My clutch pedal pressure never changes with heat, in any of the MT cars Ive owned.

How did the TOB spin when you had it out? Nice and free or old and metal on metal grind sounding? I'm wondering if an old/worn TOB is heating up the clutch fluid, but that would make more sense if you were trying to hold it in first at a stop.

That really doesn't make sense. Do you have detailed pics of the clutch parts when every thing was out? Maybe we could make an a better judgment if we could see the parts in question.

~Alex

 

the presser should not change, you should be able to push the slave pin back somewhat easy when the pedal is out and the spring should push it back to the the arm. did you put the heat shield on the slave cylinder? it should make much differences you might have to rebuild it sooner due to the heat heating the rubber parts in it.
Alex the TOB is no where near the fluid.

 

no i didn't take ANY pics b/c i was embarrassed at how they looked. and that's sadly not a lie. there's a shiny ring dug into the metal tho that you can see but the bearing seemed 'ok' to me but i wouldn't have known. no noise from the TOB when the car is running or anything. but this is the best pic i've got:


well theoretically since it's all metal the heat could transfer up the release fork and through the pushrod on the slave cylinder.

what heat shield? pics? mebbe 2nd gen specific? i never saw a heatshield on the slave cylinder, even before i started to take the parts car apart. I put everything in baggies... with labels.


and for the record everybody the clutch pedal increases pressure when the car is sitting at idle in neutral, not when at speed or anything. i mean, it does increase heat at speed but neutral causes it to heat up faster, but the engine has to be hot first. Like, i opened the bleeder at a gas station after my clutch started slipping and it shot out a little bit of fluid, at which point my clutch was super-soft (catching the moment i started to lift, and having a bunch of freeplay) but 2 miles down the road it was back to normal and stayed as such until we got home, 60 miles later. but those 60 miles were on I-40... so there was 70mph worth of air blowing past everything at all times.

 

Normal issues zillions of stickies are facing 24/7 w/o problems... work cylinder does not never ever need any special heat shields.

Bleed carefully all of your cranberry juice out, buy add all new Brake Fluid, bleed until absolutely no bubbles, maybe use bleeder bottle with one way valve. (Cranberry juice; one possibe wassup: old brake fluid, stored outside, water is now mixed in. Google how brake fluid glycol 'sucks' moisture from ambient air.)

Seen this: When fluid is never replaced, moist seeps in. Water in fluid will boil. Steam bubbles cause pedal to go further, disengaging clutch will become harder. Syncros will start to be noisy...

 

yes, this is what i consider to be the most likely situation, now that i've cut the rod and it's still being mean to me. I'm thinking that somehow the fluid had "dissolved air" or like, TINY bubbles in it maybe. Sometimes when bleeding the fluid would look a bit.. milky? Maybe the milkyness caused by tiny tiny tiny bubbles that don't make the same sound that air does on its way out.. just sounds like fluid b/c the bubbles aren't big enough to make that same spurting sound.

 

How did the TOB feel when you had it in your hands I'm asking. Did it feel smooth or notchy when you turned it. Thats assuming you inspected it before you put it in.

And when you drove the 89 did it do anything similar? I mean minus the clutch MC its all the same parts. Maybe you need to replace the clutch SC as well and rebleed every thing. Also I wonder if torching the distribution block and by passing it could help.

~Alex

 

my bad your right the Y pipe doesn't go over the back of the engine. I was trying to think about whats in the way when bleeding it and must of been thinking about the brace for the coolant hose.

did you rebuild the SC yet?

 

haven't rebuilt the s/c yet but today i saw a bleeding method that is slightly different from mine, which after i spent 10 minutes at the slave cylinder of my friend's car and thought it was bled fine, Mack had me pump the pedal his way and he got a TON more air out. So i'll have to try that before i do anything else, because my friend's pedal was real soft and it took another 12 pumps "Mack's Way" to firm it up. I'd been having my friend pump it up every time, hold it to the floor, and repeat. Mack had me push it mostly to the floor, and then finish pushing as he released the bleeder, and not pumping in between. Then after 5 bleeds he had me pump it up, then push the pedal to the floor then back off a quarter-pedal and do it all over again. Worked great.

 

That 'milk' is water ... which will boil at +100C ... and yes, heat shields are needed. However, boilers commonly not used these days, splash in an update.

 

so um, if i use a small tire air compressor i'm going to mess up my clutch hydraulic system from oil, yes? if so then what will be the best way to COMPLETELY drain my system of all traces of the old fluid?

and for what it's worth, I left the brake fluid bottle outside for... a while. And yes it's been rained on but it was always closed tightly.

