ihiryu

iTrader: (7)

I did the LS, and was upset with the pedal feel, but when I did the SS lines, it made a helluva difference

Kaydee

I actually saw one website where this SC had a brake brace, but can't remember what it was. Anyways for that car, the brace is mounted to one of the strut towers and looked more stable than most brace I see on other cars

I have NO welding skills, but I do have a relatively easy access to a welding machine. Hopefully I can whip out something that performs better than a SS lines at tenth of the price

dejacky

iTrader: (2)

nice info, thanks! So, has anyone used a Supra TT or LS400 brake master cylinder on their 2-bolt compatible style SC with no fitment issue?

5sp_jzz30

iTrader: (2)

its not about the master cylinder having the same size pistons. its about when the rears start activating compared to the front. brake bias. different cars have different setting for that from factory. this is based on vehicle weight, weight distribution, brake setup, as well as application(street, preformance, or track).

ill try to find some chart made by the nissan guys for a bunch of different nissan cars and master cylinders. ill try to rummage the forums and find the example.

ICONYQ

iTrader: (3)

hmmm very interesting as I will be doing my brakes soon. I have the 2 bolt style so looks like I will be looking for a TT one.

RyanV

iTrader: (9)

The TT brake master looks exactly the same as the sc300 95+ brake master.

I even opened it up, and the pistons all look the exactly the same too as does the reservoir. It does not hold anymore fluid than the sc300 reservoir.

I'm thinking that the proportioning/bypass valve is different though..

But, yes the TT master does bolt right up to the stock 95 sc300 brake booster AND the lines bolt right up perfectly.

The only thing I know is different is that the TT brake booster is about 1/2 the width of the sc300 booster, and the rear shaft is longer for some reason.

If you try to install the TT brake booster, then you have fitment issues with the lines and how it fits in relation to the brake pedal bracket..

Ryeno

iTrader: (3)

I've always had a feeling that to fix the brake pedel distance a supra tt/ls400 proportional value could be swapped onto an sc. But i am not sure if the value fits onto a 2 bolt sc master cylinder. So that begs the question, has anyone tried out swapping the proportional value onto the sc?

JohnEd

iTrader: (1)

I installed my LS brakes on my SC400 yesterday. The pedal is up and hard as a rock(lucky pedal). All of the fluid drained out of my front brake system during the time I had the calipers disconnected. The calipers I put on were dry as i did not bench bleed them. It took about a half pint of fluid poured in the MC resevoir before it stayed full cause I left both brake bleeds open for the first fill. THEN I closed the bleed on one front caliper and did the normal bleed procedure. Took about 6 pumps till the fluid started coming out without bubbles. The left front took the pedal to "hard" in less than 6 pumps.

PROBLEM My right front caliper had the holes drilled too close together for both bolts to be started. Really confused me till I took the caliper back off and looked at the metal around the bolt holes. There was bare aluminum gouged out at spots. The LS caliper was different by just a little but that little prevented me from moving it far enuf forward to line up the top hole. I used a rat tale file to gring out some of the metal that was interfering. I finally, after three grinding sessions AFTER taking the thing back off, got it to line up with the hole but only in the horizontal axis. I put the bottom bolt in and snugged it and then, with out the rotor installed, I screwed the top bolt in from the "outside" and it went thru the caliper hole with a lot of drag. After remoning the caliper I inspected the unthreaded hole on the spindle and saw deep thread marks at about the 7 o'clock position. I rat tailed that out and it all went together easily. I have never heard of anyone else having this problem and I am certain Aliga would have warned me if it was at all common.

YOUR PROBLEM(maybe) I noticed that the mating metal sides between the caliper and the spindle holes WOULD NOT LAY FLAT till I removed interfering material from the caliper. Not difficult since it is aluminum. If your caliper is not properly aligned with the rotor, you pads will flex under pressure. This would feel like pedal slop/mush at the top and would firm up with pedal travel. If you have this condition the caliper will be flexing during braking. Being alu it will fatigue and crack at the bolt tang cause it wasn't designed to endure force in that axis or bending under load. To make sure that there is no interference from the casting you will have to remove the wheel and care full sight down the mating surfaces. Had I reamed out that spindle bracket hole FIRST, inadvertently, I would have the same problem you are having and I might not have figured it out.

Stainless Steele brake lines are bogus. The improvement that people feel could have been realized from simply bleeding the brakes properly. Take that to the bank.

The POWER of brakes is due to their being a difference in the "total" area of the piston and those slave cylinders it drives. The bigger the ratio the more power you have but the less the pads/shoes travel with a full stroke of the pedal. NOW, going to the LS caliper, you double the area of the slave cylinder because you double the number of pistons. All other things being equal, you get DOUBLE the stopping force FOR A GIVEN AMT OF PEDAL PRESSURE. The ability to stop is governed by the friction of the tire on the ground and without a change there.....same stopping distance. What improves is the pedal pressure needed to lock up the tire is reduced by only 1/3 cause the back brakes weren't involved in the upgrade, remember? Still, your stopping distance will be reduced only because you get more brake a tad quicker. You can put any MC on there you like and unless the piston is SMALLER, you will not have any more braking force and if it is bigger you wll need more pedal pressure for the same stopping force. It is the ratio that determine advantage and advantage is braking power.

Same goes for that TT power booster. If it is the same diameter as the stock item you will have exactly the same BOOST cause that number is linked to the total square inches of the boost diaphragm and the inches of vacuum applied. If the TT diaphragm is the same diameter, you will only upgrade your bragging wrights and spend a lot of money to do that. Zero bang for those bucks!

