BMW 2003 Mini Cooper S

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Posts: 590
Joined: November 26th, 2012, 3:50 pm
Location: Dumfries, Scotland

Re: BMW 2003 Mini Cooper S

Post by Will01 » May 15th, 2018, 11:58 am

So the story for the past few years!
Well the Mini has lived just sitting there on the driveway for over 2 years, i started her every now and again, but there was always an issue!
The electrics all went mad and unacceptable and unpredictable, it then spat off it's supercharger belt and i lost interest.

I did however want to make my wife a bit more happy so a few months ago i deiced to get the Mini running again for my wife to use.

First job, fix the slight water leak in the radiator, so luckily i got a free replacement alloy radiator under warranty and this was swapped in.
But the bonnet had rusted shut with the release clips! That took quite a bit of work and we absolutely mullered the bonnet pull cables.
That was a fun job having to run 2 new bonnet pull cables down both sides of the bonnet and under the scuttle in behind the dash and around all the wiring. Lost alot of skin off my knuckles!
Decided to replace coolant hoses, so BMW wanted something silly, so decided to spruce the engine bay up a little with new blue silicone hoses and stainless hoseclips to make it look nicer and shinier, but ultimately protect myself from water leaks.
Gave the intake boots and gaskets off and replaced with new OE gaskets especially for the supercharger and made sure everything fitted well. Alot of adjustments to be made to get it all to fit back together as all the pipework is interweaved all around the engine bay which is truly awlful to work on!

Took the airbox off and i always wanted to put a better intake system in her, but all the kits had filter sitting in hot engine bay with no protection from the heat!
I did some researching and found some guys had made hybrid style airboxes which use a upgrade cone type filter(i decided to use a long cylinder filter) and then fit it inside the stock airbox. Then made more provision to get cold air into the airbox and this also means it is slightly better insulated from hot engine and hot supercharger.

Brakes! well all the steel brake lines from the factory were ROTTEN! wow i have never seen any quite so bad!
I bought some new steel brake lines as was expecting to get them bent to fit in place as per the BMW dealer told me! However when they turned up they were straight and had to be bent to shape and cut. Which i thought was a bit nonsense as they had flared both ends and fitted unions just for you to cut them off and make them fit???? I replaced the front with the steel lines, but for the rear i decided to cut out the old poor and fit cupro-nickel hard lines and fitted a few different unions in so i could get in and around the exhaust, the fuel tanks and various suspension components.
Quite lucky i bought a really nice brake pipe flaring tool which made those very easy work.

Then fitted new braided flexible lines to the calipers. The rear calipers were cleaned up and painted red, but so far the fronts i have left as i will be fitting the John Cooper Works calipers to the car with larger discs soon.

Had to fit new handbrake cables, expecting an easy job, but NO. Another pain in the backside job! The design is far more complicated than required, but also it means servicing is a bit of a nightmare undoing small 10mm bolts from a rusty part of the car, which means the inevitable bolts shear off and there is no way to get access to drill and re-tap. Genius!
But we got round that eventually aswell!

So the car has been treated to quite a minor overhaul. New belts, parts and servicing and new fluids and she fired up straight away, only to get a slight miss-fire!
Found the spark plugs had all worked loose! Actually so loose they could have spat out at any time! Was getting alot of blow by past the threads.
Have tightened it all down and i cannot for the life of me understand how that happened, but as soon as they were tightened down she ran well.

Took her for an MOT and told the guys please be VERY critical as it has been off the road for too long.
She passed :)
Had a minor or 2, one of which was the exhaust seems on the verge of excessive noise and have been told to quieten it down for next year.

Since then i have clocked up a few miles and had an exhaust failure. I think with it just laying the flexi section straight off the manifold got heat and flex back into it and it sheared open. I think i found the issue about the loud exhaust, it must have been blowing slightly but not all too noticeably!
I was going to replace with a full custom stainless manifold and high flow cat, but since i got to do a major overhaul on another car, i simply decided to repair for time being.
Getting the manifold off past the antiroll bar and steering rack was tricky but just possible!
I bought a new flexi section and have welded it back on. It should buyu me a year or 2 before it needs replacing. At which point we will upgrade again.

So have now used for a bit of commuting and just enjoying the car again and getting the confidence back in the car.
The reason for the original electrical issues was down to a poor earth in the boot caused by a water leak causing alot of condensation around the battery terminals which sits where a spare wheel should normally sit in a normal car.
Also found the alternator had cracked open all around the casing and the alternator had seized causing the belt to be spat off. I guess the re-jig of the pulley ratio's on the auxillary drive was giving the old alternator a bit too much punishment!
So on the next list of upgrades is to get a slightly larger alternator pulley to bring it's speed down slightly when it's getting abused on the back roads.

My wife is happy it is working again. I am relieved that i have done that work and it is behind me for the time being. So onto the next project!

Posts: 590
Joined: November 26th, 2012, 3:50 pm
Location: Dumfries, Scotland

Re: BMW 2003 Mini Cooper S

Post by Will01 » September 7th, 2021, 11:35 am

Bit sad, but we decided to sell our beloved Mini after owning it for over 12 years.
It was fun, but the age of the vehicle and list of potential issues which were next on the list at somepoint soon meant it was better to move it on and concentrate on something else
If anyone wants to know how much fun these cars are and what they are like to work on, let me know i got to know ours very well haha

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