Front discs (or rotors)

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sharkfan
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Front discs (or rotors)

Post by sharkfan »

Hi,

My 82 (E28) 635 Auto is due a new set of front discs - I was originally thinking of just going for Original Equipment but thought I'd canvas opinion on anyone with upgraded / non-standard / super-whizz-bang front discs.

Has anyone fitted anything other OE? any difference in braking? any difference to your wallet? :shock: was it worth it? :? any problems on the way? :evil:

I'm figuring on staying with the standard calipers and OE pads (I have a brand new set already :oops: ) but any opinion is valued :D

Sharkfan :twisted:
horsetan

Post by horsetan »

You need to have a look at THIS THREAD

In it, you will see the photos of the new discs and pads that I bought, and which were fitted last weekend.

The new front discs are: ATE "Power Discs" (which have a built-in wear indicator groove)

The new front pads are: PAGID "fast road" pads.

The new rear discs are: standard Bendix OEM

The new rear pads are: standard JURID OEM.

I still need to get replacement calipers fitted in the next two weeks, but am running on the above set-up now, whilst I wait for the calipers to be delivered.

The difference, whilst not exactly breathtaking yet (still being bedded-in), is still noticeable, and will be more noticeable once the calipers are in and the brake fluid has been changed. There is a reassuring amount of "bite" already. :D

Note that the upgraded discs and pads are on the FRONT only. The difference in cost over standard was about 30 quid more. I like what I'm feeling via the brake pedal at the moment.

I did want to experiment by fitting an E32 750 master cylinder, but couldn't get hold of one, so have stayed with the original standard.
TorQue_635

Re: Front discs (or rotors)

Post by TorQue_635 »

sharkfan wrote:Hi,

My 82 (E28) 635 Auto is due a new set of front discs - I was originally thinking of just going for Original Equipment but thought I'd canvas opinion on anyone with upgraded / non-standard / super-whizz-bang front discs.

Has anyone fitted anything other OE? any difference in braking? any difference to your wallet? :shock: was it worth it? :? any problems on the way? :evil:

I'm figuring on staying with the standard calipers and OE pads (I have a brand new set already :oops: ) but any opinion is valued :D

Sharkfan :twisted:
I went for a semi super whizz-bang upgrade all around.

I got 850i front discs (324x30), e34 m5 vented rears (300x20) both cross drilled. Also running 4 pot AP calipers front and M5 single piston calipers rear with ferrodo pads.

Difference in wallet, heaps (so light now my bank manager feels the pain). Worth it? Most definately, literally takes my breath away. I was never happy with the OE brakes that came with the highline 635. It just didnt seem stop the car liked i'd thought it should do. Now it does 8)

Problems. Brake dust, lots of it. Brake squeal. Brake pedal travel has also increased greatly, but that should be sorted soon with a 750i master cylinder.
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Brucey
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Post by Brucey »

Out of interest how much did all that set you back?

Incidentally EBC greenstuff pads are meant to be low dust; any comments anyone?

Also, how do you know your brake balance front to rear is OK?

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
horsetan

Post by horsetan »

Brucey wrote:Out of interest how much did all that set you back?
The front calipers (which are reconditioned ones, by the way) were delivered today.

I know your question wasn't aimed at me but, for the record, Motormec's invoices read as follows (prices net of VAT):

FR0413 Pagid Fast Road Pads (front set) = ?25.00

8290175POW Power Discs ATE 032501041= ?89.74

571300J/AS OE Brake Pad (rear set) = ?17.96

561162B Brake Disc (rear) 4092M = ?32.00

160369 NSF Caliper E24 = ?80.00
160370 OSF Caliper E24 = ?80.00
Old Unit Surcharge (refundable) = ?40.00


Delivery charges (in total) = ?23.94

VAT on the above= ? 68.01


GRAND TOTAL = ?456.65 :shock:

So, imagine my displeasure when I found out that, if I'd ordered brand new calipers from BMW, I would have paid ?301 (and that doesn't include VAT) for them alone.... :evil:
Brucey wrote:....Incidentally EBC greenstuff pads are meant to be low dust; any comments anyone?
I'd heard the same. I'd also heard comments from other quarters that the EBC Greenstuff type generated almost as much dust as OEM (and by this, I presume Jurid or *urgh* Textar).

