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redxr7
06-13-2009, 12:15 AM
I have an 89 XR7 with 70K on the car. The car is all original and I rarely drive the car. Today I took the car out and parked the car on my driveway that has an incline to it. When I turned the car off and put the car in gear to park the car, the car kind of inched forward a little bit. I also noticed that the car seemed to be slipping in gear while in park with the parking break off. When I put the parking brake on, I had no problems. I rarely drive this car but I was wondering if this sound like the clutch is slipping. I did take the car for a drive to see if it looked like the clutch was slipping and I did not notice a difference or jerking. This just seemed to happen on an inclined hill. Any thoughts related to this and if I will be in need for a new clutch.

XR7 Dave
06-13-2009, 09:47 AM
Your clutch is most definitely not slipping when the car is not running. However, when you say you "put it in park" that makes no sense. Manual transmissions have no "park" selection.

Instead, what you were experiencing is the force of the weight of the car being sufficient to rotate the motor since when not running, the only think stopping the car from rolling away is the compression of the engine. The leverage that the rear wheels have against the motor is increased in the higher gears, and conversely, reverse gear has the least which means that for maximum roll protection the car should always be parked on an incline in reverse gear. Furthermore, there is no set determined parking angle at which the weight of the car will overcome the compression of the engine and begin to move. Therefore it is imperitive that when parking a manual transmission car on an incline, you utilize a working parking brake as well as turn your wheels sharply to prevent the car from being able to roll away indefinitely.

redxr7
06-13-2009, 10:31 AM
Thanks for the response. I actually put the car in first gear and the car started to move forward every min or so. I also tried this in reverse and it seemed to happen in reverse also. I will check it again in reverse to verify and give you an update.

birds4us
06-13-2009, 10:58 AM
That is why there is a "parking" brake in the car. Think about it like this, how do you start a manual transmission car if the starter is inoperarive?

the-big-e
06-13-2009, 11:47 AM
How steep is your driveway....

redxr7
06-13-2009, 06:53 PM
I am an engineer but since I知 not a ASE Certified technician I知 an idiot. The question is a valid question and I do understand the operation of a manual and the parking brake. My goal is to keep the car running and if I see or hear something wrong with the car I fix it. I知 not in to trying to drive a car that I have to push to get the car started or going. If something needs fixed, I fix it. The car is stored during the winters. Last summer I did not notice this problem because I had the brakes and rotors replaced. The spring on one of the rear rotors broke off and I had to have it replaced. Until I had the new spring put on my car did not move forward when parked in my drive way and in gear. The missing spring caused the parking brake to not work completely and I had the car in reverse or first while it is parked. The car is all original and everything works on the car. My goal is to keep the car in working condition and if I need a new clutch I will get a new one. My drive way has a grade of 20% - 30 %. Thanks for responding.

XR7 Dave
06-13-2009, 08:47 PM
It's still not your clutch. If your clutch were not strong enough to hold the car on a grade, then it certainly wouldn't have enough grip to drive the car up there in the first place.

I don't consider that anything is "wrong" at all, but it may be that a drop in engine compression over time has made it "easier" for gravity to turn over the motor.

birds4us
06-13-2009, 09:34 PM
No one said you were an idiot, but if you don't like the advise given, that is your problem. You ask a question over the internet, and then get an answer, but that is not good enough. Diagnosing a car over the internet is not the same as a software issue. If you are so worried about it take it to someone that can put their hands on it and give you the answer that you may or may not like. By the way, engineers don't impress me. I work on the things they think are a good idea all day long.

redxr7
06-14-2009, 02:07 AM
XR7 Dave thanks for answering the question. I did take the car to have it checked and they also said the clutch seemed fine. Probably over reacted.

Birds4us it not that I don稚 like your advice but the approach in the way you gave your advice. More than likely your approach is to make people feel dumb. If I知 wrong about that I apologize. If your approach makes you feel good then great. We ask questions on sccoa because someone more than likely has had the same issue. If I take the car to a dealer or another shop, most of those guys there have never worked on these cars and they may give me an answer to replace the clutch or something else that may not need to be fixed. I do understand that diagnosing the problem over the internet is not the same. I tried to search for similar issues on sccoa prior to asking the question. Many of my questions are answered when I search sccoa. I just did not find anything related to my issue.
You should be lucky to be fixing things right now especially in an economy like this. I知 sure there are dozens of guys that would love to be in your position. As I see it without engineers making mistakes you would probably be fixing nothing. Feel lucky you are employed and fixing things. Remember there are thousands of ways to design things and get them to market. That idea they deliver has a lot of factors involved in the idea. There may have been a better idea and it might have been the idea that you thought of when you were fixing the problem, but due to cost and schedules it was never corrected or implemented. Many times they are forced to deliver an idea that works ok but has a few defects that they can deal with. If they continue to over designed things and correct problems the idea would never get to market and once it did, the cost of the product would be out of reach for the common consumer. I get opinions on how to fix things and most of the time those giving the opinions don稚 understand how the whole process works. If you have a better way then maybe you should become and engineer.

birds4us
06-14-2009, 08:04 AM
First off, I was not trying to make you feel dumb. The internet has a funny way of having no emotion in it's responses, therefore the individual reading them can interpret them in any way that they feel. Second off, maybe you should read some of my former posts to questions and see how my answers come off. Or better yet why don't you ask some of the people I have helped on here, gone to their house, or called them on the phone, My second response was what it was because of my interpretation of your attitude to me, nothing more, nothing less.

redxr7
06-14-2009, 10:20 AM
No hard feeling. All is good. Things can be taken out of context by reading some of these posts. My question was answered. I only wish I there were more guys around here that knew these cars as well as the guys on SCCOA that I could go to. Between me and you I would rather pay one of the guys on SCCOA to fix a problem then one of the local mechanics or dealers. The guys you help are lucky. I do have one issue that will need resolved in due time (right upper control arm and lower ball joint ). Just debating on doing it myself or taking it somewhere. If I had guys around here like you I would rather pay them or you then someone else who does not know the cars. .

birds4us
06-14-2009, 10:31 AM
I have to do the same thing on 3 cars here of my own. My problem is that by the time I am done working on cars all day long I do not feel like working on my own. My best advise is to ask around and find a mechanic that is reputable and has a good customer following. The work you are referring to is not that technical, just time consuming, plus you will most likely need an alignment as well.

redxr7
06-14-2009, 10:51 AM
I know exactly what you are talking about. I know it will probably take a day and an alignement. Since I rarely drive the car I can probably hold off. Im still looking for a good mechanic. Thanks for your help.

Duffy Floyd
06-14-2009, 11:01 AM
We do have members in CO that might be able to help you or suggest places to get your car worked on.

As far as the lower ball joint you would probably be further ahead to replace the entire lower control arm. One problem is finding the correct parts to do the job. The TRW 10771 and 10772 SC specific lower control arms are getting hard to find. I would suggest getting the Ford OEM upper control arms as replacements. Buying the cheap Chinese junk off of eBay is NOT the way to go.

the-big-e
06-14-2009, 07:41 PM
Group hug......:)