front caliper changes

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pedro20001
Joined: Sat 29 Jan, 2011 20:34
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Location: tamworth

front caliper changes

Post by pedro20001 »

hi all, looks like i have a sticky rh fr caliper; seems quite common. Just wandering how easy to bleed after fitting replacements? I don't mind swapping the calipers over but a bit worried about bleeding regarding the abs. any tips, thanks in advance!!
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wildeboy
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Re: front caliper changes

Post by wildeboy »

Hi Pedro,

I changed one of my front calipers a couple of months ago, pretty straightforward really. The caliper slider bolts are a 7mm allen fitting, I bought a 7mm allen fitting for my socket set, I can't remember if a standard allen key wouldn't fit or it they were too tight to get off like that.

Bleeding was very simple using a Gunsens Easibleed, fill it with brake fluid (you can use it empty but have to watch the level in the reservoir carefully!) and connect to a tyre to pressurise, then just open the bleed nipple (7mm spanner required and very easy to round over!).
1997 Z3 2.8 in Montreal Blue, only 130k on the clock!
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Del
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Re: front caliper changes

Post by Del »

Hi Wildeboy

How did you stop the brake fluid pouring out whilst you disconnected the caliper? Did you clamp the rubber hose?

Does anybody have a view on whether the brake hoses should be renewed just for preventative maintenance. I'd be interested to get an expert view. I've inspected mine and they look fine but I notice at least two still have the OEM date stamp 1998 on them which is now some 14 years ago!
VikingSven
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Re: front caliper changes

Post by VikingSven »

My rear brake hoses had to be replaced for the first time at its last MOT - it's also a 1998 :)
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wildeboy
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Re: front caliper changes

Post by wildeboy »

Del wrote:How did you stop the brake fluid pouring out whilst you disconnected the caliper? Did you clamp the rubber hose?
No I didn't clamp the hose, I put 2 or 3 layers of clingfilm over the reservoir opening and screwed one of the caps from the Easibleed over to create a seal, nothing came out of the hose.
Del wrote:Does anybody have a view on whether the brake hoses should be renewed just for preventative maintenance. I'd be interested to get an expert view. I've inspected mine and they look fine but I notice at least two still have the OEM date stamp 1998 on them which is now some 14 years ago!
I am no expert but if you can afford/justify the cost, braided hoses would be the way to go, I couldn't so mine are still original!
1997 Z3 2.8 in Montreal Blue, only 130k on the clock!
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pedro20001
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Re: front caliper changes

Post by pedro20001 »

Cheers guys, now my next job on the list !
siwilson
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Re: front caliper changes

Post by siwilson »

wildeboy wrote:
Del wrote:How did you stop the brake fluid pouring out whilst you disconnected the caliper? Did you clamp the rubber hose?
No I didn't clamp the hose, I put 2 or 3 layers of clingfilm over the reservoir opening and screwed one of the caps from the Easibleed over to create a seal, nothing came out of the hose.
You can also depress the brake pedal slightly so it pushes the main cylinder piston a little and covers the hole from the reservoir. Then afterwards I bleed the old school way by pumping the pedal. My 15 years old son has become quite adept at the process now :)
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pingu
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Re: front caliper changes

Post by pingu »

siwilson wrote:
wildeboy wrote:
Del wrote:How did you stop the brake fluid pouring out whilst you disconnected the caliper? Did you clamp the rubber hose?
No I didn't clamp the hose, I put 2 or 3 layers of clingfilm over the reservoir opening and screwed one of the caps from the Easibleed over to create a seal, nothing came out of the hose.
You can also depress the brake pedal slightly so it pushes the main cylinder piston a little and covers the hole from the reservoir. Then afterwards I bleed the old school way by pumping the pedal. My 15 years old son has become quite adept at the process now :)
I use the Easibleed rather than the pedal as once upon a time in a galaxy far far away my son pressed the pedal before I was ready and knackered the seals in the master cylinder. Pedal went to the floor and was a bugga to sort.

Make sure that you reduce the tyre pressure before using the Easibleed as I had the lid pop off once and my engine bay was covered in brake fluid :shock: . No harm done as it was only a Metro.

