Clutch Hydraulics Maintenance

[T-Cut]

It seems to me that a lack of regular maintenance may well exacerbate the poor design of the clutch hydraulic system. Though the slave cylinder incorporates an accessible bleed valve, little use is made of it until something is obviously amiss with the clutch. Bleeding it at that juncture may be too late to prevent failure. So, why not incorporate a clutch cylinder maintenance regime akin to the brakes? All clutch cylinder autopsies I've read indicate fluid contamination as a contributory factor. The original fixed charge of fluid is paltry, a design that's got failure written all over it. So replacing this on a regular basis should increase the life of the system.

What I'm suggesting is a hydraulic fluid change on a regular basis, maybe annually. However, with the existing arrangement, it hardly encourages servicing and that's really the problem - accessibility. I've therefore designed a modification which should work in practice. It just needs someone with the will to check it out. I'd do it myself, but I'm getting too long in the tooth for the acrobatics required to access the master cylinder.

Anyway, what I've designed is a secondary fluid reservoir to supply the master cylinder. This new unit is mounted somewhere under the bonnet with easy access that's higher than the clutch pedal. The new reservior connects to the master cylinder cap with flexible hose. Gravity does the rest. This is what I've come up with so far.

http://i5.photobucket.com/albums/y191/waveguide/clutch_Hydraulics.jpg

The main problem is incorporating a reliable hose connection in the original cylinder cap. I'd prefer to see a remanufactured cap with integral connector, but that's unlikely to happen. The same issue applies to the new reservior, but I guess something like this will be available off the shelf. The diaphragm seal inside the old cap would be removed and the cap sealed with a suitable gasket.

Charging the system with hydraulic fluid might be subject to air bubbles in the hose, but if the cylinder reservior were filled before sealing with the new cap, I believe the fluid will transfer naturally. Any air under the cap would not be an issue and evacuation of the new reservior would remove any air as necessary. No air would get into the high pressure side of the cylinder.

This design would allow convenient fluid replacement just as is done with the brakes. I reckon an annual fluid change would increase the life of the clutch system significantly.

I'll be interested in your opinions and suggestions on this idea.

TC

[Mel Dawson]

Hi T-Cut,
Ive been thinking about doing the same thing so please post up how you get on with it.

Cheers Mel:lol:

[chris75]

I definitely like the look of this idea , and an effective reservoir on the bulkhead would transform fluid maintenance . I find it very difficult indeed to do anything meaningful with the reservoir where it is. My wife's 416 k series has a similar master cylinder but the reservoir is located on the engine side of the bulkhead , making access easy . It has the same "condom" rubber insert in the reservoir ; interestingly , it has never needed topping up in some 74k miles and the fluid remains clean !

[picky747]

How about modifying a Gunson easybleed ,cost around £15.Extra length of tubing from a pet shop and a bicycle drink holder attached to the bulkhead.The Gunson has a lid to fit the master cylinder and the original rubber seal can be left in situ with the bottom cut off as this acts as a seal between the lid and the cylinder reservoir.Just remove the air line and plug the hole.
http://img269.imageshack.us/i/gunson.jpg/
http://img44.imageshack.us/i/holder.jpg/

[Departed]

For the remote reservoir, why not use a remote reservoir.

There's one for Morris Minors been around for years!

EDIT:

there's loads of choice. Just one example here:

http://www.merlinmotorsport.co.uk/BRAKE-&-CLUTCH-PARTS-Reservoirs/c29_160/index.html

[oldcodger]

T-Cut - you say that all failed clutch systems report fluid contanination. What has caused this contsminstion? In failed hydraulic systems I have come across the same contamination is present, but it is usually black and thw dege of the seals that has, over a period of time, been worn away. If this is correct I feel that just changing the fluid would not help to prolong the life of the system.

Jim

[T-Cut]

T-Cut - you say that all failed clutch systems report fluid contanination. What has caused this contsminstion? In failed hydraulic systems I have come across the same contamination is present, but it is usually black and thw dege of the seals that has, over a period of time, been worn away. If this is correct I feel that just changing the fluid would not help to prolong the life of the system.

