This is advisable for anyone who finds gear shifting is a problem. Especially if it happens when your engine is hot & perhaps in traffic you have a problem selecting 1st gear.
This is because the rubber clutch hose becomes more elastic when warm so some of the oil you pump when you depress the cluch pedal simply goes to making the clutch hose balloon slightly instead of separating the clutch plates properly.
It may also occurr when shifting into higher gears, especially when trying to make good progress.
Mine was replaced under extended warranty.
The improvement is remarkable. It's like getting a new clutch & gearbox !
They are available from this company who have them in stock for the ///M at time of writing this & they are £24.50 each +vat or will make up to order to suit your car.
Paul Blaxall
'Hampshire Hose Services'
Crosshouse Rd
Southampton
Tel 023 80335588
See also related thread
viewtopic.php?p=53449#53449
Fitting steel braided clutch hose give slicker gearshifting
You only bleed the clutch line, not the brakes. Ideally you want to bleed the whole clutch system, i.e. the cylinder as well, but this is not compulsory.
I've had a perfect custom line for my M Coupe made up in 10 minutes by Earl's @ Silverstone (located right on the racing circuit grounds!). They've been in the business forever. I gave them the design I found and it is spot on.
Earls Performance Products (UK) Ltd
Unit 17
Silverstone Circuit
Silverstone, Towcester
Northamptonshire, NN12 8TL
Tel: 01327 858221
If you need any more info on the install try this page:
http://128.83.80.200/mcoupe/cdv.html
http://www.PowerManiacs.com
I've had a perfect custom line for my M Coupe made up in 10 minutes by Earl's @ Silverstone (located right on the racing circuit grounds!). They've been in the business forever. I gave them the design I found and it is spot on.
Earls Performance Products (UK) Ltd
Unit 17
Silverstone Circuit
Silverstone, Towcester
Northamptonshire, NN12 8TL
Tel: 01327 858221
If you need any more info on the install try this page:
http://128.83.80.200/mcoupe/cdv.html
http://www.PowerManiacs.com
-
Paul.Stuhlfelder
- Joined: Wed 01 Dec, 2004 14:31
- Posts: 1020
- Location: Caernarfon
- Contact:
It shares the fluid with the brakes so you would have to top up the brake fluid reservoir and then bleed the clutch; I think the bleed screw is near where the pipe fits.Paul.Stuhlfelder wrote:Anyone got a writeup on how to do this?
I take it once you take off the hose all the hydraulic fluid will piss out all over the place, if so how do you fill it back up?
1st can be a PITA sometimes!
I've never noticed any clutch problems on mine though, its always light and feels fine, the gearchange is really precise too.
-
Guest
Two things happening here!
I have seen this thread pop up a few times and each time it reminded me of something I read on bimmerfest.
When you replace the stock clutch hose with a steel braided one you are actually getting the benefit of two upgrades for the price of one.
Firstly, you are benefiting from the fact that a braided hose does not expand under pressure like a stock rubber one does.
Secondly, you are also getting the benefit of removing a flow restrictor that is built into the stock hose. This restrictor is usually called a CDV or clutch delay valve. If you search on www.bimmerfest.com you will see plenty of threads on this. Rather than re-invent the wheel, take a look at this excellent write-up on the subject. http://128.83.80.200/mcoupe/cdv.html.
You can also take a look at this analysis of the CDV by a guy called Dave Zeckhausen of Zeckhausen Racing. http://www.zeckhausen.com/CDV.htm. Note though, that the CDV on the ///M is actually built into the hose.
There is plenty of speculation as to why BMW chose to implement the CDV. It could be to protect the transmission from those neck snapping getaways at the local traffic light grand prix! It could also be to ensure future sales of replacement clutches. I know I have gone for a quick 2nd to 3rd change in my ///M, only to give get on the gas a little early and have clutch slip, a nasty smell and the engine hitting the limiter!
Interesting eh!
