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Discussion Starter #1
When i bought my M5 the dealer said that clutches tend to go at 25000 miles, as mine had done 19k he said he on top of the warrenty he would replace my clutch if it went in the first year. Looks like im taking him up on that offer sooner than i expected!

He came with me on the test drive and i didnt wanna rag it too badly (always feel like im on a driving test when dealers insisit on comin with me!) so the clutch seemed fine. But since ive got more confident in it im finding that with the sport button pressed :wroom: she will slip under hard acceleration on the change to 4th. Thats with waiting a second after lifting the clutch before bootin the throttle.

So, long story short, the cars booked in for clutch .. however, i also think she could do with new pads cause i have a bit of peddle travel and under really hard braking they are getting that "hum" sound (thin pads gettin hot), so what i wanted was to ask for opinions on what i should get? OE BMW pads or somthing else ?? ? ?
 

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Try AXXIS ultimate pads, I have heard good things about them and have a set on my desk waiting to be installed on my car, and I got all the pads for cheaper then the fronts alone at the dealership, Josh
 

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I went with the Axxis Ulitmate Pads, Euro Floating Rotors all around, Euro Brake Ducts and Stop Tech SS Brake Lines. Pedal feel is better but still soft. Brakes work great. I was at Pocono last week for some awesome track time. Brakes held up well throughout the day and continuously brought my M5 down from 130+ mph to around 50 or so for turn in to the infield course from the super speedway. The pads did get hot as they were smoking when I pulled off the track and finally brought the mighty beast to a halt. Had the fluid flushed and am ready to do it all over again!!
 

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Must be pretty cool to drive an M5 on Man. Many cops when driving over the top?

Steve
 

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Discussion Starter #5
Cheers for the responses guys, ill try and find someone selling them.

Steve, its rare to get interupted by cops going over the mountain section, anyway they cant do much even if they see you! :nono:

It sounds like you know the TT course, so far the M5 has pulled 142mph up the hill from Brandish towards the creg na baa pub! She does 130mph in 4th!
Tom
 

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Manx M5 said:
It sounds like you know the TT course, so far the M5 has pulled 142mph up the hill from Brandish towards the creg na baa pub! She does 130mph in 4th!
Tom
U da man, Tom!

Every so often I get out the tape of Hailwood going thru that section at about the same speed. I especially like the part where he says "it's getting a bit foggy" but never rolls off the throttle. My hero.

Steve
 

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Tom,

The clutch slipping can be due to:

1. Worn clutch liner
2. Damaged pressure-plate or clutch spring-cage.
3. Leaking dual-mass-flywheel-damping-fluid.
4. Leaking engine crankshaft seal

Or any combination of the above. Either way you need to remove the clutch and have a good look at the area.

If there is any oil leak int the clutch area, you simply have got to fix it or the new clutch wil fail too. Aceeptable oil leakage in this area is zero, and I do mean zero.

If the flywheel surface is damaged or the flywheel-seal is leaking, you definitely want that fixed while covered by warranty.

I would suggest to take a good long look at the flywheel yourself. If it is even the slightest oily or greasy to the touch there is a problem. If it is scratched from the rivets holding the clutch friction liner it will not work with the new clutch. If the flywheel is discoloured it has been overheated from the slipping clutch.

Also look at the crankshaft seal for any signs of engine oil leaking.

When you get the new clutch installed, for the clutch break-in procedure, have a look at post #7 in this thread:

http://www.m5board.com/vbulletin/showthread.php?t=54906

The break-in is of extreme importance to the longivity of the new clutch.

Regarding the brake-pads, you may want to consider Axxis Deluxe. Those are street pads like the BMW OEM pads, perform the same (or slightly better) but generate very little brake-dust.

Have a look at the Zeckhausen Racing website for brake-pad run-in procedures.

David
 

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Discussion Starter #8
Thanks David,

Dont think there will be much of a chance of me getting a look at the block or gearbox. Just going to have to trust the dealer!