Rubber seal debris is obviously a big contaminant, but removing this will certainly improve the seals' working environment. Some failed systems report that the fluid is completely black. Whether this is just a rubber particle suspension or indicative of some other problem I couldn't guess. Maybe the seal would be less susceptible to wear if it were always operating in fluid less than twelve months old? In many cases of clutch hydraulics failure, a reprieve has been gained by bleeding the system and getting fresh fluid into it. Clearly the original system isn't designed to be bled or flushed and the idea is to enable this to be done easily and on a more regular basis. Whether doing that would actually increase the service life remains to be seen. To me, it seems like a valid experiment.

TC

[T-Cut]

For the remote reservoir, why not use a remote reservoir?
There's one for Morris Minors been around for years!
There's loads of choice.

Indeed. I think the main problem is devising a reliable union in the cylinder cap. Maybe there's a drilled/piped off the shelf cap that will fit? I haven't persued it beyond the basic idea.

TC

[T-Cut]

How about modifying a Gunson easybleed ,cost around £15.- - - -

Why not. I'm just tossing the idea around. I'm sure there are lots of solutions if you think long enough.

TC

[Departed]

Rubber seal debris is obviously a big contaminant, but removing this will certainly improve the seals' working environment. Some failed systems report that the fluid is completely black. Whether this is just a rubber particle suspension or indicative of some other problem I couldn't guess. Maybe the seal would be less susceptible to wear if it were always operating in fluid less than twelve months old? In many cases of clutch hydraulics failure, a reprieve has been gained by bleeding the system and getting fresh fluid into it. Clearly the original system isn't designed to be bled or flushed and the idea is to enable this to be done easily and on a more regular basis. Whether doing that would actually increase the service life remains to be seen. To me, it seems like a valid experiment.

TC

In mine the contaminant was grey. The main plastic seal was grey and I suspect this is where it came from.

There's a none return valve in the piston which should close as you press. My theory is that the grey muck can build up sufficiently to stop this closing, creating no pressure. This why they can 'recover' temporarily by pulling up the pedal, and even longer by bleeding the system which pushes a lot of the grey muck out.

However it seems the slave dies about the same time as the master. On my car this was the actual thing that died, and although the symptom was pedal to the floor, the actual failure was the release bearing, not a hydraulic failure.

[T-Cut]

it seems the slave dies about the same time as the master. On my car this was the actual thing that died, and although the symptom was pedal to the floor, the actual failure was the release bearing, not a hydraulic failure.

That's what makes me wonder what the common denominator is.

We regularly read about slaves packing up shortly after the master and this has to be a hydraulic issue or some other common fault like seal materials. Basically, this mod is as much benefit to the slave as the master. Bleeding the system thoroughly will benefit both cylinders. Indeed the slave may benefit more. I guess the fluid within the slave is subject to heating stresses via the thrust bearing that aren't felt by the master. Only by bleeding on a regular basis will clear out any thermally degraded fluid. Exactly why you replace the brake fluid every two years.

The failure of the slave through collapse of the thrust bearing wouldn't be mitigated by altering the hydraulics unless the hydralic system was the underlying cause. Maybe slave hydraulic failure leads directly to excessive loads on the bearing or bad operation of the release bearing. Who knows? Either way, the hydraulics are implicated or there wouldn't be the master-slave relationship. Only by doing the experimant will we know if the idea is valid.

TC

[jumpstart]

I don't know if this is any help at all but Hillman Imps have a remote clutch fluid reservoir mounted right at the front of the car under the bonnet. I think TCut has a very good point and if anyone is thinking of keeping a car for several years, this would be a good mod to do.

On the other hand, some of us just bite the bullet and pay up and then run the car another year and sell it on.

My clutch pedal is currently having to be floored before I can squeeze it into gear. Then the car runs fine and will do 70 for hours.

Bleeding the clutch improved matters for a couple of weeks but it's back to the floor.

I am gambling on a new master for 150 quid local spares shop ( or 175 ish from Rimmers) because it is relatively easy to do, and would need to be done anyway even if it turns out to be the slave, or even simply a worn plate.

