Hi all, I've just replacing my earth lead and I can't get the bolt off where it attaches to the engine block. It hasn't rounded off completely but I think it has very slightly as the correct allen key can only exert so much pressure before it jumps off. Not enough pressure to undo it though. Its not exactly accessible either! Any ideas anyone? I've tried WD40 and gentle persuasion with a hammer.
Is this the one that bolts into the crankcase top and earths out the battery? If so that is quite a deep bolt and I assume the engine is in situ as it is quite easy to get out when the engine is out of the frame. First choice would be to use an allen bit and get it as deep into the hole as it will allow and then use a rachet on the end of it to get good leverage. If it is really gone then you could do the same but drive a star bit into the hole as deep as possible and then do the same. I replace that bolt with an identical large head stainless bolt and then with a bit of coppaslip it will be easy to remove, if necessary in the future.
Hi Rob , As suggested above ... But also try getting a punch (Pin punch they are called or a round flat ended piece of bar ) and give it a couple of sharp blows with a hammer to try and break the "seal" You could also try an impact wrench - this allows an allen key socket to go in the bolt head then you again hit the end of the impact wrench which applies a shock load to the bolt - back before internet ect we used these to remove cross head screws(that always rounded off ) from engine cases on all the millions of Japanese bikes that were fitted with cross head bolts that had the strength of cottage cheese .
Access to this bolt is very limited unless the engine is out of the frame. An impact driver won't be able to reach and the options are limited to using an Allen key which probably won't give enough leverage, using a bit in a rachet as per my comment above or trying a punch on it. Having used all of these methods in the past, The one that worked was the rachet method as it was long, stronger and gave good purchase against the bolt, which thankfully is quite deep but can still be rounded off by a poor fitting Allen key or bit. What tends to hold the bolt in place more is the earth tag itself as the bolt bites into it and then it locks itself in place.
one i use regular is combination of both if there's enough room to get in. good pressure with allan. torex whatever then get someone with a hammer and punch on it. works a treat.
If the hex of the bolt is slightly burred, then I use to heat up the hex on the correct size allen key for the bolt, to expand it slightly with a heat gun. But if it is totally rounded off, then it won't work.
Red, would an an impact driver fitted with a 150mm or 300mm 1/2" extension and an oversize torx work? Rob5, WD40 is no good as a penetrating fluid there are plenty of much better fluids available, used to use Plusgas - not sure if it is still available but there are modern equivalents.
It depends on if you have the room to get at the head of the bolt. Without checking either the frame or the barrel or it's ancillaries will get in the way, I suspect Apart from one instance I have always taken the bolt out when removing the engine, leaving the earth wire attached until I was ready to attempt to get it out. I used the rachet with a correct bit fitted when I got the one out when the engine was in the frame. It's a job where in the frame it's very hard but fairly easy when it's out.
Plus one for hammering a slightly oversize star or torx bit into it. The hammering will go some way to shocking the bolt. Works every time for me. Replace with stainless and some form of lubricant, preferably copaslip, as suggested. Stainless is harder as well as prettier.
If you are going to shear off the head of a bolt screwed into the cases, the earthing point is the best one to pick. After all, you can attach the earth lead to a variety of alternative locations if you need to.
If you can ,try tapping the bolt on opposite sides a few times. It'll sometimes free off a bit of corrosion
And also to add to other posts - Some times you can knock in an Imperial size allen key or hex socket into a damaged Metric cap head hexagon .
This stuff works well, I normally leave it overnight/work a day ahead. Bolts I'm really worried about I'll squirt for a few days before trying. Look at this on eBay SOUDAL DEGRIP ALL 400ML SPRAY PENETRATING OIL DISSOLVES RUST & CORROSION | eBay
