Extracting Pressure Plate Bolt from Flywheel

[houserc]

Got an interesting problem.

What is the best way to remove a pressure plate bolt from a flywheel, without removing the transmission?

I was installing a Getrag 5 speed and I had a pressure plate bolt twist off on me. (Last one to install also.) This was the standard Opel Flywheel and pressure plate. The transmission was a pain to install due to aftermarket exhaust headers. So, I'm wondering if it is possible to drill it out from the engine side and then extract it.

Has anybody else had this issue.

Also, recomendations on a replacement, and place, would be greatly appreciated.

Thanks,
Chris

[markandson]

You should be able to drill it and easy-out it, but I would have this BIG question.
Torque wrench? If not then you obviously were putting to much into the tightening of the bolts, so I would question the integrity of the rest of the bolts.
Replace them ALL and use a torque wrench when you do!

[houserc]

I was using a torque wrench. In fact, it was the click kind so I would know when I reached proper toque without watching the dial. The other bolts torqued down fine. This one never did click the wrench.

I am planning on replacing the other bolts, due to this one failing.

Any suggestions on bolts to replace with and where to get them?

Thanks,
Chris

[markandson]

I think they are special thin head bolts aren't they? Best bet would either be OGTS or someone on this site. You might be stuck with used ones, I'm not sure.
Oops- I'm thinking of the flywheel bolts. I think all you need are the same graded bolts as the ones that came out, I might even have some in socket head. What is the grade?

[houserc]

Thanks for the reply.

You are correct that the flywheel bolts are the thin headed kind.

I'm not sure what grade the pressure plate bolts are. I'm currently out of town and will be getting home Friday night. I'm trying to layout my plan of attack for the weekend and next week to get this beast back on the road.

I can't wait to use the 5 speed.

The guy I bought the car from did not install a pilot bearing, which ultimately cost me a couple of gears in my four speed Of course, that was a great selling point to my wife.

[markandson]

I have a motor sitting in my garage with the clutch still on it, I will try to remember to take a look tonight for you.

[GTJIM]

With luck, as you do try to drill the bolt out from the front of the flywheel - ie: the face that is towards the motor (the "back" of the flywheel, I supose!) - the bolt should unscrew itself since the drill will be driving it in the Unscrew direction.

[markandson]

I must be missing something here . The tranny should not be in yet if you sheared off a bolt while installing the clutch.

[houserc]

The release bearing, pressure plate, and clutch plate were all mounted on the input shaft of the new transmission. the transmission was then bolted up to the block. (5 speeds have the bell housing integrated with the transmission.)

After the bell housing was bolted to the block and the transmission input shaft was inserted into the pilot bearing, I rotated the flywheel and pressure plate to start the connection process. (There is an access panel on the lower passenger side that gives great access to the bolts.

This allowed me to install the Getrag with the engine in the car and not have to worry about alligning the clutch plate and pilot bearing. (That and I don't think there was enough room for the top of the bell housing with the pressure plate pre-installed.

Hope that made sense.

[Bill Hoffmann]

I feel your pain. My manifolds had to be removed to install the Getrag because the header's collector flange interferes with the bellhousing. It's no problem with the 4-speed, because you don't have the input shaft to align when you attach the bellhousing.

I don't know if there is enough access to get at the broken cap screw from the front (by removing the sheet metal shield). I don't think you have a straight shot at it from the right side clutch arm hole, either. If you're lucky, you could possibly cut a slot in the broken screw with a dremel, and use a long screwdriver to back it out. You would have to remove the other screws and rotate the pressure plate for clearance first, and probably need a dremel with a flexible shaft extension to have a chance at that maneuver.

In my opinion, the pressure plate to flywheel cap screws should be replaced with new ones every time. The original screws will twist apart, especially if you're using the torque specs from the factory service manual. I have two Haynes manuals, copyrights 1975 and 1986. The early one is in agreement with the FSM, listing a torque of 36 lb-ft. The later one says 15 lb-ft. My Autobooks manual says 32 lb-ft. I use the latter, but only with new high strength cap screws. There is general agreement that 36 lb-ft is too much for that size screw.