The ABS pump problem the OP is concerned about is only a problem if air gets in the pump. If that happens, the ABS system has to be activated to purge it. This can be done electronically using diagnostic software or some spirited braking (not breaking :) ).
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c_w
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Re: front caliper changes

Post by c_w »

To activate the ABS pump for bleeding just bridge the relay connections with a short piece of wire. The ABS relay is usually Grey (in the engine bay relay box on the passenger side). Bridge pins 30 and 87 and the ABS pump will run. I don't think it's a common issue to have to bleed the pump though but when I had a soft pedal I did this to be sure. Besides if you block the lines when you disconnect them (mole gips with some rubber wrapped around the hose *cough*) then you won't lose much fluid at all.

I don't think it's really practical to activate the ABS on the road as a; if you're doing the brakes you don't want to have to put the wheels back on and back on the ground to take it for a test drive then come back and get it jacked up and remove wheels again and b. if the brakes are really soft they may not work enough to activate the abs.
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pingu
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Re: front caliper changes

Post by pingu »

c_w wrote:To activate the ABS pump for bleeding just bridge the relay connections with a short piece of wire. The ABS relay is usually Grey (in the engine bay relay box on the passenger side). Bridge pins 30 and 87 and the ABS pump will run. I don't think it's a common issue to have to bleed the pump though but when I had a soft pedal I did this to be sure. Besides if you block the lines when you disconnect them (mole gips with some rubber wrapped around the hose *cough*) then you won't lose much fluid at all.
Good tip about the pins to get the pump to run :D . What happens to the valves inside the ABS manifold? Are they opened when the pins are bridged? I'm guessing that the software will run the pump and open all the valves. I've never had to do it, so I don't know.
c_w wrote:I don't think it's really practical to activate the ABS on the road as a; if you're doing the brakes you don't want to have to put the wheels back on and back on the ground to take it for a test drive then come back and get it jacked up and remove wheels again and b. if the brakes are really soft they may not work enough to activate the abs.
Agreed. It's not the way I'd do it, but just thought it was an option for those without the software. Bridging the pins is the way to do it now 8-) .
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c_w
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Re: front caliper changes

Post by c_w »

It's makes like a vibrating noise, I assume the ABS pump just has one mode of function and that's to move the pistons in and out, so when you trigger the relay it just runs like that. I wouldnt advise running it for long periods; I just ran it for a 5-seconds between bleeding each caliper.
Mike Fishwick
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Re: front caliper changes

Post by Mike Fishwick »

I prevent fluid dripping out while the rubber hoses are removed by fitting a spare brake hose (of the short type which joins the rear trailing arms to the car body) which has a 10 X 1 mm female thread at each end. One end screws to the male connector of the steel pipe, and the other is blocked by means of a 10 X 1 mm bleed nipple.

When not in use it is sealed with a pair of bleed nipples.
Last edited by Mike Fishwick on Mon 18 Jun, 2012 14:41, edited 3 times in total.
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Mike Fishwick
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Re: front caliper changes

Post by Mike Fishwick »

I will probably be told that I am wrong, but I have always believed that with any dual-circuit braking system the master cylinders are in tandem, and their pistons move at the same time. If using the 'Old School' method of pressing the pedal, the first circuit to purged of air will go 'hard' and result in a non-compressible hydraulic system. This will prevent the pedal/second master cylinder being pressed far enough to bleed the second circuit.

It is therefore essential to use a pressure bleeder on any dual-circuit braking system so that both circuits can be bled fully without moving the master cylinder pistons.

It's a lot easier with a presure bleeder anyway, and saves a lot of aggro!

On the subject of original hoses, once they become resistant be bending it's time for a change, even if no cracks are visible when bending it. We all (myself included) tend to leave them for ages, but it is not good practice, particularly when considering their minimal cost.
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siwilson
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Re: front caliper changes

Post by siwilson »

Lots of opinions here. What I can say is that I have bled my brakes using the old school method a number of times when changing hoses and calipers and never had an issue. After a few pumps, new clear fluid without any bubbles emerged at each corner. No need to activate ABS at all, a rock hard pedal and solid brakes at the end of the process.

Now granted I was not trying to 100% change the fluid, I leave that for Munich Legends who also stamp the service record.
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pingu
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Re: front caliper changes

Post by pingu »

siwilson wrote:...I leave that for Munich Legend who also stamp the service record.
Luckily, you specified that particular garage, as I have no doubt that they also stamp the book compared to just stamp the book.
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Mike Fishwick
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Re: front caliper changes

Post by Mike Fishwick »

I know that a lot of people use the 'Old school' method of bleeding with modern cars, but I can't for the life of me see how it can bleed both circuits! Yes - it will give a hard pedal - due to the first circuit having been bled.

