FD Castle Nut

[cookie]

being impact guns, they can undo very tight nuts, often without much holding of any rotating parts they might be attached to.

for example, when undoing a large clutch centre nut, you may only need to hold the clutch basket by hand. you couldn't do that if you were using a breaker bar.

just wondering. still need to do it up, but that would take a lot less torque.

 

[Kremmen]

Us commercial technicians use 3/4 & 1" drive air guns, these undo LGV wheel nuts torqued to well ove 700Nm.... so this pinion castle nut will be a peice of piss.
In my experience most 1/2 drive guns dont give high torque because the air supply isn't of sufficient pressure or volume.

If the FD is mounted in a support frame which is secured down, any decent knuckle bar with 18-24" lever will do the job just as well.

 

[xjrjason]

I have read this thread with much interest.

That should shift it.

 

[Aidan1150]

A torque multiplier may be of use, but they are around £150.

 

[MattW]

A decent rattle gun (air or electric) has to be the way to go. An air gun will do stupid torques and because of the shock it puts into the job, it doesn't require nearly as hefty a hold-down as you would need when applying the torque slowly with a huge breaker bar.

Imagine doing up F1 car wheel nuts with a breaker - you'd just spin the tyre on the road.

Air tools are cheap (although decent compressors less so...)

 

[TeaPig]

Us commercial technicians use 3/4 & 1" drive air guns, these undo LGV wheel nuts torqued to well ove 700Nm.... so this pinion castle nut will be a peice of piss.
In my experience most 1/2 drive guns dont give high torque because the air supply isn't of sufficient pressure or volume.

If the FD is mounted in a support frame which is secured down, any decent knuckle bar with 18-24" lever will do the job just as well.

I've never used an air drive gun but I've no doubt they can shift all sorts of tight nuts. My only comment is that the castle nut is made of alloy and I have no idea how that would stand up to prolonged hammering.

I've done 2 FD's and despite the quoted tightening torque being quite trivial compared to commercial vehicle stuff, the torque needed to undo the nut is massive. I was literally hanging all my wieght off a 10ft bar, so what's that 2000NM? I wonder if they use threadlock maybe?

I'm only describing my experiences with the things using limited equiment and the bodging capability of a home mechanic. It'd be fantastic though if the nut can 'simply' undone with an air hammer.

It worries me a little that some people will underestimate the task ahead of them, even if armed with one of Pat's nice castle nut drivers. Once inside the fun continues, notably the rollpin securing the pinion roller bearing is a sod to pull, as is removing the inner bearing of the latter from the pinion. It's all possible but compared to something like taking a cylider head off it's a real biggie.

Check out an excellent early thread by Pat describing his FD rebuild and you'll get a good idea of the job.

 

[MattW]

However the torque is applied to Pat's tool (ooh' er' missus), it'll also be important to ensure that it remains firmly located on the nut. Having it slip out of engagement while beasting a gazzilion Nm's of torque into it will likely ruin a day. I could see an air gun being a bit easier in this respect as you're leaning into it, pushing it into engagement - not so sure how it would be with a 6' breaker bar.

Just thinking aloud ...

 

[cookie]

i didn't realise the tool was ali.

a windy gun would probably mullah that in short order.

 

[MattW]

i didn't realise the tool was ali.

a windy gun would probably mullah that in short order.

I don't think the tool is ali - but the nut is?

 

[(RIP) Bin Ridin]

take drive and tool to tyre garage, open using their rattle gun?

 

[(RIP) Bin Ridin]

or: http://www.hirehere.ie/searchproducts.asp?uid=d596d27d24ff5ec6077646ed831d14a4&uidn=37

 

[ebbo]

If you do use a long bar to slacken it off, what do you use to tighten it again to the right torque. I’ve nothing that will go anywhere near these torque values

Back to the hire shop I guess

 

[Aidan1150]

If you do use a long bar to slacken it off, what do you use to tighten it again to the right torque. I’ve nothing that will go anywhere near these torque values

Back to the hire shop I guess

A torque multiplier will do it, but they are around £150. Unless you could borrow one to do the job.

 

[TeaPig]

i didn't realise the tool was ali.

a windy gun would probably mullah that in short order.

The nut is alloy. I'm sure Pat makes his castle socket out of sterner stuff

 

[TeaPig]

If you do use a long bar to slacken it off, what do you use to tighten it again to the right torque. I’ve nothing that will go anywhere near these torque values

Back to the hire shop I guess

I didn't try and use a torque setting but marked the position of the nut against the FD housing and then tried to tighten it back up somewhere close to that position but failed about 10 deg' short. Seemed to work OK though and still tighter than the nut holding on the propeller of the Titanic.

 

[TeaPig]

However the torque is applied to Pat's tool (ooh' er' missus), it'll also be important to ensure that it remains firmly located on the nut. Having it slip out of engagement while beasting a gazzilion Nm's of torque into it will likely ruin a day. I could see an air gun being a bit easier in this respect as you're leaning into it, pushing it into engagement - not so sure how it would be with a 6' breaker bar.

Just thinking aloud ...

Yeah, dead right. As I said earlier, I made a jig that included a large threaded screw that jammed up against the back of the breaker bar forcing the socket hard into the nut and preventing it from backing out. The 'teeth' on the alloy castle nut are only about 6mm deep and are easily rounded if the socket pops out. Once the castle nut starts to rotate the screw system is slowly backed off little by little as the nut winds out until it's slack enough to easily turn. Reverse process when tightening it up.

 

[Pukmeister]

If I need to undo the castellated nut it will either be on the bench within a fabricated fixture, or most likely bolted down to a machine bed at work and a 1" sq. drive and scaffold bar used. I did see a vice-mountable fixture on the REPROM for this job which used the hollow centre spindle for securing plus paralever holes as a reaction post.

In a previous career we used to have a tool made by Facom which you charged up with internal leaf springs then let it go (a clockwork impact driver). That could undo corroded ships main plummer bearing holding down bolts with 3 blows (makes the GS job look pretty small).

 

[MattW]

Yeah, dead right. As I said earlier, I made a jig that included a large threaded screw that jammed up against the back of the breaker bar forcing the socket hard into the nut and preventing it from backing out. The 'teeth' on the alloy castle nut are only about 6mm deep and are easily rounded if the socket pops out. Once the castle nut starts to rotate the screw system is slowly backed off little by little as the nut winds out until it's slack enough to easily turn. Reverse process when tightening it up.

Ah - that'd do it
Missed that in your earlier post.

 

[ebbo]

A torque multiplier will do it, but they are around £150. Unless you could borrow one to do the job.

Interesting , How to use a torque multiplier,
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[Steptoe]

Put some studs in the wheel nut threads and put them in a vice to hold the unit.
That'll work if you have a big enough airgun but won't work if your using a bar. I have use of a friends workshop who repairs dustcart hydraulics with an airgun and compressor that on full power will spin the earth on it's axis.

Payment on it's way later Pat.

cheers