So, given the uncertainty, I went with Pagid "fast" pads on front, whilst sticking to OEM standard Jurid on rear. As I wrote earlier, the combination seems to be working OK during the bedding-in process, given that I don't actually drive all that fast anyway - can't afford to with the cost of petrol as it is. There's a lot to be said for wafting. :D

Too early to say whether the Pagid pads are low-dust - Andy Howlett at Motormec couldn't provide a definitive answer - but they surely can't be as bad as the Textar ones which were in there previously....

I also forgot to add that I now have no brake squeal at all (I've driven in the cold mornings and evenings this week with the window open to listen in). No more

Image

Shakin' Stevens steering wheel when testing at 50-55mph speed range, and only the merest hint of tremor when braking from 60mph down to 50mph.

This suggests to me (which my mechanic was trying to drum into my thick skull previously) that the previous discs were both very worn and out-of-true, and that the O/S/F caliper had more or less seized, which was a major factor in the infamous shaking steering (which Dave has personally witnessed when we took that trip to the Donington show back in October '04).

Hopefully once the new calipers are in (sometime next week) and the brake fluid changed, there should be no shaking at all, and Dave can then enjoy a trouble-free waft the next time he's chauffeured by me :lol:

This also means that I don't have to worry about fecked control-arm bushes just yet..... :roll:
sohlman

Post by sohlman »

Sounds good Ivan. I will be fitting all mine next week with the 540/M5 set up. I got the 540 brakes on the Motormec sale discount so were a little bit cheaper than yours.

will be nice to get rid of the wobble
horsetan

Post by horsetan »

Sohlman wrote:Sounds good Ivan.
Sounds good? It feels good....
I will be fitting all mine next week with the 540/M5 set up. I got the 540 brakes on the Motormec sale discount so were a little bit cheaper than yours.
Go on, rub it in. I wasn't going to use larger diameter discs anyway...
will be nice to get rid of the wobble
Everyone would like to be rid of the wobble.... :roll:
ron
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Front discs

Post by ron »

Question: Do the 750 discs and calipers bolt staight on??
TorQue_635

Post by TorQue_635 »

Brucey wrote:Out of interest how much did all that set you back?

Incidentally EBC greenstuff pads are meant to be low dust; any comments anyone?

Also, how do you know your brake balance front to rear is OK?

cheers
Price wise i spent about AUD5500 on it (translates to about 2300 GBP) so not a cheap upgrade. Major expense went into the AP calipers and the custom mounts to suit.

If i had found a set of e31 (single or 4 piston) calipers to fit they would have bolted straight on.

Here's a url related to brake upgrades for e34's. Most of the information applies to e24/e28/e32/e34 vehicles. You can basically swap any of the larger gear straight into e24's. You just need to get larger rims to fit around them.

http://www.bmwe34.net/e34main/upgrade/brakes.htm
sohlman

Post by sohlman »

E32 750 Single pot callipers bolt straight on without any need for modification and give you a 302x28mm disc with a 60mm bore piston as opposed to the standard 635 brakes which are 282x22mm with a 57mm piston. M6 4 pots have 4x32mm pistons and require discs of 300x25mm. An easy modification for M6 owners is to machine down some 750 discs which are better at dealing with heat then the standard M6 rotors.

