ma61 spongy brakes after upgrade and many bleedings

[naten]

ARG!

tried different way of bleeding and it didnt make a difference maybe even a bit worse.

Going to give it another full bleed at all corners on the weekend.

Tis a possibility but i dont see why a brand newy wouldnt work, other people have used them with no issues too (hilux ones)

If i could drive it would probably try to get it pressure bled, though ive never had to do it before.

Only other thing i can think of the push rod length that comes from the booster may be slightly wrong but i cant see it being a huge issue

[naten]

pushrod was checked on the weekend, its adjusted pretty much perfectly, also checked the throw of the pushrod was the same as the total piston movement and it was.

Did a full bleed with a different color fluid to make sure new stuff was all the way through, bled all the ports out of the proportioning valve

and no joy.

Im going to probably put the stock calipers/discs back on and see if it still does it, should let me isolate what the problem is a little better, its not a driveable solution though as i have the rotor rings on the hubs

[SupraM8]

when you took the valve out of the master cylinder for the rear circuit you need to replace it with the same restrictor as the front has ive had a fair bit of experience with this.the firewall mounted proportion valve will work fine because your car has 4 wheel disc brakes from standard.the nissan type cylinders are tadem split with the proportioning valve built in

[naten]

thanks for you reply

Ive attached a picture of what i think is the restrictor i took out from the rear port. I had a look and the front has something that looks the same (might be a different spring?)



Is that what you mean by restrictor?

I havent bled the brakes with it in btw

Its still odd that this would affect the fronts?

[naten]

hmmm after reading your post a few times do you mean the factory nissan master cylinders have the proportioning built in so they dont have a separte proportioning valve like toyotas?

[CrUZida]

Nah, he's talking about the master cyl.

[naten]

ah i get it now

Will wait to see if that rubber thing is the restrictor and go from there

[CrUZida]

Whoops, sorry, your interpretation was correct.
The Nissan MC has the proportioning valve inside it (as opposed to separate)

[SupraM8]

now you have to be very careful it can be in the amount of grooves around the top.also it can be confusing its the way the master cylinder distibutes fluid whencars have drums onthe back they need very little fluid flow for the wheel cyliders to react or not react affecting the pedal height.Now with the brakes your using for all those caliper pistons moving out it takes ahell of alot of fluid flow so be careful with master cylinder choice.

[naten]

okay..................

hard to follow what you mean man

[SupraM8]

early in the morning here man does the rubber thing have the exact amount of grooves

[JustCallMeOrlando]

Now with the brakes your using for all those caliper pistons moving out it takes ahell of alot of fluid flow so be careful with master cylinder choice.

The piston area for the Nissan calipers is almost exactly the same as the factory MA61 ones, and he's retained the factory rear brakes. That's what makes it so puzzling as none of us have had any issues.

[SupraM8]

it is a strange one i used to rebuild m/cylinders and brakes the restricter is the only problem ive come accross with

[thechuckster]

fwiw: the 15/16 MC from my MZ10 has restrictors in both outlets - but these are nothing to do with proportioning braking effort - they simply slow down the return of fluid to the MC (preventing the pistons/pads from withdrawing too far away from the disk)

This is the restrictor

(click for bigger version of image)

And this exploded view shows that there are two of them - one for each outlet.

(clicky for bigger version of image)

(note: the right-hand outlet on my MC has a banjo style connector)

[naten]

hmmmm interesting chuck

ive since put the stock calipers back on and tried to bleed it with both those check valves in and out and no go still crappy pedal

im now assuming its something to do with the master cylinder, i dont want to pull it apart to see if its dodgy as it will probably lower my chances of getting it replaced with the place i bought it from

searching for a m61 MC to rebuld now