brake master cylinder/booster size

[Gly]

ok, as a few of you know,
ive changed to brembos...

car originally started with the single pot caliper and 254mm disks,


can anyone confirm that the v6 brake cylinder and/or booster is smaller or the same size as the VR4 one?

ive bleed my brakes a couple of times now,
pretty sure theres no air in the lines,

basically when i need to break i really have to give it half a pedal first and then one the second push the brakes work real well!

just not on the first,

im thinking i may have to get either a booster and cyinder from a vr4 or evo?

but will rebleed them again just in case,

just getting tyred of taking the wheels on and off.

[Subaru ETA]

from what i remeber i dont think there is any difference.... no leaks or anything?? vaccum hose to booster ok? no kinks in any lines? i have you manually bled them or you using a air sucker? know they are stupid questions but you know anything is poss!

[Gly]

no leaks that i can find,
no kinks i can find,

i manually bleed them using a one man bleeding kit, (one way valve on a hose)

basically when the cars not runing,
i can pump the breaks a couple of times and its rock hard,

once the cars started it becomes soft and squishy,
and lacks feeling

[bradc]

To me that problem sounds like a problem with the lines or something like that, I can't imagine that fitting bigger calipers would cause that sort of problem.

[Gly]

theres 8 more pistons to move then there originally was,
they are somewhat smaller now thou.

maybe now the cylinder cant push enough fluid?

will bleed it again later,
no motivation left at the mo,

****en hot outside!

[Subaru ETA]

what i find sometimes helps is to crack all the nipples and just let it slowly gravity bleed for awhile

[bradc]

We could always have a look and compare the sizes tomorrow

[Gly]

well, i just bleed the whole lot again,

had the whole car up in the air on stands....

there was no air, went thru another 500ml botle of fluid,
and it still seems to have the same issue?!

will have a look at some other cars tomorrow i think.
see if theres any diff in the cylinder/booster sizes

[bernmc]

I've got an EVO master cylinder in the garage - measured it once but can't remember the sizes! I'll check for you this w/end when I finish work. I don;t think it looks any bigger than the VR4 item.

[Gly]

ok cool thanks,

now just to find out if the v6 item is smaller than the vr4 item,

ive looked up some part numbers in caps

54107A for the booster assembly
54010A for the cyliner assembly


can any one comfirm if these are the same as the vr4 (prefacelift??) items

[Gly]

ok the parts on a vr4 have the same numbers.

so there goes that thorey!

so i either have a massive air bubble in the lines,
or my master cylinder is on the way out?


will depressing the brake to the floor when bleeding damage it?

[bradc]

does Kenneth still have his one from his 2002 VR-4?

[Gly]

yep he doz,
will see how the day goes tomorrow.
have another go at bleeding them,

or might just take it to the workshop thats done my servicing
on my car befor and let them have a go.

[bernmc]

I think Marcus (rally205) might have had a similar problem.. or SGHOM? can't remember. Solved by a pressure bleed...

Might be worth searching the brembo threads.

[Gly]

what pressure bleeding?

is it something i should get a workshop to do for me?

[bernmc]

what pressure bleeding?

is it something i should get a workshop to do for me?

yes. some DIY kits available for it too. NOt sure of the exact methods workshops use, but essentially brake fluid gets pummped through the system under pressure rather than you pumping the brake pedal.

[Gly]

ah yep.

seen a kit on trademe, but wasnt cheap $200...

ill take it to the workshop during the week,

[AncientOfMu]

ah yep.

seen a kit on trademe, but wasnt cheap $200...

ill take it to the workshop during the week,

did the pressure bleeding fix the problem? I seem to have a similar issue at the moment...

[Gly]

having it bleed at a workshop tomorrow,

got tired and lost motivation in the weekend,


been searching the MLR, one found one guy that has the exact same problem as me...
he never said he resolved it or how!

but from other posts ive read it sounds like air in the line or abs system.

the workshop is going to vaccum bleed the system for me tomorrow moring so will know if its fixed it then

[Gly]

well,
today my pocket is $100nz lighter,

and there isnt much (if any improvement) in the sponginess,
they think the master cyilinder may not be big enough.


also ive been doing some more fiddling with it...

will disks that are to thin make a diff??
the fronts are just on there limits,
and the rears are a 2-3mm thinner than minimum!