That's one of the reasons for using a pressure bleeder - it's not all about being easier, although for only about £10 it seems silly not to.

Can anyone produce a reasoned argument to persuade me otherwise?
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gookah
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Re: front caliper changes

Post by gookah »

Mike Fishwick wrote:I will probably be told that I am wrong, but I have always believed that with any dual-circuit braking system the master cylinders are in tandem, and their pistons move at the same time. If using the 'Old School' method of pressing the pedal, the first circuit to purged of air will go 'hard' and result in a non-compressible hydraulic system. This will prevent the pedal/second master cylinder being pressed far enough to bleed the second circuit.
But the pistons, although serving dual compartments (and hence dual circuits) will still move from zero pressure until they reach full pressure, and this piston movement will allow fluid to be pumped through the second circuit. .
Last edited by gookah on Tue 19 Jun, 2012 19:10, edited 1 time in total.
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Mike Fishwick
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Re: front caliper changes

Post by Mike Fishwick »

BUT - the two seperate cylinders and pistons are in tandem, on the same rod, and feed totally seperate hydraulic circuits. They share a common reservoir, but that is all.

I would guess that when using the 'Old School method, the fluid from the second circuit to be bled is issuing from the bleed nipple by gravity acting on the fluid above it, as the reservoir is at a higher level - just like the fluid which will pour from the pipe after a caliper has been removed.

This is all very well, but it will not guarantee that any air in the second circuit has been forced out by the weight of fluid above it, although as the first circuit is air-free you would never detect it through the pedal.
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Del
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Re: front caliper changes

Post by Del »

I am genuinely interested in this posting as I plan some brake work and I don’t claim to be an expert on brake bleeding methods. My E36 (including some Z3 info) Haynes Manual says that BMW specifies pressure bleeding as the only acceptable method for bleeding the brake system. They go on to describe a process where the system is first pressurised (they say about 14-15 psi but not beyond 29 psi as it can damage the reservoir) with an assistant still slowly pumping the brake pedal “about a dozen times” and holding it down on the last stroke whilst the other person tightens the bleeder screw. The associated diagram (about as useful as a chocolate teapot) shows a person’s hand holding a plastic bottle attached by a pipe to the bleeder screw – the only interesting thing is that the bottle has a label stating “brake bleeder for dual circuit systems”. This system sounds as if it really needs 3 people!!! :bawl:
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Re: front caliper changes

Post by gookah »

Mike Fishwick wrote:BUT - the two seperate cylinders and pistons are in tandem, on the same rod, and feed totally seperate hydraulic circuits. They share a common reservoir, but that is all.
And as the tandem piston moves from zero to full braking force on circuit one, the second piston is also moving within circuit two, against the second circuit return spring. pumping fluid around and into that circuit, and forcing the air out of it.
Just because circuit one stops the movement of the piston one when the pedal goes hard, it doesn't stop the second circuit piston movement and it is that movement that pumps fluid into circuit two.
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Re: front caliper changes

Post by gookah »

BUT--- it is a lot easier with a pressure bleeder cos you can do it on your own... :D
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Z3 2.8 Progress Journal (Mine)
Z3 1.9 Sport Progress Journal (Wifey's)

I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
pedro20001
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Re: front caliper changes

Post by pedro20001 »

wow ! this has turned out to be quite a long thread!!!! loads of good info and at least i know with the help of a pressure bleeder i can do it on my own!! thanks again guys. just hope the rain stops!
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pingu
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Re: front caliper changes

Post by pingu »

gookah wrote:Image
Gookah's image helps to illustrate the problem if you bleed the brakes just by pumping the pedal.

The 1st circuit rear seal is between the 1st circuit intake and return port & the equalistion port. Too much pedal force on an empty system could push the piston past the intake and return port, possibly breaking the return spring. (Hence the reason why you should use short pulses to bleed the system when using the pedal)

Similar for the 2nd circuit, but the spring is less likely to be compressed beyond its yield point, as it can move the 1st piston.

Easibleeder will push fluid through the ports without moving the pistons when the bleed nipples are opened.

Something that hasn't been mentioned so far is the order of bleeding...

1) RHR
2) LHR
3) RHF
4) LHF
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Mike Fishwick
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Re: front caliper changes

Post by Mike Fishwick »

I wonder where this drawing came from? It does not show any mechanical connection between the rear piston and the front piston, which appears to be forced forward by hydraulic pressure alone! If this were the case, a loss of fluid in the rear piston circuit would prevent the front circuit's piston fom moving, until the rear piston had almost moved through its ful mechanical travel.

