You are indeed a 'sick' man Mr Carl; All in a Very Good Kinda 928 Way!!

 

Hehe, so crazy in fact that I put the wrong side dust shield on....that should teach me to play in the garage at 2AM.

Carl

 

Carl-- Are those new shields or refinished? If refinished, what did you use? They look perfect! (of course...)

On the spindles, and for future searchers/readers, I can't overstress the need to avoid over-tightening the spindle nut on tapered wheel bearings. The original cold fit is loose enough to let you -easily- move the washer with a screwdriver. Way too many folks try to fudge towards tight to get the wheel to be absolutely free of all play, but that's not the goal with cold bearings and all. The alloy hub expands more quickly with heat than the steel spindle, meaning the bearings will get "tighter" after the jut a short amount of driving and brake applications. Meanwhile, the rollers depend on having a film of grease on them to survive in service. If the cold setup is snug, the hot setup will be too tight. With no grease film, the cones will expand with the heat and spin with the excess bearing friction and reduced contact with the OD of the spindle. That wll quickly damage the spindle, most notably, as Stan reminds us, on the bottom where folks seldom look. The cascade effect is that a new bearing won't fit correctly on the damaged spindle, leading folks to tighten the spindle nut even more as they try to remove play from the replacement.

A recent Ford 4WD I owned had the two front bearings very close together, to allow room for the auto- locking mechanism for the drive system. It was incredibly sensitive to adjustment. Ford's initial WSM guidance was to tighten the nut to 75 lbs/ft to make sure all the bearing bits are seated correctly, back off the tension completely, then without rotating the hub at all, tighten the nut again to 15 lbs/ft. There were a lot of subsequent failures. The "solution" was a revised recommendation to 15 inch/lbs, only after rolling the hub and restoring the grease film that was squeezed out with the initial seating instruction. For those who didn't have access to a small enough torque wrench, guidance was revised to "finger-tip" tight. No tools, no gloves, no hand wrapped around the nut. Just the finger tips, putting the nut against the washer. Nut goes looser rather than tigher if the locking key didn't line up. For the 928, I tried the 15 inch/pound setting using a torque screwdriver in the slot in the nut, and found it a little too tight to allow the washer to move easily. So you get an idea about how sensitive the adjustment can be.

Correctly set up, wheel bearings are pretty much maintenance-free for a very long time. The only reason to open them up at all is to replace the grease that's stiffened up with age and doesn't flow as well in the cages. More bearing and spindle damage is caused by incorrect setup than by anything else including tired grease. So stay loose, stay lubricated, stay cool.

 

Dr. Bob,

The mounted dust shields (now oriented correctly) are new GTS shields.The shields on the floor below are refinished S4 shields. I used high temperature ceramic paint (semi-gloss) on those, but didn't like how the finish came out. They have been in use for many years and the finish itself is very durable (probably more so than the stock factory coating) but they never had the smooth look of the factory part. I think in order to get the paint coat to flow out properly, powder coating would be the way to go if I had to do it again. Besides, since the car is getting GTS front brakes, I needed the correct size shields anyway.

Also, I wanted to express my gratitude to you, Stan, Greg and every other expert that provides us with such valuable advice and experience. I will definitely take every measure possible to follow your advice on the bearings and everything else. Resources like this makes working on the 928 so much easier.

Cheers!
Carl

 

Looks great Carl. I can't wait to see the finished car. I noticed your floors... did you do this yourself? How do you like it and which product? Sorry to sidetrack your thread but it sounds like you are well on your way to getting the bearings on.

 

Hi Don,

Yes, I did coat the floor myself, the product is Valspar Extreme Epoxy. It has held up well everywhere I DON"T park hot tires. It is bubbling where I park my Audi at each tire spot and below where the turbo is located. Everywhere else it has held up great to chemicals and dropped tools. I would recommend getting an industrial grade coating if you want it to last. And definitely put some anti-slip agent into the top coat as it otherwise turns into an ice rink when the floor gets wet....

Carl

 

And now back to the bearing races.....

Heated up the hubs for 30 minutes at 300F and had the bearing races sitting in the freezer overnight. The outer races were pressed in place perfectly and completely flush with the corresponding hub lip. However, the inner races will not go all the way in. Not even with a 20 ton press will they go any further down than seen in the picture. Is this normal or acceptable, or do I have the wrong size inner race? The inside of the hub area is smooth and no damage or protrusions can be seen or felt. The situation is the same on both hubs, outer races fit perfectly, but both inner races stop at this exact same location. Ideas?

Cheers!
Carl

 

Can you fit a feeler gauge between the race and the hub?
I am going to guess that the races are fine

FWIW the outer races ( smaller ones) should be installed first,

then the inner races installed ( larger size) then leave the hub facing outside down, till the temperature normalizes.

otherwise the inner races will possibly come out as the bores have a bit more clearance than the outer race bores

 

Hi Stan,

I can get a 0.254mm (0.010") feeler gauge just past (below) the race lip,between race and hub, but no further. Have you ever seen a race not going all the way in to the hub lip?

Cheers!
Carl

 

I have- I remember having the exact same question on my GTS's hubs, took them up to GB to show him and he said they were fine. Mine look like yours. That was 8K miles ago.

You can kind of see the 'gap' between the old races here full of old grease:

 

Thanks Rob,

That makes me feel a lot better seeing I'm not the only one with overly tight hubs Were you able to fit a feeler gauge in between as Stan suggested?

Cheers!
Carl

 

Ball and roller bearings that have inner and outer races normally have one race that is a light to heavy press fit into/onto the mating surface and one race that is a "line fit". The line fit should be a snug slip fit, but not a press fit. You want one race to gradually turn to prevent the ***** or rollers from pounding the same spots on the races forever.

The line fit on most front wheel bearings is on the spindle, leading to the wear that Mr Merlin has noted.

The perfect sealing surface is not polished, as that retains no lube to prevent the seal lip from burning/melting/wearing out. The bearing/seal experts recommended light sanding with 400-grit wet-or-dry at a 30 degree crosshatch pattern.

dr bob is spot on - never install a lip seal dry or on a dry surface.

 

Thanks Wally for the suggestions.

In my picture the spindle looks very shiny and polished, but still has a faint pattern in the metal. The metal polish (liquid, not paste) I used was just wiped on, let sit for a few minutes and then wiped off with a microfiber towel. It did "brighten" the metal somewhat. I will take some wet 400 grit paper and very gently apply your suggestion before coating the spindle with a thin film of grease.

Now that it seems the space between the race lip and hub lip is not uncommon I feel comfortable putting everything back together. Thank you again to all for the helpful inputs, as always they are greatly appreciated!

Cheers!
Carl

 

I love people who do these kind of restorations. Props for comitting the time and money, we all know you have the true passion. If i had the money i would do the same thing on my 87.