Rear Wheel Bearings

[Cream79L82]

I was putting in a new master cylinder a couple of days ago when I noticed my front bearings were definitely due for some attention. I don't know why I hadn't done that simple off-the-ground check earlier, but they are so bad you can actually hear them kind of grinding as the wheels spins freely. So anyway, I'm plan to put in new inners and outers on the fronts tomorrow and I assume my rears will need some attention too.
I understand that replacing rear bearings can be a major hassle and even impossibily without the right tools. Would I need some sort of separator to get everything all apart and back together again? Is there anyway to check for efficiency without taking more than the wheel off? Can I just jack it up and put it in neutral and try to spin the tires by hand? I would appreciate any of you expert grease monkey's input on whether it's even a feasible job to tackle in my garage over a weekend. Thanks alot.

-Jon

 

[Jack]

I understand that replacing rear bearings can be a major hassle and even impossibily without the right tools. Would I need some sort of separator to get everything all apart and back together again? Is there anyway to check for efficiency without taking more than the wheel off? Can I just jack it up and put it in neutral and try to spin the tires by hand? I would appreciate any of you expert grease monkey's input on whether it's even a feasible job to tackle in my garage over a weekend. Thanks alot. -Jon

Jon:
Special tooling is required to R&R rear wheel bearings ... they're not the sort of tools sold at sears nor rented/loaned at autozone. Running axle while on stands not recommended ... w/ wheels drooping , axles hanging down ... ujoints will be at an extreme-unnatural angle ... damage has ocurred. Turning by hand OK. Also, on stands, rock the wheel ... one hand pressing at tire top, the other pulling at tire bottom ...then pull top-press bottom. Find more info about this at www.vansteel.com ... they offer complete bearing/trailing arm rebuild parts & service.
JACK:gap

 

[Cream79L82]

Thanks alot Jack. I'm headed out to the garage now... even though it's well below freezing here in Norman, OK. I sure hope my rear's aren't in need of replacement because this college student doesn't have several hundred dollars lying around for a rear bearing rebuild service like Vansteel offers. I guess I'll let you know how it went.

 

[WayneLBurnham]

Oh man, PLEASE if there are ANY doubts, change 'em!

Sometime in November, when I was building towards enough bucks for a Gear Vendors OverDrive, I was doing about 80 on a highway right next to a magnet wall.

I didn't hear the left rear bearing seize.

For some reason they don't scream like front ones usually do.

It heated up, boiled off the grease, annealed the steel, melted the seized bearings and cut the outter axle in half like a dull bit on a lathe.

The rear wheel assembly, including rotor and caliper broke off and jettisoned away from the car, apparently bouncing off the magnet wall not a foot away. I felt a tremendous shock, like I had run over a "cinder-block" and the wheel pulled sharply to the left towards the wall.

I didn't hit the wall at all.

Thinking I had just had a bad blow out, I wasn't about to stop in the left lane of crowded traffic only to be rear-ended by some other moron going 70+ 15 secs later, so I turned on the signals, looked right and started going across, still at 60+.

The wheel was pulling hard to the left, but not so bad you couldn't control it. I remember being suprised the road hogs were letting me over. Right before I got to the right lane (and this is about 300+ yards after "the event" - we call these things "events", you know ) a bad shimmy started.

Assuming I was starting to loose the tire off the rim of the flat, I did what you do in such a case and gave it a little power to straighten it out. It worked! I stopped slowing and I think accelerated slightly. The wheel pulled even harder to the left when I did it, but still not uncontrollably.

I continued across the final, right-most lane and this time actually looked back in the rearveiw and not just sideways for traffic and was shocked to see a white wall of sparks. It looked like the space shuttle coming in!

I couldn't believe I had eaten through the tire that fast. I got it off the road, very concerned about a potential fuel leak being ignited by this shower of sparks.

I stopped it, realized it wasn't enough off the road and started it forward a little more, steering hard to the right, making a horrible grinding noise.

It was only after I had shut off the car, waited a few seconds, let go of the fire extiguisheer I had grabbed as soon as I was stopped (the first time) that I realized I was sitting way too low on the driver rear!

Having that repaired, with no 'glass damage and no center section damage - and little ancillary damage to the suspension at all, with only a few unrelated extras or minor convenient area upgrades thrown in, cost me almost $4500.

I was, other than financially, very lucky. I will get those things changed every other day and twice on Sundays! I want a thermal monitoring systems for them!!!

The bearings on the rear are not like the tapered bearing on the front that you can get on and off with hammers, simple press arrangements and freezing or baking parts. They are specific fixed diameter parts, that have to be put on under force to specific depths and not more.

