More stupid 996 questions

Now that I�ve had the car a few months, I realized I have questions I would normally ask other owners at a meet up or car show, but that�s not an option so here goes. sometimes the door lock light on the dash is on. Sometimes it�s off. Sometimes, when I go over a bump, it flickers on and off. How can I use durametric to figure out what part of the locking system is not working? I suspect the micro switch in the drivers door as sometimes the window goes down a hair when lifting the handle, and sometimes not. I�ve searched for the codes but they are vague. I had my front brakes done, rears are fine. The braking still seems underwhelming to me. Is it possible I have a bad brake booster? Is there one? I plan on doing a fluid exchange and changing brake hoses, but PPI showed brake fluid was fine (but granted, they missed other stuff so who knows) Occasionally if I am braking while there is a road imperfection like a pothole or bump, I can feel the ABS trigger. This has never been the case in any other car I own, over the same roads. Is this normal? I feel a good amount of bump steer, and not quite a looseness in the steering but more of a twitchiness. This is hard to explain but sometimes over a bump it feels like the wheel wants to go it�s own way. I have an alignment scheduled, but what else would you check? Again, is this normal and I�m just not used to the car?

Far from an �expert�, but I�ll chime in with my experience (2003 C2, manual). I�d say that the brake performance is deceptive. The pedal requires a good hard shove, but the car does shed speed quickly. I don�t think there�s a lot of power assist, so you�re kind of �pushing� yourself back into the seat, rather than feeling the deceleration. The ABS is only a 3-channel system (on the C2, non-PSM cars, don�t know about the others) and sort of primitive. I find it easy to invoke a brief intervention, at slow speeds, when I pass over a loose surface. I suspect it may just be extra noticeable due to how light the car is and how much �feedback� the brakes and steering provide. I have the M030 spec suspension, and my alignment is set with lots of negative camber, very minimal toe-in. The car is �nervous� on the SoCal rain-groove freeway pavement, but absolutely magical on the back roads. have everything �checked� by a professional, but also realize that these cars feel �alive� when you drive them.

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I have certainly noticed the third - and I'm reading that right, you're surprised because it's not really a rough road. I've got fairly new pilot sports, and I noticed on dry warm pavement when hitting a bump or pothole. It doesn't seem right - like there isnt' enough traction from (weight over?)the front wheels.

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I'm no expert but I'll respond to the 2 points that I have experience with and an opinion about. The Brakes : IMO the brakes on my 2000 C4 Cab "s*ck." They stop the car alright but they are not as firm and do not stop my car as quickly as my other 5 vehicles, including a F250 diesel and a C7 Corvette. I thought that they were so "bad" that I immediately had the brakes redone -- pads, rotors, brake lines and master cylinder -- to try to make it better, even though NONE of those parts really needed to be replaced. The brakes still seems "soft" and slow to stop the car after all this work was done, even after multiple rebleedings. Even had my local dealer check the brakes and the service manager told me that he thought they were "fine" (no problem that his people could find even after they cked/bled the system). So, apparently that's just the way they are. Bump Steering : Bought my car w/ heavy aftermarket 19" wheels w/low profile tires on it and I had exactly the problem you describe. The car jumped and wanted to change direction each time a tire hit a bump. So, the other change that I immediately wanted to make was to switch to 18" wheels and tires. Took awhile but finally found a set of OEM Carerra rims and put Michelin Pilot Super Sports on them which entirely solved the problem. Therefore, if you have +18" rims and low profile tires on your car, you should probably look into changing them.

Thanks for the replies. Mine is also a C4 Cab. I mean the car stops, but yeah it's not "whoa nellie" brakes and I expected that after decades of watching people upgrade to Porsche brakes on other cars. My wheels are stock 18" on original wheels, also Michelin sport tires.

Edit: I wrote this while you wrote the above. Sorry for redundant questions. OP, what year/model car do you have? Just my experience, I have a 2004 C4S, and I love the brakes. It will push me into the seatbelt pretty hard. Definitely enough to absolutely terrify my wife, and to stop very quickly. Pedal is nice and firm through the full range. I've never had the ABS engage unexpectedly at all, and I've never lost traction when stopping, but I haven't driven in the rain that much. On the other hand, I can't account for sgt1372's experiences. As far as twitchiness and bump steer, in addition to alignment, as sgt1372 asked, what are your wheels? If aftermarket, and if the wheel offset is significantly different than stock, that will change your scrub radius, etc, which could possibly lead to twitchy steering depending on what it now is. Have you generally inspected the suspension? Maybe get the car up and take a look. Worn/torn bushings, loose parts, etc could all lead to instability or twitchiness. Also check the wheels for play (wheel bearings). I'm a just a DIY guy, so if others weigh in, some around here are professional mechanics, so listen to them instead!!

