With all the problems 1st gen mini seats have, this one doesn't seem to get much attention but it's the problem I had on both my front sport seats in a 2006 Mini Cooper S R53.

The symptom:
Your entire seat can slide forward and back about 1/8-1/2 of an inch even when the seat rail ratchet mechanism is fully engaged. Typically you will feel this during hard braking and the seat slides forward with a jolt. Some people have confused this problem with a loose seat reclining mechanism or seat lumber mechanism. I am talking about neither of those issues.

The solution:
I first found mention of the exact problem and solution in this thread. Yo'sDad gives the solution here. But since it took me forever to find this thread, and a little bit of investigation to see what Yo'sDad was talking about, I decided I'd make a pictorial how to.

-First, disconnect the battery and remove the entire seat assembly from the car. I wont go into detail since this has been detailed in numerous threads.
-Then, locate the seat ratchet mechanism. It has 5 pawls that release into the seat rail holes to hold the seat in place. This mechanism is bolted to the rest of the seat frame with only 2 torx bolts each side. Mine had come loose. I removed one and could feel it had been squared off by sliding back and forth over the years.
-Remove the bolts on the ratchet mechanism. They can be accessed through the holes on the seat rail. Clean the lube off the threads with brake cleaner or similar. Then reinstall with blue loctite. I torqued them down as hard as I thought the little threads could handle. If you were to strip them, there is room to put a new longer bolt in and get a new nut to put on the other side.
-Now just reinstall your seats and you're good to go!

 

Good info, thanks.

 

Just found this. Super helpful after futzing around trying to figure out where the slop in my seat was.
Thanks for this

 

Excellent write up. I vote this to be a Sticky thread.

Moderators?

 

This is brilliant thanks! A few years on, and still super helpful.

I’ve just done the above today and its feels solid now… but it still has a slight bit of movement in some of the clicked positions, but solid in others (which is better than loads of movement in all positions previously! &#129315. Not used threadlock as I don’t have any.

Any idea why that could be?