Radius arms. which side is up - IRS First Time Rebuild


(Aristides Balanos) #202

Bushings are not that great in dealing with radial forces.
And I can’t see how, with metal to metal friction, they can hold their tolerances in time better than needle bearings…
When I had inspected mine, original bearings with 130.000 Km and almost 30 years of use, even with the felt seals but well lubed, they were still in very good condition and they are still in my car.

Aristides


(Mark Lee (Pay Pal Patron)) #203

Not this IRS. I assembled the hub last night and the bearing is snug, but not as snug as the other side. The end play could be adjusted with two screw drivers. This was handy cause I got the end play right where I wanted it and the shim/spacer turned out to
be the 0.140 which I have a bunch of. The other side however I’m gonna need a 0.127 naturally nobody has them on stock. Go figure.

I did decide to use the JB carrier well because I have to get the tools back. I have had them way too long and I feel really bad about that.

I’ve learned a lot in this process, and have discovered that I can set the proper end play and figure out what shim I need without the use of the mandrel. Frankly I think it’s easier,
the way I’m doing it either that or I’m doing it wrong and will be making a complete hash of the hub and carrier.

It

Sent from my BlackBerry 10 smartphone on the Verizon Wireless 4G LTE network.


(Frank Andersen) #204

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The advantage of the mandrel is two-fold, Mark…

The mandrel ensures that the inner race is pushed on squarely. Secondly, the calibrated 0,15" shim gives a reference point for computing the correct shim thickness from the measured play from that…

The logic behind the mandrels was to locate the inner race with excessive play. It is easier to push the inner race further down the hub, reducing play, than to ‘lift’ the inner race to increase play.

Fitting the inner race without the mandrel is fair enough, but with a measured shim in place; the difference between the measured and desired play still dictates the proper shim to use…

Frank
xj6 85 Soc Europe (UK/NZ)
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(Mark Lee (Pay Pal Patron)) #205

well either I was doing something wrong. of there is a lot of excessive play. :blush:

Also, in an earlier post, I understood what I read something about (I’m too lazy to search for it in order to quote it or I misunderstood) the inner bearing being able to move on a hub. The last carrier I put together, the inner bearing wasn’t as tight on the hub shaft as the previous one. I assembled it anyway, Am I going to regret it? and should I search for a new carrier assembly?

Thanx again
Mark


(Mark Lee (Pay Pal Patron)) #206

I posted a new video on installing the bearings in the inner fulcrum bearing with a bolt.


(Frank Andersen) #207

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It is a press fit, Mark - pressed on with the mandrel, or whatever. Then, with the proper shim computed and installed - the inner race must be pressed home against that shim. If this is not done, the inner bearing will stay in its original 015" shim position - with excessive play.

However, when the driveshaft is inserted and torqued up, the inner race will be forced it contact with the installed shim - and the play should be correct. if everything was computed correctly…:slight_smile:

If the inner bearing is too loose it may cause it to slip on the hub - which is ‘not good’. However, ‘wasn’t as tight on the hub shaft as the previous one’ may not be alarming. the old one may have been grubby - or there was unwanted grease on the hub shaft? It’s a dry fit…

Frank
xj6 85 Sov Europe (UK/NZ)
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(Mark Lee (Pay Pal Patron)) #208

Crap! well I think this is going to fall into the category of not good. for example, I can adjust the endplay with two screw drivers prying on the carrier against the water ring. the PO had, what looked like home made knurling with a drift to keep the bearing snug. Worse case it spins a bearing, right? when the hub is tightened on the axle, the bearing should also be tightened to the seal ring which is pressed against the spindle on the half shaft holding everything in place. kinda like the front wheel bearing and spindle arrangement.

Well this sucks!


