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Brake/Clutch Fluid Change and Bleeding Instructions


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I have a strange problem on my 968. I put on new pads and rotors, repacked the front bearings. All is going well.

I have my assistant pumping the brakes for a system flush. She pumps the brake pedal and I get only 2-3 squirts of fluid out of the right rear caliper and then nothing. Brake pedal is firm even though the bleeder is open. I try the left rear and same thing - 2-3 squirts and then nothing. Now I'm really confused. I try the left front and that seems to be operating correctly.

I have my assistant hold down the brake pedal. Front brakes are engaged - rear brakes - nothing. It seems like there is no longer any pressure to the rear system.

Anybody have any suggestions?

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View this tutorial Brake/Clutch Fluid Change and Bleeding Instructions Note: Part numbers sometimes change without notice. Always double check with your supp

Thanks to the RennTech DIY instructions and others on this board, I bled my brake fluid today. The instructions were very helpful. Here are a few other tips I can pass along to anyone else who plans

I'll add a key point to keep in mind: the bleeder valve CAN introduce air into your drain tube when the fluid is flowing! This will give the appearance of air coming out of the caliper when in fact it

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I have a strange problem on my 968. I put on new pads and rotors, repacked the front bearings. All is going well.

I have my assistant pumping the brakes for a system flush. She pumps the brake pedal and I get only 2-3 squirts of fluid out of the right rear caliper and then nothing. Brake pedal is firm even though the bleeder is open. I try the left rear and same thing - 2-3 squirts and then nothing. Now I'm really confused. I try the left front and that seems to be operating correctly.

I have my assistant hold down the brake pedal. Front brakes are engaged - rear brakes - nothing. It seems like there is no longer any pressure to the rear system.

Anybody have any suggestions?

Get a Motive power bleeder - a very worthwhile investment (IMHO).

Pumping the brake pedal still allows for air to be sucked back into the system.

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Yep - just might have to get one.

So I took the lines off the back of the rear calipers - no fluid.

So is my master brake cylinder dead? The booster?

Thanks

I would wait for the power bleeder and try again.

Could be a clog or debris in the (booster) block where the reservoir connects.

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I ordered up a motive power bleeder - it must be better than the hand unit I've got.

I used a hand vacuum pump and was able to get 25 psi of vacuum and still couldn't pull any fluid. I'll use the motive when that comes in but my gut is telling me this is something else...

Any other ideas on what is preventing the fluid from reaching the rear calipers? Is there brake bias that could be stuck or some kind of circuit actuator?

Thanks

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  • 3 weeks later...
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Yesterday I did my 04 boxster s. THank you for the detailed instructions. Only took about an hour to do all four corners. Is the clutch really optional though or needed?

I usually bleed the clutch also - you already have everything there to do it. Maybe another 10-15 minutes at the most.

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I do not know if anyone would be interested. But I purchased a motive european power bleeder from Pelican Parts and ended up not using it to bleed my brake lines. I hate to see it go to waste, so if anyone is interested in it, please PM me. Thanks!

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  • 2 weeks later...
I do not know if anyone would be interested. But I purchased a motive european power bleeder from Pelican Parts and ended up not using it to bleed my brake lines. I hate to see it go to waste, so if anyone is interested in it, please PM me. Thanks!

Just reliving an old thread...

Found this tube at China Freight. Makes bleeding brakes a lot easier.

http://www.harborfreight.com/cpi/ctaf/disp...temnumber=98864

post-16847-1242965612.gif

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  • 1 month later...

hi,

i am bleeding my brakes for the first time. I do not have the luxury of a Motive Bleeder and have to do the manual way of depressing the clutch from an assistant.

Loren mentioned that it is not the best way to do it as air may be introduced as compared to the bleeder, but if I really have to do it, do i have to keep the pedal depressed all the way while releasing the valves? Or do I keep pumping it? Also, do I drain the old fluid till it comes to the MIN level on the reservior before topping up with the new one?

Is there a good way of doing it the manual way?

I am changing my fluid to the super blue now and would be switching it between the gold and blue every 2 years, has anyone experienced the blue dye (ATE) staining the reservior?

Thanks

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hi,

i am bleeding my brakes for the first time. I do not have the luxury of a Motive Bleeder and have to do the manual way of depressing the clutch from an assistant.

