Fitting new Defender drop arm

sorry you are right i actually have NTC 1582 per the photos above (PAS box) and the arm showing is RTC6398 which is the one i have -

so with a few whacks i got arm on this far (see pics) and will probably got 1-2mm more when tightened fully but still be 4-5mm short of where the old arm was. Any ideas is this enough ? ?

not quite right ,and are you sure its on the right master spline

yep think so there are 3 wider key ways at 3 6 and 9 o'clock which mean it can only go on the way it is because otherwise when the box is in the truck the arm would foul and wouldn't move full lock - have checked the old arm which is still in one piece despite the fact i cut it to remove and that goes on all the way - baffled. i have also checked other new arms all the same

is it possible to take box in and try arms in the shop ?

yep did that last week took to craddocks near stafford arm they gave me was the same , bloke there said they press the arms on but suggested i fit box and jack up under the arm and that would do the trick - needless to say it didnt which is whats baffling me because i am sure these should go on easier even though they are a tapered fit.

ive reconned and fitted hundreds and not yet have had to press arm on ,measure top and bottom of taper on arm and shaft i will have a look on monday

ok so i got the arm on this far see pictures - full nut engagement but didnt go as far as the old one. if i tightened more on the vehicle i am sure the thread will strip. What does anyone think, it certainly isnt coming off

jon123 said:

ok so i got the arm on this far see pictures - full nut engagement but didnt go as far as the old one. if i tightened more on the vehicle i am sure the thread will strip. What does anyone think, it certainly isnt coming off

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it doesnt look to be on far enough, are the splines damaged on the box or arm

splines on box look fine and old arm goes up 4mm more without a fight. have tried 3 new different arms now and this one was the only one that went near.

jon123 said:

have attached pics of the PAS box which i believe to be a Gemma 6 bolt and have the right arm that doesnt fit. also does any one have a good link to a site showing how to fit the ball joint in the drop arm

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Busters guides are on this site mate

http://www.landyzone.co.uk/lz/f41/drop-arm-ball-joint-renewal-63811.html

Did you resolve this ? I ask simply as I have the same problem, I have some spline damage and was about to file them straighter but after reading this thread I think its the same issue.

et voila