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-   -   Troubleshoot a couple items? (http://forums.pelicanparts.com/porsche-911-technical-forum/96733-troubleshoot-couple-items.html)

bigchillcar 02-03-2003 05:37 AM

Troubleshoot a couple items?
 
Jacked up the rear this weekend to get a look at the condition of my axles. I've got a clunk I can hear if I tap the gas lightly while rolling at slow speed. Felt the axles and can move them back and forth by hand between the cv joints (i.e in and out of the joints direction, I can't rotate them laterally. In 4th gear, I can turn the wheels and transmission through, but there's about a centimeter (couple of degrees) of freeplay before the axles engage the gears...how much should be present? The car's a '74 and don't know if they're original or not...about 80K on the car.

Also, do you know your sunroof motor is having trouble when it doesn't want to close at the end? The back of the sunroof doesn't want to make the climb in the back to seal without assistance. Had no trouble with it beofre my headliner replacement a month ago and it was just warm enough to have open over the weekend. For some reason, they butched the sunroof seal doing the job and I worked the weekend some repairing it for the time being. Any thoughts? Thanks.
Ryan

bigchillcar 02-03-2003 11:42 AM

ker...bump!

Superman 02-03-2003 11:54 AM

All I know about the sunroof mechanism is how to operate the button, so someone else will help you more than I. As far as CVs go, they should slide in and out, that's normal, but they should not rotate. The play that you feel by turning the tires could be elsewhere in the tranny. I think CV evaluation should be done with your hands around the axles. There should be no play whatsoever. The best way to make this judgement would be to remove the axle and try to rotate the joints themselves while the axle is held in a vise (without crushing them, of course). My guess is there is no play in them. Generally, when they go bad, the problem is with the balls' abilities to slide back and forth in their little cages. Klunking like you describe could be a number of things. Suspension and motor mounts come to mind first.

bigchillcar 02-03-2003 12:08 PM

Thanks for the reply superman,
I definitely had my hands around them...had the black hands to prove it (not now thankfully)! Didn't know the 'in and out' was normal...good to know. I felt no lateral play in the axles themselves...in other words they feel snug along that axis. However, the play I felt while turning the tire...the tire will rotate a few degrees before the axles engage the gears in the tranny...I think this is responsible for the 'clunk' I can get the car to make with light gas while rollling...jerking it slightly. It just feels like there's some obvious play somewhere along the drivetrain. Still think it could be mounts or suspension? Watching the engine and the chassis while jacking up the car, it seems the mounts are secure.
Ryan

jester911 02-03-2003 12:28 PM

I think what you may have with the sunroof is the problem I had.
There is a little device that ramps up on the the deflector as it closes. The thing is only plastic I think. As the panel closes this part slides against the little arm on each side and pushes it down as the sunroof closes.


On my car the plastic ramp broke and so the thing would bind and not push down the deflector.


Believe it or not I fixed this with one of those furniture sliders that you can buy at hardware etc.

The slider I used was about 1 1/4" wide and 3" long. I cut it down it half. It had that self-stick on the other side. With the roof open I eased up on the panel and stuck it to the underside making sure to line up with the deflector arm.


I have had in it about 2 years now and not a single problem since.

Hope this helps:D

Superman 02-03-2003 02:59 PM

I still do not think your CV's have axial play, and neither do you. In and out is normal. Necessary, since the suspension moves.

Overall axial play in the wheels is not something that would get my attention. That seems to always be there, on all cars. In fact, my wheels have some axial play WITH THE E-BRAKE ON!!!! I've been meaning to ask about that, but it seems to be no problem and it seems to me I have asked about it and folks said it is not unusual.

Anyway, I guess I would suggest you not get "wrapped around the axle" so to speak on the axial play. The problem you want to solve is a clunk, and I have my doubts about a CV or tranny cause. I still think that stuff like motor mounts is where I would be suspicious. Or spring plate bushings or something like that. Actually, I think my spring plate bushings are worn, and I get an occasional clunk, but not from acceleration or deceleration. Rather, from going over railroad tracks and the like.

Anyway, that's my input. If it's just a clunk, and you've checked all the fasteners to make sure they don't back out while you're driving, I'd continue to just gather info and consider stuff. Perhaps some day it will be on a lift and the problem will get discussed and sorted.

BTW, I lift the rear of my car by placing the jack under the seam just behind the sump plate. When I lower the car back down, it is easy to see that my engine moves an inch or so, relative to the chassis, when that pressure is unloaded. Motor mounts are common causes of clunks.

stomachmonkey 02-03-2003 05:36 PM

I've got a reproducable clunk. Also know I need motor mounts. Also have a drivers seat that has a bit of fore/aft slack in the slider and sometimes it makes a sound just like the motor mounts but not quite as hollow.


Just make a list and go after the stuff 1 at a time.

Scott

bigchillcar 02-03-2003 06:55 PM

Jester,
Thanks for the lead...I'll check that out on mine. Sounds like another guy with a penchant for 'invention'...I applaud ingenuity!
Superman,
Odd...I'm a starving writer (formerly a pilot in a formerly employed life) and a character in my fiction novel (350 pages to date) has the nickname 'superman'...kind of funny to be addressing you as same! Anyway, I guess I should ask the question...under the condition of jacked-up off the ground, in fourth gear, when you go to turn the wheel...should the axles simultaneously turn the tranny at the same instant? Or is there supposed to be some play...as in my case of several degrees...or about a centimeter measured circumferentially? Really wanting to eliminate drivetrain possibilities...
Ryan

Jason 74 911 03-27-2003 11:47 AM

74 Sunroof
 
Hi Ryan,

Did you ever resolve your sunroof issue?

I had/have a similar issue with my 74 for which I have been unable to resolve, broken cable ends. It appears the 74's have the sunroof transmission in the front and different guides and cables than all the other years. Therefore, the commonly available cables can not be modified to work in the 74's. I have temporarily repaired my cable ends with JB Weld and stainless steel but would like to fix them correctly.

I would like to hear from someone with a similar car and situation so I can verify my findings are correct.

Thanks for your help.

Jason 74 911

thabaer 03-27-2003 12:29 PM

I had a similar sound many moons ago, it turned out to be one of the bolts at the ends of the support plate across the rear of the engine.

A little gas and the torque would lift up the end of the plate and thunk it into the mount.


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