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Discussion Starter · #1 ·
Can the Front brake stopping power be improved by up grading to a newer Master cylinder?
I have SS lines and fresh EBC pads, on an 88 GSXR1100j. With a stock Master cylinder.
Would using DOT 5 fluid help?(thats whats in it now). Complete front end is stock.
 

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YOur master cylinder is very good. The only thing you have to do is get newer calippers. By newer I mean the 1989-1992. They work very well. Get some steel braded lines also. You will notice a big improvement. I believe that all you have to do is shim the 1990 calipers to make it fit. I don't think changing different fluid will do much. I wouln't go against the manufacturers advice.
 

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Yeah, unless your master is leaking or something, it should be good, I wouls seriosly suggest steel braided lines, they don't expand as much under heavy load, resulting in a harder feeling response.
 

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Discussion Starter · #4 ·
Thanks Guys, already have Stainless(SS) lines.
Fresh brake fluid and bleeding.
Read somewhere that a 92 brake master cylinder had a larger piston, and adjustable lever.
Ideas?
 

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Do NOT use DOT5 fluid! It's not compatible with the DOT 3/4 stuff and will create a jello-like MESS inside your hoses/calipers/etc. ...as for changing the fluid to one of those high-tech DOT 5.1 or other high-boiling-point stuff - it won't change anything unless you're having trouble cooking the brakes now (fade when hot).

Try using HH-rated pads (assuming that you're not already) and if that doesn't do it for ya, then you'll be better off to go ahead and swap to a newer front-end with a 17" wheel with larger diameter rotors. The 2nd-gen calipers won't bolt on to the first-gen forks without using an adapter-plate.

If you do decide to replace the master-cylinder, be sure to stay with the 5/8" bore - avoid the 14mm bore (like is found on Yams). I gotta agree with stoneagegixxer though - the OEM master is very good.

If you recently installed new pads on old rotors, don't forget that it takes some miles to get the new pads "bedded in" - they will show reduced-power and feel until they get bedded-in. Which brings me to my next question - what kinda condition are your rotors in? The rotors can have a fair amount of runout in them and still function - but you will notice markedly reduced stopping-power. Sticky dust-seals in the calipers can cause the same thing.

WhatEVER you do, do NOT use DOT5 (silicone) brake-fluid.

---edited to add---
um... I just re-read the original post and noticed that you are already using the DOT5. Unless you completely disassembled the entire system before you installed the DOT5 stuff, then that's probly the source of your trouble. Are you sure it's DOT5 in there? if so, you're gonna hafta disassemble everything and replace seals after cleaning all the goop out.

If you're using DOT 5.1 then that's compatible with the DOT3/4 stuff and disregard what I said about disassembly and cleaning. They (brake fluid mfg's) effed-up (IMO) when they started labelling the hi-boiling-point stuff DOT 5.1 - it leads to a lot of confusion. The DOT5 stuff is silicone-based and was developed for HD so that it wouldn't eat that nice, purty paint on the tank when you spill it. It does not function as well as the glycol-based DOT3/4 stuff, and it will make an unholy-mess if you mix the silicone-based stuff with the glycol-based stuff. Read all about it here:

http://www.xs11.com/tips/maintenance/maint1.shtml

Good luck!
 

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Cat is WAY to smart!
 

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Discussion Starter · #7 ·
Re: DOT 5
System was bled, and flushed with alcohol, then DOT 5 was introduced.
System Bled again.
Thank You for the concern.
Jim
PS DOT3/4 is also hydroscopic, meaning it absorbs water, silicone based DOT 5, Doesnt.
The water is flushed out when you bleed your brakes, once a year. DOT 5 requires more maintance.
 

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yup, dot 3/4/5.1 is hygroscopic, meaning it absorbs water.

dot5 doesnt, so if you get water in there, you get a nice bubble of water at the bottom of your calipers that will rust everything....

Im almost sure the 88 used 14mm MC, swap to a 5/8' one. *any* 93+ gsxr MC will fit.
 
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