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Hi folks. I have a '67 122S coupe with a B20B (out of a '71) and an automatic. So I'm likely going to purchase the bits for a manual conversion to get the terrible BW35 out of my car. I found a guy who can sell me: two M40s, driveshaft, shifter, pedals, clutch and pressure plate, bellhousing, clutch master and slave. I do have a couple questions:
1. I could take the clutch and pressure plate from the donor car - should I also take the flywheel? Or do I want to plan on getting my old flywheel machined and use a new clutch? Basically, what clutch/flywheel parts should I get from where?
2. When I have pull the BW35 off my car, is there anything I should do "while I'm in there?" Is this a good time to do the rear main seal? (I don't think mine leaks but I want to do as much preventative maintenance as possible while major parts are off the car.)
3. The donor car comes with two M40s. Is there a way to "bench test" the transmissions to see which one is a better candidate to install? I would prefer not to rebuild one if I don't have to. Can I pull off the cover and visually inspect the gears? What should I look for?
4. I'll be swapping driveshafts to the correct M40 one. What should I be looking at on the driveshaft? Are there seals or bushings that might need to be replaced? How do I check the condition of the U-joint?
5. This is coming off a 122 that was in a front end collision, so I think I have free reign to take any bits that could be useful for the swap. Is there anything I didn't list above that's a "must-have" to make the swap easier.
6. Should I be taking the M40's crossmember, or will my automatic one be adaptable if I move it forward?
That's all I can think of right now. If I have more questions I'll ask them. Thanks!
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OK - first real question. I appear to have a driveshaft center bearing mismatch. Picture at the link below:
http://s1265.photobucket.com/albums/jj520/akierstein/?action=view¤t=WP_000942.jpg
The one I just pulled off my car, the shorter BW35 driveshaft, is on the left. Note the rubber donut thing that supports the center bearing, and the easily removeable rear driveshaft segment - it just pulled right out. The manual driveshaft that came off the donor car (I believe a '64) is on the right, and it had the kind of center driveshaft support that has two pins. I was planning on using this when I put in the M40.
First question: can I disassemble the driveshaft and put the rubber donut style center bearing on the longer driveshaft?
If not, can I swap out the part on my car so as to use the longer driveshaft as is?
Lastly, if neither of those are an option, do I just get my old shaft lengthened?
PS - my rubber driveshaft donut situation on the BW35 driveshaft is a bit torn. Are replacements available?
Thanks!
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I've got no input regarding the interchangability of driveshaft supports.
Yes, driveshaft bearing donuts (and the donuts) are available from most of the usual sources (iRoll, IPD, Eric Hamlet, etc). Getting that nut off is a pain in the rear, I really struggled with mine.
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Quick update - parts acquired from the donor car. It was a long but educational process getting all the bits out. The driveshaft took some headscratching but then we figured out how to pull it through. And convincing the M40 to divorce itself from the engine took a little thought and a lot of creative jacking. And yes, the pedal pivot bolt barely came out. That was fun.
Anyways, I'm gathering all the bits needed now. Definitely getting the rear main seal, pilot and throwout bearings, and an alignment tool.
But here's another question - will I need to get new flywheel and clutch bolts?
I did save all the hardware I pulled off and it all looks to be in perfect shape, but I wanna be sure. They aren't torque-to-yield or anything are they?
Thanks for the help.
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The clutch bolts are nothing special -- you can reuse the old ones if they are in good shape, or replace with Grade 5 from the hardware store.
The flywheel bolts are special, and you'll want to use the old ones if they are the same for a flex plate as for a flywheel. The flex plate ones may or may not be shorter. They should have an unthreaded shoulder to locate the flywheel accurately. Do NOT replace these with generic bolts, not even Grade 8.
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You will need to get the flywheel. An automatic doesn't have a flywheel. Definitely get the flywheel resurfaced unless you feel like gambling.
I would certainly get a new clutch unless, again, you feel like gambling.
Replace the rear main. It's cheap and easy to get to while doing this job.
The U-joints should have no play in them at all, nor should they bind
A major issue that you have not asked about is the size of the transmission tunnel. The transmission tunnel on a 122 automatic is larger than that of a 122 with a manual transmission. Because of this, the accelerator pedal is positioned farther to the left than in a manual car. The pedal cluster for the manual will not simply bolt in like it would on a 140 or a 240. I've never done this conversion, so I can't tell you what all is involved, but it does involve some significant modification. I'm sure someone else on here can tell you more about that.
--
1966 122s, 1968 142s, 1969 144s, 1979 245dl, 1989 244gl
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Thanks for the response! I'll order a rear main seal and a clutch, that sounds reasonable. And I'll eyeball the u-joints.
As for the pedals, my understanding in talking with other folks and reading through some of the swap threads is that the entire pedal pivot and pedal assembly from the manual car will bolt in. It will leave the accelerator with some degree of clearance. I don't have particularly large feet or drive in boots, so since other folks seem to manage it after the swap without modifying the tunnel, I will give it a try.
I will tell ya this - if it is unbearable with my normal-sized feet, I will document a modification and share it with the 'board. I'm not averse to modifying my tunnel to accommodate it if necessary.
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I wear size 10.5 or 11. I don't have any issues with my manual-swapped automatic unless I'm wearing something really wide like Chaco sandals. I'm planning on modifying the pedals (not the tunnel) to get a bit more clearance, but it's been far down the priority list as the legroom is less of a nuisance than I anticipated.
The manual pedals will bolt right in. You just need to move the brake MC over one space, as it's mounted where the clutch MC needs to mount.
Getting the pivot bolt in and out is a pain. There is juuuuuuust enough clearance.
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I "took my chances" when I put the M41 transmission in my 122. I used the clutch from the donor car. It appeared to have a lot of life left on it. I used the flywheel from the donor car without resurfacing it. I didn't replace the rear main because it wasn't leaking. I was being cheap. Now, the clutch judders a lot and the rear main leaks. Lesson learned.
--
1966 122s, 1968 142s, 1969 144s, 1979 245dl, 1989 244gl
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Bummer that happened to you, but good lesson nonetheless. I'll buy the rear main seal for sure. Do you know if I should plan on ordering both a pilot and throwout bearing at the same time? I'm not sure if those are both normally replaced when doing a clutch job (which is basically what I'll be doing during the swap).
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The throwout bearing is usually included with the clutch kit. Pilot bearings are often separate. Again, a cheap part. Might as well do it. It would also be a good idea to get an alignment tool to get the clutch disc properly centered. When I ordered the clutch kit for my Volkswagen the alignment tool was included. When I ordered the kit for my 240 there was not one included.
--
1966 122s, 1968 142s, 1969 144s, 1979 245dl, 1989 244gl
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The pilot bearing should defintely be changed. One thing I'd suggest regarding the rear crankshaft seal--based on my own experience--if the car is going to be used often there's nothing wrong with the original felt seal. If it will be sitting for long periods I'd look to upgrade the seal housing to one from a B21/23/230 (or rarer '75 B20F or B30). I found the seal in my '69 144 dried, shrank and split after having been sitting for a long while. If you use one from a B21/23/230 be sure to take the two screws that hold the pan on (metric threads in the housing). -- Dave
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