Folks,

 

Had the Fabia in having the front OS wheel bearing replaced. They pressed the old one out of the hub, and replaced with a new one.

 

Since getting it back the brakes have felt juddery while under a medium load (ie stopping on a slip way after exiting the motorway). It's a very similar feeling to when the ABS is kicking in.

 

Took it back to the garage, the dude plugged the computer in, and said no faults were showing. They stuck it on the ramp, and couldn't see anything obviously wrong.

 

It's back with them today as he gave me some theory that I didn't understand. Being a man in a garage i didn't want to confess that at the time...

 

Something along the lines of when they pressed the bearing back in it may not be totally in line, which may have caused the brake disc to be a bit off. Said they're going to remove the disc, assess it on a (didn't catch the name) machine, then maybe use their lathe to fix it if possible.

 

I just blindly nodded and said cool...

 

Any idea what they're on about?

If they didn't get the bearing in completely straight then you will have hub run out which means the break disc will wobble very slightly. This leads to friction material being laid down on the disc unevenly and results in the brakes grabbing slightly at certain points and will only get worse. If they've caught it early enough then you might not need new discs.

Special tooling is required to fit these bearings, did they use it?

 

See e.g. https://www.youtube.com/watch?v=M69uwMLib80

Possibly a bit of crud between the disc and hub, but suspect they've not fitted the bearing correctly. As above, the correct tool is required.

Interesting.

 

No idea if they used that tool or not. The invoice just mentions it was 'pressed out' and pressed back in again...

 

They definitely mentioned something about hub run out yesterday... I guess they must have come to the same conclusion then; wonky bearing.

 

Thanks for input chaps - always nice to be armed with a bit of info. Hopefully they wont try to sting me for a new hub, discs and pads.

Interesting.

 

No idea if they used that tool or not. The invoice just mentions it was 'pressed out' and pressed back in again...

 

They definitely mentioned something about hub run out yesterday... I guess they must have come to the same conclusion then; wonky bearing.

 

Thanks for input chaps - always nice to be armed with a bit of info. Hopefully they wont try to sting me for a new hub, discs and pads.

 

Don't hold your breath, they sound like incompetent muppets.

Bearings on my car have been the bain of my life, the previous owner was having them pressed in so both failed, they must be fitted with a gen 2 puller and good quality bearing units or they will fail in no time, sounds like its been forced in on a press as garages cant be bothered buying the proper tooling.

Don't hold your breath, they sound like incompetent muppets.

 

Been using the same place for all my mechanical needs for about the last 6 years, over 5 different cars and this is the first time there's been an issue. They give the impression they're a quality outfit, but i guess we'll see.

 

I wonder how well "the internet reckons you're a bunch of useless idiots" will go down when i go back to pick it up

Been using the same place for all my mechanical needs for about the last 6 years, over 5 different cars and this is the first time there's been an issue. They give the impression they're a quality outfit, but i guess we'll see.

 

I wonder how well "the internet reckons you're a bunch of useless idiots" will go down when i go back to pick it up

 

It's not just 'the internet', we're specialists, your garage are generalists. Most people buy a complete hub assembly with the wheel bearing already correctly fitted, the part is more expensive but the labour incurred is far less. Now you know why.

I'd imagine that's what was bought.

Even the hub assy with bearing requires the correct tooling to insert it into the bearing carrier. That's why those tools exist.

I'd imagine that's what was bought.

Even the hub assy with bearing requires the correct tooling to insert it into the bearing carrier. That's why those tools exist.

 

I meant the carrier assembly with the bearing pre-installed.

Last I heard from Tech1e, they don't come with bearing fitted, more like this:

What's the reason for using the gen2 puller system out of interest?

 

Watching that video I can't see why you can't fit them using a normal press if you know what your doing and use the correct size tooling,and support the carrier correctly,so your not pushing on the centre of bearing?

Had exactly the same way back when I had my Fabia, they're not used the correct tool and damaged the ABS sensor/ring whatever. New one fitted by a garage with the correct tool and it was good as new. 

What's the reason for using the gen2 puller system out of interest?

 

Watching that video I can't see why you can't fit them using a normal press if you know what your doing and use the correct size tooling,and support the carrier correctly,so your not pushing on the centre of bearing?

I didn't know the answer to this when you asked, but I think I might have a small clue now. Have a look at this much longer, and nicely commentated video: https://www.youtube.com/watch?v=txD5CiHgin8

The silver rings that press the new bearing in have a step which means that they press on a step in the bearing that's completely inaccessible behind the drive flange unless you have these clam-shell bits.

 

This area:

Quite how that differs from pressing evenly on the outside face of the drive flange isn't clear to me, but that's what this tooling seems to do.

 

Edit: I suppose logic says that the drive flange is rigidly connected to the inner of the bearing, and this surface that gets pressed is the outer??

Edited 29 April, 201610 yr by Wino

Ah cheers,I can totally understand why it's needed if the bearing/drive flange is a complete unit like in that video

So are all bearings complete with the drive flange?

 

Only VAG bearing I've done was on a W reg polo,and that was a separate bearing and you reused the drive flange so a standard press was used.

Ah cheers,I can totally understand why it's needed if the bearing/drive flange is a complete unit like in that video

So are all bearings complete with the drive flange?

 

Only VAG bearing I've done was on a W reg polo,and that was a separate bearing and you reused the drive flange so a standard press was used.

Yep, that's my understanding.

Ok cheers 

 

Really struggling to understand how anyone with any mechanical knowledge would use a press on the drive flange to press in the bearing though tbh!!!! 

 

That must be what people are doing when they knacker the new bearings fitting them?

Yeah, once I'd realised what I wrote in my edit, it seems obvious that pressing on the drive flange is wrong, but up 'til then I hadn't worked it out. One of those things where it just 'clicks' in your brain. Your brain more readily than mine by the sounds of it.

Got one to do on a m8's GtTdi Mk4 Golf tomoz,but that's just a new bearing with a circlip in the box.

 

So a normal press job luckily