No worries. PPI, and my eyes, show there's nothing weird or obvious under there. I bought a stock 50k mile car, and while the shocks should be fine in theory, they are also 20 years old so that could be a factor. I may have a different shop take a look/drive and see what they think.

I�ve never owned a car like this before so it does drive differently. Brakes seems to be fine, don�t really have much to compare it with. I wouldn�t be surprised if I need to change some suspension components due to age. I suspect alignment could be need d as well. I know at low speeds the front tires seem to scrub backing out of the driveway. A brake fluid change is probably due as well though I may choose to have someone else do that because I have PSM.

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From what I've read doing it with PSM is no big deal. Use a power bleeder, trigger PSM with the Durametric, follow the specific bleed order.

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i too was surprised by the feel of the brakes when I first drove the car and it catches me when I haven�t driven the car in a while. But i have come to think of the brake feel as extraordinary progressive and it has been effective in stopping quickly when needed. You can really modulate the reduction in speed where modern brake pedals are very touchy. Sort of like the aggressive throttle tip-in programmed into so many modern cars to make them seem �fast�. if you think a c4 has bump steer, try a c2s some time. I like the modulation that an extra 100+ lbs adds to the front of my c4 vs my friends 997 S. But that�s not a popular view.

Get the brakes bled and a good four wheel alignment, while making sure the tire pressures are correct. Then re-evaluate the symptoms. Oh, and how old are the tires?

Why is this exactly? I always wig out for second the minute my car hits pavement with those rain grooves cut in it. Not just my '99 996, but also my wife's new MB SUV. It feels like the vehicles will "float" more on this type of pavement. Just curious and glad I'm not the only one whoever noticed. Sorry for the hijack. Thanks jim

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To over simplify, think of the pavement as an LP, and your tires are the needle of the record player, only there�s 4 of �em and they are in no way synchronized to each other. Makes the vehicle dance a little. The first time I experienced it on a motorcycle was a real special moment. I would point out that the extreme rear weight bias of the 911, combined with its minimal chassis flex and stiff suspension, creates a very different feel from everything else.

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it's called "Tram lining", like a tram car on rails the grooves in the tires line up with the grooves in the road and don't want to track straight

My tires are Pilot Super Sports, 2016 date codes. Going to get it aligned, change brake hoses and fluid, and will report back. On the alarm system, I need to do more searching, I am convinced there is a problem. New stupid 996 question: How do you position your seat? In other cars, for example an e46 BMW, the headrest cradles your head the whole time, but the headrest on the 996 seems to be very far back. I have to check the owners manual but it occurred to me maybe I am positioning the seat all wrong? I have the seat set correctly for my arms and legs, and it always seems odd that I am holding my head up.

I'm currently very pleased with the brakes on my 996.2. If you're not happy, consider changing pads & rotors. That made a world of difference! I tried Brembo brand pads and didn't like them. Switched to new Pagid rotors and Akebono pads and they're great. I have a new "Big Brake Kit" which uses 350mm rotors vs 317mm rotors that will be going on the car this week. I'll be reusing the existing Akebono pads. I'll probably create a new thread after the install.

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I installed Akebono pads w/the latest drilled Brembo rotors on my 2000 C4 Cab and the braking response still s*cks. Not going to throw any more $ at it trying to make it better.

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Forgot to mention that I also had a problem w/the Central Locking System (CLS) in my 2000 C4 Cab. When I bought the car, the CLS light was ALWAYS on and the car would not "beep" and the lights would not flash the way they were supposed to. Took it to my Porsche dealer to fix the problem. They found a short in the driver's door latch (which was replaced) and recoded the car so that the locking system would activate after driving away (the options are listed in the manual). Works fine now. There are only a few things that I will attempt to do myself. Electronics/electrical work is NOT one of them. Sounds like you want to DIY but it may be a problem that you'll be better off taking to the dealer, especially if any recoding is required. However, as I recall from my research on the problem, some faults in the CLS are found to be related to one of the seat belt clips which are also wired into the system. An intermittant blinking of the CLS light "might" be related to a seat belt clip that could be jostled (on/off) while driving. Have no idea if this has anything to do w/it at all but (based on my reading) CLS problems have been found to be due to things as obscure as that. Good luck!

