Won’t shift into 1st or Reverse

[JimSuke]

I am the recently new owners of a 1968 912, modified to be a 1974 RSR clone, with a 3.0 SC motor and 915 transmission. The motor, clutch and transmission are supposed to be fresh 800 miles ago.

I just got the car on the road today and had it out 2 times with no issues. The 3rd time I got about 5 blocks from the house and it wouldn’t go into 3rd after pushing it a bit. I coasted to a stop and then discovered it wouldn’t go into 1st or reverse but just grind….ouch. I finally started it in 2nd and limped home.

I’m definitely getting clutch drag. I checked the clutch adjustment and it was tighter than spec so this should not be the cause. I adjusted it to the specified gaps but no change. I went to the extreme adjustment possible with the cable and adjuster bolt to the throw arm and still no improvement. I got out the ruler and with my wife’s help measured a 25mm travel of the clutch cable and 13mm of the throw arm (this was achieved with maximum pedal movement).

I checked the tranny fluid level and it’s OK.

I’ve read the many postings with common problems but am hoping for advice to get me on the right track. From what I’ve read, my problem could be a release bearing operating fork beginning to break. This sounds like a lot of work.

I’m new to the 911 world and help on this would be greatly appreciated.
Cheers,

Jim

[Oh Haha]

Darn fine first post, my new friend!!

You described the issue, what you have already done, and used the search function.

Welcome aboard!!!!



Did the clutch pedal action change at all when the problem first occurred?

it sounds like you have pretty much covered the cable and adjustment but I think you need to check the linkage coupler between the rear seats. it may have moved and needs to adjusted again.(The 1st/reverse issue is a clue, I believe, because they are at the opposite ends of the shift pattern.

Try doing that adjustment before going further. Your wife can help with that task as well.

if that checks out ok then I would remove the shift fork cover plate and see if the fork attaching bolts have worked loose.

Post your finding here and we'll try our best to get you back on the road.







Oh, you need to post some pics of what sounds like a pretty sweet 911.

[JimSuke]

Oh Ha Ha,

Thanks for the response!

I’ll check the linkage coupler but I replaced the stock one for a Wevo unit…should be good.

Pedal action didn’t seem to change.

I’ll drain the fluid and check the shift fork but really think this is a clutch issue.

I forgot to mention that when stuck at the side of the road and starting in 2nd, the starter had a hard time because the car was trying to move under starter power with the clutch pedal fully pressed.

Photo attached

Thanks again,

[Flieger]

I am guessing a throwout bearing release fork. I assume you inspected the pedals for worn bushings?

[JimSuke]

Flieger,

The pedal bushings are good. How can I check if it’s the throwout bearing release fork?

What involved in fixing it?

Many thanks

[Flieger]

Well, if you can get an endoscopic camera into the clutch inspection window maybe?

The clutch should keep getting worse and worse if it is the problem.

[masterdave]

I had a similar issue except with 2nd and 4th and reverse, turned out that the joint where the shifter meet the rod that connects it to the trans, had failed. If you take the shifter base off you will see the cup joint where it meets the rod, my rod had split down the side and the whole joint had fallen apart. This prevented the shifter from pulling the rod forward. It was not a bad fix, new rod was around 75$ took some interesting maneuvering to get it out of the E-Brake hole but over can be done in 6 hours no problem.

Also check your shifter bushings, mine were all worn out, it did not cause the issue but it defiantly added to it. When i was in there changing the shaft i put all new ones in and now it shifts like new.

Best
Dave

[Grady Clay]

Jim,
First, welcome to the Forum
I agree – excellent first post.
Very nice ‘second-life’ for a ’68 912.

Good ideas all.

I’ll speculate on another possibility:
There is a rubber-centered clutch disc that has disintegrated.
This should be easy to confirm or eliminate by looking for rubber shards.
These usually appear on top of the transmission having come out the top holes and in the little drain opening in the bottom of the bell housing.

I think the most likely culprit is the clutch TO bearing fork breaking.

Best,
Grady

[rwest]

Hi,

Also check the roll pin holding the clutch pedal to the pedal cluster; mine had sheared once and the pedal then moved, but not the shaft.

-Rutager

[CT944]

Go back to square 1 and re-adjust the shifter and coupler.

Make sure transmission is in 1st gear, loosen shift rod from coupler, hold shifter all the way up and to the left - 1st gear, then re-tighten the shift coupler.

If you installed the Wevo coupler, perhaps it was not tight enough and went out of adjustment. That, in my opinion, is the best place to start.

[JimSuke]

To All,

Thanks a bunch for all the replies.

It looks like Grady Clay is right with his speculation. Once I got the car home I ran the car in the garage, trying to sort this mess out. I now have rubber shards all over the floor under the tranny. I didn’t see any at the bell housing drain hole and can’t really see above the tranny, but, unless there’s another possible source of rubber shrapnel, it looks like it’s the rubber-centered clutch disc.

If the TO bearing fork is what damaged this disc, could the root cause be that the previous owner adjusted the clutch pedal for too much throw and breaking the TO bearing fork? Or is it just age? The tranny and clutch were supposed to be “fresh”.
I read that the way to go is with a spring centered disk instead.

Could someone please roughly outline the procedure and parts required to fix this. I’m going to do this myself. I’ve never worked on a Porsche but am mechanically inclined and have no reservations about tackling this. A knowledge base such as this forum makes it so much easier that being on your own!