 

The best way is to keep flushing it out with new, clear, fresh fluid. Brake fluid is cheap, just keep pumping it through. I use a vacuum bleeder, but doing manually will work just as well.

Brake fluid is EXTREMLY hydroscopic. If left alone in a plastic or tin can it WILL pull water through the container. But this can take months or years to get appreciable amounts.

Most passenger cars over a couple years old have water in their hydralic systems, but in very small amounts. In most cases this is not a problem. Water is hydraulic after all. The problem with it is two fold. Corrosion and a boiling point of 212 degrees F. Small amounts of water in your fluid boiling off when you clutch or brake will not cause large problems. Large amounts of water boiling off will cause HUGE problems. This boiling off can cause a long feeling pedal. If bad enough it can cause the pedal to go to the floor without any real braking or TOB movement occurring.

Long story short, unless your can of brake fluid is old it's probably good enough for everyday use. But if you're an aggressive driver or going to autox or track day you better buy new fluid with a high boiling point (Motul = $$$, Ford HD Truck is almost as good for about 1/6 the money) and bleed the CRAP out of your brakes and clutch.

 

except that the hotter it gets my pedal won't fall to the floor, it gets stiffer. and stiffer. and stiffer. until it's so preloaded that the clutch slips.

 

Some small compressors dont use any lube. I dont know what u have - but I know and have experience of brake dedicated rubber parts been spoiled via oil, oil rubber parts been ruined via brake fluid. Chemistry google can help... I just trust manufacturers - also in their storage requirements which are quite tight for brk fluid. Closed bottle has to stay ALWAYS in dry storage, stable temp.

Car brake systems will rust inside out if fluid is not swapped every 2-3 yrs, this is because of the water 'condensing' in.. Also every year will lower its boiling point. This might be very dangerous in harsh environment.

 

But ALL compressors suck in outside air which has..........

.......water in the form of humidity in it.

 

Yes, problematic. This means also ugly dimples on fresh paint ... droplet qty depends on weather.
There may be (?) somewhere good condensed water filters...

 

how about canned air? can i use that? it's pure CO2

 

id be wary of the canned co2, because its so cold, it could cause water to condense(note the frosbite warnings on the cans

 

wellalright. are there any other non-cold compressed air-type things i can use? or should i just always keep fluid in the system and just push it out until i go through a whole bottle of fluid?

 

keep going until you wasted a bottle.

 

or two... or three....

Like I said before, brake fluid is cheap!

 

well cape, at this point, I'm thinking you may have done something wrong in the swap process, something misaligned/backwards/whatever, but something isn't right here, and i don't really think it has anything to do with the clutch master/slave..possibly improper bleeding technique, not sure, but something is just not right with your setup.

 

the only things i was "unsure about" and just had to be intuitive about were the tranny mounts and the TOB. But the way i put the TOB back on made sense for how it was going to have to angle itself against the IS sleeve. I used lithium/moly grease on the IS sleeve, clips where TOB goes into fork, pivot where fork goes to tranny casing, and on the tip of the slave cylinder. I mounted the clutch pedal using the spacer i stole from the firewall of my parts car, one bolt upward, and the 2 nuts on the end of the studs. I reinstalled the clutch hoses as-were.

I'm going to adjust the clevis rod a little more and see if that changes anything. The car drives PERFECTLY after i let it sit for a while. But as the ride wears on, about 15 minutes later, it starts to firm up too much, the spring on the pedal starts squeaking and popping b/c the little blue bushing is gone from the spring's center, and the car just gets harder to drive. Shifting is super super easy when i first start driving but once the clutch is too stiff it shifts poorly on the clutch end, and when i release pressure the clutch can't disengage enough, making it rough on the tranny end. It's never the same after that until i let the car sit for a while. Probably b/c at that point it's already really hot, and it just expands too fast for that 'comfort zone' to last for more than a shift or two, somewhere between the time i release the pressure to the time it gets too stiff again. I figure that a few NEW bottles of fluid (tho my first one was just purchased, although i left it outside, capped, in the rain), through and back the clevis rod out a tiny bit, and hopefully that'll be that.

 

I wonder if there is something wrong with the MC cuz even if it heats up it shouldn't hold presser with the clutch out, you should be able to push the piston back in the SC with your fingers when the clutch is out, and only hold presser when the clutch is pushed in.