Im pritty convinced its simply a worn clutch, so ill have to wait and see how it turns out.
 

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Most BMW techs are quite unaware of how extremely little fluid it takes to get the completely underdimensioned M5 clutch to start wandering down the road of slipping and overheating to destruction.

When you make a perfect sporty upshift, even if you take your foot completely off the accelerator the very heavy flywheel will happily stay at high revs for quite some time, until you release the clutch peadal. Then the clutch will transfer rotational energy to the gearbox and on to the rear wheels. At the moment of clutch engagment, with a 40% RPM difference (as typical on a 1st to 2nd upshift) the clutch will transfer about 1500 HP from the (now rapidly) downspinning flywheel to the (very slowly) upspinning gearbox for a few 10s of milliseconds.

During this very short interval the clutch will slip, but the better the clutch works the shorter the interval will be, and the lower the heating of the clutch will be.

This is why it is so exteremely important to have the clutch and flywheel surface in top shape.

I would definitely suggest to chat a bit with the tech about the clutch. If he seems knowledgable and aware of the complete absense of error margin on the M5 clutch, then fine, but if he seems to think a tiny bit of fluid contamination is ok (as on for example a 540) then watch out, because your tech won´t.

On the other hand, you are on Isle of Man, and I can imagine your tech has seen a lot of sporty cars, so chanses are you are far better off than most people in the UK.

What is expensive is the labour to remove and reinstall the gearbox and clutch. While the tech is at it, you might just as well have him replace the throwout bearing, and probably the spring-cage and clutcch-arm too. It will cost you a few tens of GBP in parts, but shouldn´t add more than pennies in labour time.

Cheers,

David
 

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Discussion Starter #10
Car is in at the moment having a new clutch and front pads fitted. The bloke I bought the car from owns a number of garages, one of them is a Honda dealer

So its this honda garage who is doing the work. So far its taken them two days! zzzzz Dropped it of yesterday am...

They told me it was a day job but it wasnt ready last night so had the pleasure of a 1.4 Civic last night, so this morning they told me before lunch, and i still havent had a call from them yet and im supposed to leave work in 20 mins..

Still if it takes them longer i am not really bothered so long as its working well when i pick it up.. and at least i am not paying for the Labour or parts!
 

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Discussion Starter #12 (Edited)
Collected her last night, im very impressed with the garage's customer service etc. Although it took them 2 days they appear to have done a great job.. they were laughing when i went in cause it took the mechanic so long to fit the exhaust.. took 3 of them i think! they said its very big and heavy!

Clutch bite point is now very low and seems nice and smooth.. just need to keep a calm right foot now and gt the clutch well bedded in and not glazed!

PS.. They gave me a FULL vallet as well, inside and out.. never used to get that with Nissan .. or Audi come to think of it.
 

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mikeoski said:
I went with the Axxis Ulitmate Pads, Euro Floating Rotors all around, Euro Brake Ducts and Stop Tech SS Brake Lines. Pedal feel is better but still soft. Brakes work great. I was at Pocono last week for some awesome track time. Brakes held up well throughout the day and continuously brought my M5 down from 130+ mph to around 50 or so for turn in to the infield course from the super speedway. The pads did get hot as they were smoking when I pulled off the track and finally brought the mighty beast to a halt. Had the fluid flushed and am ready to do it all over again!!
Please consider swapping out your front pads, before the next track event, to Hawk HT10 track pads. The Axxis Ultimate is not a track pad and, as you get better, will let you down big time. At the temperatures you already subjected them to, the Kevlar will vaporize and the pads will begin to crack and chunk. And they will leave massive deposits on your rotors, resulting in a judder problem while braking.

When swapping back and forth between street and track pads, follow these guidelines to avoid issues with incompatible transfer layer: http://www.zeckhausen.com/avoiding_brake_judder.htm
 
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