Slipping clutch...

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acarlson
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Slipping clutch...

Post by acarlson »

Well, I finally got my '65 Corsa running and street-worthy so I decided it was time for a test drive. Only went 3 miles or so. The car ran and shifted great but... I noticed that a hard acceleration would run up the RPM's but not the MPH. I assume that's a slipping clutch problem - not sure what else it could be.

So, assuming it is a clutch problem, I'm looking at pulling the drivetrain and engine out in order to fix it. My question is, for those who have been here before: "What else should I replace or at least inspect while I have the transmission and transaxle out on my workbench"?

Alec
Alec Carlson
Dahlonega, GA
1965 Regal Red Corsa 4 Speed Turbo Convertible
Restoration "In Progress"...
Scott V
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Joined: Wed Jun 30, 2010 2:31 am

Re: Slipping clutch...

Post by Scott V »

your clutch maybe adjusted too tight. before pulling the drivetrain......follow the shop manual & adjust your clutch.

if you pull the drivetrain replace:
- pilot bushing
- t/o bearing
- input shaft seal
- check the condition of the split ring/washer in front of the input shaft seal.
- bell house seal
- bell house gasket
- oil pan gasket
- clutch disk
- make sure your pressure plate is good.
- make sure your flywheel is good. the factory flywheel had cold rivets holding it together. the rivets get loose & the flywheel rattles. a good rebuilt flywheel will be bolted or hot riveted.
- check your input shaft. make sure its not bent or worn on the bushing end.

- good idea to have the flywheel & pressure plate balanced.

other stuff......you can do it later......but easier to replace w/the engine & transaxle out

- check your trans mounts.
-check your engine mount.
- check your lower cntl arm bushings.

-Scott V.
Jerry Whitt
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Re: Slipping clutch...

Post by Jerry Whitt »

There are two ways to do this job.
1. Pull the engine, leaving the trans and differential assembly in the car.

2. Pull the engine, trans and differential all at the same time.

If you suspect other items, as Scott mentioned, pull both.

Harbor Freight has a lift table that works very well. Have used it many many times and will hold engine and trans assembly.

Good luck, hope there aren't too many other items.
Jerry Whitt
ASE CERTIFIED MASTER TECHNICIAN
Retired
Hemet, Callifornia
65 Monza, purchased new
65 Corsa convertible
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acarlson
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Re: Slipping clutch...

Post by acarlson »

Scott V - Thanks, I will check the clutch linkage first (now why didn't I think of that ?) :banghead:

Jerry - great suggestion on the table lift. I'll look into that.

Alec
Alec Carlson
Dahlonega, GA
1965 Regal Red Corsa 4 Speed Turbo Convertible
Restoration "In Progress"...
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bbodie52
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Re: Slipping clutch...

Post by bbodie52 »

:chevy: See "Clutch Linkage Adjustment" on page 7-2...
1965 Corvair Chassis Shop Manual - SECTION 7 - CLUTCH AND CONTROLS.pdf
1965 Corvair Chassis Shop Manual - SECTION 7 - CLUTCH AND CONTROLS
(4.83 MiB) Downloaded 37 times
CLUTCH LINKAGE ADJUSTMENT
:link: viewtopic.php?f=225&t=5032
Image

Should you find that the clutch cable is binding and not releasing fully, or is showing signs of wear, replacing the clutch cable and/or servicing the pulleys may be in order. This supplemental guide is for a 1964 (EM) Corvair, but the procedure is similar on a 1965 and later model...
Replacing a Corvair Clutch Cable (1964 Corvair).pdf
Replacing a Corvair Clutch Cable (1964 Corvair)
(2.25 MiB) Downloaded 42 times
Parts are listed below. Since a broken clutch cable can occur without warning, is a "show stopper", and parts cannot be found locally — requiring a parts shipment from an often-distant Corvair supplier, it is often a good idea to keep a spare clutch cable in the trunk! (NOTE: The Late Model (LM) cable used in a 1965 Corvair is a lengthy rigid assembly and would not fit in the trunk. But Clark's Corvair Parts offer a "Take-Apart Cable" that you might consider. This will allow a spare to be a part of your emergency spares kit).
ImageImage
:link: http://www.corvair.com/user-cgi/catalog ... N&page=112
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The websites listed in the following link may be useful to you...

Common and Useful Corvair Websites

Corvair Forum :link: viewtopic.php?f=225&t=6007
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
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bbodie52
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Re: Slipping clutch...

