tsjoel

I am having a problem with a normally simple diy. I put my car up on jack stands. Took the wheels off. Drained the fluid in the reservoir. Filled the reservoir with ATE Blue. Filled the pressure bleeder bottle. Hooked up a pressure bleeder with 20lb pressure to the master cylinder. I loosened the valves on the right rear and let them bleed into a jar. The fluid moved at a snails pace but finally I could see blue. I went the left rear and the fluid filled about an inch of the tube and then quit. I checked the pressure in the bleeder and it was still 20lbs. I pumped the brakes and was able to finish that one. Now I am at the front right and I could only get brake fluid out by pumping the brakes and now even that won't work. This is the first time doing this on my 993. I have done it on my bmw and it was always simple. Any hints to why the pressure will not flush my system.

Stuttgart

one question: How did you drain the fluid in the resevoir?

I ask b/c if you disconnected the line at the bottom of the resevoir you will get air in the system which will eventually stop at the abs unit. Once you get air bubbles in the abs unit you cannot get it out, and you have to buy a new one.

As for the slow bleeding, my best guess is that you may have a lot of air in the system, and the air compresses instead of forcing out the fluid (just a guess).

tsjoel

I used a syringe to get the the brake fluid out of the resevoir. Then poured the ate blue into resevoir. So I don't think I let any air into the system. The brake is real hard to push. I hope the abs is not shot.

Matt Romanowski

Hi Joel,

I don't mean this as an insult, but it sounds like you didn't crack the bleeders enough. Also, Phil is correct that if you pulled the line, there may be air in the system now. If it is in the ABS unit, you'll need someone with a hammer (daig. tool) to bleed the brakes for you.

Matt

Chris L

May be a stupid question, but did you put the rest of the liter of new brake fluid in the pressure bleeder? The car's reservoir doesn't hold enough to flush the system.

Chris.

Steve Weiner-Rennsport Systems

I don't think you've done any harm although you might now need the brakes re-bled using either the Hammer or PST-2 to cycle and bleed the ABS controller.

FWIW, I never drain (or otherwise remove old fluid from the reserviour), I just fill my pressure bleeder with fresh fluid, pressurize to 15 lbs, and start the bleed process at the outer side of RR caliper. The bleed screws need about a 270 deg loosening to open far enough for good flow rates.

Ray Calvo

tsjoel (whoever the heck you are), I can't come up with an error. Your procedure is similar to mine, and only time I've run into a problem is when I've forgotten to fill the reservoir during the procedure and I inadvertently drained the entire system. One thing I do is my bleeder has a "T" on the lines so I can drain both bleed screws on one caliper at one time if desired (I also tap the caliper with a rubber mallet to ensure I jar loose any air bubbles). The thought about not opening the brake bleeder might be right, but as I remember I don't have to turn mine 270 degrees as Steve suggests (esp. when I occassionally crack then close a bleed screw - I also like to "cycle" the bleed from one bleed screw to another).

I have a '95 which far as I know has the same vacuum brake booster as you. Car also has ABS/ABD.

Oh yeah - I use the GOOD ATE fluid - Type 200 without the Stupid Blue color!

tsjoel

Ok bust a guys chops when he is down Well I did fill the bleeder bottle and the reservoir. So far the resevoir is completely filled and I have a small amount left in the bottle. I turned those bleed screws till they almost came off (at least 3 complete revolutions). I thought as soon as I cracked them the fluid would start running fast but it didn't. I tried having both bleed screws open at a time, one at a time and same results. Let me just ask an really really obvious question.... the bleed screws are at the top of each caliper (2 for each wheel)?.

I did NOT disconnect the line at the bottom of the resevoir.

Let me explain some pre bleed symptoms I was having. When I would back out of my garage down a sloped driveway, I would have the brake on while rolling. As I reached the bottom of the driveway the brake pedal would suddenly push up toward me. I noticed that I would get some brake fade while driving very easily. Yesterday, while stopped at a light, I pressed very hard on the brake and it went to the floor. When I released it and pressed again it was solid. Could I have air somewhere in the system? I have not done a search on "the hammer" yet and since I do not know what it is, it sounds like I am going to need to take the car to a shop to have them work on it.

Ray don't worry I will use the GOOD ate next time... if there is a next time, and far as "who the heck I am" I am just another steeler fan in the South Hills, and used tsjoel the first time I logged on because my company name is Triangle Systems and Joel was already gone.

I was going to attempt an oil change next but this "simple" job has me rattled.

Thanks for the responses so far.

Steve Weiner-Rennsport Systems

Hi Joel:

The Hammer and PST-2 are the names for the two Porsche scan tools required to cycle the ABS controller.

If I might offer some advice,......

Based on your last post, I would suggest that you get your brake system completely re-bled by a shop with either the Bosch Hammer or PST-2.

Matt Romanowski

I definitely think Steve is right on this one. Have a shop with the hammer (or PST-2) bleed the system for you. It sounds like there may be some other problems, but this is the best place to start.

Matt

Greg Fishman

Your pre-bleed symptoms sound similar to the ones I had when I needed a new master cylinder.

Ray Calvo

Your pre-bleed symptoms sound similar to the ones I had when I needed a new master cylinder[QUOTE]

Sounds somewhat similar to symptons I had on my old '76 911S too when the master cylinder went. First brake pump was soft; if I rapidly pumped again the next pump was firm. Never had the brake pedal kickup, but that was a non-power assisted car.

What causes these to go? A big contributor is bleeding procedure; use the old-fashioned pump-the-pedal-and-open-the-bleed screw procedure and you'll destroy one quickly, especially if you track a car and subsequently bleed brakes often. I proved this to myself on my old 911; went thru 2 master cylinders in a bit over a year. This pump-&-bleed process forces the master piston cylinders past their normal wear points and prematurely destroys the piston seals. I proved this to myself when I dismantled a master cylinder; the normal travel pattern is clearly visible.

Switched to the air pressure bleed method; never had another master cylinder problem in another 50K miles on the '76, 122K miles on my '84, and 80K miles (at present) on my 993.

I'll agree with Steve, think it's time you take it in to a professional.

ApexL8

I agree with Greg and Ray, the symptoms you have sound like you have something wrong besides just air in the system. I had a vacuum problem on a non-porsche car which produced similar symptoms, but if Greg and Ray say master cylinder I would check that first.

Greg Fishman

Problem with the master cylinder diagnosis is that there is only one way to check it out. Replace it. They aren't rebuildable, or at least not economically feasible to do so. I got a new MC for around $300.
Joel could have a problem with the ABS pump but that is a lot more expensive of a part so I would start with the MC, provided he can be assured the system was bleed properly.

914und993

Was there any waxy looking stuff in your fluid reservoir?

When I bought my 96 993 and proceeded to flush the brakes, the bottom of the reservoir was filled with a sort of waxy solid. When I bled the brakes, the brake fluid at the calipers was very cloudy, probably the same solid in suspension. Although this did not keep me from bleeding the brakes, nor was it interfering with street brake function, I can imagine that had it progressed far enough problems would have arisen.

I can only surmise that the brake fluid was very old, maybe had never been changed, and this waxy stuff was the result.

Anyway, after getting as much of the waxy stuff out of the reservoir as possible, and a complete flush, the brake fluid has remained clear with no evidence of a return of the sludge.

Chip