SteveHobart 57 Posted June 1, 2020 Hi all! I’m just trying to change the oil in my single rail gearbox. It appears that the fellow who owned the car before my has partially rounded off the fill but. Can someone please confirm:- the proper size of the filler nut- any tips for removal Cheers Steve Sent from my iPhone using Tapatalk Share this post Link to post Share on other sites
gerg 10,871 Posted June 1, 2020 If you have access to a welder, you can weld on a large nut and undo it with that.Or try and reverse a 1/2" drive extension bar, pushing the female end over the square on the plug and undo with a spanner on the square end.One of those old school ratchets with the push-pull square drive in the middle might work if you remove the 1/2" drive part.A double hex socket might tap on if you have a size that fits snuglyA Stillsons wrench might get it but probably mangle it tooThread should be 1/2" NPT ( 3/4"-14 tapered) or possibly BSPT, best to double check with the drain plug (same plug size I believe) as there is 1 tpi difference in the two.Sent from my CPH1607 using Tapatalk Share this post Link to post Share on other sites
deankxf 20,231 Posted June 1, 2020 i had to google what they have even(been well over 10yrs since i've had one) i remember having to file the rounded off nut to a smaller size to get a different socket on one once looking at it in the pics below.. if you got despeate(saw a video recently where someone said make sure you can undo the filler, before draining the oil... good tip) but it looks like you could fill it from the speedo drive if need be.. but you'd need to make sure you got the correct amount of oil in. Share this post Link to post Share on other sites
SteveHobart 57 Posted June 1, 2020 H ha Yeah, I know. I actually had the box out and rebuilt. Only fitted it dry to save the weight. Sent from my iPhone using Tapatalk Share this post Link to post Share on other sites
deankxf 20,231 Posted June 1, 2020 they are one of the easiest gearboxes to remove. if you have the means, it would be a lot easier to work on... or take back to the builder with a WTF.. undo this please Share this post Link to post Share on other sites