Most people who lose a wheel lose a lot more than I did. Don't neglect those bearings.

 

[Cream79L82]

Well it turns out I was wrong again with what I thought my problem was. As soon as I took the dust cap off of the bearing assembly and saw grease that was still blue I knew they were fine. The noise that I was hearing was from my brake pads rubbing on the rotor under no pressure. I replaced four seals and boots.
Of course, I still have a number of questions... is it necessary to bleed the whole brake system if just the fronts were opened? How freely should the wheel spin when jacked up under no pressure? Is it normal for the pads to engage the rotors when the brakes are not applied due to the piston spring pressing out or should the seals keep the pistons back and clear of the rotor when rolling down the road?? And finally, how much play should there be on the rear wheels with the rear end jacked up when you push in on the top/ pull the bottom, etc.
I guess I'll go bleed the whole system while I wait for a response.
Thanks.

-Jon

 

[WayneLBurnham]

I'm more a Remove-and-Replace dude...

But don't usually mind disc brakes, except on vettes...

Vettes were early to feature four wheel disc brakes, but C3 vettes use an early type of disc brake. They are fully in contact - always. Unlike most discs I was used to, these things don't "hold off" - they always contact the rotor surface. It's for this reason that not only is rotor thickness and surface smoothness condition critical, as in all disc brakes, but so is perpendicular run-out.

The rotor has to be within some absurd tolerance like 0.004" of true dead rotation or it will so constantly work the "live" pistons back and forth it will foam up the fluid. Shims are used somehow to achieve this, as well as the usual machining.

I'd have my brakes set-up by a vette shop or brake shop with vette experience.

There is nothing wrong with bleeding them however. Do the whole system though, possibly including the master cylinder if the fluid was too foamed. Go by the bleeding directions in a vette manual - the fronts have two bleed screws as I recall (so far, the same shops that rebuiilt 'em, bled 'em.) Use that Ford DOT4 or other higher end super high boiling DOT4 fluid instead of the DOT3 or earlier or generic DOT4. I went with DOT5 silicone fluid, which does not mix with DOT3 or DOT4, but works with all normal brake gear, which boils even higher and, most importantly to me, is almost a silicone oil and completely non-corrosive and non-hygroscopic. (Incidentally, an even more expensive silicone fluid has been formulated and starting to be marketted which is much thinner - behaving in most ways like DOT3 or DOT4, but with all the desirable characteristics of "regular" DOT5 - but I haven't seen it yet.

 

[Jack]

vette rear bearings

And finally, how much play should there be on the rear wheels with the rear end jacked up when you push in on the top/ pull the bottom, etc-Jon

Jon:
I don't know how to quantify the push-pull/rocking method ... it's a function of "feel" & prior experience. In lieu of that, I highly recommend taking it to a bona fide vette shop. I don't mean a tire-muffler-alignment shop ... unlikely anyone there will have either vette-rear bearing skills or tooling. Whether van steel or a local vette shop, it's gonna cost to get this somewhat specialized work done. BTW, if the rear bearings are bad ... the rotors will exhibit gross runout ... and will pump the calipers. The rear bearings, spacer & shim(s) should be a press-fit on axle stub ... requiring specialized tooling & gaging to remove, replace & setup tolerances. G'luck!
JACK:gap

 

[Cream79L82]

That bearing story of yours Wayne is scary to even think about, much less drive it. Glad you could save it. Thanks for the info Jack. I hadn't thought of rotor run-out being bad. I believe they're fine, but I'll keep an eye on them and I guess be forced to shell out to have them fixed... so I don't end up like Wayne. :L

-Jon

 

[HammerDown]

Bearing Spindle Trick>

Good topic...there's a local shop here that dose a ton of Vette Work...the owner is a good friend of mine...and what they do is chuck the spindle in a lath...and take the diameter down just to where the inner and outter bearing is a hand press on and off. This can be done with a piece of emery in front of something hard, like a file. I did it on my 81 and it sure makes it easer to remove the bearings for service. No more hard banging with the spindle knocker!
Anyone else done that?

 

[Gunther]

No, but I heard this already.
Should be fine as long as the spindle nut is kept very tight to avoid the bearing shell from spinning.
Only throwback is that you loose those reworked spindles as cores in case of a complete rebuild because they will be undersized.
Gunther

 

[Blue82]

I had a mechanic at one of our Vette shops tell me to order new spindles and have them machined down. He swears that is how it should have been done in the first place.

 

[HammerDown]

Cut Down Spindels

Blue 82...thats what I've been told also...As I said above I did mine myself...only a few seconds time with a piece of emery paper.