1st gen VR4 brake conversion big issues :(

[TUFFTR]

Sorry Joe, But re-oiled I did mean brake fluid! So yes, lubed em all back up with brake fluid and I'm almost certain this should be it. Really should of done this when I got them a few years back. Im almost certain it goes like this
I put pressure on brake pedal > fluid gets pushed to all calipers to push out pistons > front pistons stuck at a certain point > pressure cant go anywhere > comes out the Master Cylinder instead.

buffed a few of up with 2000G, but they were actually in great nick for the most part. Will report back anyway. Spanks dudes.

[TUFFTR]

So is the fluid returning to the reservoir when you put the brakes on.?
That's a faulty seal in the master cylinder.

Steve

No idea, Never done this before the conversion, but it was pushing fluid UP and OUT the cap. Will see how this goes, if not, another master cyl will be going on.

[TUFFTR]

yeah but I always keep spares. I'll be getting one off a non ABS TJ magna (2002 model) for around $30, so it'll be cheap, and not 20 years old like the other ones. That's of course, if

[TUFFTR]

Re-bled the whole system again and took it for a drive around the block ~10 times. After lubing up the caliper pistons and taking it for a drive it defiantly feels 'better' but not 'great' Upon returning home and having a look, it looks like they are def biting the rotor a bit better. However I noticed it's pulling in the rubber at the front (i.e. closest to the front of the car) of the master cylinder.

Went wreckers, grabbed another master cylinder for $20. Will clean this up and get it painted, and suss out a rebuild kit while I'm at it.
*sigh*

[GTOJOE]

Maybe it's too small to push 10 pistons [8 on the front and 2 on the back]? that's a lot of fluid to be moved.

[TUFFTR]

I agree in part, doesn't explain how N/A 3000GT guys can upgrade with no issues though!

[GTOJOE]

All GTO have the same braking setup... Only different models are the USDM ones. Maybe they have the same master cylinders?

[TUFFTR]

Well by that logic, the NA master cyl will have the same as the TT.
I am thinking this is very well a master cyl issue. come to think of it now braking with the old twin pot's wasn't that great either....I always blamed the pads...(herpa derp)
I will get tot the bottom of this!

[tabasco122]

The amount of fluid moved is negligible. Changing the bore diameter of the master cylinder changes the ratio of pedal pressure to caliper pressure. It's just broken, that's all.

Steve

larger bore MC moves more fluid with the same amount of pedal travel, so thats just plain wrong

If you have a mc with a 1 inch bore and you push your pedal in 4 inches, it doesnt move as much fluid as pushing the pedal in 4 inches on a 1.5 inch bore mc. generally systems with more pots have larger MC's because there is more area to fill with fluid in order to apply pressure.

[TUFFTR]

I agree, This Master cyl was only bought out on cars with a total of 6 pistons. it now has 10.
however, It's the same MC as on NA GTO's (Its a 4 port MC, not 3 or 2) and they upgrade no problems, So I dont see why my car should be any different!
Anyway, you guys have been GREAT. I will leave the thread for a few weeks until I get my master cyl back on and let you guys know how it goes.
Thanks to everyone again.