Jump to content

GT6 differential front flange castellated nut


Doctor slow
 Share

Recommended Posts

I'm stuck getting this castellated nut undone. Am i missing something? I don't have an impact gun, but i've tried with a 3 ft extension on a socket, and it won't budge. Wheels are locked with a firm handbrake, and they're not turning, but neither is this wretched nut! Is there anything else I can try?

Link to comment
Share on other sites

I take it the split pin is out?🤣 No they are very tight and really you need the special tool that bolts on to the flange (see ebay) because otherwise your just winding up the gears/axles and then if you start bashing you could take a gear tooth off. Ive done it with a bodge where I put a couple of the flange bolts back in, tightened up, and then use a flat ring spanner on one of the bolts wedged against the other to hold the flange while undoing the castellated nut. Even then its tight so you risk distorting the flange and/or getting a hernia....

Link to comment
Share on other sites

I had the same problem with the pinion nut on my Scimitar GTE a few years ago, so I feel your pain. Have you already dosed it repeatedly with penetrating oil, Plus Gas or the like (WD40 isn't much help with stubborn nuts)? Here are three suggestions that helped me:

- Trying to tighten a fraction before undoing can sometimes help.

- Use the socket with a shorter extension (say about 12 inches) and hit the end of extension bar hard with a big hammer to start the nut by shocking it.

- Last resort, try a bit of heat by playing a blowlamp carefully over the nut.

Good luck.

Nigel

Link to comment
Share on other sites

Thanks for the replies. I've tried tightening it, but that won't budge either. As Johny said, I am a bit concerned that if i bash it, I may damage the internals, and Using a blowtorch under there seems a bit risky - there's oil and release oil there, and its near enough to the petrol line and tank to be a concern. It's been soaking in release oil for a couple of days. If I can beg, steal or borrow an electric impact gun, is that likely to damage the internals, do you think? Even then, I wonder if an electric one has enough oomph to shift it. Looks like this may be a "pay someone else" jobby.

Link to comment
Share on other sites

they are not highly torqued up  there are two thread sizes depends on model but

9/16unf  70 /80 lbft

5/8 unf 90/100 lbft

all atainable witha decent wrench 

i agree  use two old bolts in the coupling and lock rotation with a lever or whatever,     then 2 shreaded wheat will unscrew the nut once the coupling is held firm

an impact gun will not damage the internals ,  ( ie thats what was used on production to do it up in the first place ) 

as it works of the reaction to the impact there is little action through the a joining mechanisms

Pete

Link to comment
Share on other sites

Can you scrounge a Battery powered Impact Wrench off someone?

I'm sure it will undo with one of these, if not there are lots of Battery ones now available at reasonable prices (I've seen them at Lidl/Aldi before too)

I'm sure it would come in handy in the future?

Link to comment
Share on other sites

+1 to Gary, an impact wrench will take it off in seconds. Can you get it to a local tyre centre, they'll usually have an air-powered setup and may loosen it for you.

I had the same problem with a crank nut on a 1500, days of using breaker bars, force, heat and oil, all overcome in 20 seconds with an air impact gun. 

Link to comment
Share on other sites

I never use my air impact wrench. 

If something is really tight, long bar, apply as much pressure as I can then a hefty whack with a big hammer  always seems to work.

Other than than that, I use my 1/4" impact driver for nuts/bolts but needs a proper wrench for final tightening.

Link to comment
Share on other sites

The prop shaft oil seal is leaking. I have been persuaded by this club to replace it myself! Don't mind doing jobs above wheel level, but rolling around on the ground covered in diff oil trying to wrench off this nut is not my idea of fun - at my age I should be watching day-time television in my slippers!

I have heard of these lidl impact drivers before. Are they generally available, or was it (they) a one-off? We don't have a lidl near here, so I won't have seen them

 

Link to comment
Share on other sites

I think a nut gun will do it as theyre pretty good. Ive just done my front oil seal (Vitesse) but I took the diff out to do it. I could have done it in situ but as you say it isnt nice and I took the opportunity to give it a flush out (Ive got no drain plug fitted) and install a 1/2" lowering block.

Link to comment
Share on other sites

should have said before, make sure you mark up the flange and nut position relative to shaft plus count number of turns to remove because when it goes back on you dont torque it to what the manual says (unless youre putting in new bearings) but just get the nut back to where it was. This is because you preload new bearings so that as they settle in (and wear) theres no chance of freeplay but later during the life of the bearings you dont want to load em up all over again.....

Link to comment
Share on other sites

i agree with castle nut you ( should have a solid spacer) this is not affected by a  release and re torque  

just use the same method of holding the coupling whilst re torquing the nut 

if the torqued up doesnt align a split pin hole turn  to the next one  but measure the thread dia and check out the correct torque

collapsible spacer  ( nylock nut)  is a different kettle of fish and you must return all to exactly where they came from or fit a new spacer and follow the manual 

Pete

Link to comment
Share on other sites

Once again, thanks for ALL the help. Now, having established that we torque it up, let's just confirm that for the Mk 3 GT6 with the castellated nut, the torque should be 70-80 lb ft. Just making sure - belt and braces! New seal and new nut ordered. Getting there, but with help from a very good mechanic friend - ex BA engineer and Elan owner for 40 odd years. When I said that I did it, i have to give him a great deal of credit as well as you lot - if for nothing else, then just for preventing me from losing my marbles!

Link to comment
Share on other sites

as i said you need to roughly measure the thread diameter to ensure the correct torque  

if its 9/16 " its 70 /80 lbft                   if its 5/8" its 90/100lbft                both diameters can use a castle nut  

 

unless its been damaged you dont need a new nut , use whats removed 

Pete

Link to comment
Share on other sites

oops, sorry misunderstood.

Yes, the nut is damaged, and maybe I've bought the wrong nut?! Rimmer bros showed only two, 5/8 for the vitesse 1600 engine, and 9/16 for the vitesse 2 litre - I assumed the 9/16 would be the correct one for the 2 litre GT6 as well. and it was about 8 quid as well.

Link to comment
Share on other sites

Having to reopen this topic, i'm afraid. Done everything according to the book and all your kind help, but took it for a drive after completion, and the oil leak is still there, exactly the same as before (except the oil is new!). Firstly i should say that the shaft of the flange, although not shiny and new was not pitted or scored, nor was the seating of the oil seal in the diff. Now, my question, before I start all over again, concerns the origin of this leak. There is no leak while the car is stationary, and there is no evidence of the leak where the flange fits into the diff, viewed from the front. The oil is leaking from behind the ....not sure what it's called - the cross member that the front of the diff is bolted onto. Is that where I should expect it to leak from if the oil seal or a worn flange is still the culprit, or is there some other cause? Help, please, before  I torch the thing!  

Link to comment
Share on other sites

The front pinion oil seal should prevent leaks from here in normal use, so if you've replaced yours properly then that should have cured this problem - however - I remember replacing these before then leaving the diff on a floor prior to fitting and finding the oil had still run out past the seal, due to the slight downward angle of the front end. It did not run out when fitted level or in use, but I'm wondering that if there is still potential for leaks in this area even with a new seal, is it possible that yours has been overfilled, and will stop leaking once the oil drops down to the proper level? 

Is your breather pin on the top clear, so that pressure is not blowing the oil out? Just a couple of thoughts...

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...