7 replies to this topic

[Minitrio]

Model:MPI
Year:97
Description of problem (please be as in depth as possible):I have had clutch problems for years on my MPI. After changing the entire hydraulic parts on the clutch system, i'd still end up with no operative clutch after 24-48hrs sometimes after 8 hrs. So i was forever having to bleed the system to get the clutch to work. I still to this day don't know where the air ingress into the system is occuring, but i have temporarily solved it, by accident!

Basically every morning for the last 6 weeks, i've had to get up early to bleed the clutch, so i can drive to work and i would normally start losing the clutch on the way home. This was until 2 weeks ago, i got up slightly late and had to rush to get the clutch done to get to work on time, managed it and wasn't late!! phew! Still had high bite point all the way home, got up next morning and still had a high bite point and operating gears, this continued for 2 weeks up until Tuesday morning. I had a quick look under the bonnet whilst having a general check over, i noticed that the Clutch Master cylinder cap was off. So replaced it with a spare one from the old one i'd taken off almost a year ago. After a few miles of country lanes, i could feel the bite point going and by the time i'd finished work the bite point was just off the floor and i was back to the same old problems and morning routine. Arrrgghhh!!

I have now left the cap off, after rebleed and have a high bite point and didn't need to rebleed yesterday morning and probably shouldn't have to this morning.

So to you engineering boys and girls out there: Why does the hydraulic system work better, when technically its unsealed? I thought hydralics had to be a sealed system to work effectively!

Can anyone shed some light on this, please?

[Ethel]

The only explanation I can dream up is that there's a leak somewhere and leaving the cap off makes just enough difference in pressure to keep the fluid escaping rather than air gulping back due to the pressure in the reservoir dropping.

Has it been using much fluid? If it bleeds though quickly it would suggest the slave cylinder but you could try bleeding it at the master cylinder pipe union to help decide.

[tomdale86]

would have thought there would be a visible leak if it was going that fast

[pantera2075]

Are you losing fluid? or just sucking in air?

Are you sure you've not got a brake master in place of your clutch?

When you say you've replaced EVERYTHING, does that include the pipes, both rigid and flexi?

It's such a simple system there can't be that much wrong.

[bmcecosse]

Drill a little hole right through the cap - to let air in -and refit it!

[Guess-Works.com]

Personally, I'd replace the master cylinder

[minidan]

how old is the slave cylinder?

[Minitrio]

Are you losing fluid? or just sucking in air?

Are you sure you've not got a brake master in place of your clutch?

When you say you've replaced EVERYTHING, does that include the pipes, both rigid and flexi?

It's such a simple system there can't be that much wrong.

Sucking in air. Yeah everything including pipes.

Drill a little hole right through the cap - to let air in -and refit it!

Thats what i decided to do. It seemed to solved the problem and ended the early starts, with gallons of clutch fluid!

how old is the slave cylinder?

Just over a year old now. I have had the problem for nearly 18 months. It use to go every few weeks, then weekly, every few days to everyday. Not a problem anymore with the now drilled cap!!

I'm just a bit puzzled, as to why it did it.

Thanks for all the replies so far