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Replace hubs with bearings? (75 Eldorado)

Started by benji808, May 25, 2023, 05:29:40 PM

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benji808

Front wheel bearings seem to be bad (noise and a lot of play). I'm being advised that replacing the hubs at the same time is best, because of how the bearings are pressed in. Can anyone confirm?

The Tassie Devil(le)

I had no trouble replacing the bearings in the hubs on my '72.

No special tools required, apart from a big torque wrench to tighten the main nut back up.

Plus, the replacement bearing sets come with the correct thickness centre divider.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

TJ Hopland

Later and current stuff the hub and bearings are sold and replaced as an assembly that just bolts on so that is likely where the 'advice' is coming from.  I would imagine back in the day you could buy a new hub but I don't think it was a common failure and I have never seen any indication that aftermarket ever made one.  In more recent times I have occasionally heard of the hubs being damaged but it must take quite a bit to damage them.  I had one that was so loose when I jacked the wheel off the ground it had like an inch of flop at the tire tread.  I figured for sure that had to have destroyed things but the shop I took the knuckle to said it was all good.  I don't know for sure how long I drove like that or how long it would take to really wreck things. Maybe I was really lucky or maybe these things are just really hard metal. 

The bearings are supposed to be sold as a matched set that includes factory set shims which is how the preload is set after they are clamped together by the big axle nut.  I have seen them listed as individuals which would make it really complicated to get the preload set and correct.

The manuals show special tools and pressing.  There used to be some decent videos online by the GMC RV folks showing tools they made and pressing things but those seem to be gone now.  I tried to do one once with just a hammer and vice and it didn't seem like it was going anywhere so I took it to a driveline shop, this was the one I mentioned above that was flopping around.  Bruce's just seemed to just come apart and slide back together.  Seems like there was a similar thread maybe last summer on the subject where someone was going to attempt them at home,  I don't recall how that ended up working out.  Anyone remember the thread or is that person still here and can comment on how they either did it or failed?

The newer and current assembly style the hub comes already pressed into the bearings and the bearings are in a housing that then bolts onto the knuckle.  In the case of our cads there isn't that separate housing, the outer bearing races are directly in the knuckle.  I never looked in the old parts books but maybe GM sold the whole knuckle bearing and hub as an assembly back in the day?  I don't think there was any sort of maintenance interval for these bearings, they were a 'lifetime' item.  The GMC RV people do or did do a mod to the knuckle to install a grease fitting which apparently helped them last longer in the RV application where they put a lot more stress on them than we do.  I don't closely follow the GMC RV's but it seems in recent years they have lost a lot of their leaders and companies that were innovating and keeping those things on the road.                     
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Grouse

Quote from: benji808 on May 25, 2023, 05:29:40 PMFront wheel bearings seem to be bad (noise and a lot of play). I'm being advised that replacing the hubs at the same time is best, because of how the bearings are pressed in. Can anyone confirm?

This is the Achilles heel of this great car. If not torqued correctly then causes premature failure, either bearings or bearings spinning in the tolerance press fit cups in knuckle.
As the gentleman mentioned and this subject has been coveted in other threads, it's possible to diy with correct tools and manual.

If new bearing set is loose then there is a way to restore the OEM knuckle cup tolerance. If the bearings have spun and the wear is uniform then it can be hard chrome to correct tolerance. If the wear is not uniform, it will have to be ground and hardchromed a few times to bring to OEM tolerance.

I had to go this path because one reconditioned completed knuckle ex USA was about USD 2k.( I am in Australia).
John Meimaris

benji808

Thanks everyone! I am going to go ahead and replace the hubs- I'd rather be in the safe side. Thanks!

TJ Hopland

Where have you found replacements?  If its new production I would be a little concerned about the quality.    The GMC RV's I think used a slightly different hub and I know were buying up Eldo and Toro front ends to use as cores so they would certainly have good used hubs laying around that had little value to most of their customers.  I'm pretty sure they would sell you a rebuilt knuckle assembly too you just had to let them know that you wanted it for an Eldo and not an RV.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Chopper1942

If the bore in the hub is slightly oversized (the bearing race is a slip fit) and is still concentric, it can be repaired without a great deal of expense.  When Locktite first came out, the green Locktite  was called "bearing mount". Its purpose is to lock the bearing races in place so they can not spin.  The drawback to using it is that if you need to remove the bearing or race, it was almost impossible to remove without heating the hub very hot.

benji808

Update on this. I was working with a shop on this one (I was tired lol), and they could not source a hub, so we just replaced bearings. I think the hub recommendation was more "best practice" than necessity. All seems well for now.