If all is well, fine. If it turns out to need a new master and or plate, I've lost little. Even if the thing works for a while and then the new master causes the slave to fail by being, say just too powerful for it, well it probably would have happened anyway.

When the master goes, could it be that the fluid simply does not go anywhere other than back past the seal and then in front of it again?

eg as the pedal goes up and down?

In the old days it was possible to just dismantle the clutch master and pop a new rubber seal or two round the spindle. They sold a repair kit which made good sense - say two or three hours work to save 175 or so pounds. Does anyone know of a repair kit for these - ( I know it's unlikely but you never know!)

Does anyone have any turnbuckles that hold up the under engine cover to sell?

Jumpstart:lol:

[Dallas]

T-cut blooming great work there and the rest of you guys excellent! I can sort of understand what you all are on about but its going over my head, so to speak....

I have a few questions..... :D
Q1, Why does the 75 have such a clutch problem?
Q2, Why use a hydraulic clutch and not the easy cable version?
Q3, Where is the clutch reservoir?
Q4, Does this fluid need to be checked and topped up?
Q4, Is the cause of a worn clutch still the same on a 75? i.e when a clutch is worn the pedal will bite at the floor. Good clutch bites at the top.....

I am being slowly put of the 75's for all the problems they suffer from...eeeeeek! :confused: but I luv the look and feel of em......... and I have two of the blooming things........ please tell me these cars are bullet proof..... :shrug:

[Departed]

T-cut blooming great work there and the rest of you guys excellent! I can sort of understand what you all are on about but its going over my head, so to speak....

I have a few questions..... :D
Q1, Why does the 75 have such a clutch problem?
Q2, Why use a hydraulic clutch and not the easy cable version?
Q3, Where is the clutch reservoir?
Q4, Does this fluid need to be checked and topped up?
Q4, Is the cause of a worn clutch still the same on a 75? i.e when a clutch is worn the pedal will bite at the floor. Good clutch bites at the top.....

I am being slowly put of the 75's for all the problems they suffer from...eeeeeek! :confused: but I luv the look and feel of em......... and I have two of the blooming things........ please tell me these cars are bullet proof..... :shrug:

The 75 clutch may sound bad, but I've had an Audi A3 since new and the hydraulics failed at around 5000 miles. The clutch was replaced again at about 40k when the oil seal failed. The third is still on the car at 112k.

Most modern cars have a hydraulic clutch, but the arrangment varies. The said Audi uses the brake master cylinder as a reservoir. Didn't stop it failing at 5k though.

[andrewmsteve]

Hi earlier this year I fitted a vauxhall slave be it did not last more than 6 months I have spent a great deal of time on the reason for failure and the reason is that the lugs in the slave cylinder wear away the the release bearing housing spins this causes the piston to spin wearing out the seals and the body I have now modified the bearing housing to stop the spinning ie I have put slots in the housing and screws in the body also fitted a remote reservoir by drilling the cap 8mm fitting an 8mm bolt with a washer made from rubber brake pipe then drilled 3mm hole down the centre then the bolt end is turned down to 6mm to take 6mm hose you need to leave enough thread to fit a nut to hold the bolt in the cap if you drill in the centre of the cap you can fit the hose tap out the bleed hole in the cap 2mm and fit screw to seal fit an o ring to the cap to seal the master cylinder Hope this helps

Andrewmsteve

[T-Cut]

Hello Andrew, thanks for your input.

Hi earlier this year I fitted a vauxhall slave but it did not last more than 6 months

This was to a Vauxhall car I assume? If not, a lot of members will be interested in this.

I have spent a great deal of time on the reason for failure and the reason is that the lugs in the slave cylinder wear away the the release bearing housing spins this causes the piston to spin wearing out the seals and the body

Is this the primary cause of MGR slave failure or specifically a Vauxhall weakness?

also fitted a remote reservoir by drilling the cap 8mm fitting an 8mm bolt with a washer made from rubber brake pipe then drilled 3mm hole down the centre then the bolt end is turned down to 6mm to take 6mm hose you need to leave enough thread to fit a nut to hold the bolt in the cap if you drill in the centre of the cap you can fit the hose tap out the bleed hole in the cap 2mm and fit screw to seal fit an o ring to the cap to seal the master cylinder

A drawing would help I think. Any chance of doing a sketch and uploading it?