 

Yeah that's basically why i'm going to adjust the pedal back out a little bit. When i first installed it it seemed a wee bit weak on the pressure even when bled (ie, wouldn't even push the pedal back up from the floor, no matter what) so I'm going to look for a happy medium here.

 

Fluid flows from top down, no help needed.

If u insist, suck the 'old' fluid from reservoir, then add fill with new. Open bleeder. Then pressurize the reservoir somehow a little bit, stop before all fluid has bled. Add new, repeat = flushing... But why would u do ? that, Gravity can do all the work...

Only after fluid change return to the mechanical issues (my bet is that there is no need).

 

will gravity pull the fluid down through the resevoir into the line all by itself? hmm. interesting. should have known but i never did.

 

aight. got 2 jumbo bottles of synthetic DOT3. i'll flush on saturday while out of town doing my friend's head gasket.

 

Sadly true. Proven by a tiny hole in gas tank hose... Empirical test/proof will arrive, just wait

 

Hows it going did you get the bugs worked out?

 

not yet, i haven't done anything to it since i know i'm going to have to redo it if I do. I got the SS clutch line and the pedal bushing and the fluid but haven't installed them yet.

 

i'm replacing my clutch in a couple weeks and i'm going ahead and researching it now.

i was looking at a bunch of old flywheel-resurfacing threads and this thread said that you can't resurface a flywheel with microcracks on it (http://forums.maxima.org/showpost.ph...44&postcount=9)
well here's what my flywheel looks like (pics taken during swap in february)

so you can see the cracks (sorry i didn't focus directly on them when i took the pics) fairly clearly, and you see that they are spread across the whole friction surface. So can this one still be resurfaced or should I go new? I can't afford a fidanza right now, as much as i'd like to give it a shot, so i'm looking at oe-replacement. if i had to get an OE replacement are az/aa/cq OK to use? like this one:
http://www.partsamerica.com/productd...pe=267&PTSet=A

I'm thinking to get an exedy OEM-replacement clutch since i'm a pretty gentle driver and don't need the quicker grab of a stage-1 (nor the added cost). I'll do the rear main this time too, another thing i had to grin-and-bear during the initial swap.

EDIT: also just ordered upper clutch piping (mc to junction.. mine won't come out of the junction b/c of mad-crazy rust and the MC nut is stripped as well), striking rod seal, release fork dustboot, shifter return spring and reverse/neutral position switch (neither circuit works properly... reverse lights flicker randomly and neutral just flat doesn't work.)
$77 shipped from Courtesy. should have added a slave cylinder rebuild kit to the order but i'll just grab that at the local dealer sometime before those other parts come in.

i'm letting you guys know what i'm going to do before i do it in case anyone would like to request a write-up

EDIT again: also added rear main, rear main gasket, and slave cylinder rebuild kit to my Courtesy order. Total now stands at $104 shipped.

 

Looks bad. Considering all the effort, I would find a replacement.

 

that flywheel won't cut right

 

What would cause a solid chunk of metal like a flywheel to crack in the first place?

 

heat, previously cut poorly, bad metallurgy.

 

I'd go new (or good used) and OE. Lightened flywheels will allow more HP to the front wheels and slightly increased throttle response but will make the car a much more finicky car to drive around town. The mass of the flywheel allows you engage gears at a much lower rpm without stalling. Lower rpm engagements = less heat generation (heat is one of the things that causes micro cracks), less wear on the clutch and better gas mileage. You can still do high RPM slam shifts if you want. For a daily driver a lightened flywheel is again one of those bragging rights things.

For a daily driver without big HP gains over stock then OEM is a great choice, especially if you are a gentle on the clutch driver. For those who like to generate smoke or those who are into 1/4 mile times then an uprated clutch is needed no matter the power. If you've got a 15-20% HP increase over stock I'd say go with the stage 1 even for a gentle driver.

 

+1 on heat. look how badly it's glazed and burnt! That SHOULD fix the chatter too to have a new clutch and new flywheel and rear main. And i'm rebuilding the slave cylinder too (and putting in the new clutch line w/ SS lower line and still-essentially-new MC) to make sure everything's in tip-top shape.... basically to atone for my sins that i made during el cheapo swap-o.

 

I would go with a new one, be careful cuz if you get one that has been turned it could be on the thin side which will cause disengagement issues (sets the presser plate to far away from the TOB) and I haven't been able to find spacers for the fly wheel.

 

not to mention that the more it's turned more it will build up heat, amirite?

 

technically, the less mass will cause it to shed heat slower....... resulting in greater heat buildup