16 replies to this topic

[eilz1999]

I have a 1980 Mini 998. My clutch hydraulics have been causing me a lot of problems recently. I thought the issue was with the slave but I've renewed that and despite bleeding, I'm still having 'lack of pressure' issues. My master cylinder is the metal lockeed version and I've got plenty of fluid in the reservoir.

 

I've tested the master cylinder by removing the pipe at the top of the cylinder piston and replaced it with the bleed nipple screw from the slave (they are interchangeable). When pressing the clutch pedal, I was expecting the pedal to be solid with good pressure. Unfortunately, I have very little pressure and I've even tried bleeding it using the convenient screw that I've inserted in the piston.

 

What could be the problems and/or solutions? I've heard that removing the master cylinder is really difficult/awkward.

 

Any help would be much appreciated.

[Captain Mainwaring]

It's not that bad dropping the master cylinder - take the drivers seat out and lay on your back and you can get to the pin.

 

I'd guess from your description that master cylinder seals have failed.

[McPhie]

Managed to get the master out of mine in around 10-15 minutes working at a leisurely pace. My brother got short straw, the job of doing the pin attaching it to the pedal, but it wasn't too bad

[greenwheels]

A really long pair of long nosed pliers is good when re-inserting the pin.

[Captain Mainwaring]

You can also use the old red indian trick of taping the pin to a bit of coat hanger wire.

Didn't know many red indians had Minis 

[Fossy313]

is it definantly tour clutch master? check your slave as well and the flexi pipe leading from the master to the slave...

 

i have recently just replaced my master cylinder with help from mk1leg on here. Its a pretty simple job but takes time if anything is seized....the main trouble is the space and one of the nuts to get the cylinder off, but with aid from a slightly modified spanner (cut in half it was easy). I had a fuel line rounded off but a pair of mole grips and it was off but the thread was done for inside the master which is why i had to change.

 

+1 on the long nosed pliers and some at and angle may be of benefit....its either going to come out quickly or just take time.... key is to get the split pin as strght first time round.

 

replace with an "R" clip which will aid removal next time!,

[Jordie]

Theres pros and cons to the R clip.

 

Pro: easier and quicker to fit and remove

Con: many have worked loose, causing loss of clutch pedal, possibly leaving you stranded if you dont have anything to repair it with (or brakes if fitted to that pedal)

[Fossy313]

each to their own i guess, but an R clip is designed in the same way as a split pin, to hold something in, id be very surprised if it worked loose, each to their own

[eilz1999]

Hi all. Just to keep you updated. The long-nose pliers worked but getting the clip off did ruin my back! All the components of the clutch hydraulics is now off - From the master right through to the slave. I've bought the repair kit: http://www.minispare.../classic/clutch. I've cleaned the bore of the master cylinder but there is slight resistance when trying to put the old piston back (some scoring or rust marks about 1/3 of the way in the bore. I hope that a new piston, seals and light lubrication of brake fluid will do the trick. Bought an R-clip as well and all new hoses and slave. Around £50 spent all in. I hope this is worth the effort - This mini hasn't run since 1997! I've loosened the pre-verto arm from the clutch housing with Plusgas. Let's hope I can get everything moving again! Thanks to all who have contributed.

[Fossy313]

No dramas mate, I haven't had any problems with the R clip since and the advice was given to me by a person who has lived and breathed minis for the majority of his life.

All the best,

No problem with the repair kit I have repaired a mk1 brake cylinder with said kit and they work great, wasn't an option with me because my hydraulic line thread was knackered.

[Eiriktell]

Hi, I've just replaced my throwout bearing and every other component between it and the master cylinder, including the same repair kit you've used.( http://www.minispare.../classic/clutch ) I then attempted to bleed it to no avail and eventually ended up doing the same thing you did, putting the bleed screw from the slave directly into the master cylinder. Pedal went straight to the floor, even after attempting to bleed it and with a full resovoir.

 

I therfor suspect I may have put one of the seals in the wrong spot, likely the one that was meant to replace the "cup type seal". Does anyone here know excactly how these bits are meant to go into the master cylinder?

 

Or any other potential causes?