New metric cap screws in correct length are commonly available at most hardware stores these days.

Bill

[GTJIM]

The 36 lbs-ft is for the "clutch" bellhousing bolts !!
15 lbs-ft is any amount enough for the "clutch" pressure plate mounting bolts.
Just another little trap laid by Opel in the FSM!

[jeff denton]

Some time ago there was a thread about installing clutches, I gave a tip that I used on my car. We who work on BIG trucks tend to know a little trick that once you see it, you'll never do it the hard way again. In the case of the Opel, a hole cut in the bellhousing gives access to the pressure plate bolts. Too simple. I used about a three inch holesaw. A cover can then be made for the hole, gee, just like on a truck...
I used new bolts and loctited them, checked 'em a couple times during the racing season, they were fine.

[kwilford]

Originally Posted by houserc I was using a torque wrench. In fact, it was the click kind so I would know when I reached proper toque without watching the dial. The other bolts torqued down fine. This one never did click the wrench.

What torque value did you use? The FSM's have a significant error (actually a problem with the writing) and many folks read it to say to torque the pressure plate bolts to 32-36 lbs-ft. But the correct value is 15 lbs-ft. Here is the text of an earlier thread where this was discussed:

Originally Posted by GTJIM The clearest info I can find is in the current Brookland Books "OPEL GT Owners Workshop Manual" which is one of the better manuals still available new. Clearly stated therein : Clutch Housing to Cylinder Block 36 lbs.ft. Gearbox to clutch housing 29 lbs.ft.

Originally Posted by kwilford ...the '72 FSM calls for 32-36 lbs.ft for the "Transmission to Clutch Housing" (page 71-9, bolt tightening specs)

As I stated, the '72, '73 and '74 Genuine Opel Factory Service Manuals clearly state to torque the transmission to bell-housing bolts to 32-36 lbs.ft. Nothing ambiguous about that, after you get over the fact that each of the previous FSM's had a different, and conflicting, value.
Reminds me that the '71, '72, '73 FSM recommended torque values are 36 lbs.ft. for the pressure plate to flywheel bolts (referred to as the "Clutch cover" in the FSM's), which will nicely twist off those poor little grade 8.8 M8 bolts. The '69 FSM gets it right in the text (at 15 lbs.ft.) but still says 36 lbs.ft in the specs.

[soybean]

Jeffs idea is a very good one. I plan on using it on my "Red one", and if the Brown Gt ever has to have the clutch replaced again it will be done as well. My trucks and tractors are done the way Jeff suggested, most came with a cover plate for that exact purpose. Keiths correct about the FSMs being wrong is correct as well. It is 15 lbs.ft. I had almost wrung a bolt off the same way as you did last year as I was reinstalling my clutch. I could feel it starting to twist off, when I remembered what was discussed in the thread that was spoken about, and backed off. Not much help with this response as to getting the broken bolt out, but just my experience with this item. I also used the "Blue Loctite" not the "Red". Jarrell

[houserc]

I also got an email back from OGTS that stated the torque at either 15 or 18 foot pounds. I found the 36 foot pounds spec in the manual. The first bolt torqued down fine. The second is the one that gave me fits.

The Getrag already has the access panel you described cutting. It even comes with a rubber cover to keep the road grim out. It was pretty handy.

Bill, did your collector flange, or down near it, rub up against the bellhousing? Mine does and I'm wondering about the heat transfer that will happen and what harm it might do.

Thanks all for the responses.

Chris

[Bill Hoffmann]

Originally Posted by houserc Bill, did your collector flange, or down near it, rub up against the bellhousing? Mine does and I'm wondering about the heat transfer that will happen and what harm it might do. Chris

The Getrag is set up for either Left Hand or Right Hand Drive, which is why there's a second opening for the clutch arm on the opposite side. There is also a matching flange to accept the clutch cable, and this had to be ground off to make clearance for the header collector on my car. You can sort of see the situation in the attached photo.

[Bill Hoffmann]

I forgot to mention: As you can see in the photo, the exhaust pipe is very close to the rubber cover over the opening, but it hasn't been a problem at all. There is no actual rubbing between the header collector and the bellhousing, but it's very close.