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The mkiv Supra Owners Club

Upgraded Brake master cylinder with upgraded brakes?


Glanza_Mike

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Hi guys, i've recently installed brembo 4 pot rear and 6 pot fronts on my 98' tiptronic supra, i used to have the 2 pot rear and 4 pot front setup. I also have braided lines all round, running ate super blue fluid and a brake master cylinder stopper.

 

So my question is: i presumed doing this upgrade would make a huge difference to pedal feel and braking power, and while it has made a difference its no where near as much as i thought it would be. The pedal still feels a bit meh, a little spongey, ive bled the brakes twice.

My dad has APs on his Skyline, same sizes all round and that stops waaayyyyy better and has instant bite on the pedal.

 

Could this be a master cylinder problem? Are there master cylinder upgrades for our cars? Or is it more than likely something else?

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Do you know if the setup has better braking torque and similar brake bias to stock?

 

DanDan did a brilliant thread on various brake upgrades, which showed that some of the aftermarket caliper setups were inferior to stock UK brakes.

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Yeah ill try another bleed mate this weekend to see if it coukd be that thanks.

 

Yeah Nason i read dandans thread but to be honest it doesnt really make sense to me how these brakes couldnt be considerably better than the Uk spec setup i had, i was on stock discs and stock pads with like 320mm discs and 4 pistons and now im using brand new caliprs with 6 pistons, brand new fast road poads and 360mm discs. These brakes wont be in dandans thread also so j cant check that mate.

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But just because they are 6 piston doesn't mean that the overall surface area of the pistons is more than that of the UK brakes.

 

Front to rear brake bias can have a huge effect on braking and stopping distances too.

 

But as per your original question, I've seen plenty of Supras using the massive Brembo and Alcon racing spec brake kits in Japan, with the massive monobloc calipers they use and they're still using the stock master cylinder.

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Before you bleed them again, activate the ABS a few times (i.e. lock up in a safe area/manner) and then bleed. I've had issues before with changing calipers and holding air in the ABS system, the activation should move the air into the lines and you should be able to bleed it out after.

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But just because they are 6 piston doesn't mean that the overall surface area of the pistons is more than that of the UK brakes.

 

Front to rear brake bias can have a huge effect on braking and stopping distances too.

 

But as per your original question, I've seen plenty of Supras using the massive Brembo and Alcon racing spec brake kits in Japan, with the massive monobloc calipers they use and they're still using the stock master cylinder.

Right okay, well the pistons on the front are 40mm each and obviously there are 6 of them at the rear they are 32 & 28mm. I'm not sure what the standard UK spec ones are but the pad size in the these on both front and rear is considerably larger.

 

And thanks for the comment about the master cylinder, i presume it isn't that then.

Those master cylinder braces are meant to firm things up are they not?

That is correct Sir.

Before you bleed them again, activate the ABS a few times (i.e. lock up in a safe area/manner) and then bleed. I've had issues before with changing calipers and holding air in the ABS system, the activation should move the air into the lines and you should be able to bleed it out after.

Okay cool thank you mate, i'll give that a go then before i bleed the whole system again on Saturday morning.

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Just a quick one to consider.

Which is something I'm doing later.

 

The vacuum pipe for the brake servo that goes from the inlet manifold. What condition is that in?

 

As mine is cracked and old and I'm pretty sure I'm leaking air from there as there is a difference in pedal feel if the revs are slightly higher.

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Just a quick one to consider.

Which is something I'm doing later.

 

The vacuum pipe for the brake servo that goes from the inlet manifold. What condition is that in?

 

As mine is cracked and old and I'm pretty sure I'm leaking air from there as there is a difference in pedal feel if the revs are slightly higher.

Cheers Al, ill have a check of that mate, although the pedal feel seems to be consistent throughout the rev range.

Make sure that brake stopper is screwed tight up to the master cylinder. Also make sure you are running decent pads as my 8 Pot D2 kit had crap pads. Now running Pagid SR19 competition pads, awesome braking!

Yeah i've got decent pads so cant be that, brembo at the back and Hawk HPS at the front. Thanks for the suggestions.

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  • 1 year later...

That's good to know!

 

Mine still aren't fitted. Needed to get 19s" in the end, which arrived this week, but am about to have engine rebuilt and am going single so still 2-3 months off. Give's me time to sort out the paint on them from the chips and grinding a couple of mm off in an attempt to get my 18s" over them.

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That's useful to know, thanks, and I have some more on the shelf if anyone needs fast road pads for Greddy 6 pot fronts! :) (Or for an R35 GTR front or rear)

 

Any idea what the rear Greddy 4 pot pads are also fitted to Mark?

 

Mine and Mike' aren't Greddy's. We have the Brembo 6 & 4 pot Calipers from the Jeep SRT-8.

 

$_57.JPG

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Ahh, got you, I thought it odd some Greddy calipers took such huge pads. Those calipers are similar to the Cadillac ones I think.

 

The GReddy calipers are made by Alcon I believe.

 

I don't know if this will be of use but there are tech drawings of aftermarket brake kit pads here

http://endless-sport.co.jp/products/brake_pad/RacingCaliperPad.html

 

It may be possible to cross reference the part numbers with the car manufacturer lists here

http://endless-sport.co.jp/products/brake_pad/car_list.html

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