Loren mentioned that it is not the best way to do it as air may be introduced as compared to the bleeder, but if I really have to do it, do i have to keep the pedal depressed all the way while releasing the valves? Or do I keep pumping it? Also, do I drain the old fluid till it comes to the MIN level on the reservior before topping up with the new one?

Is there a good way of doing it the manual way?

I am changing my fluid to the super blue now and would be switching it between the gold and blue every 2 years, has anyone experienced the blue dye (ATE) staining the reservior?

Thanks

Don't confuse the clutch with the brakes - it is a somewhat separate process.

If you are manually bleeding the brakes then the process is to have the assistant apply pressure to the pedal while you release a bleed valve. If the pedal hit the floor they need to hold it there until you tighten the valve. Then pump the pedal up and continue the same process until there is no air. The $40 I spent for a Motive Power bleeder has been a huge time savings for me.

When bleeding the clutch I don't think it can be done without a power bleeder -as the clutch pedal needs to remain fully depressed when fluid is pushed through the lines to remove any air.

Where do you live? Perhaps another member can loan you a power bleeder.

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I live in Singapore, a part of the world where seldom one does their maintenance on their own. So difficult to loan. Parts are hard to find here too. I would probably indent one from US and ship it back before I bleed my brakes in that case.

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  • 2 months later...

Just bled my brakes and clutch, and Loren's instructions worked like a charm. Thanks Loren, especially for the detailed clutch bleeding instructions (the wood worked great, and because of the comment you made about the possibility of the clutch pedal sticking in the down position, it didn't scare the crap out of me! :D )

I have three tips I'd like to add, and a question too.

Tip 1)

I couldn't find a turkey baster small enough (or a syringe) to get into the reservoir to suck out the old fluid. So, I removed the interior cover in the trunk so I could see the reservoir and its level. I then put the Motive bleeder on it with NO FLUID inside, and simply pushed the old fluid out thru the right rear caliper, but not so much as to introduce air in the system. Watch it carefully!

Question though: there is a small tube going from mid-reservoir into the cab (see attached). I was afraid of getting any air into this line (don't know what it's for, clutch?), so only pushed the fluid down to this point, not letting the level get lower than the tube. There was still a decent amount fluid left in the reservoir, so maybe it's best to suck it all out down past this tube using a syringe, thus allowing most of the fluid to be removed and for old fluid to stay in that tube instead of air getting forced into it. But, this pushing it out at least got rid of a bit of the old stuff first.

Tip 2)

So you don't round any of the bleed screws off with a line wrench or 12pointed end wrench, break them loose first with a 6point socket, and then close. If you do it with pressure applied, there's no fear of air feeding back into the system, just be sure to just crack them and close to minimize any spillage; I was able to do it with no leakage. Then you can put your tube and end wrench on the bleed screw and open it up easily . If you have 6pointed end wrenches, you've got more money for tools than I, and there's no need. ; )

Tip 3)

Follow Loren's directions to a T!!

My fluid was a bit dirty and only a tiny bit dark, but was green! Yikes!

Happy bleeding!

post-48213-1254155679_thumb.jpg

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  • 2 months later...
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i am getting new durametric which allows for break bleed but there is no explanation anywhere on how to do it. where can i look it up? tks

here is what they say for the Porsche tools (PST and PIWIS) so I suspect the Durametric emulates them.

"Press the Start button on the System Tester. This initiates certain functions in the hydraulic control unit (return pump, switch-off and switch-over valves are actuated).

Bleed until clear, bubble-free brake fluid emerges. In addition (throughout bleeding operation) fully depress (pump) brake pedal as far as the stop at least ten times.

Caution: In vehicles with high mileage or in old vehicles, double the pumping cycles and use only half the brake master cylinder stroke (damage to the brake master cylinder could result / primary boot damage)."

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i am getting new durametric which allows for break bleed but there is no explanation anywhere on how to do it. where can i look it up? tks

Here is what they say for the Porsche tools (PST and PIWIS) so I suspect the Durametric emulates them.

"Open the rear right bleeder valve (use collecting bottle).

Press the Start button on the System Tester. This initiates certain functions in the hydraulic control unit (return pump, switch-off and switch-over valves are actuated).

Bleed until clear, bubble-free brake fluid emerges. In addition (throughout bleeding operation) fully depress (pump) brake pedal as far as the stop at least ten times.

Caution: In vehicles with high mileage or in old vehicles, double the pumping cycles and use only half the brake master cylinder stroke (damage to the brake master cylinder could result / primary boot damage).