When you replace the stock clutch hose with a steel braided one you are actually getting the benefit of two upgrades for the price of one.
Firstly, you are benefiting from the fact that a braided hose does not expand under pressure like a stock rubber one does.
Secondly, you are also getting the benefit of removing a flow restrictor that is built into the stock hose. This restrictor is usually called a CDV or clutch delay valve. If you search on www.bimmerfest.com you will see plenty of threads on this. Rather than re-invent the wheel, take a look at this excellent write-up on the subject. http://128.83.80.200/mcoupe/cdv.html.
You can also take a look at this analysis of the CDV by a guy called Dave Zeckhausen of Zeckhausen Racing. http://www.zeckhausen.com/CDV.htm. Note though, that the CDV on the ///M is actually built into the hose.
There is plenty of speculation as to why BMW chose to implement the CDV. It could be to protect the transmission from those neck snapping getaways at the local traffic light grand prix! It could also be to ensure future sales of replacement clutches. I know I have gone for a quick 2nd to 3rd change in my ///M, only to give get on the gas a little early and have clutch slip, a nasty smell and the engine hitting the limiter!
Interesting eh!
Another job I've just completed on the M. There are some jobs that are just a complete pain in the ar*e to do - AND THIS IS ONE OF THEM!
I used the guide here which is very good... http://128.83.80.200/mcoupe/cdv.html
If you attempt this job yourself, be prepared for poor access, brake fluid all over your arms and lots of swearing. I found it difficult to undo the top union as the flats on the fitting are very difficult to get to. When you do get it apart be prepared for brake fluid everywhere! A very good tip is to use the little rubber cap from the clutch slave cylinder bleed nipple to cap the end of the soild clutch pipe. The other end (nearest the slave) is easier to get apart.
With the old hose removed you can see the restriction at one end of the hose - the hole is tiny. The new hose (got mine from Hampshire Hose Services) doesn't fit into the brakcet at the slave cylinder end so you have to either drill the bracket out to the correct size or dremmel it to slide the fitting in from the side.
The next bit which I hated was trying to screw the top union back into the new hose. Access is so poor it's difficult to get it square and you have to push the hose fitting quite hard through the rubber grommet to get enough through to screw into. Of course all the time you are attempting this, brake fluid is piss*ng out all up your arms and eventually all over your shoulders and neck. It took me almost 30 seconds before I managed to engage the union thread properly, by which time I had to top up my brake fluid reservoir. Not nice.
So, after finally getting the new hose on and all the unions tight, I started to bleed the clutch by getting a second person to pump the pedal while I was underneath the car, opening and closing the bleed nipple (open whilst pressing clutch down, close when returning clutch). I did this without too much trouble until no bubbles came out.
Get back into car and clutch pedal drops half way to floor before feeling any resistance. No good.
I suspected this would be a problem as it is pointed out in the guide on the link above. What you have to do is remove the clutch slave cylinder and bleed the clutch with the slave cylinder plunger depressed. The slave cylinder mounitng bolts are a bitch to get to as one is hidden and access is lousy. I finally managed it with a couple of extension bars on my socket and removed the slave (with all hoses still attached).
I bodged a clamp togther from a G clamp to hold the plunger in and started the bleed process again. This time though the clutch pedal just went all the way to the floor and back with virtually no resistance whatsoever - no pumping action, and no fluid coming out of the slave cylinder bleed nipple!
I was pretty much stuck at this point - can't bleed the clutch if it's not pumping fluid through. I guess I had an airlock somewhere in the clutch master cylinder - the only way I would get it out was with a pressure bleeder.
The next day I came back with a Gunsons Easy Bleed pressure bleeder which pressurises the brake fluid reservoir. This did work and sure enough I got plenty more bubbles out of the slave cylinder. Getting the slave cylinder back on is a complete b*tch though as the plunger has to be depressed as you offer the slave back upto the stud mountings on the gearbox and then screw one of the nuts back on at the same time. Eventualy I managed it and finally the clutch felt back to normal at last (in terms of height and biting point).
