Mini Cooper, Strut Top Shrooms

Whilst wrapping up the servicing work on the Mini the other week, I happened to catch a glimpse of something that bothered me.

The R5x series of Mini (and some other BMW’s) have an issue with the front strut tops and mountings. It’s extremely common for the rubber strut tops to fail, and for the metal strut tower tops to actually bend and “mushroom”. My Mini had a badly torn RH front strut top rubber.

Thankfully, visually, the tower didn’t appear to be mushrooming much if at all, but I still needed to fix the strut top rubber before it caused more damage. If the rubber is torn, it can no longer absorb impact from the likes of potholes, and this impact is then transferred to the metal tower. The Mushrooming can be “fixed” with a block of wood, a BFH (Big Funky Hammer) and some gentle persuasion.

There are ways to reinforce the strut towers, such as fancy plates that go on the top

Or flat metal plates that fit under the strut tower, on top of the strut top, called Indurators.

Anyway, so my rubber was torn, but my metal rigid. I ordered a replacement strut top from the States the other day and had it shipped over via YouShop, as it was cheaper than buying it from any closer supplier, and it was quicker than waiting on one from China (not to mention better quality).

The one that arrived is a legit Meyle, and looks to be good quality (although still has an unsealed bearing)

First we crack off the wheel nuts. Look at that lovely dusty wheel. Much spirited driving. Wow.

And then jack the car up. I did a lot of research on how to lift the Mini with a floor jack, as I wanted to use the jacking block for the axle stand, so couldn’t jack from there. PelicanParts has a good photo of where to lift the car from. It’s this large raised section, just inboard from the sill.

I used a piece of wood on the jack to help spread the load. Thanks to the short wheelbase and super rigid body, lifting from here will also completely lift the rear wheel on that side of the car off the ground too.

With the car in the air and on the stand, I removed the wheel and had a look around. There is a reasonable lip on the rotor, which may be why the brakes squeal occasionally, but everything else looks to be in good shape. No leaks from the shock or anything.

There are a couple of ways to do this job, including not removing the strut or using spring compressors, but I chose to remove the strut completely and work on it off the car. YouTube shows a couple of different videos for removing it, including one that removes all the inner guard linings and everything, but I didn’t find that necessary.

The first step was to whip off the three top mount nuts

And remove the swaybar link. This will require using a jack to lift the hub upwards, to relieve the pressure from the swaybar. Use a hex key in the center to stop it spinning, and then remove the nut.

You need to remove the ABS sensor cable and brake hose from the strut. These are just a push fit into the brackets.

Lower the jack, and the whole strut should lower down. It wont clear the inner guard though, you need to remove the pinch bolt in the back of the hub to release the strut and then you can wiggle it free.

Oh hey, confirms the “sport” shocks are just the standard Cooper S shocks I guess

Now for the fun. I purchased some spring compressors to do this job, and to also do the suspension on Tess when the time comes. I did a lot of research on this too, and settled on the style I did as it’s what a lot of Americans use with success, and seems to be more compact and safer to use. In the past I have used the traditional style that have two hooks spaced apart, but you can never seem to get them to sit properly on the spring and end up only using two hooks instead of four. The ones I purchased only have a single, solid, hook, but also have a locking pin that stops the spring from being able to “jump” out of the hook.

They did the job, and were quick and easy to use. They also felt safe, with no signs of slipping or binding. I did make sure to lubricate the threads before use though, which helps.

Because of how short the Mini spring is there isn’t a lot of room to compress them, but all we are trying to do is to relieve the pressure on the strut top and stop it from pinging across the garage (or heaven forbid, pinging into your face) when the top nut is removed.

You can see the top mount removed in the above photo. This is done by removing the large nut in the center. To remove this you need to hold the shock shaft in place with a hex key, whilst using a socket to actually undo the nut. I gave the nut a couple of Ugga Duggas to crack it off, and then used a combo of the socket and some vice grips to spin it off

Comparing the two side by side, you can see the old one was looking a bit worn out

The old bearing spun freely on the shock, but was noisy and you could feel it grinding. The new strut top bearing is much smoother and silent to spin, but offers some drag when spinning. The old bearing looked like the grease had chosen to be somewhere else. This is why some manufacturers have changed a sealed bearing.

And that’s that. Reassembly is the reverse of disassembly. Remember to torque everything up properly, and away you go.

I was surprised at how easy this job actually was, and how little time it took. Driving the car afterwards doesn’t feel any different, but just knowing its fixed is good enough for me. The LH side is showing signs of perishing but no serious cracking. It will need changing in the future, but it’s not urgent.

Now to actually clean the car….