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Chrysler Model 72 Rear Bearing Retainers Correct Fit?


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The photo shows the rear drivers side axle bearing retainer, kind of like a star held in place by 6 bolts.  I was missing one on the passenger side and now that I have it I've become aware they need to be "fitted" correctly with spacer shims?  How is this done?  What type of grease is used to pack these bearings?

Driver Side Rear.jpg

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Posted (edited)

I too could use advice on this. I removed my CD8's rear bearings (except for inner race which is back-shimmed at factory for correct end play so I left it in place) checked and regreased them. In meantime, I sandblasted, primed and painted (rustoleum) both sides of brake backing plate, which originally would have likely only be painted on back side. Regardless, overall thickness is now altered slightly. I installed the backing plate and the "outer seal" retainer using the thin paper shims that were there originally behind the seal, but have not paid attention to the query leomara is asking. I assume you tighten the 6 bolts with no paper shims behind the backing plate and turn axle, if too tight, remove and add a shim and tighten again, and repeat until it seems about right. 

Edited by Gunsmoke (see edit history)
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You have to add or subtract shims until there is 0,002 to 0,003 of an inch end play on the shaft, with the 6 retainer bolts firmly tightened.

The bearings should be packed with good quality wheel bearing grease.

 In gunsmokes case, where the backing plate and diff have been sandblasted, I recommend removing the shafts completely from the axle, clean the bearings thoroughly and repack them with grease, also remove the grease nipple fittings from the housing and thoroughly clean them. The sand is shot under high pressure and may well have gone thru the grease nipples and any seals on the axle, pinion included and will act as a nice grinding compound if not cleaned properly.

Viv.

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viv W, yes after sandblasting priming and painting the rear end, I pulled both axles out to clean, check and re-install bearings. I also removed grease nipple and cleaned it as well and checked condition of inner seal. On my car, the backing plate acts as the bearing retainer, and I can likely use a .002/.003 feeler gauge to check clearance when the 6 bolts are tightened. This can be done before installing the outer seal. I must say when I disassembled all these 90 years old parts their overall condition was remarkable, no signs of wear, corrosion etc, the tapered roller bearings were near perfect. Grease was still soft but chewy, so new grease will no doubt be welcome. Leomara, you may find that star-shaped gizmo with the 6 holes is the outer seal retainer, does not have anything to do with the bearings other than trying to keep the dust out of there. The tapered part of the rear hub fits snug against it's leather seal (at least that's how mine works).Thanks VW.

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If it is similar to those on my '31 CD8, it has a leather seal backed by a circular spring that maintains a small amount of pressure against the hub, just enough to prevent dust from getting into bearings, and excessive grease/oil from migrating outwards from bearing area. If you are careful, usually the spring can be gently pried out of place and leather oiled a bit to make supple and spring re-installed. Then take seal assembly and slip it on back of hub and see if it fits snugly at proper spot. If so, it should be fine. Remember in these restorations, most restored cars will have very few miles put on them annually and in typically favorable conditions, such as no dirt roads. Most could likely run fine without these seals at all. I do have a pair of spare used CD8 outer seals, but may not have same diameter as yours. 

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These seals sometimes cut grooves in the wheel hub and grease could leak in the brake drums, mine did. I was able to install speedi-sleeves on the hubs that the seals grooved. Then I removed my old damaged leather seals and fit new lip seals in the original seal housings. No leaks.

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There should not ordinarily be any "oil" in these areas, and grease seepage from bearings should be minimal. However, if a rear end/differential is overfilled, or not vented, or vehicle parked on side slopes, oil can pass through inner seal and wheel bearing area into hub area. I installed a differential vent on my rear-end housing during the restoration, they did not have one from factory. It relieves pressure created as rear end oil heats and sprays (and creates an oil mist inside housing) during operation and helps prevent the pressure created as hot air expands from pushing/forcing oil into hub area. Got this advice on here a couple of years ago. Here is pic of installed vent. Drilled and taped a hole in location opposite of the brake fitting on other end of housing.

IMG_6650.JPG

IMG_6649.JPG

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When I set up the rear axles on the model 72 coupe I just sold I used a dial indicator on the end of the axle. I bought a shim pack before proceeding. The seal retainer is also the bearing retainer and the shims under it sets the amount of clearance. When everything finally warms up there will be a pre-load on the tapered axle bearings. Don't forget the slotted spacer between the axle ends also comes into play. Do not jamb it to one side and assume everything will be alright. These were precision class automobile for their time, and cost 4 times what my little Chevrolet coupe did. Art

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a sell, thanks for the input.  I consider myself a reasonably versed mechanic having restored several cars.  I'm unfamiliar with this type of work and being a visual learner it would be most beneficial to see something in print with diagrams discussing how this is done.  Does it require specialized tools?  There has to be a way to measure these tight clearances properly.  I don't see how it can be done by "feel".

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On ‎7‎/‎8‎/‎2020 at 6:43 AM, leomara said:

a sell, thanks for the input.  I consider myself a reasonably versed mechanic having restored several cars.  I'm unfamiliar with this type of work and being a visual learner it would be most beneficial to see something in print with diagrams discussing how this is done.  Does it require specialized tools?  There has to be a way to measure these tight clearances properly.  I don't see how it can be done by "feel".

 

You need a dial indicator with a magnetic holder.

Fix the holder so that the indicator can read the clearance as you push and pull the work back and forth.

Sorry, I don't have any pictures, but I can relate to the visual thing.

 

https://www.penntoolco.com/precise-0-1-dial-indicator-with-flexible-magnetic-base-401-007/?matchtype=&network=g&device=c&keyword=&campaign=744568461&adgroup=pla-48740232924&gclid=EAIaIQobChMI9MvqpfrC6gIV8Ql9Ch0M7w0aEAQYBCABEgKh5fD_BwE

Edited by JACK M (see edit history)
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