I ran into another problem in my install: I had to reuse my old brake lines and yes I know that is a bad idea cause the safety locks don't align. Problem is the holes that allow fluid flow thru the line is WAY WAY smaller on the original than on the LS cause the LS has twice the area for its 4 pistons vice 2 for SC. I drilled those holes out to the diameter of the LS lines that didn't match my brake connectors and I will change out the lines soon.

While I am at it: If your rear brakes are locking or the fronts for that matter.....your ABS is broken and your stopping distance will be greatly increased. Dangerous! After you install the LS brakes you will lock up those fronts quicker than before but the ABS will keep them turning and your stopping distance shouldn't change much.... if any. It is the brake proportioning valve that keeps the rears from locking up. I'm not sure but I think that that device is embedded in the ABS system. Any way....you need it fixed cause there is one thing about brakes....you need'em. I have pushed that brake nearly thru the floor while going 90 in Idaho, at night, on a lonesome stretch of Freeway. I discovered a F'en HERD of deer play'in in the STREET just around a slight curve where my driving lights wouldn't shine till the road straightened. I went THROUGH THE HERD with the ABS in full swing and the car making a machine gun sound, BAM BAM BAM, as the brakes were cut out by the ABS as they started into a skid. Went thru the herd straight as an arrow exactly where I pointed her at the last second. There was only one line that didn't have at least one deer in it and they all gave me that DEER IN THE HEADLIGHTS look. God bless ABS and the nerd that invented them and the Lex engineer that applied the science.

The Lex pads have a anti squeek metal shim installed between the pad backing. New pads I have purchased also had an additional shim. I got the metal shim in crooked years ago and it prevented the pad from getting right up against the rotor and staying there when the brake was released. That symptom was a soft pedal at the top that got firm. A loose wheel bearing will also tend to back off the pads and then when you apply the brake the pads move till they contact and then back off as the wheel settles on the bearing.

YMMV,

John

RyanV

iTrader: (9)

I installed a TT master cyl earlier and the pedal distance was the same as with the sc master cyl.

I'm thinking my booster is bad.

JohnEd

iTrader: (1)

Ryan,

If you booster goes bad you will have less boost. Booster...get it? A bad booster sympt is a hard to push pedal. My previous post will give you lots of things to check. Did you install LS brakes? If no, skip all the caliper mating stuff cause you probably don't have a mating surface problem. Keep it in mind though as it is a very very peculiar problem and would kick most of our butts if we ran into it cold.

And your experience rules out changing the master cylinder as a possible solution. Do you have any idea how much money you have saved people on this board? Lots!

So there are others out there with this symptom.

Good luck,

John

5sp_jzz30

iTrader: (2)

hey JohnEd,

i had the same issue with my ls400 calipers. i had to take out the grinder and remove a bit of material from around the top caliper mounting bolt in order for all the bolts to line up.

other have had this problem too. i think it depends on the year of the LS400. mine came off a 98 and i had to mod it. i sold a set locally that came off a 97 and the guy never mentioned this issue so i would assume he didnt run into problems.

RyanV

iTrader: (9)

I installed the front TT brakes a year ago, and my pedal sucked, and I just installed the rear TT brakes recently, and the pedal is worse now.

Symptoms of a bad brake booster- If the booster is leaking vacuum pressure, your pedal will get really hard...if your pedal goes all the way to the floor the booster could also be bad, but not have a vacuum leak.
http://autorepair.about.com/od/troub.../ts_brakes.htm

I also noticed that on my sc300 booster, I noticed some front to rear movement/play with the front shaft, but with the TT booster the front shaft is tight and doesn't move front to rear, nor does it spin easily.

I also realized that if I quickly pump the brakes hard I get momentary full pressure, but then it pushes through to the floor than catches and stops.

5sp_jzz30

iTrader: (2)

^^^^bad seals in master cylinder. problem solved. had exact same issue on my old celica. replaced the master and all problems went away.

JohnEd

iTrader: (1)

What 5 speed said!!

If you pump the brake pedal and the pedal gets hard but "leaks down". That is a master cylinder for sure.

If you press on the pedal and it goes down and then gets hard... you know: The master cylinder seems to be holding and is probably good up at the top of the stroke also. Then you also KNOW that fluid is being pumped "SOMEWHERE" in the system and isn't leaking out on the ground. That somewhere MUST be caliper pistons moving. They should ONLY move the first time you install the pads. After that they rest right up against the rotor and move precious little when you push on the brake P. They do press into the caliper though and stop the car. If the pad is somehow moving back away from the rotor, then when you press the brake you must move enuf fluid to move the pad up against the rotor to get the pedal hard and breaking to start. Still, could be only half the MC is functioning.

The ways to get the pad to move back on its own are: Loose wheel bearing that allows the wheel to push on the pad in corners and when it "sets" on the play. An out of spec rotor that has thick and thin parts....pulsating brake is the tip off but the brake will also travel a little to far at first application also. Something spongy between the caliper piston and the pad. The caliper is not squarely aligned with the rotor so the pads are cocked and with pedal pressure they are forced to align and/or the caliper flexes to align them.

Bad ABS???????

All of this is easy to illimanate except the ABS but it should give you a warning light.

Ryan,

By hard in this case you mean difficult to push. The way the booster is designed it cannot fail in such a manner that it allows the pedal to go to the floor. All of the boost requirement is felt and acted upon in the first half inch. If the boost isn't there it then becomes a "manual" unassisted/boosted brake and is more difficult to push. When you push that pedal to the floor the master cylinder piston is moving through it's full travel. If there is fluid in the master cylinder that fluid MUST be going somewhere. I once had a brake line that had herniated and would blow up like a balloon when the brakes were applied but the pedal only went half way to the floor cause that is where the front and rear braking system are separated.

HTH,

John

RyanV

iTrader: (9)

I rebuilt the master with OEM pistons, and it didn't fix my problem.

I also tried a TT master and it was the same.