The thing with the brakes on my car that caught me off guard early on in my ownership is the lack of pedal travel relative to my other vehicles. My Audi's brake pedal feels like a sponge, (not to be confused with "spongy brakes",) whereas my 996 feels like a block of wood. The Audi feels more like what my brain is used to where pedal travel correlates to brake pressure, if I push the pedal 25% of the way down, I get 25% braking action. The 996 is more like foot pressure correlates to braking pressure. I don't feel like the pedal is moving all that much but the harder I press on it I can definitely feel more braking force being applied. To the point, in fact, where I feel the tissue of my face being pulled forward by the forward momentum. It seems like the brake pedal in my 996 has an initial, smaller spongy zone that I use in 95% of driving where I'm getting light to moderate braking force to slow down for, say, a light or sign. After that I hit that block of wood, so to speak, and if I press on that block of wood hard enough the car seems to say "Oh, you're serious! Ok, let's stop NOW!"

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I've had the opposite experience. My 996 brakes are as soft as a sponge and it initially scared me when I tried to do quicks stops to only find the pedal sinking and the car not stopping as quick as I expected. I'm used to how the brakes function now and know NOT to try any abrupt stops and to allow additional time/distance for stopping but they still do sometimes scare and almost always annoy me. Just one of the reasons that I don't drive the car as often as I do others and why I'd sell it before all of the others. In contrast, the brakes on my BMW 335i (OEM rotors w/Akebono pads) stops on a dime w/minimal pressure (like stepping on wood, as you say). The brakes on my C7 Vette (OEM rotors/pads) are almost as good. The brakes on my F250 (stock), MR2 (stock) and MB (stock) are next in line but all still stop better than my 996. So, I do have a broad basis of comparison in terms of types, sizes and weight of vehicles and my 996 brakes pale in comparison.

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When the brakes get old and have been used a lot, the seals in the calipers deteriorate from rubber to a plastic-like substance and can sort-of glue the pistons in place. This gives a lot of free movement of the pistons before the pads contact the rotors and gives spongy brakes & excessive travel, no matter how much you bleed the system. The solution can be as simple as rebuilding the calipers with new seals.

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Oh, and I have rebuilt/re-powder coated calipers on my car. But I didn't notice a difference when I installed them, except for looks.

What happens if you panic brake in 50mph on a dry road? You should feel the ABS kick in. If it doesn't kick in and it feels like the pedal goes to the floor then something is wrong. Maybe a leaking caliper?

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i think this is more like what OP was talking about - not sponginess, or feel, but that on a dry road with a bump or pothole, the abs seems to kick in as soon as you hit that uneven surface. that's what happens to me. It doesn't seem like i'm braking hard, but the slightest imperfection in the road surface reduces traction enough for the ABS to kick in. Maybe it's a suspension issue, rather than a braking issue?

Thanks for the responses. Yeah, I try to do everything myself if I can. Pretty sure the problem with the alarm/locking is the door microswitches, from what I have read. I'm going to tackle the brakes first. Note the 996 does have a brake booster, discussed here and here Symptoms don't seem to relate to ineffective braking though. I mean, it's a 911. I expected "holy sh*t that stopped fast brakes!" not "yeah it eventually stops". Hard to say if that's just the way it is. I have new Sebro rotors and Akebono pads on the front, properly bedded.

Maybe im just lucky but my car stops great on pagid yellows even when they r cold. I also dont get any abs input on rough roads. Its a y2k with no psm. im guessing there is something causing the poor preformance maybe old/soft rubber hoses at the calipers?

My car has always stopped really fast. Stopping over bumpy stuff doesn't trigger the ABS. Shortly after buying it I replaced the rear pads and rotor and bled the brakes. The pedal was noticeably firmer. It never sank or improved with pumping. The firmer pedal was just new vs old brake fluid. The only problem I have now isn't really a problem. The Akebono pads on the rear cause significantly less dust than the current unknown front pads. But I'm too cheap to change the fronts out for just this reason... I just means I need to wash the car more often. The discussion brings up the question about how to test the trigger point for the ABS and what sensor is sending an incorrect signal to the controller. Another thing to look up, later...

Lots of Bay Area responses, maybe we should just drive each others cars and compare I'm going to get it into Pacific Power Motorsports and see what they think, since they see lots of these.

