My exhaust flange bolts are rusted solid , and the cat-back Magnaflow system I bought doesn't make my MINI sound one bit better sitting in a corner of the garage . I plan on going at them again this weekend with an impact wrench, but am pretty sure they will break (or need to be cut) to remove the stock exhaust.

Does anyone know what size these bolts are? I've read from other posts that they may be special "exhaust bolts". If so, can I get them anywhere or just from a MINI dealer?

Any tips on getting these bolts loose/off would be appreciated!

Dave

 

The stock exhaust bolts (I have new ones) to the rear of the cat are splined and press fit into the stock exhaust flange so you will need to only remove the nut, the bolt stays affixed. Penetrating oil, time, and a long breaker bar or impact wrench will help get the nut off. You will need to buy new bolts, washers, and nuts to mount the aftermarket exhaust any way. Nothing special about the fasteners needed except buy the best, long enough to get good thread purchase, and bolts smaller than the holes. I’ll get some measurements for you later tonight if no one else chimes in.

 

Thanks for the info, and any specifics you have would be great!

 

i heat them untill they are orange then bump them off with an impact. works everytime i've never broke one.

 

Having spent time running an exhaust shop in a former life, one thing we did as a rule on studs (same as on the manifold on a reg auto) was to put brass nuts on them (no pun). We would clean the threads really well after getting the rusted on nut off, then put on a lock washer and follow it with 2 nuts per stud. Be careful with over torqing the nuts as you can strip out the threads fairly easily.

And yes, heating the nut will get it off the stud. One of those butane pen torches works very well since you can transer most of the heat to the nut instead of the stud.

Not sure what the size and pitch are, But I am sure someone here knows.
Tim

 

An update: I ended up having to cut the nuts and washers off the cat side to separate the flanges. I used an air driven die grinder (selected for its small size) equipped with cutting wheel. It took a couple of hours, but eventually worked. I installed 1.5 3/8" stainless steel bolts with the new exhaust (thanks to K-huevo for the specs!) to make it easier (hopefully) the next time.

Thanks for all the tips!

Dave