Cheers

TC

[andrewmsteve]

Hi No it was to a rover 75 but it did not last more than 6 months so I went back to the rover one and modfied it to stop it spinning as this is less expensive way of doing it as with the vauxhall I needed to fit a Girling master cylinder which worked ok the master cylinder was quite cheep but the bracket to hold cost about £80 to have made to my drawings.

Andrewmsteve

Ps If you send me a pm I will phone you to talk about this project ok

[T-Cut]

I'm sure a lot of members will be interested in your project. Why don't you post an account or How To?

TC

[Greeners]

ISTR that someone on .org, looked into this.Might be worth digging that thread up

I did think of this

remote cylinders (http://www.demon-tweeks.co.uk/products/search.asp?keyword=master+cylinder&classCode=MSPORT&brandCode=all&x=0&y=0&filterBrandCode=&OrderBy=NameAsc)

[andrewmsteve]

Hi Thanks T-CUT I Just need to get my act together and do drawings etc then i will post in due course

[andrewmsteve]

Hi Hope you understand this.Take one new slave cylinder, Buy the landrover one and swap the pipes if you need to,The landrover one is only about £46.

Remove the bearing sleeve [it just unclips] Remove the piston it wll come out easily,It will leave the seal in place,do not try to remove it it is ok where it is. Modify the the bearing sleeve to the drawings ie two slots as shown, Then make or modify screws to slide in the slots.

Then modify slave cylinder body to take the 4ba screws, use 4ba as the thread is much courser than metric ,as it is in a nylon body and be much stronger. Replace piston back in the body [ make sure it is the right way round] reclip the sleeve over the body then fit screws tight but not over tight,then check that the sleeve slides ok.If all ok take out the screws one at a time put locktite on the threads and refit.With rubber grease put a small amount in the slots and over the fixing screws.
You will now need an old inner tube 2.5"to 3" cut off a section the same width as the sleeve length. Fit the inner tube sleeve over the bearing sleeve to cover the slots to stop clutch dust getting in the cylinder.

If you want to fit a remote reservior follow the drawings for that. Its up to you to where fit it.I put mine in the engine bay in front of the brake master cylinder on spare studs it is up to you to find a way through the bulkhead. After you have done this you can put the whole lo back together fill and bleed the system

Hope this helps Andrewmsteve

[T-Cut]

Another interesting post Andrew, thanks. I'm sure all of us are intrigued by the cause of slave failure and whether your fix is successful long term. Great work!

Sorry do not know how to send the drawings

It's pretty simple, but you first have to set up a free account with an image hosting company such as Photobucket. Link: http://photobucket.com/

That done, you can upload as many images as you wish. You'll be given an 'album' in which you can set up different folders for different subjects. Or just leave everything as it comes.
Anyway, as soon as your image is uploaded, it will be given a URL to enable you to place a copy in whatever type of webpage you want. This site is a good example.
To do that, you simply copy (Ctrl c) the image URL from Photobucket and insert it in the message panel that's used for all your posts. If you click the insert image button (the square one with mountains), you can paste (Ctrl v) the URL into the pop up box and it will show your image wherever the cursor is when you clicked the button.

Looking forward to your drawings.

TC

[T-Cut]

Thanks for the link Andrew. The images are too faint to see properly, so if you'd like, I'll do some fancy stuff to enhance them and post them on here for you. Let me know.

TC

[andrewmsteve]

HI T cut if you could do that I would most grateful thanks a lot

Andrewmsteve

[T-Cut]

OK, here's Andrew's drawings of his slave cylinder modification. It looks pretty straightforward to me. You will need access to some basic metalworking tools but I reckon it could be done without a lathe, etc. I'm sure Andrew will be pleased to answer any queries on the design and function.

