seized diff mount bush bolt

Post Wed Nov 18, 2020 11:58 am

morning folks,

i'm in the process of swapping the diff back plate on my sport for a Z3M finned cover & poly bush (had them on the shelf for ages) & the big M12 (19mm) bolt through the mounting bush is seized solid & looks to be starting to round out. all the other bolts are loose (& will be replaced with new ones).

so i'm looking for ideas on how to get it out,

dropping the diff on the floor is out the question, & i know i can change the cover/bush without removing the diff as i've done one on a mates car.

i'm wondering if a nut splitter would work? maybe cut into the nut then tap the splitter with a lump hammer to get the but to turn?

i've been soaking the nuts for a few days with gt85/wd40 & plus gas for a good few days before i tackled this.

so, does anyone have any ideas? would the nut splitter work?

Post Wed Nov 18, 2020 12:08 pm

Have to admit I have used a nut-splitter like that. It is one of the things I have two of (one good one and one for smacking with a lump hammer

)

Lately though I have found my set of Irwin Bolt-Grips have worked on everything I have tried.

Post Wed Nov 18, 2020 12:16 pm

flybynite wrote: ↑
Wed Nov 18, 2020 12:08 pm
Have to admit I have used a nut-splitter like that. It is one of the things I have two of (one good one and one for smacking with a lump hammer )

Lately though I have found my set of Irwin Bolt-Grips have worked on everything I have tried.

thanks buddy

the nut splitter is looking like the best option, i've got some irwin bolt grips but couldn't get them on to it so looks like the splitter is going to get a hammering (again) but i might try the bolt grips on the bolt head on the other side.

nearly as bad as getting too the two top bolts near the ARB (cut down, offset ring spanner & jack handle help there).

i'll give it another go when the rain stops (in the next few days).

Post Wed Nov 18, 2020 12:29 pm

well just found out i need to get another large nut splitter as mine has decided to fall apart

i'll have to check if the hardware shop in town has any, if not its a trip to machine mart.

Post Wed Nov 18, 2020 12:48 pm

steve_k wrote: ↑
Wed Nov 18, 2020 12:29 pm
well just found out i need to get another large nut splitter as mine has decided to fall apart

i'll have to check if the hardware shop in town has any, if not its a trip to machine mart.

Aww bugger

Post Wed Nov 18, 2020 12:49 pm

Have you hit it with a blow torch?

Paul

Post Wed Nov 18, 2020 5:52 pm

paultv wrote: ↑
Wed Nov 18, 2020 12:49 pm
Have you hit it with a blow torch?

Paul

not yet, i need to get a new gas cannister, how long would you say to heat it up for? (never done it before).

Post Wed Nov 18, 2020 6:06 pm

Can't be tight if it's liquid

But seriously don't do that, If you can heat it as you keep trying it or get a helper.

Post Wed Nov 18, 2020 6:19 pm

Dlb26 wrote: ↑
Wed Nov 18, 2020 6:06 pm
Can't be tight if it's liquid
But seriously don't do that, If you can heat it as you keep trying it or get a helper.

i've seen that a few times

i'll dig out the irwin extractors & give them a try first.

Post Thu Nov 19, 2020 9:12 am

Even a hot air gun will make a difference, a good fitting hexagon socket is always the best option, if the nut is already damaged then hammer an 18mm socket on

Post Thu Nov 19, 2020 9:14 am

DanThe wrote: ↑
Thu Nov 19, 2020 9:12 am
Even a hot air gun will make a difference, a good fitting hexagon socket is always the best option, if the nut is already damaged then hammer an 18mm socket on

cheers dan, been letting it soak to ease off the rust, got a hot air gun somewhere a couple of cheap 18mm sockets.

Post Sat Nov 21, 2020 12:12 pm

well just been out to have another look at that bolt,

don't fancy using either the hot ait gun/blow torch as it's still dripping with gt85/plus gas,

so it looks like it going to be a case of going at it with a wire wheel on the drill then a combination of irwin extractor, slogging spanner & lump hammer as i cant get the nut splitter to seat on the bolt correctly.

fingers crossed the above combo works.

Post Sat Nov 21, 2020 2:38 pm

Another method of removing a seized and rounded large nut is to attack it with a MIG welder, building up weld on opposite sides to form a crude wing nut which can be undone with grips. The heat from the welding will loosen the rust.

Post Sat Nov 21, 2020 3:24 pm

Brianmoooore wrote: ↑
Sat Nov 21, 2020 2:38 pm
Another method of removing a seized and rounded large nut is to attack it with a MIG welder, building up weld on opposite sides to form a crude wing nut which can be undone with grips. The heat from the welding will loosen the rust.

Or if access allows weld a suitable nut to the end of the worn bolt head by filling the centre of the nut with weld thus forming a new bolt head.

Post Sat Nov 21, 2020 5:54 pm

thanks for the tips folks,

looks like i've got the bolt moving after using the irwin extractor & slogging spanner,
jusy need to get another 19mm extractor on the other side to crack it off but at least its moving now.

Post Sun Nov 22, 2020 4:08 pm

Do you have room to drill small holes in the nut then smack it with a chistle ?

Mart.

Post Sun Nov 22, 2020 5:06 pm

martauto wrote: ↑
Sun Nov 22, 2020 4:08 pm
Do you have room to drill small holes in the nut then smack it with a chistle ?

Mart.

i think there might be enough room.

Post Fri Nov 27, 2020 6:13 pm

thought i'd better update this.

managed to get the mounting bolt out.

i used 2 bolt extractors (1 per side)
torque wrench,
27mm socket,
27mm ring spanner.

then came the "fun" part, dropping the diff down.

after scaping my knuckles countless times i was able to drop the diff down about an inch so i could get the two recessed bolts at the top of the diff back plate.

cover off, mounting surface all cleaned up & z3m finned cover all back in place.

i really hope i dont have to do that job again in a very long time.

3 days later & i'm still trying to get the smell of used diff oil out my nose