I will look into the easier fixes before I start taking things apart but think the centering ring is the most likely issue.

Thanks again for all the help!

[Flieger]

Funny, I never thought of the rubber clutch because I was thinking of an early car, modified to an RSR. But it does have an SC powertrain.

[Oh Haha]

Can you contact the PO or look at work invoices to find out how old the clutch is and if it IS rubber centered?

Replacing the clutch is not difficult but I would recommend pulling the engine and gearbox as a unit and then separating them once on the floor.

Get yourself a Sachs PowerClutch(from Pelican of course) and be sure to inspect the flywheel for scoring and have it surfaced or replace it with new.



You'll fit in around here, that's for sure. I dig your "screw it, I'll just jump in and fix it myself" attitude.

Sweet looking 911, BTW.

If I was closer I'd lend a hand.

[911Tfan]

What I have to say to you, seriously form my wallet, make sure there is no issues with the cable, ends, adjustment, slack, etc... its critical. I read all the books but I didn't get it. If all is well just a slight wear or cable adjustment will give a non expert to have all kinds of worries like worn synchros, etc... i read the manual and it gives a spec. My mechanic did it by guesstimation an it was perfect (prolly a turn)

[911Tfan]

Yhe diffeence is amazing. At one adjustment it seems to not go in any gear and when it's right, smooth as silk. definatley explore this possibility to the maximum extent before teardown. I am a budget road racer.

[JimSuke]

Well, I yanked the motor and transmission today and found the rubber centered clutch plate pretty much finished. Looks like Grady Clay was on the money. I’m not an expert but this doesn’t look like a clutch and transmission that were fresh 800 miles ago as advertised by the PO. Not impressed. Thought by speaking with someone over the phone, who claims and seemed to be reputable that a level of trust could be established. Guess not. Lesson learned and will not do another eBay deal of this magnitude again…I’ve had over 75 buys on eBay, first time burned.

From the looks of things I’ll need to replace the entire clutch and flywheel. I’m repacking the CV joints and replacing the boot while I’m at it. I’m a little worried about the tranny. It shifted OK but I’m wondering if there anything I should look at while it’s out of the car.

Any advice is again appreciated.

[Oh Haha]

Nasty. Too bad you couldn't get some $$$ for the repair fro the PO.



You are on the right track with the repair but you need to get that flywheel resurfaced or get a new one.

As well, you should inspect the rear main seal while you have the engine out. Post pics and we can give you an opinion.

I found the Sachs PowerClutch kit to be a good street setup. Pedal pressue will remain about the same but you get a bit more clamping force.

[Grady Clay]

Jim,

Sorry about getting the ‘burned’ clutch (or ‘burned’ with the clutch).

Here is a thread about CV joints you should study:
Reconstructing Constant Velocity (CV) Joints
While very long, it has a wealth of info and can help prevent issues from arising.

How are the axles/CV joints adapted to the SWB stub axles?
What CV joints? (CV diameter and number & size of bolts.)




I would drain the transmission (remove fill plug first) and inspect the magnetic drain plug.
Note the condition of the oil.
Strain for any debris.
You can remove the shift plate from the bottom and visually inspect inside.
(You will need a new gasket.)




With the engine out, you can perform a cylinder leak test.
This will give you some quantified info about condition.
Post images of the spark plug business ends (with cylinder #).

I would remove the valve covers and inspect for broken head studs and valve clearance (don’t adjust the valves yet and don't 're-torque' the head nuts - just check).
(You will need a valve cover gasket set with hardware.)

Does your engine have a sump plate (probably not)?
If so, inspect the sump screen.
If not, at least inspect the magnetic drain plug.



More pictures please.

Best,
Grady

[dentist90]

Originally Posted by JimSuke

. The motor, clutch and transmission are supposed to be fresh 800 miles ago.
Jim

Hmmm... I hope the mechanic paid more attention to the inside of the tranny than the outside!
It will be interesting to see the condition of the tranny oil. I wouldn't be surprised if even that weren't 'fresh'.

Oh well, by the time you get all this sorted out you will have bonded with your new car and have a much better ride for the effort!

PS: did the PO provide any receipts for the clutch work supposedly done? (re: warranty) I don't think anyone installs the rubber clutches anymore, outside the concours people.

[JimSuke]

Again, thanks for all the help. I really appreciate it.

I didn’t have a lot of time to spend on the car today so I just tackled getting the CV joints apart and somewhat cleaned up. A parts washer would be nice….many, many paper towels. Again I’m scratching the old noggin with what I’ve found. Have a look at the pictures below. For the inside right CV, instead of having a clip, someone drilled and tapped the axle for a bolt and washer to hold on the CV rather than the clip. Notice the amount slop with this. For some reason the CV won’t go on the axle far enough to install a clip. Obviously a mismatch between axle and CV. On the other side they cut an extra groove into the axle for the clip (see picture)

The CV joints are 100mm dia with 6 8mm bolts each. The axles are 412mm long

The questions that come to mind are:

1. Is this a mixture of parts due to this being a transplanted SC powertrain into a 912?
2. Should I replace the axle with the bolt? I can see this letting loose in the worst time and place possible.
3. How do I tell if the CV joints are worn?