DG fitting new pailpipe

[waltraud]

83 DG with late exhaust system mild steel. Just cut off my old tailpipe and rusted bolts holding tailpipe onto silencer and am now tring to drill through the (about 7mm) flange on the silencer end where the remains of the bolts are still in. Problem is partly lying on my back on pavement......but i've tried ordinary metal drill and a spotweld drill both 8mm , with oil to lubricate and at fairly low speed but its really hard to make any progress. Is it me or why would these old bolts stuck in the flange be so hard to get through? thanks. I'm assuming i can't just heat them up and whack em with a large hammr and drift?? Thanks for any ideas.

[Hacksawbob]

Get a better drill/drill bit? you have centre punched it I take it. There is always a small chance that they are not steel bolts but something tougher, unlikely though.Sorry just re-read your post. Start off with a smaller drill to get it going 3mm maybe.then widen it out progressivly you may also grind off the bolt heads if you have access, at least one is always going to be hard in situ. (not sure if they are threaded holes, I dont think they are from memory) then punch them out.

[Ian Hulley]

First thing to do is drill out the stooooopid threaded flange and put 8mm nuts and bolts through instead

Ian

[waltraud]

Thanks both. I ground off the outer bolt heads first and then cut off the pipe and its flange . Now just left with the inner flange on end of silencer with aboyt 7mm of mild steel but as you say i don't know what the old bolts were made of. Hav tried to ounch them through but i suspect they are threaded into the plate. I guess they might be stainless or toughened as they had allen heads - having said that the heads were quite rusty so clearly not stainless.....will get a better drill bit or two tomorrow hopefully and have another go. Not that easy to get purchase on it lying on side in road though.........nice shiny bit to go back on!

[Rich Tea]

I did this job a couple of weeks back, I have to agree with what everyone else has said, as that's the way I did it.

I had the silencer off the van at the time, which meant I could stand it on the other flange and drill downwards. It's going to be a lot harder with it horizontal on the van. Of course that means undoing the bolts to the J-pipe (or more grinding).

Drilling out to 8mm worked for me.

Make sure the short pipe from the silencer to the flange is up to it, I've had one fall in two before when picking up the exhaust by the tail pipe.

Rich

[waltraud]

Cheers Rich, all done now and put back with stainless allen headed bolts and lcknuts. I nearly got so pissed with it that i was going to splash out 200 on a stainless back box- as I know it will be needed at some point. I have stainless manifolds on boh sides which at 300 for the two i think is a great and hassle free fitment- even if change engine to a gti later on they've still got to be worth 150+ s/h. All done, funny though, now i've got a shiny (s/h) tailpipe of here it looks a bit tarty!!

[Ian Hulley]

It won't stay shiney for long, don't worry.