Rear Brake, Caliper and disk change

JJJJNR

Stupid question alert!

Going to upgrade my rear brakes this weekend (my05 Seat Altea 2.0Tdi) with some 312mm disks but have a quick question, when I got the disks (second hand very cheap etc) they were very badly corroded, I had to submerged them in paint thinners to remove the corrosion which worked great, however in the middle of the disks there are some ball barings these were submerged in the paint thinners also, in hindsight this was possibly a bad idea, anyone know what the purpose these serve ? are they the actual bearings?? and will they be destroyed now, they look fine from examination by an untrained eye, also if they are destryed I presume the ones that are on the car now will fit, is it a big job?

Can of worms maybe?

JJJJNR

anyway did some research and they bearings should be fine with a good bit of grease according to this guy who did almost exactly what I did.

https://www.youtube.com/watch?v=uL1IhSX3VwQ

mickdw

You will have to pack grease into them bearings. Keep forcing it in with the palm of your hand for a few mins even if it looks like there is nothing going in. You would need the correct type of grease also.
In relation to the upgrade, In my opinion, doing an upgrade like this on your REAR brakes is a pointless exercise on something like an altea.
Have you already done the front?

JJJJNR

yeah I've already done the front and like the extra bite, the reason I upgraded these is the rear caliper bleed nipple is fooked on rear left and it cost the same to upgrade all four to these inc disks as it would have been to get one new caliper fitted.

George Dalton

You don't need to change rear bearings when changing to the larger rear discs. The disc is a separate part to the hub/bearing assembly. So when doing the upgrade you simply change the caliper carrier and fit the larger rear discs onto the existing hub.

If the discs were badly corroded then you should do yourself a favour and buy new parts. Using old corroded discs will mean you won't get the full benefit of the larger brake setup.

Hermy

JJJJNR wrote: »

(second hand very cheap etc) they were very badly corroded...

I wouldn't call that an upgrade.

JJJJNR

I would as the disks were completely corroision free when I put them on, they were like new the paint thinners removed all the rust.

mickdw

JJJJNR wrote: »

I would as the disks were completely corroision free when I put them on, they were like new the paint thinners removed all the rust.

It was only a bit of surface rust then like you get on any car that has been parked for a few days.

JJJJNR

Yea they were fairly bad in fairness, i had considered getting new disks but someone mentioned steeping them in paint thinners for a couple of days would get rid of it, they came out fairly well considering, the front ones are 100% now, even after i managed to mess up by putting on the incorrect pads..

Thanks George,mick I've attached a pic of the disk, they are in very good condition as you can see, it would be a shame to waste these disks as they've got a good bit of mileage left on them, so the bearing in the middle I need to grease them up with proper grade grease or will normal grease do the trick.

George Dalton

JJJJNR wrote: »

Thanks George,mick I've attached a pic of the disk, they are in very good condition as you can see, it would be a shame to waste these disks as they've got a good bit of mileage left on them, so the bearing in the middle I need to grease them up with proper grade grease or will normal grease do the trick.

The disc in that picture looks pretty worn to me. It also looks like a 260mm or 280mm disc rather than a 310mm. What car did the brake setup come off? Mk5 platform 260mm and 280mm discs are so cheap new that bothering with the likes of the parts in that picture is pretty pointless IMO.

Those bearings in my opinion are only fit for the bin after being steeped in paint thinners. I certainly wouldn't use them on any car of mine or fit them to a customer's car either. They are a sealed bearing and are not designed to be re-greased. If you are dead set on using the secondhand discs then just remove them from the old bearings and use your existing bearings.

JJJJNR

Fair point taken, they came off a Mk5 GTI, what would you be looking at for new disks micks are quoting 115 for two "abs" 280mm are they decent..? yea the 312 mm are on the front.

George Dalton

You should be able to get a pair of 286mm rear discs for a good bit less than €115. I would say €70 or so for the pair should be do-able easily enough.

Hermy

JJJJNR wrote: »

I would as the disks were completely corroision free when I put them on, they were like new the paint thinners removed all the rust.

But you said in your opening post that they were very badly corroded.
And now you're saying that they're completely corrosion free.
I must get me some of that corrosion removing, metal renewal thinners so.;)

DanWall

I would be very surprised if you did not get and judder when applying the brakes

JJJJNR

When I put the fronts on I drove for a couple of km's with the brakes slightly (it was a quiet sunday) on which cleared any remaining crap from the disks, which in fairness to this project your supposed to take it handy with new disks anyway, rear disks are about 70 euros from local motor factors which is a great price, but wonder how they compare to OEMs though as I still think the disks themselves would be fine once I remove the bearings.

JJJJNR

Also how do you remove the bearing assembly from the disks in pic.

JJJJNR

boards calling George boards calling George!..only jokin!

looks like my front left bottom control arm bush is gone, theres a bit of movement on it, myself and one of the lads were having a look around troubshooting a knocking noise from there, so is it a big job to replace it, and does the whole arm need to be replaced or just the seal.?

George Dalton

The bushes are available separately so you don't need to change the whole arm.

As for removing the rear discs from the bearings, hit them with a hammer :pac:

JJJJNR

Tried that today, looks like I'll have to get a much bigger hammer.! theres 10mm left on the disks, shame to get rid of them with that much left.. so the bushes is it a big job presume the whole arm has to come out to replace the bushe or is there an easier way.

George Dalton

10mm is the minimum thickness on those discs IIRC so at 10mm they are due to be changed.

You have to remove the arm to change the bush but they are very easy to take out.

JJJJNR

Hey George just from looking at new ones online they come new with 12mm for the rears so still fairly new..

Will give that a go in a few weeks no major rush to get it done but good to know it should be a straight enough job.

George Dalton

JJJJNR wrote: »

Hey George just from looking at new ones online they come new with 12mm for the rears so still fairly new..

Yes the new discs are 12mm but I am pretty sure the recommended minimum thickness is 10mm, so if yours are at 10mm then they are not fairly new, they are worn out

landcrzr

Just an observation, but if you are putting 312mm discs on the rear, I am guessing the ones on the front are 312mm also?

If so, is there not an issue with brake bias now between front and rear. Generally the front discs are larger than the rear. If you have the same sized discs on the rear now, will they not tend to lock up before the front wheels? assuming no abs of course.

JJJJNR

that was a typo they are 280mm at the back..