Drill and tap size for grease fittings?

clean8485

Royal Smart Person
Dec 18, 2005
2,200
317
83
Ontario, Canada
#1
I'm upgrading the front sway bar on my Malibu, and going with greaseable bushings where it bolts to the front frame rails. I'm going to be drilling and tapping holes in the frame mounting brackets for the grease fittings (zerks). Does anyone know the drill bit size for the hole, and tap thread size for the grease fitting? Thanks in advance.
 
Aug 8, 2011
5,110
1,914
113
Michigan
#2
Are you talking about making something like this?
 
Aug 8, 2011
5,110
1,914
113
Michigan
#4
The above style was designed with a dedicated raised up area for the grease fitting and it's threads, on a stock one wouldn't that leave you with very little metal to tap into and once you install the grease fitting wouldn't it be pushing against the bushing inside and possibly not have enough room to release the grease properly. Just my thoughts without seeing what you are working with.
 

Zspoiler

Apprentice
Jun 3, 2018
89
29
18
61
#5
Judt check and see what the fitting size is on the grease able aftermarket bushings
 

clean8485

Royal Smart Person
Dec 18, 2005
2,200
317
83
Ontario, Canada
#6
I've done this modification on my '84 Monte, and it worked well. I bought the bushings from a company called Top Down Solutions. I've lost the information on the drill and tap sizes that came with those bushings, and that's why I'm asking.
 

pontiacgp

Canadian Prime Minister
Mar 31, 2006
22,260
3,328
113
Kitchener, Ontario
#7
I have drilled and installed the zerks. I don't recall what size drill I used but I didn't bother tapping the hole, the zerk made it own threads. If do tap just remember the threads on the zerk is tapered fo if you tap all the way through the hole the zerk will fall out
 

bob64

Master Mechanic
Mar 30, 2017
405
173
43
54
Niagara Falls, Canada
#9
Grease nipples come in a wide range of sizes an depth of threads, so best to get them first. So that alone makes it hard to tell you what to drill an thread.

If it was me l would check the grease nipples with a caliper for size and drill a hole 1 size smaller an force thread it in. Buy short threaded nipples just enough to go threw the metal an not into the bushings.

I've done it a few times and it worked well, Just some thoughts
 

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