Trouble bleeding brakes (still spongy)

[CrUZida]

I've replaced the stock brakes on my MZ10 with Skyline/300ZX gear, both front and rear.

Came to bleeding the brakes on the weekend, and my foot goes about 2/3 of the way down before they apply any pressure.

We've bled each caliper about 3 times, in the correct order, and put through almost 500mL of fluid just as a flush.

Now the tricky part is that the front calipers are no longer vertical, they are on about a 45deg angle.
Thinking about it I'm pretty sure the bleed valve is higher than any of the pistons, but I'll verify that with some photos tonight.

Assuming the bleed valve is the highest point, can anyone think of any reason why they are spongy?
The stock setup was fine, and the differences in pistons sizes stock vs nissan is negligible.

I drove the car around for a bit yesterday hoping that may help the situation, but no different.
We'll rebleed the whole system tomorrow night with the calipers mounted where they are, see if any air has surfaced.
If thats a no go we'll move the caliper to a vertical position, and bleed it there.


This thread is just here to see if anyone can think of anything I've forgotten.

[kingmick]

Master cylinder is wrong size

[CrUZida]

Perhaps you missed...

and the differences in pistons sizes stock vs nissan is negligible.

[JustCallMeOrlando]

They're the same calipers as on my setup which work a treat, only mounted differently.

[kingmick]

yes i did miss it. you might need to get them bled as well as you can and then go to a place with a pressure bleeder! it must be trapping air in the caliper.

[CrUZida]

Thats the final option I can think of.

[oldcorollas]

Now the tricky part is that the front calipers are no longer vertical, they are on about a 45deg angle.
Thinking about it I'm pretty sure the bleed valve is higher than any of the pistons, but I'll verify that with some photos tonight.

thats my first thought.... could have put them on wrong side?
know where the bleed hole enters the piston bore?

[Pure_In_Sanity]

What if you unbolt the calipers, pivot them up so the bleeders are right up the top, then let them gravity bleed for a little while.
May help get any extra air out?
Cheers
-Phil

[BeRad]

when will people learn..... its because its a nissan item

[CrUZida]

thats my first thought.... could have put them on wrong side?
know where the bleed hole enters the piston bore?

Normally about 1" above the piston bore.
So they should still be ~10mm above the bore.

What if you unbolt the calipers, pivot them up so the bleeders are right up the top, then let them gravity bleed for a little while.
May help get any extra air out?

Do people not read things these days?

If thats a no go we'll move the caliper to a vertical position, and bleed it there.

[jonra23]

Sounds like either the angle of the calliper is causing air to be trapped above the bleed point, maybe in oposite side of caliper depending on where the bridge passage is oriented, or that air is trapped in a loop in the feed hoses.

Have you tried hooking a length of clear tubing onto bleed nipple, putting the other end into the bottom of a small bottle (orchy or similar) and just pump a fair bit through with the pedal, sometimes the pump up and crack bleed nipple method doesnt push through enough volume to clear trapped air bubles in line.

Sort of a home pressure bleed job, dont like pressure bleeders much as you dont have much control over what fluid they put in your system.

regards
jon

[CrUZida]

Have you tried hooking a length of clear tubing onto bleed nipple, putting the other end into the bottom of a small bottle (orchy or similar) and just pump a fair bit through with the pedal, sometimes

That was the way I originally did the bleeding, which left it spongy.
And then we did the pump up and crack method multiple times.

We'll give all the methods a few tries next time, make sure we eliminate everything.

[oldcorollas]

Normally about 1" above the piston bore.
So they should still be ~10mm above the bore.

i was more meaning.. when you look into the piston bore, where is the hole that leads to the bleed valve.

ie, at what angle will this hole stop functioning correctly, and can you slot the hole to allow a greater angle of mounting to be used? (dremel disc ftw )

[Robbos_Toyotas]

interesting as my ma61 has the same problem. Did you replace the brake lines? sorry if thats an obvious question...

but for my ma61 with stock brakes and the ma70 master cylinder im sure its clogged up brake lines...as no air comes out the bleed nipples but the brakes are useless....to the stage where ive parked it until i upgrade them....

[PlacentaJuan]

i had something similar when i changed brake boosters, i think i depressed the brake pedal too far on the first few strokes and it broke a valve or something in the booster which left the brakes worthless and really spongy, requiring the booster to be repaired.

after it was repaired i only depressed the pedal no more than half way until the system started to firm up, and that seemed to work.

having air in the system would probably be easyer, good luck.