Post by bbodie52 »

If you find that the clutch cable is not binding and that the clutch pressure plate has fully released when you take your foot off the clutch pedal (throw out bearing not in contact with the clutch pressure plate diaphragm spring "fingers"), you can probably assume that the clutch slip is you have detected is caused by one of the following…
  • Oil contamination of the clutch disc material.
  • Badly worn friction material on the clutch disc.
  • Defective or faulty pressure plate.
If the clutch slippage has been taking place for some time, you may discover that the friction surfaces on the flywheel and on the clutch pressure plate may show signs of overheating, burning, or an uneven mating surface that has been worn excessively by the slipping clutch material. Other things that should be inspected include a careful inspection of the starter ring gear for excessive wear, broken teeth, or broken welds at the ring attachment points where it is welded to the pressure plate. The Corvair flywheel is also a unique multi piece assembly made up of a flex plate and a flywheel that are riveted together. Over time these rivets can loosen, which causes a rattling sound when the engine is idling. The rattling sound will usually stop if the clutch pedal is depressed slightly, which brings the throw out bearing into contact with the pressure plate diaphragm spring (dampening the rattling sound). The throw out bearing itself should also be inspected for rough operation, and the pilot bushing should be inspected for excessive wear as well.

Because of the amount of work involved in removing the entire powertrain from the car and separating the transaxle from the engine, many owners who are having clutch problems opt to replace the entire assembly including the pressure plate, flywheel, clutch disc, throw out bearing, and pilot bushing, as well as the seals in the bell housing and transaxle "snout". The throw out bearing rides on the transaxle "snout", which is a machined casting that is also subject to damage. The outer surface of this component should be carefully inspected for cracks that may have formed over time. Damage can occur during the process of separating the engine from the transaxle. Both the engine and the heavy transaxle should be carefully supported when the two components are unbolted and separated, to ensure that the alignment between the two components is maintained while pulling them apart. The problem here is the input shaft, which is splined at both ends. When pulling the transaxle away from the engine, the large splined end that is embedded in the clutch disc and pilot bushing may remain in place, while the smaller splined end pulls free from the transmission. This leaves a long shaft protruding from the clutch assembly. The heavy transaxle must be moved away from the engine without allowing the input shaft to act as a lever that can apply lateral force against the transaxle "snout". Such leverage can cause this machined casting to crack or break. Replacing the "snout" requires complete disassembly of the differential. The input shaft seal inside the "snout" prevents transaxle fluid from leaking onto the clutch assembly. That seal should also be replaced when overhauling the clutch assembly.
Transmission Input Shafts.jpg
Corvair Throw Out Bearing Shaft.jpg
The Clark's Corvair Parts online catalog section that covers the Corvair clutch assembly begins on page 108 and extends through page 114. While you are planning your clutch job I would suggest carefully reading through these pages, which you should find to be very informative. If you develop any questions after reviewing this material you can ask them here on the Corvair Forum when deciding which items you wish to order in support of your clutch job.

:link: http://www.corvair.com/user-cgi/catalog ... w_page=108
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The OTTO Parts specialty catalog section also contains numerous performance components for the clutch assembly. You may want to look this section over as well. High-performance clutch discs, flywheels, input shafts, universal joints, etc. are all listed throughout this section.

:link: http://www.corvair.com/user-cgi/catalog ... ge=OTTO-22
Image
Clutch Cross-Section.jpg
Corvair Clutch Cross-Section.jpg
Clutch Release Bearing Assembly.jpg
Manual Transmission Clutch Bell Housing.jpg
The attached manual, Corvair and Corvair 95 Power Train Removal & Installation, can be a useful supplement to the shop manual when removing the powertrain. Although written for early model Corvairs, the procedure is similar to the process for the late model Corvair. Combined with the 1965 Corvair Chassis Shop Manual it can provide you with a good overview of the procedure.
Attachments
Corvair and Corvair 95 Power Train Removal & Installation.pdf
Corvair and Corvair 95 Power Train Removal & Installation
(3.35 MiB) Downloaded 34 times
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
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acarlson
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Location: Dahlonega, GA

Re: Slipping clutch...

Post by acarlson »

Brad,

Thanks ! As usual you have provided a complete synopsis of the task ahead of me. I appreciate all your time and effort to boil this down. I have pulled the drivetrain and engines before but it was some time ago and on EM Monza's. This will help a lot when I get started (gives me something to do in the winter) !!

Alec
Alec Carlson
Dahlonega, GA
1965 Regal Red Corsa 4 Speed Turbo Convertible
Restoration "In Progress"...
Paradox1559
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Joined: Tue Dec 04, 2018 2:44 pm
Location: Defiance, ohio

Re: Slipping clutch...

Post by Paradox1559 »

What did it turn out to be?
If it works, it ain't stupid.
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acarlson
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Location: Dahlonega, GA

Re: Slipping clutch...

Post by acarlson »

Paradox1559 wrote: Wed Dec 19, 2018 8:08 pm What did it turn out to be?
The clutch disc was worn down to the rivets and the bellhousing seal was leaking oil onto the pressure plate, flywheel and disc.

Alec
Alec Carlson
Dahlonega, GA
1965 Regal Red Corsa 4 Speed Turbo Convertible
Restoration "In Progress"...
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