Cayman 987 pumping brake pedal in order to brake!

Hello, I am new here. Recently bought a cayman 987. I had a scary instance on the freeway where I tried to use the brake pedal and it went all the way to the floor. After pumping twice it was able to brake. Any suggestions? What can it be?

In my long history of driving that was usually only related to failing master cylinder seals or slave cylinder seals. I have never had a disk brake system act that way. Low fluid may cause that. Air in the system as well. Time for a full brake inspect and potentail repair

I checked the brake fluid and it was at full level. Thanks for your response.

You stated the master reservoir is full, mark it with a piece of painter's tape. If it's losing no brake fluid and pumps up enough to apply the brakes with vigorous pedal activity then my guess is air in the system which needs to be bled. Has it been for brake service recently? Also, just for future information, the Brembo's have twin bleeders, so whoever bleeds it needs to know you can't do just one and be good. There's also a part of the brake system that requires a Foxwell or equivalent to run pumps I believe are part of the ABS? This is Don's wheelhouse, he has the experience and knowledge I'm sure he'll drop a post soon.

Almost certainly a failing master cylinder. Air in the lines will give you a spongy pedal all the time, it won't give you a pedal that works sometimes and only works other times when you "pump it up". If the MC seals are going a sharp press will get them to catch, but very often you can get the pedal to go to the floor by pressing it very slowly down, or by gently jiggling it. If it behaves like that then it's certainly bad. MC replacement on a 987 is a relatively easy job provided you have the ability to properly bleed the brakes afterwards.

I agree with Gubi I was just hung up on the zero brake fluid consumption but his answer is better than mine because air doesn't just show up in the system and if it does then fluid leaks from where air is going in.

Most likely the master cylinder sucked some air into itself due to a failing seal or as @gubi pointed out - the actual primary piston seal on the MC is failing. It's time to do a replacement on that cylinder, and then a complete brake bleed. As mentioned - you do NEED to activate the ABS system to actually remove all air from the brakes. It can make a significant difference in brake feel and is really mandatory when the system has had air in it. The Foxwell NT530 will enable you to do this correctly, it allows activating each wheel circuit (there are 4) ABS/PSM modulator individually, AS you bleed/flush the fluid through that circuit. It's probably a good time for a power bleeder so that you can get the velocity through the system that's needed to sweep any entrapped air out. I haven't checked my Durametric to see if it's capable of doing that, but a PIWIS undoubtedly is. If you don't have the tools and haven't worked on brake systems before, I'd suggest finding a good independent who has experience with the system and the tools needed to repair it. I would NOT suggest you continue driving it - at all. No brakes is a great way to have an accident and since you've posted it here to the world, you'd be liable in an accident no questions asked.

First service your system with fresh fluid and get all the air out, I would recommend to get yourself a 'Power Bleeder' this tool is not expensive and it will allow you to service the hydraulic system very easy and quickly, if you have a manual transmission, the power bleeder will help you bleed this as well as both share the same reservoir, it is not that difficult and if you still have the issue, then move on with a new master cylinder. Good luck!

This isn't something you can fix with a fluid flush. Air doesn't just randomly get into the brake system, and even if it did "suddenly losing brakes but they came back" would not be a symptom. You could lose brakes if the fluid were old and you managed to boil it going down a mountain or something, but they sure wouldn't come back. And Don's absolutely right, the car's not safe to drive. Try the test I described, if you can get the pedal to drop then it's definitely the MC. For the record when I replaced my MC I was able to get a firm brake pedal without having to trigger the ABS system via Durametric. Porsche says you should only need to do that if you replace the ABS module. It did take me two bleeds to get all the air out, but that's probably because I didn't follow the instructions in the service manual with regards to actuating the pedal during the first pressure bleed...lesson learned that if you're starting from a dry MC that helps get the air out.

I would agree this sounds exactly like a bad MC, air in the system is just a mushy pedal, been there on other cars. Sounds like a great reason to upgrade to a 997 gt3 MC

Sounds like it needs new brake fluid flush. Could be some air in the line. I had this issue before and the shop flushed new fluid and I remember them mentioning using PIWIS to prime the air out of the brake line. Btw, first shop that I brought it to said I need new master cylinder which was not the case and it was working fine according to the other shop.

Bleed/Flush the brakes and see how much air comes out. You will need to bleed the ABS/PSM to get it all out, but I fought a soft pedal (not quite all the way to the floor, but close enough to be an issue) for a long time, and finally got it where it's firm. I put a gt3 master cylinder in, and still had too much pedal travel, UNTIL bleeding the ABS/PSM. The NT- 530 can walk you through bleeding the ABS/PSM circuit...... -Eric 09 987.2 PDK 99 986 (that always had a firm brake pedal)

" the Brembo's have twin bleeders" Do you know if this is so on the 981 calipers. I've bled my breaks before from the top bleeder petcock but never looked for one on the bottom. TIA DB

Yes, that is my question: I've had the calipers off before when changing the pads and never eyeballed a second bleeder screw on the bottom. do you have a picture so I know what to look for, please and thank you.

PS, mine is a 2014 Cayman base .

Bleeders are designed at the top of a fluid system so both bleeders are on the top that way they remove the air easily. If bled from the bottom you would not remove the air in the system as the top would be the high point and furthest away from the bleeder preventing any trapped air from excaping. So both bleeders are top located.

Same here. Shawn in VA (USA)

It is explained pretty well at 3:20 in the video. Our brakes have two cylinders so you need two bleeders. Some disk brakes only have one cylinder and the calipers slide to apply (near) equal pressure on both sides of the disk. That's a cheaper and less effective setup.