Close the right rear bleeder valve. Then immediately press Stop button on the System Tester."

any specific bleed valve to open before i start this?

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i am getting new durametric which allows for break bleed but there is no explanation anywhere on how to do it. where can i look it up? tks

Here is what they say for the Porsche tools (PST and PIWIS) so I suspect the Durametric emulates them.

"Open the rear right bleeder valve (use collecting bottle).

Press the Start button on the System Tester. This initiates certain functions in the hydraulic control unit (return pump, switch-off and switch-over valves are actuated).

Bleed until clear, bubble-free brake fluid emerges. In addition (throughout bleeding operation) fully depress (pump) brake pedal as far as the stop at least ten times.

Caution: In vehicles with high mileage or in old vehicles, double the pumping cycles and use only half the brake master cylinder stroke (damage to the brake master cylinder could result / primary boot damage).

Close the right rear bleeder valve. Then immediately press Stop button on the System Tester."

any specific bleed valve to open before i start this?

Bleed the brakes as normal first. I have added the bleed valve instructions to my post above.

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  • 1 month later...

Can someone tell me what this is for, mentioned in a prior post?

I'm having some weird brake issues. My pedal goes to the floor every time, feels like there is no pressure to my front pistons. If I have to slam on brakes, I get nothing but a coast to a stop. I've bled my brakes 3 times now with no improvment. This is driving me nuts!!! My brake lines were recently changed, could it be air in the ABS or something?

post-30511-1265137007.jpg

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Can someone tell me what this is for, mentioned in a prior post?

I'm having some weird brake issues. My pedal goes to the floor every time, feels like there is no pressure to my front pistons. If I have to slam on brakes, I get nothing but a coast to a stop. I've bled my brakes 3 times now with no improvment. This is driving me nuts!!! My brake lines were recently changed, could it be air in the ABS or something?

That is the resevoir feed to the clutch master cylinder.

As long as you don't see your fluid disapearing thru a leak, you must still have air in your system, especially since you had your lines replaced. Was all the fluid allowed to drain out completely from the lines? I'm not sure how the ABS system holds fluid if the lines are drained, so I'll let someone else post a response to that. But use Loren's instructions and make sure the outcome to each step is correct, and you should be good to go. How did you try to bleed your system, using the foot-pump method, or the Motive power bleeder? Did you use Loren's technique posted here, using the Motive power bleeder? If not, I'd suggest that first. It works like a charm.

Edited by peavynation
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Hmmm, my car (03'996 TT) does not have that feed going to the reservoir........... Is there a reason for that? Is it because the Turbos use pentosin? Not sure if the picture posted earlier was a Turbo or not.

As for the bleeding, I have a Motive power bleeder and am a track rat so I have lots of experience bleeding the brakes, Lauren's technique is the one I've always used. But it feels like my brakes are only clamping at a max of 25%. Brake pedal feels almost like the clutch pedal. I can literally here air escaping in the footwell when I depress the brake. Could it be something on the inside? Is my master cylinder bad? I'm positive this isn't related to the bleeding of the calipers.

Thanks for the help and quick response though.

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Hmmm, my car (03'996 TT) does not have that feed going to the reservoir........... Is there a reason for that? Is it because the Turbos use pentosin? Not sure if the picture posted earlier was a Turbo or not.

As for the bleeding, I have a Motive power bleeder and am a track rat so I have lots of experience bleeding the brakes, Lauren's technique is the one I've always used. But it feels like my brakes are only clamping at a max of 25%. Brake pedal feels almost like the clutch pedal. I can literally here air escaping in the footwell when I depress the brake. Could it be something on the inside? Is my master cylinder bad? I'm positive this isn't related to the bleeding of the calipers.

Thanks for the help and quick response though.

I'm not familiar with TT cars, so don't know their. The picts of the resevoir are of my '01 C4.

Since you're a track guy with a lot of DIY experience, that somewhat eliminates a lot of newbi mistakes as possiblities. I thought at first that maybe there is blockage in one of the lines, but then you'd feel it pull to one side. Maybe it is with the ABS system having air in it, but I wouldn't think so. You should be able to cycle that by locking up the brakes, but that can be hard on tires. I prefer to do it on wet pavement. Hard acceleration on wet pavement will do it too, but I figure that's more shock-loading on the drivetrain/engine than a neutral-gear lockup.

