Removing broken downpipe studs?
 

Removed downpipe last night...

2 studs snapped with about 2cm protruding, one snapped inside the turbo pack.

I was thinking for the two protruding to soak with penetrating stuff (PB blaster/WD40) and try to remove using a stud extractor. WIth the one snapped inside the turbos, i was going to soak with WD40 and build up a small pool of weld on top of it until it protrudes and then weld a nut to that.

what do you guys think? any tips? has this happened to you before?
thanks

Carl

Broken studs on the DP and turbo housing are very very common. Mainly caused by the self lock nuts that Mazda uses. The studs due to heat and oxidation have frozen into the the turbo housing or exhaust manifold and the nuts have gaulled themselves also. I do not think Mazda uses anti-seize on them.

If your tricks fail, you will have to drill a hole in the studs and use a stud remover to back them out. They may end up needing to have a helicoil inserted by a machine shop.

Tricks for puting it back together: use a vey high temp anti-seize, buy a tap and die set and clean all threads for both the stud/bolt and hole, use the tap and remove some of the metal of the nuts where it self locks so that it still grabs the stud/bolt but not as tightly as Mazda made it, use the longer 14mm nuts on all studs to make removeal easier the next time.

A tap is used to cut the female portion of the mating pair (e.g. a nut). A die is used to cut the male portion of the mating pair (e.g. a bolt).

if you can drill and tap them go for it.When i was doing mine they snapped 1/4 inch into the manifold and i couldn't get in there to drill ,so i had to yank the manifold.Good luck

I'd avoid applying more heat to the remaining stud material inside the manifold, as it will just make it more difficult to remove. You will probably have to drill it out, and then tap it for a larger size thread.

Once you've snapped off a DP stud, chances are pretty damn high that you'll have to remove the whole turbo assembly regardless, due to the lack of working space.

please post pictures after the welding!

I've heard many good things about using weld to remove a snapped stud. The heat and shock from welding actually helps the stud come out. Haven't tried in on a rotary, but that should work quite well - it's quite common on other cars.

Good luck - broken studs are zero fun!

Dale

If you have some of the stud protruding, and you don't have a welder (I don't), try this:

Use a dremel or small grinder to carefully create two flats on opposite sides of the stud. I used the largest possible open-ended wrench and made sure to grind the flats to fit that wrench as closely as possble. Then when the fit was just right I had a 2nd chance to get it out. The extra-snug fit to the flats helps generate a lot of torque without rounding it.

Dave

If you are going to weld I presume you would remove the manifold. If you go that far a machine shop would be a route and may be less hassle and time than DIY frustration. I have seen welds done with great success (not on and FD) but it takes time. I would think a machine shop cost would be within reason and it will not be the first time they have seen the problem. I would rather have a machinist drill on a machine than try and do this with hand tools and really have an issue. Good luck and if you weld do take a picture.

I had a broken stud in my engine housing 1/4 inch below when Kevin was rebuilding it. He had welder build it up and was able to remove it.

If i'm going to weld it im going to leave the turbos attatched to the car - only 1 stud needs welding. The plan is to build the stud up so its higher than flush, then weld a big nut to the weld and try and get it out that way. If that don't work, ill have to pull the turbos.

Im not really worried about the ones that are protruding, im sure they will come out pretty easy Its the one thats snapped inside that im worried about...

any updates?

well the thing is, if you mess up the center manifold on the turbos (where the dp bolts to), it is easy to replace if you already have the turbo assembly out.

if you have stud protruding, why not use a 10mm stud remover? most garages will have a set and would probably remove it for little or no cost if you're already a customer.

+1 - makes sense to me. Beats the weld and hope plan.

i have two studs poking out that im going to remove with a stud remover. Im concentrating on other areas of the car at the moment and letting penetrating fluid soak the studs.

I do, however have one stud thats snapped INSDIE the manifold, about 2mm in. Plan is to build a blob of weld on top, the weld a nut to that blob and hope the penetrating fluid has done its job well.

Soak with AeroKroil or Kroil for 12-16 hrs., instead of WD40 or PB Blaster.

AeroKroil has saved me more than dozen times.

Use some NEW Vise-Grips (no needle-nose) to get a nice "bite" on the remaining studs.

Also, use the nickle-based high-temp anti-seize.

Good luck!

:-) neil

got them out, the one that snapped inside the manifold i built up with weld and welded a nut to it, came out. One i used a stud remover, the other i broke the stud remover on and had to grind it almost flat, drill it with a very small drill and get larger and larger till i drilled it out. however, the small drill bit snapped INSIDE the stud! (Doh!)

I managed to drill around it but it meant my further drillings were off centre. I drilled slightly larger holes in 0.5mm incremements till i could see the brown of the manifold throught the wall of the stud on one side, leaving me with a half moon shape that i prised away from the wall of the thread and then knocked it through with an air hammer.

the threads arent exactly pretty but they are all solid (3 are as new) and theyve gone on and tightened up ok. i over tightened them the check the thread integrity and its all good...

but phew what a pain!