15/16 M/C woes, need to get inspected and have no brakes!

[flatcat19]

I deserve that, but try finding a NOS M/C and you will understand. haha

Honestly, I would have been chasing a 7/8" master if I was not going to use a booster. Way easier to find than a 15/16".

 

Hind sight for ya though.

 

15/16" is a big cylinder to move fluid through without assistance.

[TheBirdistheWord]

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.

 

I found this while searching for answers.  Initially the pedal tight with no play.  I have since loosened it back up.

[yello620]

Any chance of getting pics of the calipers mounted on the car front and rear.

 

I don't think that you have a master cylinder seal issue.

 

I can think of three easily possible issues.

Master cylinder pushrod length. Make sure it has some play in it as Mike mentioned. Generally, adjust as long as you can freely install and remove the pedal attachment pin.

 

Rear caliper bleeder orientation. Could you unbolt the caliper and use the gravity method for bleeding and just tip the caliper around a little pointing the bleeder more towards up? I have had to do this before on a conversion that changed the bleeder position from the stock(280zx) position. 

 

Rear caliper parking brake adjustment. This depends on what year/style calipers you are using. This comment will not apply to early 280zx calipers, but the late calipers will be affected by this. The rear caliper pistons will retract far enough to give you a pedal that needs pumped up each time if the parking brake arm is not actuated repeatedly also. I have no idea really how to explain it though. 

Take a look at how much clearance you have between the pads and the rotor on all pads, inner and outer, top and bottom. They should all appear to be touching the rotor with basically only enough clearance for the rotor to turn. 

[MikeRL411]

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.

 

Never use Teflon tape on brake fittings!  If it won't seal, you have mixed SAE and Metric threads.

[TheBirdistheWord]

I have some braided flex lines made for in between the M/C and prop valve, they were 9 and 13 inches long.  When I went to pick up the lines I noticed the bottom fitting matched the OE hard lines, and top two didnt have the "guide collar" at the beginning of the threads I am not sure what else to call it.  I asked them about it and they insisted it would be ok to use.  Before I payed I promptly asked them if they would fix it if it didnt seal and they reluctantly halfassedly agreed.  After playing with the OE hard lines I am pretty sure the collar is necessary to preserve the threads on the line and housing as well as seal any gap that the taper of the housing leaves

 

am I warm with any of this?   

 

 

Any chance of getting pics of the calipers mounted on the car front and rear.

 

I don't think that you have a master cylinder seal issue.

 

I can think of three easily possible issues.

Master cylinder pushrod length. Make sure it has some play in it as Mike mentioned. Generally, adjust as long as you can freely install and remove the pedal attachment pin.

 

Rear caliper bleeder orientation. Could you unbolt the caliper and use the gravity method for bleeding and just tip the caliper around a little pointing the bleeder more towards up? I have had to do this before on a conversion that changed the bleeder position from the stock(280zx) position. 

 

Rear caliper parking brake adjustment. This depends on what year/style calipers you are using. This comment will not apply to early 280zx calipers, but the late calipers will be affected by this. The rear caliper pistons will retract far enough to give you a pedal that needs pumped up each time if the parking brake arm is not actuated repeatedly also. I have no idea really how to explain it though. 

Take a look at how much clearance you have between the pads and the rotor on all pads, inner and outer, top and bottom. They should all appear to be touching the rotor with basically only enough clearance for the rotor to turn. 

pushrod has been adjusted properly ill try for a photo soon

 

The brackets are the same design used in the "rear disks" DQ article, I assumed that "up" meant anywhere in between the 11 o clock to 1 o clock position, I will try to shimmy the caliper to see if I get any more air. I am starting to think this is less of an air issue and more of an adjustment issue.  ::edit:: The lines are definitely full, and clear of any air bubbles.  

 

I am using the later style calipers, and the instant I saw you mention the ebrake tension something occurred to me.  While I havent yet inspected pad clearance, when I was trying to verify piston pressure to all 4 corners I had someone push the pedal while I tested rotors for movement.  While the brakes are at rest I noticed the rear rotors have notably less resistance respective to the front.  If the e brake removes that extra play in the rear piston, it would make sense the play in the pedal would be effected assuming the hydro lines are free of air and clean.  I am going to button up the ebrake setup and try this next.