Other brake applications include E34 M5 single pots with 315x30mm discs. 850 pre 1993 discs which are 315x30mm on single pot callipers. E34 M5 3.8 Brembo 4 pots with 345x32mm discs with 4x45mm pistons. 840/850 post 1993 with 325x30mm discs and 4 pot brembo's with 4x40mm pistons and 850csi 4 pot brembo's using 345x35mm discs. All of these will bolt onto a 635, however 750's need 15" wheels, M5 singles and 850 singles require 16" wheels. 840/850 4 pots fit some 16" wheels, but definantly fit 17" Wheels and M5 and 850csi 4 pots require 18" wheels.

I have done a fair amount of research into this using some of the articles on bigcoupe. I will be fitting 540/750 front callipers with 540/M5 rear callipers and vented discs on the rear. I already have a 750 master cylinder which has a larger bore allowing more fluid to be moved and will be fitting stainless braided brake hoses. Last year i fitted 840 4 pots which were awsomely powerfull, but they would not fit on the later purchased Alpina 16" rims and so the brakes were brought back to standard untill i found a good 540/750 set up.

Hope this helps
James
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Brucey
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Post by Brucey »

That is really good information James- I do worry about brake balance though- has anyone worked out the caliper pressures/mean effective disc radius for each combo vs. standard? This would be a step in the right direction here.

Cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sohlman

Post by sohlman »

Please find listed below the Big coupe research i have gained my information from. It does explain a lot about the affect on brake balance.

http://www.nwlink.com/%7Ejrallen/mforma ... mbrake.pdf

and

http://member.rivernet.com.au/btaylor/B ... E28M5.html
ron
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Front discs

Post by ron »

Thanks to everyone for all the info.supplied.There is certainly a lot of it!! I've got my 750 front calipers and master cylinder,just need to get the new discs and then work out what to do at the back.Having read through a vast amount of info.I see that a lot of people don't recommend using braided hoses for road use.Any comments on that? Regds.Ron.
sohlman

Post by sohlman »

I think that depends. With the sixes as far as i can work out there are three braking systems. On the e12 cars they have 2 master cylinders and a brake biassed controller. Then from 1983 - 1987 the master is one one side and the servo is on the other conected by a torsion bar and then you have the highline models which have a servo and master all together in one unit. The E12 and Highline M6 system are very reliable and generally have a firm brake pedal as standard with the e12 system being the most adjustable. The Highline system has very good pedal feel and both these systems unless callipers with larger bore diameters have been added, adding stainless hoses may make the pedal feel a little bit hard, but as i have never driven either of these cars with braided hoses i can't comment other than with theory.

The problem is with the 1983 - 1987 cars like mine. Due to the servo being on the left side and the master being on the right side the torsion bar flexes giving a very spongy pedal. This has been driving me mad since i bought the car 7 years ago. Hopefully stainless steel hoses along with my callipers upgrade will improve things significantly, but if it does not i will be forced to go down one of two routes.

1: - to Mount the master cylinder in reverse on the servo and have it sitting in the passenger foot well. Now this is not an option for a road car, but for a race car is the cheapest solution. or

2: - Find a late model highline or My and take the braking, servo and piping system from it, cut a hole in the bulk head and move everything across.

I am told buy my specialist who has done this to three sixes that option 2 takes about 3 hours for him to do, while option 1 takes a little longer but allows a much more powerful servo and master to be fitted and is what he did with his M6 race car. It's running a full wilwood system with 4 pot AP's. The reson this takes longer is that a braket needs to be made to hold the servo and master cylinder in the passenger foot well.

Hope this helps
James
carrie

Post by carrie »

^^^ that must explain why my brakes seem to do nothing for a part of the travel then haul up big time later
horsetan

Post by horsetan »

Sohlman wrote:...from 1983 - 1987 the master is one one side and the servo is on the other conected by a torsion bar...
....which can jam.... leaving you with a brake pedal that falls limply straight to the floor, and a car that keeps on moving regardless.....

