Machined vs cast part

[wagonist]

Well, I've done it again. I've managed to wear out another front left hand stub axle such that the wheel bearing is no longer a press fit. This then causes it to start moving around, causing more damage (you should see the back side of the brake rotor).

This will be the 3rd replacement one I'll have installed in the last 18 months.
In this case, the cause might have been the loose hub to strut bolts causing the hub to move around slightly, but I reckon the main cause is these were never designed to handle the ST205 brakes & sticky tyres I run (even though the replacement parts I've been using are ST205 stub axles).

I'm guessing that race teams avoided this situation either through regular replacement, or having custom parts made up.

Would having a replacement hub machined up alleviate this problem? ie would the metal be harder to resist the small amount of wear required to cause the part to fail?

if so, anyone got an idea of what kind of costs might be involved? There are no splines, just machined faces and holes (for the wheel studs).

I'll provide pics later or what I'm talking about.

[Ben Wilson]

With increased loads, usually the best bet is better maintenance.

Can you upgrade the bearings grease you are using? Can you machine out the hub for bigger bearings?

[wagonist]

Its actually the part that fits inside the bearing that's wearing.

The ST205 inner race is bigger to move the bearing cage outwards compared to my car.



As much as I'd like to do better maintenance, it requires a press everytime its disassembled & then a wheel alignment as well.
Besides, its not letting me do periodic maintenance by failing all the time.

at least the bearing remained intact this time, so I didn't need to spend $180 there

[oldcorollas]

if the bit that is inside the bearing is flogging out, then it is not a proper fit on the bearing.
the bearing should be pressfit, and thus not move around.

perhaps the hub is being done up too tight, so the bearing gets hot, expands, allows movement, and then it flogs out?

were the 205 bits rooted before you got them?
are you going thru bearings, or stub axles or..... is the bearing absoluteyl correct? couldnt be a fraction out?

oh, and you could probably get something machined up.
cast iron is used cos of it's cheapness, but also it's resistance to cracking from road knocks....

[wagonist]

Bearings are the right part listed for my car (& about 20 other Toyotas ) & they always need to be press fit on. I can turn the hub any which way & nothing falls out. When I removed this from the car, half the inner race literally fell out.

It's always where the inside inner race sits that flogs out. It only needs to be a couple of thou before its no longer a press fit. Then more corrosion gets in, yada yada yada.

The 205 parts looked absolutely perfect. Bit of surface rust near where the brake rotor goes on, & I had to rpess them out of the 205 hubs to use them, so they hadn't been exposed to the weather.
The bearings are surviving intact except if the plastic cage holding the balls breaks during disassembly (but not this time ), its always the hub that's wearing.

Bear in mind that this time, I discovered about a week after re-assembling my car, that the 2 bolts holding the strut to the hub were loose & had movement (especially as one has been replaced with a camber pin). There is a thought that because the entire hub was free to move, the week of driving & exerting forces could've caused skewing forces on the bearing.
I've also just had to replace the bush holding the steering rack at the left side because it had deformed, causing the rack to have some slight movement.

[legend]

what bearing grease are u using and how much
the extra load and heat could be breaking down the grease

i had a bearing fail at work 7 times runs 24/7 turned out the other maintenance
guy installed wrong bearings set after set of ball race bearings i bought roller bearings
they lasted 5 yrs

can u bronze bush the shaft ?

[wagonist]

You could be right there.
there was very little grease in my bearing compared with what was still in the 205 one.

Any suggestions on what I should be using? & is there a way to get it in there without dismantling the hub itself? Pulling out the driveshaft exposes the inside of the bearing, & that is a fairly simple job.

[legend]

i use catrol high temp bearing grease and heaps of it

pull it all down clean it and repack with heaps of grease and new bearings check the pre load is within spec

[wagonist]

Not sure how you'd check the pre-load on a modern wide double bearing like these. You can literally pull them apart into 5 pieces in your hand. 1 Outer race, 2 cages with balls & 2 inner races.
It's stopped from falling apart by the driveshaft on one side & the axle nut clamping onto the shaft via the stub axle from the other.

[1jzracing]

sounds like an installation or preload issue to me,

if you press or beat a bearing on the wrong part .... ie put load across its balls it will get brused and fail premiturly

same goes if it has the wrong pre load... i havnt seen the part in question but some front wheel drive hubs have a small crushable sleeve

[2jzhilux]

i would also check that your cv joint is butting up aganist the inner race of the bearing correctly
if it doesnt the inner race of the bearing can flop/spin around causing wear like that

[allencr]

What is 'stub axle'?
What is '18 months'?
What is 'machined vs cast'?
********************************
Single or 2 bearings? Either way, a bearing seizes and its inner race chews up the hub.


Parts incompatability, or poor assembly!!

[crostek]

You can get the shaft of the hub hard chromed, same as crank shafts, this will make it more ware resistant, have you try multi angler contact bearings? These are designed for high thrust / side loading?

Get you self a copy of the service manual and reassemble the hubs with plenty of hi-temp grease and set the preload on the axel nut as per the book, you may need a spring scale to measure the drag.

I have found that in the past if the hub nut is to tight the bearing run hot and crap them self real quickly,

[wagonist]

The croming might be something to look at, although the standard part is fairly shiny where the bearing is pressed on. And what about the extra thickness caused? Yes I know its going to be small, but we're only talking about small distances here.

I did notice that this stub axle seemed to press in further than those previously

I've also got a big issue with brake rotor wear on that corner of the car. Inside face is not worn evenly across the face of the rotor, the inside pad was only half as thick as the outside one.
Having swapped the pads over last night, I can feel the steering wheel moving around, so new rotors are now on the shopping list

[Sunchaser]

Hard chroming isn't to make it all shiny. It is used to add slightly more material to the surface in question (in this case where the bearing presses onto). It can then be machined down to the correct size. An added benefit is that it is generally harder and more wear resistant than the original metal.

It used on cranks and so on when they are so badly worn that they cannot be completely cleaned up by grinding to the smallest undersize. Rather than scrap the crank the journals can be hard chromed to build up the diameter of the journal, then machined down to suit the standard bearings.