sLADe781

iTrader: (1)

Okay, finally got it to work. I could not build any pressure by pumping...maybe we did it wrong? Since we were supposed to pump slowly, we took about 3-5 seconds to push the pedal down and another 3-5 to bring it up. Not sure if we were going too slow which may have caused air to come in but either way, pumping never gave us any resistance. However, gravity bleeding worked. I just cracked open the nipple a bit and let it bleed out. When it first started you can totally see the air bubbles popping as it dripped out. The weird thing though is that eventually, it just stopped dripping. Like in the previous cars that I've gravity bled, it just keeps dripping until I closed it but for some weird reason, the G would just stop by itself after awhile. Thoughts?

Anyways, thanks for all the help guys. Hopefully the spongy pedal issue won't return again!

sLADe781

iTrader: (1)

UGH!! So the spongy pedal issue came back today. I drove it around all day today and eventually came home and parked the car for about 2.5 hours. When I went back out there to drive off, the pedal was spongy again. I ended up taking my other car and about 5 hours later, I came back to check and the pedal was still spongy.

Here's the weird thing though. I just started pumping the pedal...20...30...40...maybe even 50 times and all of a sudden, it started building pressure and the pedal was nice and stiff again. Anyone have any thoughts as to what's going on? I checked the fluid and its full and clean still so I have no idea what's causing it to lose pressure but pumping will bring it back.

Do you guys think it's really my CSC and/or MC? Any additional help would be greatly appreciated. Thanks.

vqsmile

I'm sorry to say, but yes.

sLADe781

iTrader: (1)

Okay so I'm going to replace the CSC with the Heavy Duty CSC from ZSpeed. What do you guys recommend for the master cylinder? Is there a better alternative than the stock MC or is that the only option we have? I want a good setup that will actually last.

vqsmile, I noticed that you're from the bay area as well. Any chance you've tackled this project before? If so would you be interested in doing it again and if so, how much? :biggrin:

vqsmile

Before you leap, you should really do your due diligence at the diagnosis. Don't just take it from some old hack on the interwebz (), you need to verify whether you have a leak or not (and where).

I'm pretty darn sure that's what's going on there, but it is troubling when you say that the fluid level in the reservoir hasn't gone down at all. Are you absolutely positive about that?

If it is leaking outside of the hydraulic system, then it has to be going down, even if it is very slowly/slightly. It is amazing how little air needs to be let in for the pedal to get mushy again. Your description of pumping the pedal repeatedly and then it suddenly getting firm again sounds like a dead on description for having accomplished a defacto re-bleeding.

If it is leaking within the hydraulic system, then it would not be going down; it could just be just bypassing the fluid. The only scenario I'd see for that would be if the master cylinder seals are shot, and are allowing fluid to squeak around them instead of building pressure toward the CSC.

When my own CSC failed, I had it (and the MC) replaced by the dealership during the last few months of my Elite ext. warr., which is why I went ahead and replaced it with stock parts. If I were doing it myself and paying out of pocket, I'd seriously consider the aftermarket options. Though I've done quite a few clutch and tranny jobs over the years, I don't do any 'outside' work. Ive got too many cars, and hence too many projects, as it is.

sLADe781

iTrader: (1)

Yeah I was kinda thinking something along those lines. This morning the pedal was mushy again but when I pumped it 30-50 times, it got stiff again. I didn't drive the car and when I checked it this evening, it was mushy again. Pumping it multiple times again got it nice and firm.

Well, while I could possibly be getting a bit influenced by you (lol), it does look like it may have gotten a bit lower afterall. I remember fully topping it off to the max line (not going over it though) and when I pulled the cap off tonight, it did look ever so slightly lower. Here are some pictures:





When I read your comment about the MC seals, I took a closer look at the rubber of the MC near the clutch pedal and found this:



There seems to be a lot of gunk on the rod of the MC...could that be the culprit? Or is that normal?

Yeah, I'll do the heavy duty CSC from ZSpeed but is there something like a heavy duty MC aftermarket option available too? Or do most people just go OEM here?

JSolo

iTrader: (14)

I don't believe there is an aftermarket MC available for these cars. That said, while a pain to replace the MC, it does not require dropping the trans. If you're mechanically includes, I would replace the MC first. Bleed it well, then go from there. Much cheaper than replacing the CSC.

sLADe781

iTrader: (1)

So I take it that the gunk on the MC is not normal and that it is the culprit?

vqsmile

I'm not sure. It looks to be just some grease they pack under that black seal on the end of the shaft, but I can't recall seeing one with it squeezed out like that before. IDK if that's because the grease is getting diluted by some fluid and causing it to seep out, or if it is just because you've been pumping the poor thing like mad lately.

I wish I could tell you more; maybe someone else here will chime in with something better for you to go on.

Have you gotten down there and done a thorough inspection of all the clutch lines and looked for any leakage? If it is leaking inside the bellhousing it pretty sealed off, but I wonder if it is possible to slip an inspection camera probe in and look for leakage there.

Short of anything else to go on, I think I would agree that swapping the MC first and seeing if that fixes the problem makes sense. The only concern I can think of is possible cross contamination. Once a CSC begins to leak, it's usually got some contamination in the lines which propagates back up into the MC. IF you swap the MC only, and it turns out to be the CSC, then you may expose the MC to that. Not a deal breaker per se, but noteworthy nonetheless.

sLADe781

iTrader: (1)

Question: when replacing the slave cylinder, I know you have to drop the transmission to access the CSC. Since the tranny needs to be dropped, does the transmission fluid need to be replaced as well when putting everything back together again? I won't be doing the job myself but I'm getting all the parts and supplies together so that the shop will have everything they need to do the job.

