Help with stripping Scorcher Gearbox

[jujutsuboy 8]

Hey all, I am in the process of stripping, cleaning and rebuilding an old Scorcher. However I have come up against 2 problems that I would be greatful for advice on........

The first is the grub screw on the front of the suspension arm (where the spring runs through) is well and truely stuck and partially rounded off. Any suggestopns for how to remove?

Secondly, the 2 halves of the gearbox are stuck solid. I think I have stripped all bolts out, so was after any suggestions for how to break the seal?

thanks all

[TA-Mark 195]

Try an imperial size 1/16" hex key in the front arms. 1/16" is slightly larger than 1.5mm metric hex key.

For bolts that are seized (or gearbox halves that have grown together) I use Inox spray to soak them in for a good 10 minutes before I try to shift them.

The gearbox halves could have been glued together with a sealant too. A little bit of acetone (paint thinner) around the seam will make most sealants or glues let go.

[Badboy 94]

Got any pics on the leftside of gearbox? (Side with all screws)

If we may spot any left screws or so...

Badboy

[Shodog 1835]

An easy out will get that grub screw out. An easy out is a four sided ******* that diges inton the metal when you turn it counter clockwise

[jujutsuboy 8]

Got any pics on the leftside of gearbox? (Side with all screws)

If we may spot any left screws or so...

Badboy

Doh! This prompted me to check under the front arm that I cannot remove, surprise, another bolt! Just got to get that grub screw out now, unfortunately 1/16 hex too big :-(

[Shodog 1835]

Try heating the arm. The dissimilar metals will expand at different rates

[jujutsuboy 8]

An easy out will get that grub screw out. An easy out is a four sided ******* that diges inton the metal when you turn it counter clockwise

Try heating the arm. The dissimilar metals will expand at different rates

Thanks for further suggestions. Did some searching for easy out extractors but all the sizes are way too big that I can find.

So far have tried using soldering iron to heat up screw to release thread lock but no luck and have also tried some acetone.

Don't suppose any suggestions for a 'safe' (ish) way of heating up the arm that may be more effective.

cheers

[SB_Aust 42]

Actually I had a similar problem a few weeks ago regarding the stuck case (massive sealant use) . They wouldn't budge whilst dry. With fear of cracking the case halves I let them soak in (sprayed heavily WD40 around the join) and left 24 hours. They parted quite easily after that. The grub screws i always soak in wd40 for 24 hours prior to attempting screwing out. But my rounded grub screw experience in the past some resulted in drilling out, worst case i had to drill and re-tap others.

[SteveU30 1011]

You could try and tighten the grub screw a little to try and break the seal and then loosen it?

[bromvw 744]

Thanks for further suggestions. Did some searching for easy out extractors but all the sizes are way too big that I can find.

So far have tried using soldering iron to heat up screw to release thread lock but no luck and have also tried some acetone.

Don't suppose any suggestions for a 'safe' (ish) way of heating up the arm that may be more effective.

cheers

got a gas stove ? works well if your careful . Just hold the arm over the gas ring with some grips and then give the screw a go mate .

[jujutsuboy 8]

Thanks for all your input guys, unfortunately I have failed miserably on all counts

This leaves the drilling out option, something I have never tried before so any pointers on types of drill bits, drill speeds etc would be appreciated.

thanks again

[SteveU30 1011]

I think we all knew it was going to end up here. You need a nice sharp drill bit, to start with just slightly bigger than the rounded off hole you have. I'm assuming you don't have a pillar drill so failing that, a Dremel is next best, failing that a standard DIY drill will do the job but you'll have to be very careful.

Drill straight through the grub screw (taking care to stop once you're through as you don't want to damage what's on the other side). Once through and you are left with essentially just a tubular grub screw you may find that it has weakened enough that you can 'pick' and 'unwind' it out with a small screwdriver or sharp metal point. If its still not budging, go up another side drill bit (ideally still smaller than the thread as you want to preserve this at all cost) and then try to pick what's left again. Then simply rinse and repeat.

If you find you end up damaging the thread altogether then you may be into new parts unless you can re-tap the thread but at least you'll be able to strip the gearbox finally.

Hope this helps and let us know how you get on.

[TA-Mark 195]

One thing to add to SteveU30's post. Use a coolant/lubricant as you drill through the grub screw. Keeps the drill bit sharper for longer.

[SB_Aust 42]

I use a good old Stanley hand drill (non electric). My drill dates back to the 1960's and still goes strong. I bought it at a flea market. New hand drills can be bought from a hardware store. I always use this when drilling out screws or grub screw in this case. Nice and slow wins the race. Works for me all the time. I have a dremel but prefer the hand drill when i come across this situation. I always keep a few 1mm,2mm and 3mm drill bits handy for this purpose depending on the job. The hardest part is trying to clamp the item firm to work on. Just take it slowly and follow the great advice from the posters above ^^^ .Good luck.

[jujutsuboy 8]

Weel, I'm back and have failed . Though I have a nice collection of dead drill bits (including cobalt ones)! I have managed to seperate the arm from the gear box which is good, but that grub screw will just not come out. I think it may be time to accept defeat, so the question I have (which I think the answer is yes based on what I have read), is can I replace an original Scorcher rear suspension arm with that off a re-re??

thanks all

[Grastens 2795]

I believe you can. While certain detail changes were made to the re-release models compared to the originals, the rear suspension arms appear unchanged and so they should be compatible.

[SteveU30 1011]

Do your current arms have one or two bearings as the re-re arms only have 1. They're still compatible, they will just look slightly different.

[oz-trash-cowboy 63]

Some people can get a bit heavy handed with the thread lock. Have you tried to knock out the pin which is held in by the set screw?? If you can get that out, ( pin punch etc) then the load on the set screw will be gone and it might come out easier. Or if you can find a left handed 2.0mm drill bit. Put the drill in reverse, at its slowest speed, keep it in the set screw seat and try not to lean the drill off 90 degrees. It should grab and then unwind the set screw. If you cant get your hands on a left hand bit, still with a normal HSS 2.0mm, try again and slowly once you have the gone through with the 2.0 any remaining bits of set screw should fall out. If they dont, a gentle run through with a M3 tap will sort it out. If it all goes wrong and the set screw hole gets messed up, dont stress, you can retap from the other side. Sorted!!!!!!

[IBIFTKH 1369]

...can I replace an original Scorcher rear suspension arm with that off a re-re??

Yes, but it's not quite identical. The re-re arms are slightly wider so you may need to file a small amount off to get it to fit between the gearbox lugs.

[biggamehunter 127]

if you soak the stuck bolt and part, in coke , the soft drink ,overnight , then get a torque/ star drive just bigger than the hex , and drift it in gently with light taps the star drive will cut its own shape in the old rounded hex cavity as it goes in, it will come out , i promise you , we use coke to free stuck injectors in diesel heads , its incredible ......... and the star drive for rounded car wheel locking nuts , i have used this method many many times and its never failed , the acid in the coke disolves the deoxidisation on the alloy ,