Throw out bearing

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Throw out bearing

Unread post by naderwaswrong » Sat Oct 07, 2017 8:30 pm

Need to replace the throw out and pilot bearing on my 63 (66 engine). Have done this before on conventional setups where I could just move the trans back for access, but unsure of the proper way on a Corvair. Do I drop the entire package or just remove the trans? Looks like either would be just as easy (or not).
Also, I found the 66 engine is a code RD which in the Motors Manual at least says it is a HPE or high performance engine. It has 2 carbs; I would think a HPE would have 4 carbs. Is this a frankenvair? Thanks.

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Re: Throw out bearing

Unread post by bbodie52 » Sat Oct 07, 2017 10:08 pm

:chevy: Suffix code "RD" on the engine serial number decodes as a 1965-1967 110 hp 164 CI engine (2 carburetors) configured for a Manual Transmission in a Corvair 500 or Monza, according to the attached CORSA Corvair Technical Guide 1+2 - Corvair Code Numbers.

The first time I ever removed a Corvair engine by itself — leaving the transaxle in the car — was actually the first time ever removed the Corvair engine at all! I was 16 years old in 1969 and spending my high school summer vacation learning to overhaul my first Corvair engine. The car was a 1963 Corvair 500 coupe that was fitted with an automatic transmission. I found it was very awkward and difficult to separate the engine from the transaxle while balancing the engine on the floor jack. Carefully maneuvering the engine bell housing around the torque converter was not an easy job! From that point on I never attempted removing the Corvair engine by itself while leaving the transaxle in the car. I'm assuming it would be even more difficult with a manual transmission car!

You will discover that detaching the entire powertrain (engine plus transaxle) from the car is actually easier than trying to separate the two with the transaxle still hanging in the car.

The attached Corvair and Corvair 95 Power Train Removal & Installation guide should be helpful as a supplement to the shop manual when removing the powertrain from the car. With the car elevated and level on four jack stands, lowering the transaxle and engine using a standard hydraulic floor jack is something of a balancing act. For your information I have attached a couple of documents that describe building and using an engine and transaxle cradle that describes an alternative approach. But I have always managed to get the job done without dropping the powertrain using a sheet of three-quarter inch plywood to protect the engine underside and isolate it from the small lifting platform on a standard service station type hydraulic floor jack. Page 10 of the attached Corvair and Corvair 95 Power Train Removal & Installation guide has a photograph that should help you to visualize the balance point (front to back) of the combined engine and transaxle. Using the oil pan drain plug location is useful for identifying the left to right balance point. After you have pulled the axles from the differential and disconnected everything around the perimeter of the transaxle and engine you will be ready to lower the powertrain from the car. With the floor jack and plywood carefully positioned and supporting the weight of the powertrain, you can remove the nut from the rear engine mount and the two nuts from the left and right front engine mount. You may find it useful to have one or two assistants can help you to lower the powertrain for the first time. As you slowly lower the jack you should see the powertrain coming down evenly from all three mounting points. If the engine and transaxle are too heavy at one end or the other, the front or rear may start to come down before the other end does. If this occurs you can raise the powertrain back up and temporarily install the three nuts so that you can reposition the floor jack and try again. After a few tries you should find the entire assembly will be coming off of the engine mounting points evenly and level. Carefully finding the correct balance point helps to prevent the heavy powertrain from tipping and sliding off of the jack (not a good thing). In a manual transmission car, the shift linkage that protrudes from the car tunnel tends to get hung up on the transmission mount bracket as you lower the powertrain. You will have to watch out for this interference problem and carefully maneuver the heavy powertrain around the shift linkage if it gets in the way as you lower the powertrain. You can then lower the powertrain all the way down and wheel it out from under the car on the jack.

When repairing your clutch, I would caution you to be careful when separating the engine from the transaxle.

:wrench: The problem with the manual transaxle is that the long input shaft (23-24 inches) tends to remain embedded in the pilot bushing and clutch disc, while the other (smaller) end of the splined shaft pulls free from the transmission. As the two heavy components separate, any misalignment that is permitted risks leverage being applied by the input shaft against the throwout bearing shaft, which can fracture this machined casting. Replacing a damaged throwout bearing shaft requires dismantling the differential.

Even if you remove the powertrain as an assembly, use caution when separating the heavy transaxle from the engine. If the input shaft remains embedded in the clutch, you must pull the transaxle straight back about 24 inches until the other end clears the transaxle. If you have an assistant, the assistant may be able to reach between the differential face and the bell housing to grab the input shaft and pull it free from the clutch assembly — reducing the risk of damaging the input shaft, clutch disc, or throwout bearing shaft.


With the engine and transaxle separated, be sure to inspect the throwout bearing shaft completely for cracks or fractures. The input shaft seal should be replaced when doing a clutch job, to ensure that no gear lube will leak onto the clutch assembly during operation. Also, when prying the input shaft retaining ring and seal out, be careful not to apply leverage against the end of the throwout bearing shaft, as excess leverage with a screwdriver or similar tool could conceivably cause a crack to form on the throwout bearing shaft.

