der Mond

I’ll be changing out brake fluid soon.
The Bentley Manual on page 470-2 says: “The brake fluid reservoir also supplies the hydraulic clutch master cylinder. It is a good idea to also flush the clutch slave cylinder when replacing the brake fluid.”
On page 301-10 there is a photo of the clutch slave cylinder, with bleeder hose attached. It appears to be at the top of the clutch housing, and I am wondering if this can be accomplished without lowering or dropping the engine.
Any one done it?
Any idea what size plastic tubing to get?

ron mcatee

der mond, I do it every couple of years. You have to get the car up on jacks so you can get under it easily. I get mine high so I have plenty of room to work. I also recommend removing the left rear wheel so accessing it is easier. The bleeder sits on the slave at the top of the tranny and points towards the front of the car. The hose diameter is fairly small, like maybe a 1/4" or so. I think it is the same size as the bleeder on one of the calipers. I have a Motive pressure bleeder which makes the effort a lot easier. I bleed the brakes and also the clutch at the same time. Getting the clutch slave bleeder to open enough is a little tiring, but can be done. There's not a lot of room to turn the bleeder. Using the pressure bleeder assures constant pressure to brakes and clutch slave. Pedal will feel better as well as the brakes. I hope to replace all my brake lines soon and will go through it again. My brakes are OK, but the lines are original from 1988 and feel it's time. Per Pete Zimmerman and Steve Weiner, I'm way overdue.

spider911
88 Carrera, Grand Prix White with Lipstick Red interior
117,000 on odometer

der Mond

Thanks, Spider. I reckon I'll give it a try.
I intend to replace brake lines also, as well as rotors and Jurid pads, and reseal the calipers.
I have never done brakes before, so I'm still learning the ropes.
Would y'all be willing to answer a few more questions?
1) Where does one get a lint-free cloth to swab out the reservoir?
2) What do you use as an overflow hose clamp for pressure bleeding?
2) Can I do this job with two quarts of ATE? That's all I have. Bentley says run a pint through each caliper, which doesn't include the clutch slave. If it takes more, I wonder if it's OK to use another brand and mix a bit. Bentley says "Porsche Recommended DOT 4".
3) I'm trying to reconcile the terms "replacing fluid" and "bleeding." I thought bleeding was letting out just enough fluid to release air bubbles. How do you know your fluid has been suitably replaced? Like, how much fluid should I release from the clutch slave?
4) Pressure bleeding vs. pedal pressure: For the clutch, Bentley describes attaching the pressure bleeder, but also then depressing the clutch pedal several times, and then closing the bleeder screw while the pedal is fully depressed. Is this correct? Not having done this, I have visions of two gallons of brake fluid coming out as I try to do this. For the brakes, Bentley says attach the pressure bleeder and also then hold the brake pedal down, open the bleeder and then pump the brakes slowly at least a dozen times, then hold pedal down and close the bleeder. Does that sound right? Again, I'm imagining gallons of brake fluid all over.
Maybe I should get the best brake fluid I can get locally here in the wilderness and practice flushing the system, then do it once more with the ATE. Or just bite the bullet and spend a fortune on shipping and get more ATE.
5) I assume I do the bleeding procedure one caliper at a time in the order specified after the seals and line are replaced. Do I do the brakes first and then the clutch slave or vice versa?
It's not easy being an **** DYI 911 owner.....thanks for your anticipated patience...

ron mcatee

der mond, I hope I can answer your questions. Here goes!
1. You might be able to find lint free cloths at a computer store or know someone with Kimwipes which are adequate.
2. I use two very small clamps, one at each end of a one and a half inch piece of the same type hose that's used as the overflow. I put a plug in one end with a clamp and a clamp on the other end the reservoir. All you are doing is preventing air/brake fluid from getting out of the reservoir. The clamps are small and I made mine using the smallest clamps I could find until I got a snug fit.
3. 2 quarts of ATE fluid should suffice. I think a pint through each caliper is a bit much. Just need enough to flush it, maybe 4 - 6 ozs. I wouldn't mix the ATE if I had enough to do the job. I think you have enough. Is the ATE Blue or Gold? If it's Blue, you'll know when it is replacing the old fluid. If it's Gold, just guess at how is being displaced, i.e., 2 ozs, 4 ozs, etc. If it's Gold, it may be a different color than what's in the car now.
4. Pressure bleeding vs pedal bleeding? I have not done the pedal bleed since I have the Motive pressure bleeder. The pedal bleed induces air into the system and can require you to do it many times to evacuate all the air bubbles. If you don't have a pressure bleeder than pedal purging is what you have to go with. I haven't done the pedal bleed on the clutch slave either. With a pressure bleeder all you do is ensure there are no leaks at the reservoir. Then fill the bleeder with your fluid and pressurize the bleeder to 10 psi. Bleeding is accomplished by going to the farthest caliper and worknig your way back. Start with Right Rear, then Left Rear, then Right Front, the Left Front. Do not pump brakes. It induces air (bubbles) into the system.
5. I would do the brakes first and the clutch last. Since air bubbles rise that's how I do it and clutch always works very well.

Note: In a recent thread, Pete Zimmerman suggested calipers be done one at a time since getting the pistons to seat is a chore. This would require you to do several bleedings to achieve what you want. I have always done my calipers in pairs without a problem. You might contact Pete and get his perspective on his recommendation(s).

Good luck in your endeavor.

Spider911

der Mond

Spider,
Thanks - I have the "European Power Bleeder Kit" from Pelican. The Bentley manual lays it out as I have stated - attach the power bleeder, then pump the pedal. That seemed to make no sense to me. You are saying that when I pressurize the bleeder, I just then open the bleeder screws with no pedal movement. Is there an issue with not clearing the master cylinder or clutch slave cylinder that way, or are they cleared anyway automatically?

KC911

Spider gave you some excellent guidelines imo.... I've never needed to use the 'pump the pedal' technique after using my Motive Power Bleeder (although some folks do), and I have an extremely firm pedal (I do have 930 brakes & M/C though). Do a search on pelican about using the power bleeder 'wet' or 'dry'. I prefer the dry technique (I don't put fluid in the Motive). If flushing the system, I'll run a bottle of some cheap stuff through (a different color than ATE Super Blue), and then fill the system with ATE Blue and wait for blue to appear at all of the bleeder valves ensuring that the system is completely flushed. Good luck!

Keith
'88 CE coupe

911URGE

Pec*Pads can be used for this. They are non-abrasive, lint free and are used to clean optics on cameras and telescopes. They come in 4x4 and 9x9 sizes and are found at larger camera stores. Locating them in Fairbanks may be tough.

BTW, is the photo of your 911 taken on one of the turnouts on Seward Hwy?

der Mond

Thanks a great deal, guys, all my questions are answered, and I guess that now it's all over but the cursing
Urge: So, you have been to our fine state?
The Seward Highway is not a bad guess, it has many beautiful views.
The photo was taken July 2004 on my return voyage to Alaska after purchasing the car in Chicago. It is a turnout in Glacier National Park.

911URGE

Ouch, just a little off I was - It looks very much like Seward Hwy. I've spent about 5 months in Alaska over the last 2 yrs. I was last there in Nov 2005 in both Fairbanks and Anchorage.

Best of luck on the clutch bleeding. Let us know how it went. Its on my To Do list.