Are you sure you're not loosing fluid? Maybe a leak that is also allowing air in as the brakes are cycled? I guess it could be a part going bad in coincidence with the new lines and bleeding, but I'd focus on what was changed first.

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No fluid leaking, my reservoir level has not gone down at all and no fluids on the ground. The brakes are so weak I can't even lock the wheels enough to bring on the ABS. When I mash the brake, the pedal goes slowly to the floor and I coast to a stop, from any speed. I don't think the lines are blocked because the fluid flows fine when I'm bleeding them. I honestly don't know what else to check next.

Edited by heavychevy
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  • 2 weeks later...

2 updates:

Update 1 (about 7 days ago): I finally figured out that if I stab the brakes extra hard, I can get the ABS to kick in in the dry. I'm fairly strong and I'm talking about standing on the brakes muscles locked (lol). So I've been doing that a lot to try and cycle the ABS and see if I can push some air out of there. Pedal feels great when I get in the car and start it, and press it a few times, but as soon as I drive down the street, it's a second clutch feel again, with minimal stopping.

Update 2 (Today): While waiting for my mechanic to make time to see my car, I have been driving the car and stabbing the brakes constantly trying to get ABS active. Still practicing stops from 70-80 mph modulating the pedal to try and get some feel. Well yesterday it was raining and all of a sudden my pedal feel started to come back. It's not all the way back by any means, but it feels like a real brake pedal and not a clutch. It was wet so I wanted to see if it felt the same in the dry and sure enough it did.

If I drive stop and pump the pedal there still feels like air initially that eventually gets pumped out. But where the pedal used to go straight to floor there is resistance now when I drive down the street. Still can't get into the shop until next week so I will continue to push the brakes and might even bleed them real good again before even taking it to the shop. I'm more encouraged that my master cylinder may in fact be ok and there is some air in there somewhere that we haven't found.

I'm not back on track for a while so I'm going to give it some miles and patience to see how it shakes out.

Thanks for all of the helpful opinions.

HC

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2 updates:

Update 1 (about 7 days ago): I finally figured out that if I stab the brakes extra hard, I can get the ABS to kick in in the dry. I'm fairly strong and I'm talking about standing on the brakes muscles locked (lol). So I've been doing that a lot to try and cycle the ABS and see if I can push some air out of there. Pedal feels great when I get in the car and start it, and press it a few times, but as soon as I drive down the street, it's a second clutch feel again, with minimal stopping.

Update 2 (Today): While waiting for my mechanic to make time to see my car, I have been driving the car and stabbing the brakes constantly trying to get ABS active. Still practicing stops from 70-80 mph modulating the pedal to try and get some feel. Well yesterday it was raining and all of a sudden my pedal feel started to come back. It's not all the way back by any means, but it feels like a real brake pedal and not a clutch. It was wet so I wanted to see if it felt the same in the dry and sure enough it did.

If I drive stop and pump the pedal there still feels like air initially that eventually gets pumped out. But where the pedal used to go straight to floor there is resistance now when I drive down the street. Still can't get into the shop until next week so I will continue to push the brakes and might even bleed them real good again before even taking it to the shop. I'm more encouraged that my master cylinder may in fact be ok and there is some air in there somewhere that we haven't found.

I'm not back on track for a while so I'm going to give it some miles and patience to see how it shakes out.

Thanks for all of the helpful opinions.

HC

If your mechanic has the Porsche scanner tool, he can cycle the ABS system while bleeding too.

A Rennlister also posted recently of a bad clutch pedal, and it turned out to be a very tiny leak at one of the line junctions, which was allowing air to get in. Could be something similar; it only takes a tiny bit of air to cause a really bad pedal feel. Just food for thought.

Keep us posted.

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If your mechanic has the Porsche scanner tool, he can cycle the ABS system while bleeding too.

A Rennlister also posted recently of a bad clutch pedal, and it turned out to be a very tiny leak at one of the line junctions, which was allowing air to get in. Could be something similar; it only takes a tiny bit of air to cause a really bad pedal feel. Just food for thought.

Keep us posted.

Yeah, it will be done at the Porsche dealership, so he has all the tools. If a line was leaking wouldn't I see fluid somewhere? I probably need to remove the underbody to make sure. Mine is custom and made from aluminum so many of the gaps of the factory plastic system are gone. But there are no leaks on the inside though.

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