Image 1

http://i5.photobucket.com/albums/y191/waveguide/scan0001.jpg

Image 2

http://i5.photobucket.com/albums/y191/waveguide/scan0002.jpg

Image 3

http://i5.photobucket.com/albums/y191/waveguide/scan0003.jpg

[andrewmsteve]

Thank you very much for that Mr T- CUT

Andrewmsteve

[T-Cut]

Andrew, your drawings are the closest I've been to a slave unit, so I'd like to learn how it works. To be sure I understand it, maybe I could ask some questions. Sorry if they seem basic, but I know there'll be others who'd like to understand it too.

I guess the bearing sleeve (Image 1) fits over the cylinder body (Image 2) and slides axially along it?

The piston presumably pushes inside the sleeve to force the release bearing onto the clutch. Is the bearing sleeve free to move back and forth independently of the piston?

What ensures the bearing doesn't remain in rubbing contact with the clutch when pressure's released?

Are the plastic lugs which usually wear away the ones seen at 12 & 6 o'clock in Image 2?

Do these lugs slide in the slots shown at 3 & 9 o'clock in Image 1?

I guess your screw heads add two more lugs running in the slots made at 12 & 6 o'clock in Image 1?

Is the bearing sleeve made of metal or plastic?

What's the piston made of?

I think these will help a lot. I'm sure there'll be more later.

Thanks, TC

[andrewmsteve]

HI T-CUT
Yes you are quite right in your summation. The sleeve is made of plastic the same as the body and the release bearing is always in contact with the clutch fingers as there is a spring between the sleeve and body so the bearing is rotating all the time and is quite a strong one perhaps a weaker spring could be fitted to reduce the load on the bearing to see if this helps in the life of the bearing but as the damage is caused bye the sleeve rotating under load when foot pedal is depressed it may not help that much.

The piston is also made of plastic. I,am going to bleed the system after sometime in use to see if any grey deposits in the fluid exist. hope this helps

Andrewmsteve

[T-Cut]

Thanks for that Andrew. It looks like they did everything wrong IMO. Anyway, we have to live with it, so maybe your cylinder mod and a regular fluid flushing will help.

As far as the external tank goes, it looks like this can be done very easily using the parts that come in those brake/clutch pressure bleeder (e.g. the Gunson EEziBleed).

This kit contains a suitable master cylinder cap with hose connection, a reservoir with hose connection and enough hose to locate the new tank somewhere under the bonnet. I may invest in a Gunson kit and take a look at it. It will require a suitable hole/grommet though the plenum floor and into the cab. That doesn't look too difficult sat here writing about it.

http://i5.photobucket.com/albums/y191/waveguide/OldHagSneer.gif

[T-Cut]

The sleeve is made of plastic the same as the body and the release bearing is always in contact with the clutch fingers as there is a spring between the sleeve and body so the bearing is rotating all the time and is quite a strong one perhaps a weaker spring could be fitted to reduce the load on the bearing

I can't see why a spring needs to be there at all (?) The release bearing should free float when not in action. That would surely reduce wear and tear on the sleeve and eliminate any heat generated by the constant contact with the clutch diaphragm.

I wonder why the spring's in there?

http://i5.photobucket.com/albums/y191/waveguide/Chav_small_TCut.gif

[andrewmsteve]

Hi T-CUT The reason the spring is there is to keep the bearing square as the clearance is so large between the bearing sleeve and the body the whole lot would fall apart without it [ ie the lugs would unclip as it moved about] it might also jam up

[T-Cut]

Jeepers! I don't think I want to hear any more!

http://i5.photobucket.com/albums/y191/waveguide/ChinWag.gif

[T-Cut]

OK, here they are:

http://i753.photobucket.com/albums/xx178/xrayone_bucket/31-10-06summer2008748.jpg

http://i753.photobucket.com/albums/xx178/xrayone_bucket/31-10-06summer2008747.jpg

Pretty neat I'd say.