I remember taking an old VW master cylinder to pieces once, and that certainly had a one-piece piston assembly. The pistons were part of the same piece of steel, which is pushed by the vacuum unit, they therefore moved together.

Anyway - an indisputable point in favour of a pressure bleeder is that it removes the risk - on a high-mileage car - of damaging the piston seals by pushing them past the small lip which forms at the end of their normal travel, whic is easily possible when using the 'Old School' method.
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Mr Silver
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Re: front caliper changes

Post by Mr Silver »

The significance of the later design of tandem master cylinder, that shown in the drawing here, is that it will compensate for inefficency of either circuit (ie. air in one of them) and will apply equal pressure to all four wheels. A further advantage over the earlier 'solid cylinder' design is that a failure of either circuit will be evident by a change in pedal travel. This was a bad failing in the original designs for obvious reasons.

It must be noted that the drawing is not to any scale and the differential movement between the two cylinders is rather exagerated.


Regards.
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pingu
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Re: front caliper changes

Post by pingu »

Mike Fishwick wrote:It does not show any mechanical connection between the rear piston and the front piston...
It looks to me like the mechanical force from piston #2 is applied to piston #1 via the 2nd return spring. I don't know how realistic the drawing is as I've never taken apart a cylinder like this.
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OldskoolRS
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Re: front caliper changes

Post by OldskoolRS »

I resent all these people complaining about doing things the oldschool way. :D

I'm away at the moment so don't have my manual to hand (Bentley) but I seem to remember reading something about having to use the INPA software when bleding the brakes/changing the fluid to 'tell' the system which brake you're working on? Did I imagine this or was it for the two year fluid change?

I would like to bleed my brakes using my easibled kit even though it isn't due for some time according to the SI. If it's just a matter of reseting the timer and bleeding in the sequence mentioned above, then I would like to do this as I still have some new fluid left over from when I bled the clutch recently.
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pingu
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Re: front caliper changes

Post by pingu »

I think the INPA is used to run the ABS pump and to reset the instrument cluster lights. As long as no air has entered the pump there is no need to run the pump and you can reset the instrument cluster with a paper clip :D .
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Mr Silver
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Re: front caliper changes

Post by Mr Silver »

Under normal operating conditions there is no mechanical connection between the two pistons. Movement of the second circuit (blue) piston (from the brake pedal) creates hydraulic pressure to the brake caliper cylinders on the secondary circuit and the first circuit (red) piston. If the secondary circuit fails then the secondary circuit (blue) piston will move down the cylinder to connect with the first circuit (red) piston and force it to operate.

The return springs are exactly that since there is no back pressure from the hydraulic lines.

Hope this helps.


Regards.
Mike Fishwick
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Re: front caliper changes

Post by Mike Fishwick »

I have finally discovered why my idea of how a dual-circuit master cylinder works, and that of others, were at variance!
My ideas were based on the system fitted to an early VW Sirocco, which did indeed have both pistons machined in a single piece of steel, but this had a rather unusual method of monitoring the operation of both circuits – let me explain:

In such a system, if one circuit fails, the other will still present resistance to the pedal, with a reduced amount of travel – meaning that the brakes do not work very well, but still have the same type of ‘feel.’

For this reason the two circuits operated separate pressure switches, each of which was a changeover type. Under zero pressure they connected their outputs to the negative earth, and when both were under pressure to positive supply. These outputs were sampled by a prehistoric form of logic circuit, which in the event of different switch outputs (i.e. one circuit failed) would give an alarm to the driver.

Obviously, those with high volume stereos, or a lack of attention to the instruments, would continue to drive, blissfully unaware of impending doom.
This potential problem caused the current type of master cylinder to be introduced, in which normal operation depends on resistance from both cylinders.
A failure of one circuit will result in the pedal travel being drastically increased, in the hope that this will make the driver wonder what is going on – a form of tactile alarm which should be able to complete with the stereos and other driver distractions.

So – my ideas were founded on the motoring world of over 35 years ago, rather than today, explaining neatly why the ‘Old School’ method of brake bleeding can still work.
Talk about old people with old ideas - but at least we can still learn from others! Many thanks to those who prompted by grey cells top get working again, and helped me to learn something.
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Re: front caliper changes

Post by gookah »

Gracefully put,
thankyou.... :thumb:
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I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
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Robert T
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Re: front caliper changes

Post by Robert T »

Dual circuit brakes - now there's a neat idea. :D

Sorry, just come back from having the frog MOT'ed (it passed by the way). No dual circuit brakes there, though it does have discs on the front (non-standard, I know).