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That's certainly another possibility but, since I don't do my own work and already paid about $2k to entirely rebuild the brake system on my 996 (apart from installing new seals) that will have to wait until (if/when) I need to do any additional work to the brakes again, which I frankly don't think will happen before I sell/trade the 996 away. I should add that I had my local Porsche dealer inspect the brakes. Spoke to the Svc Mgr directly about it and he knew what my complaint was. He told me that they rebled the brakes again and that he thought they were fine and did not even suggest the idea of replacing the seals in the calipers. I have to assume that the Svc Mgr has a pretty good idea of how the brakes in a 996 should function and if he's telling me that they are fine then that's just they way there are and nothing short of replacing the rotors/pads and calipers w/a BIG BRAKE kit probably will NOT do any good.

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Let me know what you find out from them. They are local to me too.

Delete. Sorry dup.

My brakes used to feel weak, but now very firm and strong after I bled them, changed all rotors with OEM and swap the pads to Endless MX72.

Maybe I'm old school and I don't expect that much. In addition to my 99' C4 Cabrio, I own a 76' 911S and an 01' Audi A6 Quattro. I live in the mountains, where brakes are incredibly important. My C4 seems to be the quickest stopping of all of my vehicles. It has drilled rotors with what appears to be 4 piston calipers (?)...anyway, they're huge, and in combo with the ABS and the PSM, to me, it seems they are waaay more than adequate. Since this is my first "with snow" winter with the car, I've had the opportunity to see what the car is like on snow and morning ice; Like my Audi, you get this "weird confidence" that the car's saying "I've got this, don't worry". My 911S on the other hand, while very adequate in straight line braking in the dry, is a handful in wet or ice, especially in a turn. Here in Lake Arrowhead, virtually every road is twisty and going either up or down. You literally have to search to find a straight level piece of road, so I think I'm speaking from a "good test track" Question: Are all 996's equipped with drilled rotors and huge calipers with "Porsche" engraved on them?

The brake package differs between models but i think the smallest was the c2 with a 315mm rotor and a 4 piston caliper front and rear. Which i find as fine for dropping down from 130mph on the back straight into the over the top right hander at njmp lightning track. Although i still suck at high speed track stuff.

OK, back to my steering and bump steer. I took the car for an alignment, and this is what they said: Yet another huge miss by my PPI. Sigh. I know what the front end stuff is, but having a hard time figuring out what the bits on the rear end are (again, Carrera 4). By toe arms does he mean control arms? Been looking at diagrams online and I'm still not sure...

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Toe arms are the equivalent of tie rods for the rear wheels.

Seems like most vendors call them "control arm links." There are uppers and lowers. I'm only finding Meyle in the aftermarket, and given my previous experience selling Meyle products, I'd rather avoid. There seem to be some adjustable versions on the market from Tarrett and others. Expensive, but about the same price as OE.

Control arm links are different from toe arms. Control arm links connect "coffin" arms to the frame in front.(Front-Rear) Tie arms connect from frame to the hub assembly. (side-side)

#13 is the toe link #8 (two of them) are the control arm links #21 is the control arm, front & rear are the same #17 is the thrust link although some call this part the control arm #15 and #22 are the eccentrics, #15 sets toe and #22 sets camber

Toe arm: #8 Control Arm Link (thrust/caster control arm): #1 Coffin Arm(lower control arm): #2 Upper control arms: #4 & #4