 

Anyone think ebrake tension would affect the air in the lines?

 

Never use Teflon tape on brake fittings!  If it won't seal, you have mixed SAE and Metric threads.

you hit the nail on the head.  in my case, you hit the dumbass garage mechanic right on the head. lol.  I was an idiot to assume the exterior parts on the OE and Reman unit were interchangeable.  However, this doesnt explain why the OE unit sealed at the bottom ports and the reman unit never did even after the mix and match, before and after the teflon 

 

I thought I was in the clear from the swapping parts but I just snapped the flare nut fitting clean off of the threads inside of the OE  M/C housing.  It must have been on the edge of breaking because it was sealed and I did a quick check over everything with the wrench it snapped off with the slightest of pressure.  

 

 

 

These are aluminum, is it worth it to try and fill or repair the OE master?  I have one more very used OE housing that I am decrudifying and soaking at the moment, the guts from the one I broke will go in there and ill try again and report back.

 

It seems I got very close the last try with proper pushrod throw, it only took a half pump until full pressure was built.  Whereas the try before that, and the time before that it would take 2-4 pumps to get to full pressure.  I am almost confident the ebrake may be the culprit.

THANKS FOR ALL OF THE REPLIES  Ill come back to the thread when Im done breaking the next thing........  ::sigh::

 

 

[thisismatt]

No idea what you mean by "guide collar". 

[flatcat19]

Do these calipers have the ebrake built in?

 

If so, the pistons should have slots or indentations on them. The brake pads have pins...Do these line up? I have seen other cars have these not line up and create a really squishy pedal.

 

 

Has adjusting your prop valve changed the way stuff feels?

[TheBirdistheWord]

No idea what you mean by "guide collar". 

 

Er, I may be over stating it.  Its just a slight smooth cylindrical extension past the threads on the flare nut, all of the hard lines I have removed so far have looked like this.  It may be in my head but it seemed extremely easy to line these up and catch the threads in comparison to the new fitting without this little extension.  I think possibly verifying the concern I initially expressed to the shop the made the lines for me. 

 

Do these calipers have the ebrake built in?

 

If so, the pistons should have slots or indentations on them. The brake pads have pins...Do these line up? I have seen other cars have these not line up and create a really squishy pedal.

 

 

Has adjusting your prop valve changed the way stuff feels?

 

I believe they are built in, but honestly this is the first I have ever heard or read about an e brake indentation in the piston needing to line up with a notch in the guide pin, is that correct??.  I will definitely look into it.

 

I didnt think I was far enough into the process to consider adjusting the prop valve but from what I felt the very last time I bleed the system, I am starting to reconsider!  Thats next on the list of things to do.  

[thisismatt]

Er, I may be over stating it.  Its just a slight smooth cylindrical extension past the threads on the flare nut, all of the hard lines I have removed so far have looked like this.  It may be in my head but it seemed extremely easy to line these up and catch the threads in comparison to the new fitting without this little extension.  I think possibly verifying the concern I initially expressed to the shop the made the lines for me. 

 

 

I believe they are built in, but honestly this is the first I have ever heard or read about an e brake indentation in the piston needing to line up with a notch in the guide pin, is that correct??.  I will definitely look into it.

 

I didnt think I was far enough into the process to consider adjusting the prop valve but from what I felt the very last time I bleed the system, I am starting to reconsider!  Thats next on the list of things to do.  

 

Gotcha.  Well, if the female end of the connection isn't threaded all the way down, then that could be a reason for the extended smooth section at the end of the male part.  In the case that you got a fitting with threads all the way down, the threads would bottom out before the flare made contact, causing it to tighten up but not seal.  That's just conjecture at this point, but worth looking at given what you've said.

[TheBirdistheWord]

Gotcha.  Well, if the female end of the connection isn't threaded all the way down, then that could be a reason for the extended smooth section at the end of the male part.  In the case that you got a fitting with threads all the way down, the threads would bottom out before the flare made contact, causing it to tighten up but not seal.  That's just conjecture at this point, but worth looking at given what you've said.