 

Thanks

Eirik

 

Update: I sat down and had a good think and also referred to the Hayanes manual. I had put the seals from the master cylinder repair kit on backwards. The "Lip" is meant to be facing the top of the cylinder so they'll slightly expand and provide a better seal and prevent the pressure from just blowing by the seals I guess. I put them on the way I did because the old ones were facing down, I feel pretty stupid but you have to learn somehow.

 

It works really well now after I've put them on the right way around.

Edited by Eiriktell, 13 September 2018 - 12:06 PM.

[absx2]

Hi all. Just to keep you updated. The long-nose pliers worked but getting the clip off did ruin my back! All the components of the clutch hydraulics is now off - From the master right through to the slave. I've bought the repair kit: http://www.minispare.../classic/clutch. I've cleaned the bore of the master cylinder but there is slight resistance when trying to put the old piston back (some scoring or rust marks about 1/3 of the way in the bore. I hope that a new piston, seals and light lubrication of brake fluid will do the trick.

 

I`m sorry to say 99 times out of 100 you are wasting time and money on repair kits. The clutch master is not safety critical like the brake master but you will lose vital clutch arm travel when messing about with rusty old cylinders with oval holes in the rod. The scoring and pitting that you see is just the tip of the iceberg, each pit and mark will allow a tiny amount of fluid to bypass the seal whilst prematurely wearing the seal out at the same time. 

42 quid delivered on ebay gets you a brand new AP plastic master cylinder, fit and forget.

 

Just to add. It bugs the hell out of me to see people selling old master cylinders on ebay, they are cast iron filled with hydroscopic brake fluid that eats away the cast bore. I have purchased new old stock items in the past that were corroded so what hope has a rusty old can that has been lying around for years got.

Shame on them and shame on the buyers daft enough to buy them.......Sorry , rant over :)

Edited by absx2, 09 September 2018 - 06:43 PM.

[DeadSquare]

On any competition cars, I always swapped the guts around from the brake to the clutch master cylinders, and then rotated and swapped the master cylinder / reservoirs units around.

 

This brought the filler in front instead of behind the cylinder, which made topping up very much easier.

[Spider]

I gotta agree with absx2 in regards to replacing the seals.

 

The seal kits are not really intended for repair, but a maintenance item, as it's recommended all hydraulic rubbers are replaced every 24 000 miles ( or 40 000  km).

 

From my experience, Hydraulic Cylinders give trouble or leak once they become rusty. You can temporarily remove the rust (sometimes), but you can be sure it will play up again, and before too long.

 

All the same, here's a section view of the Master (note this is an early type, so just ignore the Nut no. 7)

 

[Homersimpson]

 

Hi all. Just to keep you updated. The long-nose pliers worked but getting the clip off did ruin my back! All the components of the clutch hydraulics is now off - From the master right through to the slave. I've bought the repair kit: http://www.minispare.../classic/clutch. I've cleaned the bore of the master cylinder but there is slight resistance when trying to put the old piston back (some scoring or rust marks about 1/3 of the way in the bore. I hope that a new piston, seals and light lubrication of brake fluid will do the trick.

 

I`m sorry to say 99 times out of 100 you are wasting time and money on repair kits. The clutch master is not safety critical like the brake master but you will lose vital clutch arm travel when messing about with rusty old cylinders with oval holes in the rod. The scoring and pitting that you see is just the tip of the iceberg, each pit and mark will allow a tiny amount of fluid to bypass the seal whilst prematurely wearing the seal out at the same time. 

42 quid delivered on ebay gets you a brand new AP plastic master cylinder, fit and forget.

 

Just to add. It bugs the hell out of me to see people selling old master cylinders on ebay, they are cast iron filled with hydroscopic brake fluid that eats away the cast bore. I have purchased new old stock items in the past that were corroded so what hope has a rusty old can that has been lying around for years got.

Shame on them and shame on the buyers daft enough to buy them.......Sorry , rant over :)

 

The thing is though you can get old cylinders resleeved, if the old metal ones aren't available and you want the original look rather than the modern plastic ones then this is worth considering.

 

I had one done on a Jaguar MK2 by a firm in Stourport on Seven and it cost around £60-£70.  They sleeve them in stainless so it should be good for many years to come.