So, took it for a test drive and to be honest I can tell very little difference - first gear is still awkward to engage at times and you still get a little bit of 'clutch slip' if you are very spirited with your 1st to 2nd gear shifts. I think it has made a very small improvemnt to general shift quality but certainly nothing dramatic as some posts on here describe.
I'm changing the gerabox oil next for Royal Purple Synchromax to see if that makes any difference. I know my gerarbox is no worse than other M's that I've driven but it's still the worst part of the car in my opinion and could do with some improvement.
My conclusion - older cars may have a more degraded rubber clutch hose than my 02 car but this mod was definitely not worth the hassle for me. Try a simple clutch fluid change and new gear oil first - it's easier!
I used the guide here which is very good... http://128.83.80.200/mcoupe/cdv.html
If you attempt this job yourself, be prepared for poor access, brake fluid all over your arms and lots of swearing. I found it difficult to undo the top union as the flats on the fitting are very difficult to get to. When you do get it apart be prepared for brake fluid everywhere! A very good tip is to use the little rubber cap from the clutch slave cylinder bleed nipple to cap the end of the soild clutch pipe. The other end (nearest the slave) is easier to get apart.
With the old hose removed you can see the restriction at one end of the hose - the hole is tiny. The new hose (got mine from Hampshire Hose Services) doesn't fit into the brakcet at the slave cylinder end so you have to either drill the bracket out to the correct size or dremmel it to slide the fitting in from the side.
The next bit which I hated was trying to screw the top union back into the new hose. Access is so poor it's difficult to get it square and you have to push the hose fitting quite hard through the rubber grommet to get enough through to screw into. Of course all the time you are attempting this, brake fluid is piss*ng out all up your arms and eventually all over your shoulders and neck. It took me almost 30 seconds before I managed to engage the union thread properly, by which time I had to top up my brake fluid reservoir. Not nice.
So, after finally getting the new hose on and all the unions tight, I started to bleed the clutch by getting a second person to pump the pedal while I was underneath the car, opening and closing the bleed nipple (open whilst pressing clutch down, close when returning clutch). I did this without too much trouble until no bubbles came out.
Get back into car and clutch pedal drops half way to floor before feeling any resistance. No good.
I suspected this would be a problem as it is pointed out in the guide on the link above. What you have to do is remove the clutch slave cylinder and bleed the clutch with the slave cylinder plunger depressed. The slave cylinder mounitng bolts are a bitch to get to as one is hidden and access is lousy. I finally managed it with a couple of extension bars on my socket and removed the slave (with all hoses still attached).
I bodged a clamp togther from a G clamp to hold the plunger in and started the bleed process again. This time though the clutch pedal just went all the way to the floor and back with virtually no resistance whatsoever - no pumping action, and no fluid coming out of the slave cylinder bleed nipple!
I was pretty much stuck at this point - can't bleed the clutch if it's not pumping fluid through. I guess I had an airlock somewhere in the clutch master cylinder - the only way I would get it out was with a pressure bleeder.
The next day I came back with a Gunsons Easy Bleed pressure bleeder which pressurises the brake fluid reservoir. This did work and sure enough I got plenty more bubbles out of the slave cylinder. Getting the slave cylinder back on is a complete b*tch though as the plunger has to be depressed as you offer the slave back upto the stud mountings on the gearbox and then screw one of the nuts back on at the same time. Eventualy I managed it and finally the clutch felt back to normal at last (in terms of height and biting point).
So, took it for a test drive and to be honest I can tell very little difference - first gear is still awkward to engage at times and you still get a little bit of 'clutch slip' if you are very spirited with your 1st to 2nd gear shifts. I think it has made a very small improvemnt to general shift quality but certainly nothing dramatic as some posts on here describe.
