2nd gen spongy brakes are frigin annoying

[charles]

No sir, sorry

[Naomi]

the bleeder is for the clutch. a clutch is a lot like a brake, one disc is like a brake pad and the other is like a rotor, which is why they need brake fluid (to power the hydrolic that pulls the pressure plate, releasing the discs from contact) and why clutches wear out, much like brakes do. Clutches just last much longer because the discs ideally dont slide on eachother much. The less slip the discs have over their life, the longer the clutch lasts.

Since automatics are a totally different system with different demands, they use different fluid that is unlike brake fluid. Mazda was unique to use the master cylinder to power the braking system and the clutch, because it simplifies the system by cutting costs, parts and maintenence. However, it makes bleeding one more step. But 80% of protege owners will likely never bleed their brakes anyway because the only time you should have to is when a caliper or something fails. Some will argue this because they say water and stuff gets in there, thats BS. Your cars brake lines and master cylinder are a closed system. Nothing ever gets in there, unless you put it in there. It's air tight, water tight, and even if water did get in there, the detergents in DOT3 fluid eat water for breakfast, making it a nil issue, because all water would do is decrease the boiling temperature of the brake fluid, which is already close something like 400F. When I replaced my clutch I didn't have to bleed the system or anything, so that doesn't require a bleed.

The problems me and bruce, and some other are having, is that our system was opened at one time, wether replacing a caliper, opening a bleeder, or whatever, and air got in. We've bled all the calipers but there's still a spungy feel.

My theory is air is still in the system between the master cylinder and the clutch hydrolic, since it uses the same system as the brakes. This wouldn't neccessaily impact clutch performance (having air) because the clutch is mechanical, where as the calipers depend entirely on fluid pressure; the clutch is far less picky about air being in the system than the brakes are, to the point it wouldn't act differently at all unless there was hella air in there.

-Tim

[Intruder]

With that said, what can I do to "tighten" my brakes? Is there a sure-fire method?

[Naomi]

you can remove air. if that doesn't work, u can assume a few things. one theory we've had is the brake lines expand, since they're poly-rubber, and will stretch under intense heat (ie constand heavy braking, like when your dodging cars going into head on traffic runnin' from the popo.) I think corksport sells braided steel lines for the 2nd gen's for a pretty reasonable price, about 300 bucks.

[JesseSays]

things that ACTUALLY give spongy feel...

-old rubber lines, BOTH the brakes and the rubber clutch line
-firewall flexes
-caliper flex

brake fluid does slowly absorb fluid. water can and indeed does get into the fluid slowly, and this will give you poor brake performance.

[charles]

Yeah, how come my brake fluid gets dark when it's old?

I didn't think the sharing of the master cylinder was unique to Mazda, either.

[steeb]

since corksport ss lines came up. id like to say a few things about them. first, they arent expensive, surprisingly, and come with a outer covering to keep out dirt and rocks that might get stuck in between the stainless steel braids and the rubber hose inside. a few guys on probetalk have had other brands unshielded stainless steel lines burst while driving possibly due to not inspecting them regularly or something got lodged between the ss line and the hose and rubbed a hole in the hose over time..good thing they got out ok tho. anyway, i do plan on getting ss lines and corksport ones are the ones im getting for my car for the fact that they are better protected from the elements than others cuz it might help.

ss lines as all parts of your vehicle must be inspected regularly to see that they are in proper order. most people dont inspect their brakes cuz they expect them to work normally and fix when squealing.

[bp 1.8]

bleeding your hydraulic clutch will not in any way effect your braking performance.

all they have in common is a resivor full of fluid.
that is, however odd,
on my kia, it uses a rx-7 clutch master cylinder, with its own independant resivor that is seperate from the brake master cylinder's resivor.

