nbeihl

I went out for a drive today and made temp. readings using an inferred temp gun immediately after driving. Here is the information I got.

Outside air temp.: 85F

Drive conditions:

30 min at 75 MPH on the freeway

Exited freeway and slowed using only the engine. (One small break application from 10-0 mph)

Front wheels (both sides about the same) (36PSI)

Tire tread: 132F

Break disk: 141F

Hub: 165F (Measured where the head of the arrow is in the picture.)

Rear wheels (Both sides about the same)

Tire tread: 132F

Break disk: 115F

Hub: 109F (Measured where the head of the arrow is in the picture.)

I did some in town driving (15 min worth) after the return trip and made a few readings

Outside air temp.: 99F

Front

Tire tread: 150F

Break disk: 170F

Hub: 190-200F* (depending on the side)

*The closer I measured to the 90 deg. bend between the hub and the disk, the hotter the temp reading.

This is the hottest I have ever seen on the hub. Usually it is around 170F.

I did not measure the rear at this point.

The center of the wheel is generating a lot of heat. It is the same on both sides which leads me to believe that either something is wrong on both sides, or everything is operating normally.

In that case, the only thing creating the heat would be the bearings or the brakes. The brake calipers and rotors are cooler than the hub, so it must be the bearings.

If the hub bolt is too tight, could that cause the bearings to get hot? It is just odd that both are about the same temp. I did do the work on the bearings. I did however have a local shop press in the bearings. Is it possible that incorrectly pressing in the bearings could mess them up?

I have a C2

I have an infered temp gun, and we are definitely getting up to 170F. You can not keep your hand on the rims.

I am leaning toward the heat comming either from the bearings or the heat from he radiator. Since both front tires are the same temp, I think it is the radiator.

My break rotors are about 20F or more cooler than the hub area. I am running the recommended tire pressure from the manual.

When I get some time, I will take the rim off and do some more investigation.

I purchased a used 996 with aftermarket OZ Vella Chrome rims a few years ago and have since driven about 20,000 miles. The front rims heat up to about 170-180F after a standard drive (not using brakes). The back rims only heat up to about 120-130F. The heat does not appear to come from the brakes because the center is hotter than the caliper and rotor. I have a small vibration at highway speeds that my wife says only I notice. I replaced both front bearings right after I got the car at 40k miles and both were shot! Both wheels in the front reach approximately the same temp. When jacked up, both wheels seem to spin freely and there are not any odd noises. Is this normal?

I have the same issue. Let me know if you come up with a solution.

I just finished the clutch in my car 3 days ago, and it was quite similar to the boxster post.

Well, it is all done. It has been 5 months and I just got home and fixed the car. The wife only drove it once while i was gone and I came home to a bad clutch, dead battery, and a nail I'm the rear tire. It is going in storage next time.

The clutch issue ended up being the pressure plate welded to the clutch disk. I can not get them apart no matter what I do. I broke multiple screwdrivers prying them apart and even hit it with a 10 lb sledge hammer! The clutch was an after market clutch and had about 30k on it.

If anyone has any questions on how to do the clutch while being jacked up in the garage, I can help. Bleeding the clutch with the peddle was not to bad either! No spungieness!

Thanks for all the help.

Thanks... Sounds like an easy fix!!!

That probably explaines why my headlights have been pointed off in a crazy direction.

I was changing the clutch in my garage (barrels of fun!!!) and I noticed this broken plastic rod. I am not sure what it is. Do you have any idea?

It is located inside of the suspension area of the rear drivers side wheel. The picture is taken from underneath the car laying with my feet facing the exhaust and my head facing the front trunk.

I also attached a clutch picture just because I am proud of myself!

http://www.blackstone-labs.com/

This company checks the oil for EVERYTHING. It is $25 and is the best purchase you could make when purchasing a vehicle of any brand. I do it every time I change my oil to keep track of any trends.

Well, it seems that without an actual leak, it is tough to diagnose a bad master or slave cylinder. Once I get a chance to take it apart I will try the compressed air trick. Thanks for the information.

Here is a link to a picture of the slave cylinder for refrence to JFP in PA's post.

http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=997-116-237-02-M38&catalog_description=Clutch%20Slave%20Cylinder%2C%20Carrera%20%32%2F%34%20%28%31%39%39%39%2D%30%34%29%2C%20Each%20%20%20%20%20%20

Here is a link to the bleader mentioned above.

http://www.motiveproducts.com/

Pressure bleeder it is, thanks.

My clutch went from working perfectly to not working AT ALL. It did happen on the day of the first cold snap of the year. There is no leaking fluid which leads me to believe it is the master, slave, release lever, or pressure plate. I want to know for sure it is not the master or slave cylinder before I break into the clutch.