I'm changing the gerabox oil next for Royal Purple Synchromax to see if that makes any difference. I know my gerarbox is no worse than other M's that I've driven but it's still the worst part of the car in my opinion and could do with some improvement.
My conclusion - older cars may have a more degraded rubber clutch hose than my 02 car but this mod was definitely not worth the hassle for me. Try a simple clutch fluid change and new gear oil first - it's easier!
Last edited by SpunkyM on Mon 06 Aug, 2007 18:43, edited 1 time in total.
Sapphire Black 02 S54 M Roadster
Firstly, my sympathies. I've also done this job (twice) and it IS a real pain in the ass. One tip I was given was to use some cling film across the master cylinder opening and screw the lid back on. This restricts the amount of fluid you lose when you start undoing things.
I didn't need to do any work on the brackets, my new pipe fitted exactly like the OEM. Perhaps there are different fittings available?
You do need to bleed the slave with the push rod compressed, I used a small jack under the slave and the rod trapped against the underside of the car...
Much, much easier if you have a pressure bleeder.
The main benefit of this mod does not show in a quick blast round the block but more if you get stuck in traffic. As the engine gets hot the OEM pipe softens and balloons to a much greater extent than normal, making gear selection difficult. Replacing it with a braided version stops this happening.
Getting shot of the restriction also aids gear changes but I agree that it doesn't make it Honda slick!
I didn't need to do any work on the brackets, my new pipe fitted exactly like the OEM. Perhaps there are different fittings available?
You do need to bleed the slave with the push rod compressed, I used a small jack under the slave and the rod trapped against the underside of the car...
Much, much easier if you have a pressure bleeder.
The main benefit of this mod does not show in a quick blast round the block but more if you get stuck in traffic. As the engine gets hot the OEM pipe softens and balloons to a much greater extent than normal, making gear selection difficult. Replacing it with a braided version stops this happening.
Getting shot of the restriction also aids gear changes but I agree that it doesn't make it Honda slick!
-
Guest
Mess
You can avoid any mess when doing this by simply attaching a pressure bleeder (without fluid) and using it to vent the fluid from the clutch system, before starting work. The only fluid in the clutch system will then be a small amount left in the slave cylinder.
Bleeding after such work is best done with the slave cylinder removed, and held so that the bleed nipple is uppermost, with the piston fully compressed against the spring - it's a bit fiddly, but does remove the last bit of air.
Bleeding after such work is best done with the slave cylinder removed, and held so that the bleed nipple is uppermost, with the piston fully compressed against the spring - it's a bit fiddly, but does remove the last bit of air.
Supplied by a company called Earls I think. I will check the invoice tomorrow for the contact details. Fitted by my Indy.
Found this in this thread
Earls Performance Products (UK) Ltd
Unit 17
Silverstone Circuit
Silverstone, Towcester
Northamptonshire, NN12 8TL
Tel: 01327 858221
If you need any more info on the install try this page:
http://128.83.80.200/mcoupe/cdv.html
Found this in this thread
Earls Performance Products (UK) Ltd
Unit 17
Silverstone Circuit
Silverstone, Towcester
Northamptonshire, NN12 8TL
Tel: 01327 858221
If you need any more info on the install try this page:
http://128.83.80.200/mcoupe/cdv.html
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
, BMW Z1, BMW M3 CSL, Z4M Coupe
"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
, BMW Z1, BMW M3 CSL, Z4M Coupe-
Guest
Warn Clustch also contributes to the problem.
Good news on the upgrade gary!
It should aldo be noted that a old warn clutch exacerbates the problem. As the clutch gets older it gets stiffer, so more pressure is put on the hydrolics. I suspect this is most of the issue when the clutch becomes more problematic in traffic. Now a new clutch and a braided hose........
Si.
It should aldo be noted that a old warn clutch exacerbates the problem. As the clutch gets older it gets stiffer, so more pressure is put on the hydrolics. I suspect this is most of the issue when the clutch becomes more problematic in traffic. Now a new clutch and a braided hose........
Si.