[T-Cut]

Not a lot's happened with my easy access project (almost three years already!). I've got all the bits to do the job, but I'm floundering over a nice route for the connecting hose. I really don't want to drill a 10mm hole in the rear bulkhead, but there seems no obvious alternative route from the engine bay to the master cylinder. Anyway, here's a few more photos of the bits.

This is the new reservoir (eBay).

http://i5.photobucket.com/albums/y191/waveguide/Clutch_Stuff/New_Reservoir_zps7214adc4.jpg

This is the custom bracket to mount it on the bulkhead (1.8 engine).

http://i5.photobucket.com/albums/y191/waveguide/Clutch_Stuff/Bracket_2_Painted_zpsdfb4dd5b.jpg

This is a mock-up of the reservoir on the unpainted bracket. Bracket was Mk1, the painted one is squatter.

http://i5.photobucket.com/albums/y191/waveguide/Clutch_Stuff/Reservoir_Location_2_zpsec674522.jpg

This is a spare master cylinder cap fitted with a brass hose connector. There's an o-ring under the mounting nut.

http://i5.photobucket.com/albums/y191/waveguide/Clutch_Stuff/Cap_Connector_zps5aef58f2.jpg

And a large o-ring to replace the old diaphragm seal.

http://i5.photobucket.com/albums/y191/waveguide/Clutch_Stuff/Cap_Seal_zpsbce377e6.jpg

I plan to connect the two with clear polythene tubing. PE is resistant to hydraulic fluid, so unless there's a kinking issue it should allow a clear view of the fluid. As noted, routing the tubing through the rear bulkhead is the thing that's holding up progress. I've left it for months hoping for inspiration.

TC

[Typhoon190]

Not meaning to disrupt your thread T-cut, but my Dad has just had a clutch and slave replacement on his 12 year old 112000 mile ZT-T190.

After less than a week, there was an issue with the way the pedal felt.

If this work is done, based on the replacement slave being pre-filled, it seems very likely that old contaminated fluid could cause problems on a new clutch replacement. :shrug:

Would be interested to here from members who have replaced clutches and dealt with any issues if any that followed.

Thanks.

Ben. :}

[Mike Noc]

Ben if you use the old master cylinder best to flush it through with fresh fluid before you strip everything out.

[HarryM1BYT]

I plan to connect the two with clear polythene tubing. PE is resistant to hydraulic fluid, so unless there's a kinking issue it should allow a clear view of the fluid. As noted, routing the tubing through the rear bulkhead is the thing that's holding up progress. I've left it for months hoping for inspiration.

TC

I also planned to do it, but was brought to a stop for the same reason. It would certainly be more useful under the bonnet, but I wonder if another location might be found for it - might is work just as well installed in the cabin, maybe accessible by removing the trim which runs across the steering column/ under the IPK?

Where ever it is located, the pipe would need to have a continuous slope from original master, up to the new one, to avoid airlocks.

My own clutch remains working fine after five years of it releasing close to the bottom and being quite heavy. Nothing has changed in the way it operates, from the day I got the car and nothing done to it, apart from my flushing and bleeding it, in my attempts to improve it.

[T-Cut]

I wonder if another location might be found for it - might is work just as well installed in the cabin, maybe accessible by removing the trim which runs across the steering column/ under the IPK?

It could probably be done like that, but I don't like the idea of topping up/pouring hydraulic fluid under the dash. It's not the big step forward I wanted. I just haven't had the inclination for acrobatics recently, so the project remains in limbo.

TC

[Typhoon190]

Ben if you use the old master cylinder best to flush it through with fresh fluid before you strip everything out.

I think this is exactly what's gone wrong. My Dad had the clutch changed due to the fact it was very high. It hadn't failed in any way, no problems engaging gears, no slipping, nothing. Just wanted to avoid it failing on him, and given the age and mileage, it seemed a good idea . . . . at the time.

The place he took it to have now replaced the master cylinder with another used one, and all seems better now. I'm assuming that they will have had to bleed the system?

My problem with that is, if the system had been bled in the first place, there should have been no problem with the original master cylinder, and no reason to change it,especially for another used one, at cost.