If the transmission fluid does need to be replaced, what is a good fluid that I should use? I have a 2008 G37S coupe so I believe I have to worry about LSD additives right? I'd like something that already has the additive in the fluid so I don't have to add anything else to it besides replacing the fluid.

Thanks guys.

And vqsmile, I checked under the car today and everything is bone dry. I followed the clutch lines and cannot find a leak anywhere.

vqsmile

First Q: No, you do not have to drain the fluid. It is possible to preserve the tranny fluid by a) not lowering the tail of the tranny when removing it, and/or b) plugging the rear seal with something that takes the place of the driveshaft yoke (they make a tool, but you can use some wadding/plastic bag/etc.). Basically, once you pull out the slip yoke from the driveshaft, you open a "leak" for the oil to pour out when you tilt the back of the tranny downwards during removal. The dealership and a tranny shop generally use the tool or a salvaged end off of an old driveshaft to plug the seal for removal. Even if you don't use anything, if you minimize the the time spent tiling backwards, then only so much oil can leak out, then afterwards, you can always just top off the oil whatever it takes to fill the tranny again.

Second Q: You seem to be confusing your differential and your tranny. There is no LSD in your tranny, and hence no additives required...ever! Furthermore, the type of LSD used in these cars is a sealed unit entirely contained within the diff, so even when you change the diff oil, there is no additive required!

LASTLY: Dude, I really don't want to see you drop that tranny unnecessarily. Why are you dismissing the idea of trying the MC first and eliminating the possibility that it is all that's wrong. I understand the odds aren't in your favor there, but the high costs of dropping a tranny unnecessarily seem to make it reasonable.

Is there ANY chance of getting an inspection scope slipped in through a small opening into the bellhousing and verifying a leak from the CSC before you drop the tranny?


EDIT: I see that you also asked another question about what's a good oil to use. There are many many threads here with recommendations, and and as with most any "what's the best lube" question, there are many many opinions. I will say that I have used the factory oil (and found it ok), one from Redline oil (found it ok), and my latest is a super wizzbang synthetic from Ford (best yet, but not excellent). YMMV

sLADe781

iTrader: (1)

Thanks vqsmile! I really don't want to do the CSC either but if the MC is going out, isn't it generally better to do both at the same time? I've always thought that the general concensus is that when you replace one, you should replace the other as well. I've also read that some replace just one and not the other and not too long the other breaks as well so I was just trying to get both done a the same time. Oh and you also mentioned contamination in your other reply so I thought to be safe just get it all done at the same time.

I don't have an inspection scope unfortunately and even if I did, I'm not exactly sure which opening you're referring to and what I'm looking for. If you have a shop and are willing to take a look I would bring it by but otherwise I'm not exactly sure what else to do?

JSolo

iTrader: (14)

Side note; Rear end oil is not suitable for tranny use...

vqsmile

I think the comment that it is generally better to do both at the same time, is primarily approaching it from the position of having a failed CSC and knowing you're going to drop the tranny anyway. In which case, YES, you should always do the MC as well. However, in your case, and from the info you've posted, I'm still not 100% sure it is your CSC. That said, my point was that in the interest of isolating the immediate cause of the problem, and to avoid potentially excessive repair costs, you COULD do just the MC first in case your CSC is not the primary cause. MC's can and do fail, just not a prevalently as the CSC's.

If after replacing the MC you still have the spongy pedal, then go ahead with your CSC replacement. The amount of time the new MC would have been exposed to the bad CSC would be minimal and any contamination could likely be flushed out of it, as well as the lines, to a reasonable certainly (just feed a quart of fluid through them; it's cheap) before connecting to the new CSC which you'd be installing. Does that make sense?

Hell, if you are totally concerned about contamination, and since an MC is just a 100 bucks or so (vs the cost or R&Ring the CSC), you could even argue that it might be worth the gamble to try it, and if it doesn't fix it, just replace it again if/when the change the CSC.

I haven't gotten down there and looked thoroughly to see, but I wonder if you couldn't loosen the bracket where the fluid line runs into the CSC and pass a scope probe from there. Barring that, I think I'd consider popping the starter motor off and seeing if I could get access from there. You can pick up a cheap inspection scope at HF for like 60 bucks with a coupon.

This really isn't difficult stuff though. Any respectable mechanic should be able to see/consider these options as well, considering he's earnestly looking out for you and not just making a bigger job ($$) for himself.

All that said, if you do go ahead and just swap out everything now, even if it ultimately proves to be preemptive, you should certainly have a good working hydraulic system and you should be done with it.

good luck



Sorry, I guess I'm confused as to why you quoted that

I don't see where I ever suggested using diff oil for the tranny ...
In fact, I specifically told him he was confusing his diff oil with tranny oil.


IS it perhaps just my use of the word "oil" instead of "fluid" with regard to the transmission ?

Either terms are used anymore, but I usually prefer "fluid" when discussing an automatic, and "oil" when discussing a manual. Tranny oil and diff oil are both gear oils, just different additives/weight/ratings.

JSolo

iTrader: (14)

@vqsmile; My comment was an attempt at play on words. There is truth in the statement. GL5 fluids are not suitable for GL4 spec'd requirements. Premature syncro wear will occur. Nothing to do with the term oil/fluid.