 

Thats what im thinking, visually the threads on the master body that the female connector goes into looks tapered. Though thinking about it that may be counter intuitive to how the flare actuallly contacts the nipple.  I guess Ill find out soon

[TheBirdistheWord]

fiddling with the pushrod and more searching, I came across a couple of threads on hybridz.org about early S chassis M/C plungers resting closer to the mouth of the M/C camparative to the ZX M/C  Anyone have a clue about pushrod length differences?  mine could very well be from another car.

[wayno]

I just went thru this shit last week, I spent most the week trying to figure out why I could not get pedal unless I pumped it up(4/5/6 pumps), and when I let off it would basically go to the floor again, this happened a 100 times, I ran out of brake fluid, I changed everything, 2 different masters, all new hoses and lines, new rear brake cylinders, new calipers/rotors, the only thing that was not changed were the hard lines on the rear end itself, I was asking Mike K what could be wrong as I used his disc brake kit on this L320.

I finally decided I had to start over again from start, I went out in the garage and looked at the first things I put on, the rotors, disc brake bracket, and the calipers and it was right there in front of me, I put the calipers on the wrong sides, even though the bleeder is pointed up, it is at the bottom of the caliper piston, I was never going to get the air out of them, so I changed them to the proper sides, bled both sides, and all was good.

I just assumed I had them right, but the bleed screws were on the bottom pointed at an angle up, but they were on the bottom, not at the top pointed up.

The bleeders are on the side actually, but they were on the bottom side, not the top side, they have to be at the top of the caliper piston, if you look at the bleeders and they are lower than the top of the caliper piston, you have found your issue.

[TheBirdistheWord]

well...... shit.  I dont remember the DQ article mentioning anything about this, in fact I spoke with the author of the article about this and they definitely need to be swapped side to side for e brake function. Ill just bleed with a piece of wood in the caliper with the bleed screw pointing up and C clamp it to fit over the rotor when done and see if that does it.

[wayno]

well...... shit.  I dont remember the DQ article mentioning anything about this, in fact I spoke with the author of the article about this and they definitely need to be swapped side to side for e brake function. do I just bleed with a piece of wood in the caliper with the bleed screw pointing up and C clamp it to fit over the rotor when done? 

So are you saying they were on the wrong sides?

[TheBirdistheWord]

Yes, you called it, while still pointing "up" bleeder screws are lower on the rear calipers. I realize this had already been mentioned, i had only just now got back at it from replacing the parts i broke. Gonna figure it out this week.

[TheBirdistheWord]

THAT WAS IT!!!!! Tilted them up and got a good fart of air out of each of the rear calipers followed by immediate pedal feel.   Fucking hell, This was my first real attempt and doing a brake overhaul, is this common knowledge that I just wasnt savvy to?  Or is this something I overlooked while gathering info about the swap?  

 

this should be labeled solved for other who deal with this later..

 

now, time to figure out the dash and reverse lights for the lamp inspection

[wayno]

Can't you just switch them around, or do they need to be that way to have a functioning e-brake system?

[TheBirdistheWord]

from the looks of it, they need to be swapped for ebrake to function.  No problem now that I know the trick, maybe I etch it into the car somewhere lol

[flatcat19]

Lol. Problem solved; post tits.

[datzenmike]

Shit flows down hill, air flows up hill.

[TheBirdistheWord]

curious, yesterday all wheels spun freely with good pedal return and feel.  Now a day later, my front calipers wont release.... fml, I suppose ill give them the unbolt-and-shimmy treatment with another bleed when I can find a helper.

[flatcat19]

curious, yesterday all wheels spun freely with good pedal return and feel.  Now a day later, my front calipers wont release.... fml, I suppose ill give them the unbolt-and-shimmy treatment with another bleed when I can find a helper.

Pushrod adjustment.

[wayno]

I second push rod adjustment, you need just the slightest bit of play before the plunger in the master moves, only a sixteenth inch works.

[thisismatt]

curious, yesterday all wheels spun freely with good pedal return and feel.  Now a day later, my front calipers wont release.... fml, I suppose ill give them the unbolt-and-shimmy treatment with another bleed when I can find a helper.

Need play in the pushrod

[TheBirdistheWord]

The pushrod was a little on the tight side but there was light play, I loosened it for good measure.  no change.  Gravity bled that single caliper again seeing no air in lines and no change...

 

edit: front drivers side is free and moving, front passenger still wont budge