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Model specific boards => Golf mk2 => Topic started by: ggoodwin on 02 July 2012, 17:52

Title: Brake disc rust channels
Post by: ggoodwin on 02 July 2012, 17:52
I was checking underneath my 1991 GTi 8v over the weekend and I noticed that both the front discs had a build up of rust on the inner surfaces which had gone into grooves in line with the drilled holes.

(http://i1160.photobucket.com/albums/q500/nexstar111/Brakes-1.jpg)

The outer surface was ok.

(http://i1160.photobucket.com/albums/q500/nexstar111/Brakes-2.jpg)

I'm obviously going to change the discs and pads but I just wondered why it had gone like this and why only on the inner surface?

The pads themselves have got plenty of wear left on them.

Also what is the latest thinking on replacement discs, is there any benefit to be had in fitting grooved/drilled discs on an 8v GTi?

Graham


ps Apologies for not having got my head around the image thing here  :embarassed:

pps I'll stop trying random bits of html as I think I'm just making it worse!
Title: Re: Brake disc rust channels
Post by: Thom89 on 02 July 2012, 18:09
Get a Photobucket account, upload pics, copy IMG code, paste into thread, dead simple

I'm not an aficionado on Discs brands, but I'm sure you'll get an expert soon :smiley:

Thom
Title: Re: Brake disc rust channels
Post by: ggoodwin on 02 July 2012, 18:28
Thank you, Thom!

Much appreciated  :smiley:

Graham
Title: Re: Brake disc rust channels
Post by: Mr Blue on 02 July 2012, 19:44
Look normal. I would worry if they dont work  :grin:
Title: Re: Brake disc rust channels
Post by: X4MGS on 02 July 2012, 22:07
Gone like this due to the fact that only one side of the piston moves...

Hence why you have a thinner inner & thicker outer disc.

If they were like porsche calipers with 4 moving pistons you would have a disc with the same thickness on each side...

Good idea to change them though looking at them...
Title: Re: Brake disc rust channels
Post by: Thom89 on 02 July 2012, 22:39
Look pretty normal to me... working, but not at their best, just give the sliders a little TLC when replacing the disc's and pads.

Thom
Title: Re: Brake disc rust channels
Post by: ggoodwin on 03 July 2012, 00:59
Thanks for the feedback/comments guys.  I guess it seems to stop when needed and it passed its MOT fairly recently so they can't be too bad but, having seen them now, they just don't seem to look like a model of efficient braking  :undecided: .  As the grooves seemed to line up with the drilled holes, I wasn't sure if the drilled discs were adding to the issue or improving it. 

I like the look of drilled and grooved discs but that's not necessarily a good reason to get them!  Are they a good idea again if I decide to change these?

Look pretty normal to me... working, but not at their best, just give the sliders a little TLC when replacing the disc's and pads.

Do you mean clean/lubricate the caliper piston?

Graham
Title: Re: Brake disc rust channels
Post by: rob.043 on 03 July 2012, 15:07
General opinion in the past has suggested that there is no performance benefit for 'regular' driving. But if you like the look sufficienly, go for it!

Title: Re: Brake disc rust channels
Post by: Diamond Hell on 03 July 2012, 17:45
Do you mean clean/lubricate the caliper piston?

No - the sliders need cleaning and greasing to ensure they move freely.

These look like 239mm brakes, they're rubbish.  Grooved and vented discs will only make a marginal difference.
Title: Re: Brake disc rust channels
Post by: Thom89 on 03 July 2012, 17:52
Thanks for the feedback/comments guys.  I guess it seems to stop when needed and it passed its MOT fairly recently so they can't be too bad but, having seen them now, they just don't seem to look like a model of efficient braking  :undecided: .  As the grooves seemed to line up with the drilled holes, I wasn't sure if the drilled discs were adding to the issue or improving it. 

I like the look of drilled and grooved discs but that's not necessarily a good reason to get them!  Are they a good idea again if I decide to change these?

Look pretty normal to me... working, but not at their best, just give the sliders a little TLC when replacing the disc's and pads.

Do you mean clean/lubricate the caliper piston?

Graham

No, the sliders are what hold the 2 halves of the Caliper together, and they should be able to move freely... this says it all :smiley:
http://www.youtube.com/watch?v=LTllR-nOo28

Thom
Title: Re: Brake disc rust channels
Post by: ggoodwin on 04 July 2012, 21:48
Thanks to all for the education.  Yes, they are 239mm and probably are rubbish.  I guess I'm used to them and they do seem to stop me ok but I do also know that when I drive my son's Mk4 GTi I nearly hit the screen on the first couple of times I brake!  This is more down to the relative firmness of the pedal though and I guess that is more down to me getting around to a brake fluid change and bleeding them properly.