Cheers R.
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Mike Fishwick
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Re: front caliper changes

Post by Mike Fishwick »

I have just replaced my front calipers - I had a severe vibration, and while looking for the causes, the RH piston siezed in a big way, making the run home a slow buisness, stopping every five miles of so to remove the wheel and force the pads back a little, then trying to avoid using the brakes for as long as possible! I found that the piston would move inwards only 3 mm with a piston compressor tool wound up on it, or 3 mm outwards with 120 psi of compressed air behind it. Due to the absence of anything like GSF in France, and BMW spares costing a lot more than in the UK (so much for the eU harmonising prices!) I had to wait until a friend came this way for a long-distance motorcycle trail ride.

I ended up with a pair of Borg & Beck exchange calipers with new Zimmermann drilled discs and hoses (from GSF) fitted with new Redstuff pads, after which everything was fine again. I could not find any Smootherite silver paint, so had to paint the calipers etc with Hammerite bronze, which looks quite pleasant, even though after about ten years I had become used to the silver calipers.

Image

And I bled them using a pressure bleeder! The new Blue ATE fluid was very handy, as it clearly shows when the line to each caliper has been purged of the old clear fluid.
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Re: front caliper changes

Post by gookah »

How come (that looks like LH front wheel) the discs are fitted the wrong way around? with radial curve of the cross drilling going in the wrong direction.
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I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
Mike Fishwick
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Re: front caliper changes

Post by Mike Fishwick »

Well done for being awake! I noticed this when I unpacked the discs, but then looked at the similar discs which have covered about 90,000 miles on our Golf TDI, they are exactly the same. I doubt if I have bought two sets of incorrectly-matched discs!

The curve of the drillings is the same on both discs - and when one thinks about it, it makes no real difference, as distinct from a groove, where the curvature has to be in the correct direction to take water and gas off the edge of the disc as it rotates forwards. A hole, however, is a hole, and a sucession of holes in any direction (or no direction) simply diverts water or gas into the interior of the disc, where it is vented by centrifugal force. The important thing is for the drillings to slightly overlap each other, in order to deglaze the entire pad area, and to prevent the disc from wearing unevenly.

True - some manufacturers make left and right-handed discs, with drillings in opposite directions, but it does not make any difference interms of performance, wet or dry. The use of a standard disc does keep the price down, and at £46 each these are excellent value. The configuration of drillings does not upset the German TuV either, each pair coming with its TuV approval sheet.

Another example of using standard brake discs is found on most BMW motorcylces, where the holes or slots are disposed in a uniform pattern. True, some of the more modern models have exotic patterns, and seperate L or R discs, but that is more for fashion than function.

I have used these discs for ages on our Golf TDI and the preceding Corrado, and my Golf GTI, covering about 250,000 miles on them, and they work well in all conditions.
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Re: front caliper changes

Post by gookah »

Mike Fishwick wrote:Well done for being awake! .
Why do you 'again' have this attitude with people?


The centrifugal force of the vanes inside the disc will be more efficient at throwing out the gases if they are going in the right direction.

Image

It's good enough for Ferrari:
Image

Good enough for BMW 'M' division:
Image

but not good enough for Mike F....

maybe
Mike Fishwick wrote: Talk about old people with old ideas - but at least we can still learn from others! Many thanks to those who prompted by grey cells top get working again, and helped me to learn something.
Image

Z3 2.8 Progress Journal (Mine)
Z3 1.9 Sport Progress Journal (Wifey's)

I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
Mike Fishwick
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Re: front caliper changes

Post by Mike Fishwick »

What is the matter with people? Why do you have to spoil everyone's day by reading insults into anything I write?

As it happens, the vanes inside the dics are not helical, but radial, so the direction of rotation does not matter - hope that explanation is not construed as an insult.

I think you had better take your complaints about me to a Moderator, rather than bring this forum down with your public backbiting - please thnk of others.
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Posts: 2737

  Z3 roadster 2.8

Re: front caliper changes

Post by gookah »

Mike Fishwick wrote:What is the matter with people? Why do you have to spoil everyone's day by reading insults into anything I write?

As it happens, the vanes inside the dics are not helical, but radial, so the direction of rotation does not matter - hope that explanation is not construed as an insult.

