ma61 spongy brakes after upgrade and many bleedings

[TooF]

yup the hilux will ahvea load sensing proportioning valve at the back.

some MC;s will ahve a valve in the rear port that will keep the fluid up to the drums. this is pretty easy to check for, if you look in the port you will see a small valve like affair. this can normally be removed without too much stress.

im running a VZN130 hilux 1" mc in my aw11 and have never had any grief, that said my MC didnt have any valve in it (PBR brand)

[thechuckster]

They also have a check valve built into the MC to keep pressure on the drum when you release the pedal, which is not wanted for discs. IT also explains why the MC pushes fluid to the backs before the fronts and at a higher volume

it's actually a design feature for disk-brake not drums - you want the callipers to retract a minimum distance otherwise the more worn the disk pads get, the further the callipers would have push before engaging the disk surface. So to make this happen, the MC will restrict the flow of fluid back to the reservoir.

[TooF]

are you sure ive never seen the restrictor on MC's that were destined for disc systems, only drums

[thechuckster]

in both my MZ10 MC/s there is a form of check valve in outlet ports. The effect of them is restrict flow of fluid back to the reservoirs. They're not one-way valves or pressure restrictors.

If you look down the inlet ports on the MC, you'll see a main supply hole (about 3-4mm) and a much smaller port of ~.5mm ahead of it by a few mm, these smaller ports prevent the boot seals from collapsing by ensuring that when the pistons are starting to return from or approach full extension there is fluid behind the boot.

edit: if i can find where the disassembled 2nd MC is in our shed, i'll put up some pics.

[jzx81mx83]

Part of the reason why the brakes are spongy is because with the z32 and the r32 brakes you need a minimum of 1 inch bore master cylinder to obtain the best pedal feel.

cheers nick

[CrUZida]

Bullshit!!!!

[jzx81mx83]

Bullshit!!!!

read what i said

Part of the reason why the brakes are spongy is because with the z32 and the r32 brakes you need a minimum of 1 inch bore master cylinder to obtain the best pedal feel.(not require a 1 inch bore master cylinder ) you could also give a jza70 master cylinder a try

[CrUZida]

If the pedal feel is any different to stock MA61 then you have done something wrong.

If what you are trying to say is that from factory the MA61 has a spongy pedal then thats a completely different story.

[takai]

R32s use a 15/16" master cylinder from factory. Are you saying that Nissan got it wrong?

They do use a 1" or 1 1/16" master with ABS, but that is simply to compensate for the ABS module.

Ill say it again, you do NOT need a 1" MC for R32 brakes. Infact they work brilliantly with an unboosted 7/8" setup.

[jzx81mx83]

Ok im sorry but there is no need to get narky ok with a bigger master cylinder it reduces pedal travel and some people confuse this with spongy pedal that is all i am saying


Read this artical it is verry interesting

http://www.skylinesaustralia.com/for...=4068385&st=20

[Gavatron]

with a bigger master cylinder it reduces pedal travel

And increases pedal effort. Just because the pedal travels further doesn't mean it is spongy.

[takai]

Ok im sorry but there is no need to get narky ok with a bigger master cylinder it reduces pedal travel and some people confuse this with spongy pedal that is all i am saying


Read this artical it is verry interesting

http://www.skylinesaustralia.com/for...=4068385&st=20

The "article" is basically a bunch of part numbers where it clearly states that Non ABS R32s use 15/16" masters, while ABS equipped use either 1" or 17/16". Nothing new there.

ALL the guys who are using bigger masters were saying that they were getting better feel because they have bigger brakes, one has Wilwoods the other has CSC. Uh, no contest there.
Seriously, read before speaking.

[Rodger]

naten

When you say "rear port" on the master cylinder pumps fluid first (several posts back). Do you mean it is the port furtherest from the booster end of MC?

Do the rear brakes connect to the port furtherest from the booster on MA61s?

Regards

Rodger

[naten]

ok im back in sydney rego is due on the 16th of september so im desperate now to fix it.

Rodger- The port that pumps first is the port closest to the booster end of the MC, this port also connects to the rear brakes.

I have now taken the one way valve thing out of the rear port (used for drum brakes) and i will rebleed tomorrow to see if it makes a difference, though i really cant see it being an issue.

As stated by numerous people, if the size bore of the MC was not big enough the problem would have come up numerous times on both supras and 240sx etc which the upgrade is common.

Robs old man suggested a different way of bleeding which i will try tom night as well.

[CrUZida]

If all that fails grab a stock MA61 MC and try that.