I like the idea of the bigger brakes but I'm just not sure I can see myself changing the hubs and calipers as well at the moment.

If the calipers don't free up nicely though then it might be a different story  :smiley: .

Graham
Title: Re: Brake disc rust channels
Post by: X4MGS on 04 July 2012, 21:58
If it was me I would strip off the old discs and pads spend some time cleaning up the calipers & carriers...

Then stick on New OEM Vented Discs and New OEM Pads, bleed off the old brake fluid and that should do you fine...

I dare say that you feel the difference due to the MK4 having a much more modern braking system and calipers...

I fitted new OEM discs and pads in mine 3 years ago and still stops on a sixpence when needed...
Title: Re: Brake disc rust channels
Post by: ggoodwin on 04 July 2012, 22:11
If it was me I would strip off the old discs and pads spend some time cleaning up the calipers & carriers...

Then stick on New OEM Vented Discs and New OEM Pads, bleed off the old brake fluid and that should do you fine...

Yes, I'm tempted to go this route.  When you say 'OEM' I presume you mean from VW?  I can be quite surprised at dealer prices, sometimes they can be very reasonable and then at other times....... :shocked: .

Graham
Title: Re: Brake disc rust channels
Post by: X4MGS on 04 July 2012, 22:34
If it was me I would strip off the old discs and pads spend some time cleaning up the calipers & carriers...

Then stick on New OEM Vented Discs and New OEM Pads, bleed off the old brake fluid and that should do you fine...

Yes, I'm tempted to go this route.  When you say 'OEM' I presume you mean from VW?  I can be quite surprised at dealer prices, sometimes they can be very reasonable and then at other times....... :shocked: .

Graham

Yeah Genuine VW...

IMO - You get what you pay for....
Title: Re: Brake disc rust channels
Post by: mk2bal on 05 July 2012, 12:06
Sod that!! I paid £21.12 for a pair of 16v 256mm vented front disks from ecp last week. (With 30% discount), and they're as good as any others. Can't remember the make, but my pal said they're made by pagid..i Only go to vw for certain vw golf specific things, or oil + filter as its cheap, but not for generic things like pads and disks!! Unless they're reasonably priced, which I doubt they are!!
Title: Re: Brake disc rust channels
Post by: Diamond Hell on 05 July 2012, 14:46
Actually VW do now do an 'economy' line of discs and pads.

I think I have Pagid discs with some good 'OEM equivalent' pads on the Syncro.  I've never had any complaints.  The problem with the 239mm brakes is you'll reach the end of their talents with a standard 8V Golf, which is why people upgrade to aftermarket stuff.

What you'd be better off doing is moving up to either 256mm or 280mm vented brakes, with the hubs and carriers etc.  It is a move you will not regret, if you like stopping.
Title: Re: Brake disc rust channels
Post by: mk2bal on 05 July 2012, 15:03
So they're the same as gsf/euro's/ local motor factor pattern ones, so unless they're actually reasonable with their pricing of them there's absolutely no reason to go to vw for them!! Yeah I agree, go 256/280 for a better setup that's future proofed for more speed
Title: Re: Brake disc rust channels
Post by: Thom89 on 05 July 2012, 18:13
Lots of VW service items are very reasonable, they were losing out massively to the likes of GSF/ECP some years ago, and decided to do something about it. Even if its a few quid more, I'd buy the OE stuff from VW for the correct paperwork alone!!! VW headed invoices look very impressive in the cars service history folder! :evil: :evil:

Thom
Title: Re: Brake disc rust channels
Post by: X4MGS on 05 July 2012, 18:16
Lots of VW service items are very reasonable, they were losing out massively to the likes of GSF/ECP some years ago, and decided to do something about it. Even if its a few quid more, I'd buy the OE stuff from VW for the correct paperwork alone!!! VW headed invoices look very impressive in the cars service history folder! :evil: :evil:

Thom

You also get a 2 year warranty with VW stuff...

Which is worth having... I've just got a replacement Blue Temp Sender after mine failed after 13 months...
Title: Re: Brake disc rust channels
Post by: ggoodwin on 05 July 2012, 23:35
Thanks again guys for the input.  Lots to mull over there  :undecided: .  I'm going to take have a closer look at the calipers in the next couple of weeks and see what they're like and decide what to do from there.  I guess having driven these for the past 20+ years I've probably just got used to the brakes  :smiley: .

Graham
Title: Re: Brake disc rust channels
Post by: Ben Lessani on 12 July 2012, 23:21
Have a read, http://www.golfgtiforum.co.uk/index.php?topic=49436.msg871824#msg871824
Title: Re: Brake disc rust channels
Post by: ggoodwin on 13 July 2012, 11:03
That's brilliant, thanks!  There's nothing like a few pictures to clarify things :) .

Graham