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MG Midget and Sprite Technical - kingpin grease nipple

Whilst greasing my midget today, the lower grease nipples on the stub axle broke off at its head. I have subsequently removed the broken nipple and was ready to replace it with some spare ones which I had previously purchased from Moss and I had used on another Midget without issue. Unfortunately the new one would not screw in but the broken one with undamaged threads went back in easily! I believe these are 1/4" with 28tpi. Has anyone any idea why the replacement which appears identical does not appear to fit and advice where to source replacements.

There are at least two different grease nipple threads, at least here in the US. The ones on my MGBs are 1/4"-28 UNF thread. Both thread sizes are carried in my local parts stores.

Les Bengtson

IIRC the grease nipples on the spridget stub axles are 1/4" UNF threads as when I needed some I just bought them off the shelf at the local engineering supplier. They do also stock 6mm and 1/8" BSP nipples but those wouldn't fit correctly. Can you measure the diameter of the thread and compare the pitch, plenty of 1/4" UNF fasteners on a spridget to compare the pitch against.
David Billington

look to see which nipple it is, get the part number and look in Moss catalogue or mgb-stuff for sizes
Nigel Atkins

R C -
LN30041 GREASE NIPPLE, stub axle, lower £1.07

UHN445 GREASE NIPPLE, stub axle, upper £1.41

from here:
David Smith

from the numbers that David has got from Moss - looking on mgb-stuff web site -



now it's always advisable to check any cross reference any information from any source (including and especially suppliers catalogues on occasion)

Nigel Atkins

A quick check can determine if the grease nipple (zerk fitting) is 1/4"-28 UNF or 1/8" BSP (also 28 tpi). Measure the removed portion of the old nipple. If it measures about 1/4" (.250") it is the 1/4" size. If it measures something over 3/8" it is the 1/8" BSP which has a nominal diameter of .383". Should be rather easy to determine which it requires since Mr. Rose was able to remove the broken off stub.

Les Bengtson

Thank you for all the contributions. Further research from British Leyland part books has revealed that the lower stubb grease nipple originally had the part number UHN490 and not LN30041. Surprisingly the other grease nipples, the top stub axle nipple and wishbone nipple still maintain their original British Leyland part numbers. I have already ordered some grease nipples[ but still intend to measure the damaged one as advised ] with the UHN490 part number from a MG supplier who had them listed as such but they will probably will be the same part as LN30041! Additional research has shown that if my kingpins have been refurbished in the past then a range of grease nipple sizes may have been used!

UHN490 grease nipple 90° - (with photo here) –

>>a range of grease nipple sizes may have been used!<<
yeap, quite possible, don’t assume the part or component fitted to your car is the original or correct type or that it is fitted or working correctly, check and cross reference the information you have – and do the same when ordering parts or components, check and cross reference the information

and never assume a new part, component or fixing will not be faulty, some recent new parts have been of poor quality or faulty including rubber products like hoses, electrical items like indicator flasher units, brake light switches, CB points, condensers and rotor arms

Nigel Atkins

New parts arrived today from sussex clasic car parts. The nipples looked vitually identical to LN30041 but on closer examination they appear to have been made by a different manufacturer. It may have been a faulty grease nipple as others supplied at the time fitted without issue another Spridget. The good news is that they fitted and I have now completed the greasing of the kinpins. I fully concur re the quality of copy parts which unfortunately are the only alternatives. However over my last few of ownership [ 2002 ] I have been collecting and using original BL/BMC parts and often when sourced the parts are not always more expensive and often cheaper!

yes most NOS is better quality (but not absolutely all)

where you can always check the new parts are the correct ones and work and working in the correct way

I got a electric cooling fan and checked that it worked before I fitted it only to find after it was the wrong fan unit and went the wrong way (blow instead of suck) I hand to stand on my head and try to read a small upside down label through the recessed rad grille before the manufacturer would accept that there dispatch had made a mistake - out came the rad and shroud again and yet another refill of coolant all because I didn't check which way the fan went
Nigel Atkins

This thread was discussed between 10/04/2013 and 12/04/2013

MG Midget and Sprite Technical index

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