Rear Brake Cylinders

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Corvaircar
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Rear Brake Cylinders

Post by Corvaircar »

I am about to change the rear brake cylinders on my 66 Monza and see that there is not much room to get a wrench on the bolts. Can I unbolt the hub and pull it off to do this or is there an easier way. If I do this do I have to remove the drive shafts?
Thanks for any advice.
Robbie

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terribleted
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Re: Rear Brake Cylinders

Post by terribleted »

You can not remove the hub readily. Take off the bolts with a box wrench...6 point is best if you have one. You can loosen the hub assembly at the 4 large bolts and maybe gain a little space by forcing a wedge of some sort between the backing plate and the torque arm. If they will not come off chisel the heads off and replace with new along with the new wheel cylinders. Applying some PB blaster or other break free type solvent the day before can help. I usually do not have any trouble getting these off with a 3/8 6 point box wrench. If someone has swapped them to 7/16 heads clearance is a little harder but still generally not much trouble.
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.
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bbodie52
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Re: Rear Brake Cylinders

Post by bbodie52 »

Image

:link: http://www.corvair.com/user-cgi/catalog ... w_page=143

Brake Parts

Part number C894: BRAKE CYLINDER-65-69 LEFT REAR BOLTS- C2110

Weight: 1 lbs 0 oz
Catalog Page(s): 143
Price: $ 22.20


Image

Part number C895: BRAKE CYLINDER-65-69 RIGHT REAR BOLTS- C2110

Weight: 1 lbs 0 oz
Catalog Page(s): 143
Price: $ 22.20


Image

BOLTS: Not Included with wheel cylinder. Replace those rusted broken bolts. "1" = 1 Set for 1 wheel cylinder (2 bolts, 2 LW)

Part number C2110: GRADE 8 60-64 R & 65-69 F/R WHL CYL BOLTS- "1" DOES "1" CYLINDER (2 BOLTS)

Weight: 0 lbs 2 oz
Catalog Page(s): 143,177
Price: $ 2.40


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Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

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terribleted
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Re: Rear Brake Cylinders

Post by terribleted »

Brad I personally hate those 7/16 head bolts they supply. The 3/8 heads installed at the factory are easier to get a wrench on.
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.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

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bbodie52
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Re: Rear Brake Cylinders

Post by bbodie52 »

terribleted wrote: » Thu Mar 26, 2020 9:44 pm

Brad I personally hate those 7/16 head bolts they supply. The 3/8 heads installed at the factory are easier to get a wrench on.
Do you happen to have the bolt specs for these bolts — thread specs and length. Must they be Grade 8? The large round casting shape of the wheel cylinder would appear to take most of the torque load as it anchors in the backing plate. The small bolts only appear to anchor the cylinder in position. There are no bolt dimensions or torque specs in the Shop Manual. Clark's offers there large head bolts in Grade 8, but with unspecified torque specs in the shop manual the bolt tension is unlikely to be critical.

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Attachments
1965 Corvair Assembly Manual - BRAKES.pdf
1965 Corvair Assembly Manual - BRAKES
(2.29 MiB) Downloaded 7 times
1965 Corvair Chassis Shop Manual - SECTION 5 - BRAKES.pdf
1965 Corvair Chassis Shop Manual - SECTION 5 - BRAKES
(4.6 MiB) Downloaded 7 times
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

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terribleted
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Re: Rear Brake Cylinders

Post by terribleted »

Not sure of grade of the factory bolts, but they do not appear to be hardened. The bolts are 1/4x20 of course. I am sure Clark's supplies the 7/16 heads as they are the most common ( and likely cheapest) 1/4x20 head size bolts that are available in the necessary short length. A good hardware store can hook one up with 3/8 head 1/4x20 bolts that are short enough. I am sure I have used the 3/8 head 1/4x20 bolts the Clark's sell for engine shrouds in for these as well, but I can not remember if I needed to shorten them a little? I am thinking they do need to be a touch shorter, this is why Clark's supplies washers with their 7/16 head bolts....it is not to hold them in place but it is because they are too long, the washers make access worse as well as it puts the bolt heads even closer to the torque arm.I have not had an issue getting what is in place off any cars in a very long time and I either reinstall or cleanup and reinstall depending on the level of the repair.
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.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