Regarding brakes, two things to do before you spend a lot of money. 1. Make sure your brakes are properly bedded. You mentioned you had your front brakes done. Assuming you replaced either your front pads or rotors, or even both, it's important that you properly bed them in so the friction surface is connecting properly. You can find plenty of YouTube videos on the topic. As a side note, you want to be careful not to "glaze" them because you will never get the proper friction. This happens to a lot of "newbies" when the take their car out on the track for the first time with a new set of pads. Been there and done that. You can find info on that as well on YouTube. 2. The stock brakes are in general pretty damn powerful for just driving around town, and depending on the tires you use and temperature you use them in, will determine how much your ABS will talk to you. As an example, if you are running Michelin summer tires and the temperature is 40 degrees. The compound will harden and slip quite a bit during braking and turning, not to mention give you a he'll of an ABS "dance" on a bumpy road especially is slightly wet. Tire compounds and temperatures are everything. 3. If you want more grip, the first place to start is with more aggressive pad compounds. I have always used various versions of Pagid because I trust them on the track and therefore street. However, pagid has many different types of compounds to choose from and depending on if it's highway or track driving will determine which ones to use. Today, there is a plethora of pad choices beyond Pagid. Bottom line, the more aggressive the pad, the more your rotors will wear, but the faster you will slow. Obviously all will depend on tire compounds and temperatures. Regarding steering, the 996 and earlier 911's have a unique "alive" feel by nature to the steering. The new 911's don't. In the 996, you can feel every groove, nook and cranny on the road. This is a very cool feeling, but to someone that is new to the feel, it can be crazy. As an example, my kids thought something was wrong when they first experienced it learning to drive my 02 996 on the stock 18 wheels. I suspect this feeling will be amplified on 19s with lower profile tires, but have no experience with 19s to confirm. Lastly, suspension parts eventually need to be replaced as well and its inevitable that alignment and corner balancing work will need to be done at some point. Your shop can tell you if and when. Enjoy your 996. Get to know it's quirks, and keep asking questions. Had mine for nearly 19 years and am looking forward to the next 19.

Danix, Don't forget to keep us posted on what you find regarding brakes and suspension.

I've got the car in the air now, working through a few things. Tackling suspension first then making my way to brakes.

So, I've got the car all back together (for now). Did the rear brakes, pads and rotors. Also changed brake lines (rubber) on all 4 corners. Did a pressure bleed/fluid change of the brakes and clutch. Discovered that Durametric cannot trigger PSM despite what it says. Brakes seem better. Still not "OMG this car stops on a dime" but definitely better. Changed the outer tie rod ends, and the front wishbones. I think the lower control arms (coffin arms) need to be changed, and despite only having 50k miles on the car, I think the suspension is pretty shot so I have new Bilstein B6 going in. Also installed a 997 shifter, which is a big improvement but a little notchy. I am wondering if it needs some grease on the pivot points or possibly on the cables? Yes, I aligned it with the proper tool. Oh, I also changed the transmission fluid to Redline.

I tried reviewing but didn�t see anything as a solution mentioned for the ABS kicking in on bumps. I�ve experienced it most at low speeds and it�s not that bothersome but if there is a solution I�d be open to hearing it.

Interestingly, I haven't felt that happen since I did the work. It could be that ambient temps are higher, so the tires aren't rock hard and slipping.

Well the good news is that if you are not getting the "OMG" response to your braking, and it's not coming from tire slippage and abs, more is it coming from what you just replaced, then you can narrow it down to one of the items. Some you may have already done. Probably missed a few ideas as well. These are in no particular order. Start with cheapest solutions first. 1. Pad/rotors need to be more thoroughly bedded. 2. Need more aggressive pads front and rear. 3. Need to rebuild calipers. 4. New brake fluid. 5. New brake cylinder. 6. Big Brake kit Goods news is after you are done with figuring out the braking, you will know your car's limits inside and out.

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speaking of that T1 on Lightning - seems that every event I have driven there features some "excitement" at the junction of pit out + T1 ... i also switched to pagid yellows ( 1999 C2) from Akebono (the latter seemed fine for street driving). No issue stopping/slowing w the yellows after they were bedded.

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Im a little in the fence about diving that short track on an open day. It was fine on the DE day because of the stricter rules. Might try to get in that track early may.

I like yellows and have used them for years for both track and street. Gotta bed then in but once you do, they stop cold or warm. They are expensive, throw lots of brake dust, grind your rotors down a little quicker, but they stop the car, which to me is what's important.

Pads F/R are Akebono and properly bedded, although nothing in the Akebono installation docs talks about needed to bed them. Short of race pads, I haven't seen many issues with bedding in the many brake jobs I've done (on non-Porsches).

If that's the case and everything else checks out, you may need to consider more aggressive pads. Never used the pads you have on the car. If they are street pads, they probably produce less friction, which at the end of the day is what you need to stop.

It's entirely possible that you have one or more frozen (seized) pistons in each caliper. The car with stop with one of four caliper pistons working, just not very well. These cars are pushing 20 years old, so it's entirely possible the calipers need a rebuild with new seals.

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Very plausible. On a car with 2 piston calipers, the difference in pad wear would be obvious if a piston was not working well. This is my first with 4 piston calipers, and pad wear was even all around. Not sure if that's a good baseline or not.

If they have never been rebuilt, you will eventually have to do it. Especially if you want to make sure a 20 year old car stops.