I think you had better take your complaints about me to a Moderator, rather than bring this forum down with your public backbiting - please thnk of others.

I haven't had a thread dedicated to me...... why the need to post "well done for being awake"?

Maybe you are just not aware you get peoples backs up. which is a concern

PS Have a nice day everyone... :D
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I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
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Gazza
Joined: Tue 04 Oct, 2005 20:58
Posts: 9521

  M roadster S54
Location: Romford Essex

Re: front caliper changes

Post by Gazza »

Personally I didn't read mikes 'awake' as an insult, more like well done for actually taking notice of the pic rather than just looking at it.

I have grooved discs on my Mustang and the grooves are from outside to inside and marked as such with LH and RH, I queried this when fitted and was shown the markings.
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

Z3 S54 M roadster Image, BMW Z1, BMW M3 CSL, Z4M Coupe
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pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Re: front caliper changes

Post by pingu »

I read it like "well done for spotting my deliberate mistake". Then, upon investigation and analysis, MF found that it wasn't a mistake at all.

I agree with you both (Gookah, I agree that MF does have an effect on some people [not me, btw] and MF, I agree with your engineering analysis of the situation - the holes could be anywhere, no pattern is required).

The engineering analysis put forward by Gookah would apply if the disc were grooved. In my analysis, the holes provide additional surface area, not a pumping effect (as grooves would do).
Pingu
Mr Silver
Joined: Wed 25 Feb, 2009 09:34
Posts: 360

  Z3 roadster 3.0i

Re: front caliper changes

Post by Mr Silver »

I hesitate to mention that it's all for show! The 'gas problem' disappeared in the late 60's with improved production methods and was never a problem at road speeds anyway. The concept of gas emmission was generated recently as a marketing idea to sell discs that are effectively of lower performance than a solid disc!

...but nobody wants to know that!

...and no, holes in discs do not dissipate water, only money from wallets!


Regards.
Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2093

  Z3 roadster 2.8
Location: Daglan, France

Re: front caliper changes

Post by Mike Fishwick »

At the risk of exciting someone, I think holes do have the main functions of providing a path for any water coating (such as can build up on a long wet run if the brakes are not used much -a motorway for example) to be quickly dissipated, and that of deglazing the pads during light braking, which is the majority of brake use.

The problem is that we can never really prove it one way or the other, as we are inevitably replacing well-worn discs and pads with new, then going through a period of bedding in, after which we have become used to whatever braking level we then have.

However, it is worth noting that BMW take the problem of water build-up seriously enough to offer a system which - when the wipers re operating - periodically runs the ABS pump to lightly apply the brakes to disperse the layer of accumulated water.

I can still remember that when drilled (non-vented) discs were introduced on motorcycles in the late 'seventies, a friend had his solid discs drilled and was amazed at the improved response.

One thing I will say, however, is that the current EBC Redstuff pads are excellent, with really sharp response at all temperatures, low dust, and good life . . . or maybe I'm wrong!
A Z3 is not just for Christmas - it's for life!
fish
Joined: Thu 07 Feb, 2013 17:04
Posts: 177

  Z3 roadster 2.2i
Location: Sandbach, Cheshire

Re: front caliper changes

Post by fish »

c_w wrote:To activate the ABS pump for bleeding just bridge the relay connections with a short piece of wire. The ABS relay is usually Grey (in the engine bay relay box on the passenger side). Bridge pins 30 and 87 and the ABS pump will run. I don't think it's a common issue to have to bleed the pump though but when I had a soft pedal I did this to be sure. Besides if you block the lines when you disconnect them (mole gips with some rubber wrapped around the hose *cough*) then you won't lose much fluid at all.

I don't think it's really practical to activate the ABS on the road as a; if you're doing the brakes you don't want to have to put the wheels back on and back on the ground to take it for a test drive then come back and get it jacked up and remove wheels again and b. if the brakes are really soft they may not work enough to activate the abs.
This looks to be the problem I am facing according to Brian….i.e. just bled my brakes after caliper change etc…where are these pins to bridge? Are you saying turn the battery on and hold a wire between these pins for 5 seconds? I have a soft pedal after bleeding….
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Buz007
Joined: Fri 16 Jul, 2010 20:18
Posts: 254

  Z3 roadster 1.9
Location: Leeds

Re: front caliper changes

Post by Buz007 »

Why does the word 'bleed nipple' always make me wince? :cry:
''need I remind you 007, you have a licence to kill...not to break the traffic laws''
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