There's a large hollow space inside the rear arms which fill up with old grease.

and can split.

or they are already split in the new kit you just bought. very common over here ....

Who designs and makes this sh!t... we know who sells it. Everybody!

You cannot Sell What You cannot Get, However, if the original Metal tube is still fitted, do not change it. The metal one was not always fitted at the factory,

The top arms are straight forward enough, once you remove the old needle rollers, then its a simple case of pushing in the new bearing(carefully so as not to damage the rollers or cage.)

The rear is another matter. The bush needs to be reamed using a special tool. Not really one to do without some planning.

Best to remove all the grease from the front arms, and as much as you can from the rear. At least enough to make sure it does not migrate back into the new bearings once you start pushing grease in again. There's a large hollow space inside the rear arms which fill up with old grease.

so just take both to pedders with the new bearings and ask them to remove/install them for me

"You cannot Sell What You cannot Get,"

To some John, it reads "If I can't get quality, I will sell poo poo."

I certainly didn't read it to say that ,sounds like they have to sell what's available .,
ie: metal tubes aren't available .
Docs comment 's are basically a continuation of another thread about rubbish parts that are getting about nowdays .