Corvaircar
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Re: Rear Brake Cylinders

Post by Corvaircar »

Still having a terrible time getting to the cylinder bolts, I think they are rounded off. How far should I be able to pry the hub away from the yoke? Difficult to get a chisel on these bolts.
To remove the hub I believe that I have to pull the yoke from the inside. I watched Motohead Dave do this and he had a yoke puller, I am going to suppose that he made that himself.
My bearings feel excellent and I would like to use them again. Would this be okay?
Good thing I am shut down from working right now and have all kinds of time.

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Re: Rear Brake Cylinders

Post by terribleted »

You can not really remove the hub on your 65 as this would require removing the hub assembly and using a press (only really done when replacing the hub bearings). You can remove the axles and then remove the entire hub assembly after removing the 4 9/16 nuts that hold it to the car. I suggested above loosening the 4 nuts and trying to force the backing plate out some. This will not be easy as the axles will want to hold the hub assembly and backing plate in against the suspension arm, but forcing a large screwdriver or similar in between the center of the backing plate and the suspension arm with the hub assembly mounting bolts loose should result in a little more space. An air chisel makes chiseling these off easier as hammer swing space is annoying. If you decide to remove the hub assembly to get to them, once the axles are removed and you have taken off the 4 hub assembly bolts you should have plenty of space without taking the assembly fully off the car. In order to remove the assembly from the car it will be necessary to remove the e-brake cable from the backing plate and then you rotate the axle yoke so it is up and down. The assembly comes out of the arm by rotating it downward so the upper yoke end clears the arm. It will not come straight out. CAUTION the axle wants to hold the wheel hub assembly in toward the transaxle, so, when you loosen the u-joint bolts the arm will travel outward. To remove the axles use a cargo ratchet strap around the suspension arm and the transaxle to pull the arm in tight, then remove the bolts at the axle outer end u-joint and carefully release the strap. it is all too easy for a u-joint bearing cup and it needle bearing to fall on the floor resulting in needle bearing loss and the need for replacing the u-joint at that point. To reinstall the axle you put the u-joint ends into place while tightening the cargo strap until the u-joint is seated inn the hub yoke and then install the u bracket and bolts (here again to avoid bearing cups falling).
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.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

Corvaircar
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Re: Rear Brake Cylinders

Post by Corvaircar »

My thanks, your comments helped me out and I appreciate the time you took to share your knowledge. I ended up building a puller and pulling the yokes. Was not too bad and now I can clean up the parts and put it all back together. At this stage can I repack the bearings without pulling everything apart?

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Re: Rear Brake Cylinders

Post by terribleted »

Not sure what you removed? Are you talking about the axle yokes? Disassembly of the wheel mounting hub from the axle bearing housing is best done with the unit removed from the car and utilizing a press. Diagrams and photos on page 4-26 of the 1965 Corvair Chassis Shop Manual show how it is. Directions on this and pages around it detail servicing this assembly with some special GM tools but the tools are not necessary for off the car service. the entire yoke, hub bearing assembly is easily removed from the car as it is held by 4 nuts onto studs that are part of the suspension arm. in order to properly clearance the bearings a dial indicator is used and shims are install over remove from the stack to get the proper clearance. Here is a link to the manual should you not have one (seems like you do not). http://www.1969corvair.com/techpages/te ... Manual.pdf
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.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

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bbodie52
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Re: Rear Brake Cylinders

Post by bbodie52 »

The applicable portion of the shop manual — 1965 Corvair Chassis Shop Manual - SECTION 4 - REAR SUSPENSION — is attached.

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 (.pdf) 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 club 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.

Common and Useful Corvair Websites

:link: viewtopic.php?f=225&t=6007

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Attachments
1965 Corvair Chassis Shop Manual - SECTION 4 - REAR SUSPENSION.pdf
1965 Corvair Chassis Shop Manual - SECTION 4 - REAR SUSPENSION
(3.39 MiB) Downloaded 4 times
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

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