Rear shock replacement Sunday night rant

[speed12]

Decided to replace the rear shocks today.

Took two hours to carefully dismantle the entire boot interior to access the damn top mounts, never seen such a stupid design. The good news is that I didn't break anything. The bad news is someone has clearly been there before as two plastic clips have been poorly glued in place.

At 2pm I started the damper replacement. Never nice working on a drive this time of the year but hey ho. Changed the driver side in 20 minutes. Was feeling confident as I started the passenger side. The bolt connecting the old damper to the swing arm was really stiff but I thought nothing of it. Until I came to securing the new damper... it was soon obvious that the bolt would not go back into the swing arm. Tried carefully for 30 minutes in the failing light but it's clear that the first 2-3 threads in the swing arm are damaged. Don't want to force it as it will wreck the whole thread.

So I gave up at around 4:30 feeling really worried as it's my only car and is currently un-drivable sat on the drive. I start a new job on Tuesday so can't be late, luckily I have tomorrow off to try and sort something out but I am gutted. The only positive is that its only the first 2-3 threads which look damaged, I've checked in my tool box and I'm 99% sure that I've found a tap of the right size (seems to match up with the bolt ok). The question now is do I run the tap from the inside out or run it from the outside face in? I'm guessing inside to out? The other option is to drive the bolt in from the outside of the hanger and see if that cleans the thread up?

If the thread gets any worse I'll need a new hanger and I have no idea of the cost...

 

[ben g]

If it's the first couple of threads from inside to outside I would go for that. You don't want to be tapping threads if you don't need to.

We regularly tap crankshaft flywheel bolt threads in work as they pick up swarf during the build process. As long as the tap is lubricated and cleaned regularly, it should be fine.

 

[speed12]

Thanks. Annoyingly I have an M11 x 1.5 tap and an M12 x1.75 tap but the bolt/ hole is M12 x 1.5... just ordered a tap from amazon but won't get it until Tuesday

I have an old set of wheel bolts which are M12 x 1.5 I think, would winding that in from the outside face do the trick do you think?

Not sure how I'll get to the station on Tuesday. .. don't want to drive with a shock disconnected for obvious reasons, even if it is only 7 mlies.

 

[Smartbear]

I would try winding a bolt into the thread from the opposite side to the damaged end, it should turn through with some lubricant & clean the thread enough for the bolt to go in from the correct side.
Are you 100% sure the bolt is not damaged? Maybe try a new one?
Regards

 

[maxman]

I would do as you suggest and try cleaning the thread by screwing the bolt in from the outside using plenty of oil,this should work.

 

[speed12]

Thanks guys. I've checked the bolt and it looks fine. I've got some 3 in 1 oil in the garage to use as a lubricant. I never seem to have luck working on my z4 when I did the brakes the other year the calliper carrier had a similar issue. I'm no mechanical expert but I am a chartered engineer, I've done machining and tooling etc always follow best practice but never works on my car!

I just hope the outer face has a leading thread... I tried by hand earlier and it would not bite.

 

[Grumpyowl]

Fingers x hope it works 1st time tomorrow.

Good luck with the new job Tuesday

 

[speed12]

Fingers x hope it works 1st time tomorrow.

Good luck with the new job Tuesday

Thanks, was at my previous employer for 8.5 years straight from university so it's my first job change!

 

[fixit man]

personally I would run that bolt through from the good side that way you are sure that it's lined up properly, another tip is to cut a slot or two 180degs apart into the sacrificial bolt with a hack saw, length wise, that will help to clean the treads as it is almost like a tap , good luck

https://youtu.be/iuSk53cMsFk

 

[Mangozac]

another tip is to cut a slot or two 180degs apart into the sacrificial bolt with a hack saw, length wise, that will help to clean the treads as it is almost like a tap , good luck

I was going to suggest that too

Good luck OP!

 

[fixit man]

feedback ????

 

[speed12]

Hi gents,

Sorry for the delay.

After 1 hour of careful work I managed to succeed! I used an M11 x 1.5 tap to get rid of the worst of any barbs etc (surprising how effective this was even if the OD is 1mm less than the hole). I then used aa redundant BMW wheel stud/ bolt which happens to be the right OD and pitch.

Wound it in from the outside face using 3 in 1 oil, kept reversing out and winding back in to carefully clean the thread.

So I was a very happy bunny on Monday morning, just got to rebuild the boot. Something is knocking under the rear of the car though... Very noticeable without any sound deadening, need to try and find what it is.