Not what you want when you're fast approaching the rear end of the car in front. :shock: Ask me how I know....
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Post by Brucey »

The early E28 RHD torsion bar arrangement is very horrible indeed, going on completely ghastly; you just have to look at it to know it is not a good idea. I get one of those involuntary shudder things going on just looking at it, and when I went shopping for a 6er this did put me off.

I can only assume it is some perverse Bavarian joke that was played on anyone who wanted to drive on the left side of the road...

Fortunately they took pity on us and gave us a decent system later on. The really good news is that you don't have to buy the (admittedly luxurious but somewhat lardy) highline to have better standard brakes on RHD.

My 4/87 build RHD chrome bumper 635 has the servo and the master cylinder intimately linked on the right side in the approved fashion. I don't know when this came in exactly; anyone know this?

Anyhow, maybe this is one reason I don't feel a desperate need for upgraded brakes over standard (although I am sure they can be usefully improved and I would definitely want to do this if I was going on the track).

Admittedly I have not given the brakes really severe (ie. fade-inducing) treatment recently (and I won't again until I have done my now overdue fluid change) but for this type of car I would mark them 7/10 vs good modern brakes and 8/10 or 9/10 for the mid-eighties.

I'd mark them down mainly for initial bite, and a little bit for feel; and to be honest this seems a little churlish given how sensitive both these things are to pad type. There does not seem to be a shortage of power per se and I can pull up from 70+mph pdq, no worries.

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sohlman

Post by sohlman »

You may shudder thinking about them Brucey, but myself and Ivan shudder every time we use them. Bloody RHD cars with a steering box in the way. Ahhhhhh
UKDaveJ

Post by UKDaveJ »

Sohlman wrote:You may shudder thinking about them Brucey, but myself and Ivan shudder every time we use them. Bloody RHD cars with a steering box in the way. Ahhhhhh
Me too James, on my 84 chrome bumper!!
Though, cannot really say I've been disappointed by feel or power, but guess you guys drive harder than I do....! :roll: :wink:
horsetan

Post by horsetan »

Could I just remind everyone for the record that 'tis only James who drives hard. I prefer to waft..... :wink:
sohlman

Post by sohlman »

I assure you this is not the case. I have seen Ivan in anger twice on the roads. Once when he launched Dave's green six out of the ottershaw car park in a cloud on tyre smoke and the other time on the way to Santa Pod where Ivan went past at well over 100mph. My definitio and Ivans definition of wafting is quite different.
UKDaveJ

Wafting definition redefined thanks to Sohlman!

Post by UKDaveJ »

Sohlman wrote:I assure you this is not the case. I have seen Ivan in anger twice on the roads. Once when he launched Dave's green six out of the ottershaw car park in a cloud on tyre smoke and the other time on the way to Santa Pod where Ivan went past at well over 100mph. My definitio and Ivans definition of wafting is quite different.
My green 6 has never been the same since....... :roll: :wink:

I don't drive my 6'ers hard, not that I don't enjoy a spot of hard driving..... Image
Image
Dave 8)
horsetan

Post by horsetan »

Sohlman wrote:....on the way to Santa Pod where Ivan went past at well over 100mph. My definition and Ivan's definition of wafting is quite different.
Excuse me, since when were you able to accurately mark my speed as reaching the ton on that occasion? :?: :?: :?:
UKDaveJ

Handbags at the ready boys.....????!!!!

Post by UKDaveJ »

horsetan wrote:
Sohlman wrote:....on the way to Santa Pod where Ivan went past at well over 100mph. My definition and Ivan's definition of wafting is quite different.
Excuse me, since when were you able to accurately mark my speed as reaching the ton on that occasion? :?: :?: :?:
I'd guess that if James was doing 90+ & you sailed (sorry, wafted...) past then it would be a reasonable assumption that you were doing over 100mph........

And why not?!

Dave 8)
horsetan

Post by horsetan »

Yes, thanks Dave. Knew I could count on your support..... :roll: :wink:
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