BMC mini 9/16

[Pinewood001]

Good evening all, I am needing some help. My 9/16 diesel has typically bad starting problem. I have the cylinder head is off at the moment and the valve seats are pitted. I have a seat cutting tool but before I go mad and start hacking at it, does anyone know size and angle I should use? Any advice would be welcome. Thanks

[Ley154]

Hi the seat angle is 45 degrees and the diameters are tiny. You can't take much out without having seat inserts fitted which again are about the same size as a mower engine! Get a download of the Mini workshop manual as there is a page showing the seat dimensions. Any idea of the bore/ring condition as the Mini wears bores oval and wears the ring lands on the pistons badly. Before recent times when pistons and rings became more easily available it was a nightmare try to rebuild this engine. John Poulter

[Pinewood001]

Thanks John, I will proceed with caution. I guess I won’t find another head.

[Ley154]

As far as I know Tim Blackburn from www.bmcminitractor.co.uk still has some new bare castings available. John Poulter.

[Noseyboy]

hello i have bmc mini diesel and it’s leaking hydraulic fluid from starter l think is a seal is ‘‘tis a big job to split tractor in half

[Ley154]

Hi noseyboy. I doubt it's hydraulic fluid as the tank is separate. It's more likely the seal behind the flywheel or the gearbox input shaft. Gearbox, engine and hydraulic oils are all the same. If the oil dripping from the bellhousing is clear or white ( if the gear levers have lost their gaiters and have let water in ) then it's likely the gearbox seal. If it's black, more likely from the engine. If there is a lot of oil present when you take the starter out you may need to clean out the inside of the starter motor. Download the workshop manual it's worth its weight in gold and covers most problems. It's not difficult to split the tractor - undo as little as possible, Use two trolley jacks to wheel the two halves apart. Should it be the gearbox seal I suggest you check the gearbox/oil level by removing the level plug - if you get loads of oil out which shouldn't be there be prepared to change the hydraulic lift ram seal. John Poulter.

[Noseyboy]

thank you john

[Noseyboy]

hello John Poulter l was wondering do I have to pull the gearbox apart to change that oil seal or just pull it out from the front