gruffalo

Hi all!

I'm in the process of replacing my front wheel bearings. Previously I've been largely unsuccessful in tightening them correctly. Either sloppy or too tight leading to premature wear.

Last time I spun the wheel between my tightening attempts to find the sweet spot between wobble and binding, and failed brilliantly. A couple of thousand miles later they were ruined.

Is there an idiot proof way of getting this perfect?

m

FredR

Very few things are truly "idiot proof" as genuine idiots will always find a way to defeat the smartest procedures thus qualifying their designation.

Not sure what others do but when checking wheel bearings for play one does this with the wheels mounted and check for the slighest feel of shake in both the 12/6 and 3/9 axes. If there is only play in the 3/9 [horizontal] plane then one should be looking for issues in the steering gear.

Common sense tells us that wheel bearings only slacken off with wear so any adjustment to the front wheels logically has to be in the "more tension" direction.

When new bearings are fitted and the new operating point has to be established, one progressively tightens the bearings until no further shake can be detected. I then tighten a little more until one can feel the bearing starting to bind and then back the adjuster off until it feels free once more but no more than the point at which it initially felt free of movement. I do this iteration two or three times to give me confidence that I have it just right.

Professionals who do this regularly probably just tighten them up and leave it once they feel it is correct given they have more "feel" for what they are doing. Last time I did this adjustment was about 14 years and 80k km ago - bearings still feel perfect today. I carry out "checks" every couple of years or so and the last time was how I found one of my inner track rods had "gone south".

Don Carter

gruffalo,

I've been having the same issue with my 86.5. Watching this thread.

Chuck Z

Following. Have to do this on my GT. If I may, I'd like to ask if hubs just taken apart to get dust shields off, should I clean and repack the bearings? How to clean bearing?

dr bob

Try to hit all the issues, not necessarily in order. Bear with me...

The front wheels bearings are tapered roller bearings mounted in an aluminum hub. The bearings ride on a steel spindle. Because they expand and contract at different rates, the adjustment will be a little looser than what you might use on the Caprice. The factory recommended method is spot-on, but leaves a tiny amount of detectable "slop" in the bearings when they are cold. A small amount of space is needed to maintain a lubrication film between the rollers and races, so starting with them "just right" with minimum or no clearance when cold will cause them to tighten when hot to the point where there is no room for a grease film. Then they got even hotter, pressure increases, and very soon the bearing is damaged.

With fresh grease in a cleaned bearing, use a small wrench to snug the adjusting nut as you rotate the hub. Then back off the nut. Without rotating the hub, tighten the nut with your fingers only -- no tools. If you have wimpy fingers, try a small screwdriver in the clamping slot and very gentle pressure with fingers only on the screwdriver shaft-- no full hand grip and twist. On another car with similar bearings, the recommendation is 15 lbs/inch on the nut, to give you an idea of the massive twisting forces involved here.

Any time you feel that a bearing needs to be "adjusted" you'll probably want to know "why" before you do it. These bearings don't go out of adjustment on their own. They do wear, but by the time that wear is noticeable it's time for new bearings. More commonly, bearings are adjusted too tight, they wear and the rollers and races are heat damaged, they wear as a result of that heat. So they need to be replaced. Point is that you should clean and inspect bearings before you start tightening them to remove play. Worn bearings will seem to need some excessive pressure on the nut to get the play to "feel" right. Consider that a tell tale sign of the need for replacement.

When a bearing is over-tightened and the clearance gets too small, it causes vibration and in serious cases the inner race will spin on the spindle. Even the vibration will cause wear on the bottom of the spindle where the inner bearing sits. That wear will make adjustment tough, as the bearings are no longer concentric. Tightening even using the recommended method risk one side of the inner bearings' outer race always having more pressure/tighter clearance than the other. Use an inspection mirror to look carefully at the bottom of the spindle right outside of where the seal lip rides on that shoulder. The original surface is machined. If it's been polished by a vibrating bearing, go ahead and dry fit your new bearing on the spindle and see if you can "rock it" at all; if you can feel any play at all, think about replacing the spindle. If that area is blue from excess heat or galled by a spinning bearing, you MUST replace the spindle.

Bearings get cleaned in normal cleaning solvent to remove all the old grease from the cages that hold the rollers. All bearings should be repacked with new clean grease before installation. I use the red Mobil-1 grease in the big tube in my grease gun and bearing packer. Redline CV1 is also good. Almost any decent wheel bearing grease will do the job really. Resist the urge to pack the cavity between the bearings with grease; a little extra is OK just because it feels good to do it. Do be sure to fill the cavity between the inner race on the inner bearing and the seal, and put a light film on the spindle where the seal sits before installing the hub.

To install new bearings (or remove old ones) you'll want to clean the hub thoroughly, then heat the hub in your handy garage toaster oven to maybe 300º. Use those silicone grill gloves to move the part in and out. The steel races will easily drive in and out of the heated aluminum.

davek9

I've followed the Service manual and it says that the washer behind the nut should be able to be moved with a slight pressure/resistance, but movable, not tight.

I always figured as dr bob mentions above, that this allows for that expansion when they get heated up.

Dave K

the flyin' scotsman

I use our bbq........easier on 'she who controls all in the kitchen' relationship

gruffalo

Thanks for all the great tips!

Which way do I fit the seals?

dr bob

Undoubtedly true. I mention the WSM factory method above as the guiding instruction. The idea that one might want to tighten the nut first to get the film thickness right is where the method differs from the WSM. As I mention, loosen and then snug with fingers. The washer MUST be easily movable with a small screwdriver WITHOUT PRYING on it; push it with the screwdriver blade from the edge and it should move.

I learned many moons ago that baking car parts in the kitchen oven can be worse than a death sentence; at least the death sentence has a defined ending point. Hence the decision to add a garage-sale toaster oven to the countertop appliance collection in the garage. New they are $20 at the bargain stores like Big Lots in the U.S.

The closed face of the seal (showing in the right in your picture) goes towards the middle of the car. It's the face you push on as you install the seal into the hub. That face ends up being flush with the end of the hub when installed correctly. Again, fill the little gap between the seal lip and the inner race of the inner bearing with grease, a little on the seal lip, and a film on the spindle where the seal rides. The seal will last pretty much forever if installed this way.

Dave928S

A stellar write-up as usual Dr Bob ...

worf928

+928 what Dr. B wrote.

elring seals are the only ones you can get now that are a double-lip seal like the OE seals. Jeannie/DR stock them.

Spindle wear is becoming common. After cleaning, run your fingernail over the seating surface for the races: if you feel a lip then the race will be loose. It only takes about 2-thousandths of wear.

Edit: typically inner wear will be on the bottom of the spindle at the 'thick' end, outer wear on the top of the spindle.

There are tricks, not for the feint-of-heart, that work about 50% of the time for spindle wear.

gruffalo

Sorry I'm a moron... Top or bottom?

Dave928S

Bottom

dr bob

Put the inner bearing cone in, already packed with grease, before you install the seal. Trust me -- You'll be happier.

Also --

In this picture, the cup (outer race) of the inner bearing is showing some serious "bluing". That's a result of heat from "bearing too tight" syndrome. Be sure to replace the bearings if you haven't already. Follow previous guidance about using the garage toaster oven to heat the whole hub before you drive those races out. It will minimize any chance of galling the aluminum hub. You can get fancy and freeze the races before dropping them into the heated hub -- they will all but fall into place that way.

The Deputy

Normally, the part number on the seal faces outward...that way you can read it before removal...never seen a seal that went in part number side first.

I'm going with the top picture.

Brian.