(Frank Andersen) #209

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In principle; the inner races are held in position by the drive shaft nut, Mark…

When you levering the hub carrier without the driveshaft fitted; the outer race pushes against the inner race. With enough force the inner race will move on the hub - this is, after all, how play is adjusted…:slight_smile:

The testing procedure assumes that leverage is just enough to take up the play - and assumes that the inner race is not so loose on the hub that it moves too easily…

With the driveshaft fitted and torqued up, the inner races are held to set play. In principle, while the inner bearings can move on the hub to close up the play, the forces acting on hub/carrier and the conic construction of the of the bearings ensure that the play is maintained as set…

But only friction between the inner race and hub prevents the race from spinning on the hub. How tight the fit must be I don’t know - no specs are given. But both the hub and bearings are precision constructs - so without visible damage or signs of hub wear it should be safe…

Incidentally; the same applies to the outer races - they are press fit into the hub carrier, and friction alone prevents spinning…

Frank
xj6 85 Sov Europe (UK/NZ)]
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(Mark Lee (Pay Pal Patron)) #210

Those were my thoughts too, Frank. so I figured if I get the proper end play once it’s more or less assembled, then I should be fine. It looks like the PO took a drift and attempted to “knurl” the inner portion of the hub to get a tighter fit on the bearing / hub assembly. So I figure it is probably ok. I’ll find out, I guess. it’s a pretty easy service while on the car, so I’m not too terribly worried about it. I’m searching for a rebuildable hub to have as a spare. I figure I’ll have a rebuilt hub carrier assembly on hand just in case it turns out to be a boondoggle.

do you know what the exact placement of the bigger shims the ones that go on the outside of the fulcrum shaft assembly on the carrier? There are two shims for each side,

  • Do these shims go on between the tapered roller bearing and the inner felt seal retainer or
  • between the inner felt seal retainer and the outer portion of the fulcrum arm itself?

The PO had one side between the felt seal and the bearing and on the other side, only one big shim on the whole assembly. This shim was between the inner felt seal retainer and the fulcrum arm.

Here’s my thoughts on this.
The shims are pretty fragile, and are easily damaged, so I’d think between the bearing and the inner felt seal retainer. Being on the inside the shims serve their purpose as well as being protected from the outside elements. My placement is between the tapered roller bearing and the inner felt seal retainer.

Thanx again everyone!
Mark


(Mark Lee (Pay Pal Patron)) #211

Those were my thoughts too, Frank. so I figured if I get the proper end play once it’s more or less assembled, then I should be fine. It looks like the PO took a drift and attempted to “knurl” the inner portion of the hub to get a tighter fit on the bearing / hub assembly. So I figure it is probably ok. I’ll find out, I guess. it’s a pretty easy service while on the car, so I’m not too terribly worried about it. I’m searching for a rebuildable hub to have as a spare. I figure I’ll have a rebuilt hub carrier assembly on hand just in case it turns out to be a boondoggle.

do you know what the exact placement of the bigger shims the ones that go on the outside of the fulcrum shaft assembly on the carrier? There are two shims for each side,

  • Do these shims go on between the tapered roller bearing and the inner felt seal retainer or
  • between the inner felt seal retainer and the outer portion of the fulcrum arm itself?

The PO had one side between the felt seal and the bearing and on the other side, only one big shim on the whole assembly. This shim was between the inner felt seal retainer and the fulcrum arm.

Here’s my thoughts on this.
The shims are pretty fragile, and are easily damaged, so I’d think between the bearing and the inner felt seal retainer. Being on the inside the shims serve their purpose as well as being protected from the outside elements. so My placement is between the tapered roller bearing and the inner felt seal retainer.

Thanx again
Mark


(Frank Andersen) #212

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Such ‘modifications’ are questionable, Mark - but as you say…
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Shims are there to ensure the inner races are running true, or ensuring proper play, to the outer ones. In principle, being factory set, recording the number and placement of shims at dismantling is best practice. With PO interference this may not be right…

From the bearing; ring abuts the outer race. The seal retainer (with the seal inside) - the seal in contact with the bearing. Then a large washer. Inside this assembly the smaller ring abuts the inner race. The small shims outside abuts the ring - and are meant to the the ‘rub’ from the whishbone…

If these shims are placed adjacent to the inner race they wont do that - and will slightly displace the ring, adding leakpoints at the seal. I’m not sure of the overall result of your changes - even if, as you say, it wont affect the shims function as ‘distance’ holders…

Frank
xj6 85 Sov Europe (UK/NZ)
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(Mark Lee (Pay Pal Patron)) #213

so the larger shim is supposed to go between the inner seal retainer and the (as you refer to it as the wishbone) I refer as the outer fulcrum. If I understand correctly, the shims serve double duty

  • work as a thrust bearing between fulcrum and the inner felt seal retainer and
  • a place holder for the proper spacing for the carrier bearing / mounting assembly

Essentially the shims are in the wrong place.