31 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHSticky brakes
Reported or suspected cause
vacuum hoses
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that report identifying a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause
I had a similar issue and it turned out to be a vacuum hose that goes from the engine to the brake booster.
Leading evidence: 'vacuum hoses' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'vacuum hoses' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check drainage' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
Also, I checked the MILF bearing and its ok as well.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
I just checked over on PCA.org and one guy had the exact same symptoms.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
Did the brakes actually stick or was it just the lights - if the latter - I would suspect the switch on the brake pedal - try removing that and wiggling around - or if needed - replace the switch.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
Did the brakes actually stick or was it just the lights - if the latter - I would suspect the switch on the brake pedal - try removing that and wiggling around - or if needed - replace the switch.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
31 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T152433Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Ok brain trust, here is a new one for me. This morning on the way to work with my 99 996 C2, I noticed that the brakes would momentarily stick on after a full stop. Verified by the reflection of the brake lights. I could use my foot to pull up the brake pedal and the brakes released. It is not like they are full on but on nonetheless.
So, is this indicative of something big failing? I did check the fluid and its fine though due for a bleeding in January before track days. Also, I checked the MILF bearing and its ok as well.
Calipers can certainly stick, but I don't think it would cause your brake light to illuminate.
Does the brake pedal move smoothly? It sounds like the pedal mechanism itself is hanging up or sticking. I'd take a look in the cabin/under the dash and see if everything looks clean and lubricated.
Has anyone removed the clutch assisting spring? A lot of modders went this way on a whim about a year ago on this forum. My next move if it were mine would be to check the pads, rotors and caliper movement and bleed the brake system completely. Are the anti squeal crowns on the back of the pads still in place? A lot of 'trackers' leave this out when changing pads. Shear laziness in my eyes. Also are the wear sensors in place. Again trackers disregard these as they change pads more often than a normal driver for obvious reasons and God forbid it takes an extra minute per corner to set them up. I think anything removed/left out, from the braking system are throwing dice. Things are in place for a good reason and should be left as they are. But 'would be racing car drivers' seem to know differently. Is your car set up for track ie. Larger rotors and pads? or whatever you need. I mean you should not have to lift a foot pedal with your foot to release it from the brake pads. Is your master cylinder working correctly? I do not profess to be a top mechanic by any stretch of the imagination, only a new Porsche DIY man throwing a few ideas your way.
Did the brakes actually stick or was it just the lights - if the latter - I would suspect the switch on the brake pedal - try removing that and wiggling around - or if needed - replace the switch. If the brakes were actually binding could be a stuck caliper - I had that on my front right caliper - I started to notice "rubbing" noises after hard braking (when there was some heat in the system). When I eventually replaced the pads - one of the caliper pistons had corrosion on it (probably from salt spray on the road - and was stuck - would not push back into the cylinder - I had to clean it off - and then worked smoothly again .....
Check the drainage near the brake booster. When they are blocked, water can get into the brake booster and will produce the exact symptoms you described. In fact, Porsche has updated the booster and related mechanism for MY1999 to prevent water intrusion to fix this problem.
OP, check for leaks - a spongy pedal might mean that you're losing fluid. This sucks because (a) running into things is bad, and (b) brake fluid is bad for your paint. Keep us posted...
Ok, I just took her for a ride on my lunch break. They are definitely sticking. When I depress the clutch, the brake pedal gets firmer...really firm and the brakes stick. Once I get it moving again, they seem to be fine until I depress the brakes again. The symptoms only appear to be happening in 1st and 2nd gear.
I just checked over on PCA.org and one guy had the exact same symptoms. The tech advice was to bring it to a mechanic. No other words of wisdom. But, it looks like water seepage from a clogged drain is a popular symptom in the 99's. I have had a siginifcant leaf problem this year (oak) and I will clean the drains. If water intrusion into the booster or master is the culprit, would a bleed do the trick do you think or am I going to need a booster? I am tyring to avoid a run to the dealer for service on this one.
The car has been heavily tracked by the previous owner and by myself. Everything in the braking system is stock.
I will report back with my findings. I am hoping to god its not the booster as that sounds pricey and not a diy.
Have you tried braking hard to see if that corrects the problem?
Might be time for a caliper rebuild by replacing the piston seals. Van has a good DIY vid about his 944 brakes. Suncoast has the rubber seals. Also would be a good time to upgrade to stainless brake lines. I did mine a year ago and it is fairly straight forward.
Gator, Im assuming there is no type of warning light on and there is not a brake pedal linkage problem?
To help find your brake issue, you need all 4 wheels up.
Duplicate your problem by depressing brake pedal.
Release the pedal and go to each wheel.
If its a single wheel sticking then it may be that caliper.
If its the front pair or rear pair it may be combination valve or master cylinder.
If its all 4, it may be the combination valve, master cylinder, booster, or linkage.
In a rare case it could even be a bad line. Brakes are not hard to diagnose but you must have the car in the air.
I had a similar issue and it turned out to be a vacuum hose that goes from the engine to the brake booster. It had rubbed against something and a hole was worn through.
I will get the car in the air after the holidays. Good points Krazy. It definitely feels "hydraulic" and not a cable or bound up assembly. I am betting on a water soaked master or booster although there is no loss of pressure so I wonder if its more master cylinder than booster. Hell if I know. I will get down off my turkey and stuffing high by Monday and get er up on the jack stands.
Ok I was wrong on one point. I meant the clutch assistance spring. So you would rather come on here to complain about my posting than to help the other fellow first. OK expert would be racing car driver. Go about your business and help the guy.
KK...I've been meaning to point out something disturbing in your avatar...
Your right tailpipe is much lower than your left one. Likely IMS related.
You need to move your car into your living room pronto!
if the lights are staying on, the pedal is staying down, which is different then a sticking caliper. My bet, you got a bad master cylinder or pedal assembly.
Since the brakes & clutch share the Master cylinder reservoir, & pressing the clutch pedal make your brake problem worse, I would start at the MC. Since you can manually disengage the brakes with the pedal that points to the MC pushrod.
Kudo for a good description of your issue & another great avitar.
??"Since the brakes and clutch SHARE the Master cylinder??
Step on the clutch and the brakes go on??
They share fluid from the common reservoir but I'm pretty sure they have separate master cylinders.
This sounds like booster gone bad.
After some further research on the interwebs, all signs point to the booster. I may just replace the MC and booster. I hate to throw parts at it but Renntech had some solid info on the issue. A good reminder to check your drainage systems.
Apparently their is a parts change for the MY 99's so I need to sort that out to make sure I am getting the right pieces. I would prefer to not buy one used.