The first time I ever separated a manual transaxle from a Corvair engine, well, I didn't exactly approach it correctly. I had the engine resting upon some stacks of two by fours. I removed the starter, and I unbolted the transaxle from the engine. Being young (17), overconfident, and healthy I decided that I could simply lift the heavy transaxle away from the engine and set it on the garage floor! If you can picture this: I straddled the transaxle and bent over and cupped my hands under it — cradling all of its weight in my hands as I was completely bent over and expecting to walk away with this heavy transaxle between my legs! That was when I discovered the issue with the long input shaft that inevitably remains in the clutch disc. I was confronted with this very awkward moment (working alone, of course) when I had to try to figure out how to keep the alignment between the face of the differential and the clutch housing while balancing all of that weight in my hands, between my legs. I managed to take a whole series of very small backward steps while desperately trying to maintain the necessary alignment so that I would not damage the input shaft. That input shaft seem soooooo long! But the small splined end finally came out of the differential and I was able to set the transaxle on the floor. I think I simply went into the house after that to lay down for awhile.
:whoa: :zzzz:

With the clutch assembly exposed I would suggest performing a complete inspection of the clutch components to ensure that they are in good condition. You should also check for any signs of oil leaks from the crankshaft main seal and from the differential. If there is any sign of oil accumulation on the clutch assembly you should determine the source of the oil leak and repair it. The clutch disc should be inspected for excessive wear and the flywheel and pressure plate friction surfaces should be inspected for excessive wear or burn marks. The starter ring gear that is welded to the pressure plate should also be inspected to ensure that it is in good condition and that none of the welds are fractured or broken. Be sure to follow the shop manual procedures for disassembly, inspection, and reassembly of your clutch.

The link below will provide you with a list of useful websites that are Corvair-related. Some of the links will lead you to an extensive technical library that will allow you to download shop manuals and other technical references in Adobe Reader format at no cost. There is also a link that will help you to locate nearby CORSA (Corvair Society of America) club chapters. While the Corvair Forum can be very helpful as you work on your Corvair, having local friends and contacts in your region who are knowledgeable about the Corvair can also be very helpful. These family-friendly CORSA chapters often offer picnics, group scenic drives, technical training and assistance, car shows, and competition events that can greatly enhance your enjoyment of Corvair ownership. You will also find a list of essential Corvair parts suppliers. Clark's Corvair Parts is the biggest and oldest Corvair supplier in the world. You will find a link that can provide you with a series of videos that amount to a tour of the Clark's Corvair Parts facilities. I think you will be amazed at the quality of the reproduction components they offer — particularly the interior carpeting and re-upholstery items. Parts suppliers such as this truly make our Corvair hobby possible.

Common and Useful Corvair Websites

:link: viewtopic.php?f=225&t=6007
CORSA Corvair Technical Guide 1+2 - Corvair Code Numbers.PDF
CORSA Corvair Technical Guide 1+2 - Corvair Code Numbers
(1.25 MiB) Downloaded 6 times
(3.76 MiB) Downloaded 11 times
Corvair and Corvair 95 Power Train Removal & Installation.pdf
Corvair and Corvair 95 Power Train Removal & Installation
(3.35 MiB) Downloaded 8 times
ENGINE CART - Al Lacki's Engine Cart Isometric Drawing & Assembly Notes.pdf
ENGINE CART - Al Lacki's Engine Cart Isometric Drawing & Assembly Notes
(122.34 KiB) Downloaded 8 times
(812.77 KiB) Downloaded 11 times
1961 Chevrolet Corvair Shop Manual - Section 6 - Power Train.pdf
1961 Chevrolet Corvair Shop Manual - Section 6 - Power Train
(704.51 KiB) Downloaded 4 times
1962-1963 Supplement - Chevrolet Corvair Shop Manual - Section 6 - Power Train.pdf
1962-1963 Supplement - Chevrolet Corvair Shop Manual - Section 6 - Power Train
(34.01 KiB) Downloaded 7 times
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

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Re: Throw out bearing

Unread post by terribleted » Sat Oct 07, 2017 10:28 pm

I agree with Brad for sure on full powertrain removal for this task, particularly on an early model. You will need to disconnect all linkages anyway, and pull the axles out of the side of the differential in order to remove only the engine. Once you have all the stuff out of the way for engine removal all that remains to do complete powertrain removal is disconnecting the trans crossmember from its mounts. In-mating and re-mating the transaxle and engine is certainly easier with the powerpack out of the car. Once you have everything apart pay very close attention to the clutch and flywheel parts. Very few (if any) old Corvair flywheels are really any good any more. The rivets loosen and can cause issues with vibration and poor starter to ring gear interface. If the flywheel is not rebuilt (bolted generally) it should be replaced. ( a good stock Corvair flywheel removed from the crank should at least slightly ring when struck with a hammer...if it goes thunk then the rivets are at least a little loose) You also need to pay close attention to which clutch and flywheel parts are actually on the car. There are early and late versions of flywheel, pressure plate, and throwout bearing. Either setup can be used but the parts must match early or late. Unless it has been changed recently you should also change the front crankshaft seal in the bellhousing while it is apart (requires new crank seal, bellhousing gasket, and oil pan gasket), it sucks to re-remove the powertrain to change the crank seal. Look very closely at the seal mating spot on the crankshaft as well. If it is worn even a new seal may leak ruining a new clutch. Clark's Corvair Parts sells a front crank seal spacer that moves the seal just a little putting its contact with the crank in a different spot. This spacer works great, I highly recommend it if there is any question in this area. I do not recommend using a viton crank seal, the regular material is adequate and people have said that the viton ones leak.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.

Located in Snellville, Georgia

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Re: Throw out bearing

Unread post by naderwaswrong » Sun Oct 08, 2017 5:52 am

Thanks for the info, sounds like a workout. I should have mentioned that I'll be doing this on a lift and lowering the engine onto a sturdy table or cart. (Pictured. Ignore the Buick!) :tu:

Went over all the PDF's, very informative. I especially like the cradle-stand and will construct one to keep alignment. It looks like I can remove just the bellhousing where it meets the engine and not the end unit and I see the long shaft in the pictures. Don't get me wrong, I'm a capable mechanic, just unfamiliar with this setup. Smart enough to know not to rip willy-nilly into something new. :nono: The info you supplied will help. Thanks.
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