porschedetailr

Hello there new to the forum. Proud owner of a New "to me" 99 C4 cabrio with 141k on the clock . My first Porsche. Had some issues today. Was driving to sedona this afternoon and Noticed as I was coasting thru parking lot the brakes started to squeek and my foot was not even depressed on brake either
then the "brake wear" light came on on the instrument cluster. I had pads checked recently and were told pads had plenty of wear. And the car is strictly a sunday driver. As i was approaching a red light I pushed brake pedal down and the brake pedal went all the way to the floor!! BARELY STOPPED!! I nursed it to a parking lot and lifted frunk . I immediately noticed that there was a collection of brake fluid on the top of the resevior. The cap seemed tight. I had my gf step on brake as I listened and did hear a hissing sound as the pushrod part pushed in toward master cylinder. Felt like the brake booster was not working or something or a loose line somewhere. it was like there was no pressure of resistance on brake pedal. We started the car again and I pumped the breaks and it suddenly stopped going to floor. The pedal felt normal. I then very carefully made the drive home and brakes were fine the entire ride. But the brake wear indicator light is still on. Very weary on driving it, As If I had to stop suddenly I would have for sure rear ended someone. Any insight would be greatly appreciated. Also I am not mechanically inclined at all to tackle this myself. Would just like some general knowledge when discussing with a local porsche mechanic, thank you in advance.

zbomb

If there was fluid on top of the reservoir it is likely it, or the cap has developed a crack. If you have a code reader, you may want to plug it in, that warning is likely not notifying you of pad wear but instead an issue where they system is not seeing the pressures it expects due to air in the lines... the air is what you had to pump through to get pressure back in the lines.

My suggestion - get the car flat bedded to a mechanic and let them go through the repair process, as I'm sure you are aware - brake issues single most important to address, and address correctly.

DBJoe996

Since you started a thread with "break" issues, instead of brake issues, please get your car to a competent shop and have the entire brake system checked, including whatever codes popped up. Since it is a 2004 it might also be a good idea to have them bleed all of the calipers with new brake fluid. And don't forget, there is an emergency brake that can be feathered for a quick stop. Don't just pull it on, press the button and hold then apply braking while pulling up on the lever. It works.

porschedetailr

Yes it was late when I was writing the post last evening. But yes I do see the error the post title. It was a long day and I was pretty tired. With two Master Degrees under my belt I do know the difference between "break" and "brake" LOL. Thank you for the input btw.

ZuffenZeus

Give him a brake Joe!

Porschetech3

Nice one !! lol....because I usually don't laugh at grammar **** stuff

porschedetailr

Ok quick update. I started the car and now the "brake wear" indicator light shut off. The brakes seem fine as far a pedal feel. It sounds strange but almost feels like the pads are continually sticking now. As soon as I take my foot off gas it seems to slow down on its own. Almost like Im driving a tesla. A lot more brake dust on rims building up more than I am used too. Bringing it to mechanic on Wednesday to have a look.

fpb111

Been raining in your area lately? Check for blocked drains in the cowl area under the battery. Early 996 could suck water into the power brake booster, they changed the location of the hole that allowed this to happen.

porschedetailr

1999 C4 cabrio.
ok so a few months ago I had the issue of no brake pedal after 2 hours of driving from phoenix to sedona. took it to a porsche specialist. They bled the system added new Porsche brake fluid. they rebuilt my sticking driver side caliper, and added new front pads.
Car was fine!!!
Drove it all the way from Phoenix to Carmel by the sea california (1400 mile round trip) car drove GREAT!!! No issues whatsover. all this was in August.

This morning drove car to sedona from phoenix maybe 110 miles tops. Stop the car to do some quick shopping . car sat for 10 minutes. Jump back in and brakes start to squeek then 5 minutes into drive . NO BRAKES. pedal sinks to floor and no stopping. So like back in august when this first happened in sedona. I parked the car. let it sit for a couple of hours, and brakes re-pressurized and was totally fine driving home to phoenix. WHAT GIVES!!?!? Is this a curse of sedona telling me not drive there anymore? Last time that happened the brake light came on. this time it didnt. Please any insight would help. As now its on the Porsche mechanic to figure it out. But any suggestions or scenerios of what I can discuss with him from here would be great. Its getting to the point that im scared to drive it.

Pretty hard for mechanic to simulate unless I tell him to drive to sedona. LOL is it the altitude thats causing this? Im totally baffled!!!

hardtailer

Perhaps the piston seals in the Master cylinder are torn and fluid is leaking past them when you step on the brake pedal.

You can check for this with the car stationary in neutral, handbrake on and engine running. Now step on the brake pedal and push it slooooowwwlyyyy to the floor basically replicating what you experienced earlier.
Release the brake pedal and then you stomp on the pedal as hard and quickly as you can. Is it rock solid now and does not drop to the floor? Then most probably the piston seal(s) are leaking and it's time for a new MC.

DBJoe996

You may have to replace the master cylinder and have the calipers rebuilt with new pistons and seals. The braking system is pretty fundamental. You have something obviously wrong. Do you see any brake fluid on the garage floor or a leaking caliper?

hbdunn

It may be something sticking (the squealing) creating heat and causing the fluid to boil which will make it lose pressure. Once it cools down it goes back to normal.

hardtailer

Was your mechanic able to find the cause of your continuing brake issues? Reading your post again that it felt like a tesla it came to mind that brake hoses can sometimes swell up internally thereby basically pinching the line without any visible clues on the outside of the hose. When you step on the brake pedal the pressure is high enough to get brake fluid into the caliper and slow the car down but upon releasing the brake pedal the pull back force from the internal (piston) seals is too little to push the fluid back to the master cilinder/reservoir quickly.
This leads to a dragging brake pad, lots of heat into the fluid which eventually will start to boil and your brake pedal drops to the floor next time you step on it.
On further drives that typically happen at higher speeds perhaps brake cooling is effective enough for the fluid not boiling but it will do so as soon as speed drops to inner city speeds.
Suits your description entirely, doesnt it.

Long story short: Let your mechanic replace all the brake hoses!

blacksquid

What hardtailer said! You need to let your mechanic go over the entire braking system. Your car is 23 years old and bound to have issues. I had to replace the brake master cylinder, brake booster (water intrusion), and some related parts not long after purchasing my 99 C4 Cab.

porschedetailr

hello there everyone thank you for checking in !! Ok it turns out it was in fact the caliper that was just fried. He recommended that we replace both fronts but me being conscious I decided to just replace the one. So it has been driving great now. Thank you for all the responses.