Pjd131

Hi Guys, Need some suggestions. I have an 89 911. I have the G50 clutch fork update. I replaced the rubber centered clutch over the winter as well as the clutch slave and clutch master (just did the master). I have bleeded the hydraulic system many times. I have a very soft clutch pedal and the slave will not move the clutch fork more than 1/2 inch. I fired the car up today and cannot get into gear. So, before I drop the engine and trans again to make sure I assembled everything correctly , does anyone have any suggestions or other diagnostics before I take that major step. I was thinking about removing the slave cylinder and building a mount to make sure it is working properly. Any suggestions (anything) would be appreciated. Thanks

E Johnson

Well first things first, lets make sure that you have the correct parts.

Your slave cylinder should have had the part number 950 116 237 12, and 911 423 171 03 for your master cylinder. When you say you did the clutch fork update, I am assuming that you mean the clutch fork pin section, am I correct?

One of my first thoughts here is that you might not have driven down the hydraulic hoses so that they formed a good seal and you might be getting air into the system. Obviously, this would be a problem. It could also be that during your bleeding of the system there was a air bubble that would not bleed out and is still there. (this seems unlikely though if you have done the bleeding several times)

It could be a bad bleeder bolt that is not seating properly in the slave or master, you might want to remove them completely and make sure that there is no material in the passages, I have seen in the past that during the threading, a particle can be cut off and prevent the bleeder from seating properly.

I would check every hose to make sure that the entire path is secure and seated correctly, before pulling the gearbox again.

Did you have any issues with the clutch prior to this recent issue? Shallow engagement, etc.

I hope that this is at least a little helpful. Feel free to give me a call if you want to spit ball some additional ideas.

Good luck,

Erik Johnson
(970) 344-7761 phone

theiceman

Eric mine is cable so i dont know what the hydraulic setup looks like
is there any way he can measure the throw on the slave ? This would tell him immediately what is going on i think if he is coming up short..

Pjd131

Thanks guys. I will be double checking parts and removing the slave this weekend. I am interested in the question Ice asked about the "normal" piston throw. Hopefully it's air or something with the slave and line. Will update after the weekend.

Pjd131

Hi again. Guys, I took the clutch slave cylinder off and it looks a little odd to me. See the pic. There is not a complete bore through to the cylinder. I threw out of old one months ago so I have nothing to compare. I've got this over at Pelican too. I really hope this is the issue. If not I'll bleed again and see where I'm at.

Does that seem right. Again, I am getting no pressure in the clutch hydraulic system.

Amber Gramps

That looks right to me. If you can see into the bore you can flow fluid into it.

How exactly are you bleeding the thing? Vacuum pump, 2nd person, or pressurizing the brake reservoir?

A vacuum pump on the bleeder port should draw fluid down into the slave just like a on a brake caliper. As stated above if the port is clogged or it is too far open no amount of vacuum is going to draw out fluid.

....and for the uninitiated, there is only one shared reservoir. Both the brakes and the clutch use the same fluid. You should flush your clutch when you flush your brakes.

Pjd131

I'm using a pressure Motive bleeder. I've blead the brakes and clutch a couple times. There does seem to be restricted flow at the clutch slave bleeder. Just to clarify, the shining metal in the pic, which is basically 1/2 of the opening into the cylinder is intact and it is asymmetric. So there is no complete circular bore into the cylinder. It looks odd to me but may be the design. Was looking for some definitive pic from someone out there with a spare slave before I decide how to proceed. Thanks for the feedback. I appreciate it.

Pjd131

Here's a closeup. Hopefully you can see my concern - that the bore is not all the way through. The dark is open intone cylinder. The medal is not.

Amber Gramps

You only need the smallest of holes to force fluid through. As long as it opens up behind that, you are good. The bleeder port is purposely places high on the cylinder bore.

Pjd131

Amber L, this is the port for the hydraulic line. Still same thoughts? Thanks

Amber Gramps

Yes, same. Only need the smallest of holes.

Go to Pep Boys and buy the OEM or MityVac hand vacuum. I have 2 of them. Try sucking the fluid rather than pushing the fluid.

Really, in tinkering with this type of stuff for 35+ years it has always been my experience that hydraulic fluid will simply flow down hill. I've done lots of brakes where vacuuming or pumping wasn't even required. If you are opening the bleeder port, you should be getting fluid.....end of story. Hydraulic fluid is extremely dense/heavy....it wants to flow downhill. My mind says you have blockage or you have no fluid in the line. If you had even the smallest amount of fluid it would flow downhill.



YOU HAVE PM.

Pjd131

Thanks AL. Did not get vacuum yet (don't have one) but removed slave, blead again, filled slave, mounted slave on little stand, and built a kind of fulcrum for resistance for slave piston. Still absolutely no pressure in clutch system. Will try vacuum next but there is fluid all the way through the system. May have to look in tunnel for fluid (I think hard line runs through there). There is no fluid anywhere else. Will double check part nonfat slave. Got your PM. Will text you later when hour is more reasonable. I am on eastern time. Thanks

Amber Gramps

I gotta know...What's a nonfat slave?

OK, with the slave removed, does hooking up your Motive and pressurizing it cause fluid to flow out the line?

Pjd131

That was supposed to read check the part no for the slave. It was suggested on the Pelican forum that I double check all the parts I bought.

Pjd131

Hello all, I'm back in the saddle. I replaced the slave and the flexible hydraulic line and pressure bleeded and all is good. The new clutch performed very well too. Thanks for the ideas/suggestions. I'm not too happy with my first attempt at a valve adjustment (done over the winter when engine/trans was out). There is a some engine ticking that will have to be addressed shortly, but other than that everything is checking out nicely. Thanks again.