[Naomi]

in response to charles in particular:

yes, brake fluid does get dark over time, because it absorbes oils and water and actually changes color as it is constantly exposed to heat, however, the color doesn't neccessarily affect its performance. we're talking about air. who cares if theres water in it. brake systems rely on one thing, pressure. water, like other liquids, doesn't compress, which wouldn't affect your brake performance. since dot3 and dot4 fluids have detergents that prevent water from reaching its boiling point, it will never turn into steam unless the amount of water exceeds the amount of detergent chemical content. thats unlikely unless you have a liter or water in your brake system. if you still dont believe the facts on water, believe this. it takes years if not a decade to introduce enough moisture into a system that was never opened to decrease fluid performance.

also, every car i've ever worked on has a seperate clutch reservoir from the rest of the car's systems. my protege is the first i've ever seen with it. im sure there might be others, but the 2nd gen protege's are probably among the first. it isn't a bad thing, because its one less thing to fill and saves a substantial amount of compartment space. however, theoretically, it could still trap air if you, say, left your system open overnight to bleed and there was suction through the master cylinder ar gravity pulled the fluid from the caliper lines. this would leave air between the master cylinder and the clutch system.

[bruce95fmla]

After my motor swap, when I went to try and start the car, the clutch pedal was dead. I just used a 1 man bleeder and pumped the clutch pedal until the fluid came out. It was really easy to do ..

The brakes on protege are fealing much more solid now. They never felt this sharp with the drums. The only problem is when the brakes get hot. I will address this when I rebuild the front end (tie rods, ball joint bearings).
I am going to change the rear brakes come spring.
Bruce

[Naomi]

if you need drums and shoes, let me know, i have a virtually fresh set of both with <3000 miles on them as i did a disc conversion 2 months after installing them.

but come to think of it, i believe you did a disc conversion too. i could have the drums turned (i know someone who works at a murray's near me that could do it free) before i ship them too, which would guarantee they're nice and smooth, free or warpage and scorches. they've just been sitting in my garage since removal and they will never see the light of day unless someone needs them for something.

if you have fading, you could upgrade from 9.5" to 10.4" rotors (and calipers/pads) or just get crossdrills. 10.4" crossdrills would be the best of both worlds but initial parts would be hundreds, where as simple 9.5" crossdrills and using your existing hardware would be cost effective ($100)

[bruce95fmla]

I have discs on the rear suspension of the Protege.
I already have the front rotors and Calipers from a 1st gen LX..
Those will be installed with (new) calipers from autozone.

[Naomi]

coo. i read ur swap project thread for the discs in the back awhile ago. its on par with what i had to do.

if ur interested in planning a turbo, let me know, because i plan to boost mine from scratch in the coming months. again, its a 1.5, so the manfolds are different, but thats about all thats different.

[Sndcastle7]

in response to charles in particular:

yes, brake fluid does get dark over time, because it absorbes oils and water and actually changes color as it is constantly exposed to heat, however, the color doesn't neccessarily affect its performance. we're talking about air. who cares if theres water in it. brake systems rely on one thing, pressure. water, like other liquids, doesn't compress, which wouldn't affect your brake performance. since dot3 and dot4 fluids have detergents that prevent water from reaching its boiling point, it will never turn into steam unless the amount of water exceeds the amount of detergent chemical content. thats unlikely unless you have a liter or water in your brake system. if you still dont believe the facts on water, believe this. it takes years if not a decade to introduce enough moisture into a system that was never opened to decrease fluid performance.

also, every car i've ever worked on has a seperate clutch reservoir from the rest of the car's systems. my protege is the first i've ever seen with it. im sure there might be others, but the 2nd gen protege's are probably among the first. it isn't a bad thing, because its one less thing to fill and saves a substantial amount of compartment space. however, theoretically, it could still trap air if you, say, left your system open overnight to bleed and there was suction through the master cylinder ar gravity pulled the fluid from the caliper lines. this would leave air between the master cylinder and the clutch system.

Yes, I know this is an old thread but some get mad when a new one is started.

Based on this information, If I replaced one of my brake calipers and in the process left the line disconnected for an hour or so waiting for the new part I could possibly have gotten air in the hydraulic line to the clutch and notice problems with the clutch? (difference in pedal height at engagement, incomplete disengagement)