Is there a way to see if the slave cylinder is working by watching the actuation from under the car?

How do you know if you have a bad clutch master or slave cylinder if it is not leaking and the clutch pedal is not engaging or disengaging the clutch?

Also, can you bleed the clutch with negative pressure at the slave cylinder, or is it necessary to use positive pressure on the reservoir?

What are some of the symptoms of a slave cylinder failure. I was assuming that fluid loss or dripping on the ground around the transmission / clutch would be one of the main indications.

Can the slave cylinder fail without there being a leak?

The same indication should be true with a master slave cylinder except the leaking would be up front and you could perhaps have break issues since they share the same reservoir, right?

I am still learning this particular system on our cars.

Thanks for the pointers. I will check it out when I get home!

Update:

I had a good buddy drive my car home by starting it in 1st gear and then slipping it into 2nd gear while driving. (It was a short drive) The wrecker could not get my lowered car on the flat bed.

It has been 10 days or so, and the wife says that there is not a drop of any fluid under the car and the resevoir is still full.

I am leaning toward a new pressure plate or fork when I get home.

Just to make sure I order all the right parts, is this what I need for the job:

-------------------------------------------------------------------------------------

-Clutch (997-116-013-13-M38 ($284.00))

-Pressure Plate (996-116-027-06-M38 ($334.75))

-Release Lever (AKA Clutch Fork (New modified one) (996-116-712-04 ($31.25))

-Throw Out Bearing (AKA Pilot Bearing, Release Bearing) (996-116-080-04-M38 ($95.75))

-Clutch Guide Tube (996-116-087-01-M100 ($48.25)) (is this replaced every time?)

-Cluth Alignment Took (PEL-TOL-T136 ($8.85))

Technical Serice Bulletin on Clutch Noise

http://www.pelicanpa...s/Grp3-7-00.pdf

996 116 716 02 Ball journal ($44.75)

996 116 741 00 Retaining spring (clip) ($12.00)

996 116 743 00 Sealing ring ($3.00)

000 043 205 10 Optimol MPO (enough to many vehicles) ($45.00) (can you use something else… that is kind of pricy?)

000 043 024 00 Olista Longtime 3EP (enough to do many vehicles) ($21.75)

-------------------------------------------------------------------------------------

The IMS and RMS were replaced at 50,000 mi... the car now has 63,000 mi. The clutch was not replaced at that time.

-Fly Wheel Seal (Does this need replaced with a standard clutch job if you to not take off the fly wheel?)

I do not have any issues with the AOS. Is this something I should replace anyway?

I do not have any issues with the coolant tank… is this something that should be replaced anyway?

This seems to be a good link on how to get the job done!

http://www.pelicanpa...RANS-Clutch.htm

Well, I do have an update…

The brake reservoir is between min and max (the brake fluid is the same system as the clutch fluid)

The clutch still feels stiff… it does not fall toward the floor.

With these new bits of info, do you think that the problem could still be a clutch master or slave cylinder, or do you think it is something else?

How do you test to see if the clutch master or slave cylinder is bad?

There was a cold snap (35F in Northern Florida), and this is the first time the car has been out in the cold weather for any legnth of time.

Thanks for the updates! The Wife is suprisingly car savy and does quite well driving a manual. She called up one of my buddies and he came out and had the same issues. I will double check with her that the brake fluid resevoir is full and that there is no fluid under the front trunk!

I just began my tour in Afghanistan 3 days ago and my wife drove my car to work for the day...

When she came back after the car had been sitting for 12 hours, she went to start the car and it "leaped" forward. (It was in 1st gear) The car did the same thing when it was in reverse except it "leaped" backwards. She had the clutch pressed all the way to the ground. She then tried to put it in neutral, and the car started and idled perfectly.

She is unable to put the car in gear when the car is running.

Any suggestions?

I went with stock from pelicanparts.com. They made a noticable difference!

I did the motor mounts a few weeks ago, and it was SUPER easy. It took longer to jack the car up correctly than it did to replace the motor mounts.

Mine did the same thing when I bought it. I filled her up a year ago and I have not had any issues, and I run the top every day except for the winter.

http://www.emiata.com/996Window.htm

I replaced the window on my 1998 Boxster before I got my 996. The Boxster's window had to be sown in and was a huge pain. The entire top had to be taken off and it took >8 hours total.

The 996 plastic window is zipped in and should take less than 2 hours. The link above offers the window with instructions for $199 + $13 Shipping.

You have not talked about having an aftermarket radio, but my aftermarket radio was making my horn beep when setting the alarm. There is a way around this problem if you have changed out your radio. You just have to place some sort of barrier between the metal of the radio and the left side sensor. This solved my problem.

I used a syringe that I got at ACE hardware and a tube that I attached on the end. Total cost...$3.00. Seemed to work well.