Stranger12

Hi All,

This post is not related to 5 series but my 3 series e36 328 which is a drift car and hope someone can help as everyone on this forum is brilliant and help quite a bit.


today I took off my subframe on my drift car to change the bushes and realised one of the bolts has a stripped internal of the nut mounted on the body or welded to the body of the car. some crazy mechanic has done this.

there is a stud that goes into it which has two sides, one side is threaded and then a hex nut and then bare metal and then threaded end.

when i took out the bolt, not only the internals was damaged , the bolt had quite a bit of metal pieces on it which i guess is from the stripped hole.

would heli coil do the job considering the stress these bolts needs to take and the fact that i am drifting so excessive pressure on back end ?

would heli coil fix it as it is or do i have to go up a size which is not an option for me .

Inside the hole taken from bottom of the car



the metal bits on the head of the screw



many thanks

twh

If you can get to under the suspension member, the easiest thing you can do it bang the heck out of the welded on nut and knock it off or grind it off. Then use a regular nut, but you'll have to hold it in place when tightening and untightening.

Stranger12

how do access suspension member?

I can not access it from boot and can not see it .

have taken seats off and still can not see it ( that is rear seats)

also it seems it is not nuts rather the body of the car

is helicoil strong enough for stressed points ?

twh

You'll need to find the torque value of the bolt. Then look up if the Helicoil or other thread insert can take that same torque.

What size is the bolt?

KyleB

Take it to a body shop. They'll cut an 'access window' in the rail, remove the old nut, weld in a new one, then close up the 'window'.

This repair is very, very common in the collision industry. I've seen it done on rails, rocker panels, aprons, you name it. Doing it on your E36 shouldn't be a problem as that chassis is 100% steel.

Stranger12

but that would mean the diff and all the rest should be off the car which will be very expensive , wouldn't it ?

it is off the car now but I don't want to put it all back in and then they take it all off again .

I think helicoil might be safe hence why I am asking re its reliability

twh

Looked up some documents about Heli-Coil at the manufacturer. Everything I read says the resulting threads are stronger than the original. There are different material helicoils. Get the ones made for steel since that's what you'll be tapping.

Stranger12

many thanks all,

I have a tap and die set which I have bought and never used.

today I took the bolt and used pitch gauge and believe it is 1.5mm as that fitted in to the thread easily .

Then i used vernier to measure the circumference of the bolt and it is 10.89mm which suggests it will be m11 , right ? the spanner size is 18mm .

now looking at my tap and die set , i was trying to confirm if it is indeed 1.5 and m11 so in the set I am seeing few bits and more importantly there is a nut( rounded nut) and the metal bit .

I think the metal bit is used to create the thread and the round bit is used to fix bolt head right ?

if so when I fitted the m12, 1.5 on the bolt it screwed few turns before it stopped and needed force. does that mean it is m12 and not m11?

can tap and die fix the issue rather than helicoil ?


picture of the round nut and metal bit i am referring to

twh

Are you asking what the tap and die tool pieces do? Yes, the long thing is the tap - that is used to cut inside threads (i.e. inside the hole you have). The round thing is a die and used to cut threads on bolts or similar.

You can find your bolt characteristics in Realoem if you look up your car and go to the Front Axle page.

You can tap the hole to a larger size if you have a couple things working for you...

First, you can't just tap the existing hole you have. It needs to be cleaned up before you cut new threads. That is hard to tell in a hole that is munged up like the one you have. Each tap size has a corresponding drill bit size you must use. The tap will have it marked on the side what size drill to use. Just take the drill for that tap with your hand and see if that drill already fits in the hole -- if it does, that size isn't going to work. If it kinda fits, you may not get enough material out of the hole for the next size up. You know you'll get a good tap with a completely clean hole once drilled out.

The next thing you need to get lucky on is that the new, larger, bolt fits into the piece it is holding down, for example, a bracket. If it doesn't, you can sometimes drill that bracket hole larger, and sometimes not.

Next problem is that you are taping into a welded nut. You can't go *really* big because you may weaken the nut by drilling away too much.

Stranger12

to be honest it looks as if it not a nut and rather a thread cut into the body or chasis so nothing to replace .

helicoil is best so far so I shall do that . Thank you for all the suggestions so far and clarifying the tap and die

do you guys know what the torque settings for these nut and bolts are ?