March 3, 2017 The masters are aluminum so they don't rust. Internal metal parts only contact the bore by a rubber seal. If rebuilt then the rebuilder is suspect or it wasn't rebuilt or cheap pars used in a Nissan casting. If a Chinese knock off always best to take apart to look for machining metal chips and debris. (twenty yen an hour workers don't care) JDM are much better quality. As to requiring multiple pumps to build up brake pressure, are the flex lines soft? They can swell under pressure. Watch all four while an assistant pumps them up. Are the calipers swapped side to side? The bleeders will be at the bottom instead of the top to let the air out. Are the emergency brake cables connected and are they backed off for bleeding? Seals are best at containing pressure from inside. Air doesn't usually get in but if there is enough suction it may. the metal just behind the seals on the plungers had some build up that scored the walls of the japanese housing I used initially. the flex lines are new and firm throughout, and my rear calipers ARE swapped from side to side as per the DQ article by Dean. It appears to me they are faceing "up" as much as the front calipers, could removing the calipers to point bleed screw to 12 o clock position help? ebrake cables are routed but not connected, handle isnt mounted nor has the handle cable been extended. your saying its not likely the air is entering through and potential leaks? 15/16" master...Do you still have drums in the rear? And a proper proportioning valve? I was under the impression the prop valve was OK for 510 with this swap Quote Link to comment
wayno Posted March 3, 2017 Report Share Posted March 3, 2017 I would be looking at the pushrod length as mentioned already. Quote Link to comment
datzenmike Posted March 3, 2017 Report Share Posted March 3, 2017 If behind the seals you mean toward the pedal then the scoring isn't anywhere the seal passes over. If the rear calipers are oriented exactly like they are on the zx then the bleeder is at the high point and bubbles will get out. If not, it's up to you to decide if tilting them any more will help. You may be able to keep the caliper on the rotor just rotate it. Don't apply brakes if the caliper isn't on the rotor or the pistons will pop out. If they have to come off, a block of wood would do. Very unlikely air is being drawn in. It would have to be sucked in and the system is always under residual valve pressure. You have residual valves in? Was the master bench bled first? Didn't notice if it was mentioned. Quote Link to comment
flatcat19 Posted March 3, 2017 Report Share Posted March 3, 2017 the metal just behind the seals on the plungers had some build up that scored the walls of the japanese housing I used initially. the flex lines are new and firm throughout, and my rear calipers ARE swapped from side to side as per the DQ article by Dean. It appears to me they are faceing "up" as much as the front calipers, could removing the calipers to point bleed screw to 12 o clock position help? ebrake cables are routed but not connected, handle isnt mounted nor has the handle cable been extended. your saying its not likely the air is entering through and potential leaks? I was under the impression the prop valve was OK for 510 with this swap Which direction are your bleeders pointing? Up or down? If down, you will never get the air out of that caliper. I think the prop valve is pointless as you are using a MC designed to work with 4 wheel disc brakes...Which you have. If nothing is leaking...Pedal pushrod. Incorrect pushrod length will create funky feeling brakes. Go the complete opposite direction on your adjustment and see how it feels. Do you have a booster installed? Lots of variables not mentioned in any of your posts so far. Quote Link to comment
spdcrazy Posted March 3, 2017 Report Share Posted March 3, 2017 assuming there truly is no leaks, and things are installed as they should be, my bet it on the pushrod length as well. had the same issues with my 521. a small adjustment goes a long way Quote Link to comment
TheBirdistheWord Posted March 4, 2017 Author Report Share Posted March 4, 2017 bleeders are pointing up, no booster. The master was bled on the car using two clear tubes looped from the 8mm bleed screws into their respective reservoirs. With the open tips submerged in fluid I cracked the bleeders open and gradually pumped the brake pedal with a breaker bar to visually verify no air was cycling through. After this, I proceeded to the caliper bleed screws. RR,RL,FR,FL In light of the details about my japanese M/C not being damaged, I am going to swap that on and fiddle with pushrod and pedal adjustment and report back the results. When I got home from work I noticed some seepage from both flare nut fittings on the master cylinder, very slight but it motivates me more to take the autozone unit off because those fittings are teflon taped and TIGHT, and I didnt have issues getting the OE housing to seal. Quote Link to comment
flatcat19 Posted March 4, 2017 Report Share Posted March 4, 2017 Stop shopping at AutoZone. Quote Link to comment
Lockleaf Posted March 4, 2017 Report Share Posted March 4, 2017 Did you just laugh at your own pseudo douchery? Well done sir. Quote Link to comment
thisismatt Posted March 4, 2017 Report Share Posted March 4, 2017 Teflon tape is for pipe thread, not flare seat brake fittings Quote Link to comment
datzenmike Posted March 4, 2017 Report Share Posted March 4, 2017 Push down on the brake with your thumb.You should have a couple of mm (1/16") of pedal movement before there is a firmer resistance. There MUST be some play, but not too much. This clearance assures that the master can return fully to it's rest position and releases all pressure in the lines. Quote Link to comment
TheBirdistheWord Posted March 4, 2017 Author Report Share Posted March 4, 2017 I deserve that, but try finding a NOS M/C and you will understand. haha Quote Link to comment
flatcat19 Posted March 4, 2017 Report Share Posted March 4, 2017 Did you just laugh at your own pseudo douchery? Well done sir. I did. Thank you. It's been one of those kind of days. 1 Quote Link to comment
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