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CMOORESY · 26th January 2020, 09:08

Giving this some thought,
Generally, you are in the clutch change 'zone' from around 80,000 to 120,000 depending on driving style, type of journeys etc.

Lets say you have a hydraulic problem with the slave, seal gone for whatever reason, maybe sometime in the past someone had to reverse up a steep single track lane in Cornwall with a fully loaded car or something, this would have overheated the clutch etc which, in turn, for whatever mechanical reason may have shortened the life of the slave? who knows.

So, why would this necessitate a change of the DMF?

What I mean is, lets say your slave and the other components had held out to 120,000. Would you be thinking of changing the DMF now at 80,000 odd miles? No.

Some clutch places will say you have to change it, for whatever reason, in some cases to get a guarantee on the other parts, but some specialists will say, I have to change maybe 1 in 10 at the most, maybe less. Someone I spoke to, a Rover specialist that came through the dealerships, said he'd done hundreds of clutches ov 75 diesels and only changed two DMF's, never got any back, never got any reported failures.

I suppose what I am saying is that, if you have a hydraulic failure at around 80,000 miles then why shouldn't you DMF last another 40,000 or many more?
My original clutch set-up lasted to 114,000, then it was all changed in DMF.

Clutch plates are cheap, so I would get that done as COLVERT rightly points out, masters can be done without much fuss, no gearbox to drop etc, so its up to you. But if I were you I would fit an OE Borg and Beck clutch kit along with a new slave.

Word of warning. be very careful what slave is used. The metal TZAU ones are worse than the plastic ones in my experience and transfer the bearing noise. Try to source an original OE ex-stock AP Lockhead slave. this will be what was fitted originally and have a proven track record. unfortunately, AP no longer exist, they were taken over by Delphi, maybe the Delphi ones are made on the same tooling to the same spec, I dont know.

Just as a matter of interest given everyone seems to advocate the changing of the DMF, has anyone had one of these fail?

What is the failure rate v/s slave cylinders?

If you dont change one, what would be the mileage that it failed at?

What I mean is, is the so called out of spec backlash really ok for another 100,000?

26th January 2020, 09:08	#7
CMOORESY Avid contributor MG ZT Auto and 75 Tourer Join Date: Feb 2013 Location: Nantwich Posts: 182 Thanks: 8 Thanked 52 Times in 20 Posts	Giving this some thought, Generally, you are in the clutch change 'zone' from around 80,000 to 120,000 depending on driving style, type of journeys etc. Lets say you have a hydraulic problem with the slave, seal gone for whatever reason, maybe sometime in the past someone had to reverse up a steep single track lane in Cornwall with a fully loaded car or something, this would have overheated the clutch etc which, in turn, for whatever mechanical reason may have shortened the life of the slave? who knows. So, why would this necessitate a change of the DMF? What I mean is, lets say your slave and the other components had held out to 120,000. Would you be thinking of changing the DMF now at 80,000 odd miles? No. Some clutch places will say you have to change it, for whatever reason, in some cases to get a guarantee on the other parts, but some specialists will say, I have to change maybe 1 in 10 at the most, maybe less. Someone I spoke to, a Rover specialist that came through the dealerships, said he'd done hundreds of clutches ov 75 diesels and only changed two DMF's, never got any back, never got any reported failures. I suppose what I am saying is that, if you have a hydraulic failure at around 80,000 miles then why shouldn't you DMF last another 40,000 or many more? My original clutch set-up lasted to 114,000, then it was all changed in DMF. Clutch plates are cheap, so I would get that done as COLVERT rightly points out, masters can be done without much fuss, no gearbox to drop etc, so its up to you. But if I were you I would fit an OE Borg and Beck clutch kit along with a new slave. Word of warning. be very careful what slave is used. The metal TZAU ones are worse than the plastic ones in my experience and transfer the bearing noise. Try to source an original OE ex-stock AP Lockhead slave. this will be what was fitted originally and have a proven track record. unfortunately, AP no longer exist, they were taken over by Delphi, maybe the Delphi ones are made on the same tooling to the same spec, I dont know. Just as a matter of interest given everyone seems to advocate the changing of the DMF, has anyone had one of these fail? What is the failure rate v/s slave cylinders? If you dont change one, what would be the mileage that it failed at? What I mean is, is the so called out of spec backlash really ok for another 100,000? Last edited by CMOORESY; 26th January 2020 at 09:16..