Lock Washer; GM # 103328

[Gary B.]

According to the '66 AIM, lock washer GM# 103328 was used in a total qty=56 at the following locations

Front Bumpers
Rear Bumpers
Radiator Support & Supply Tank
Spring & Differential Mounting Bracket
# 1, 2, 3 & 4 Body Mounts
Steering Knuckle & Front Wheel Hub Assembly & Lower Control Arm Bumper
Strut
Crossmember & Suspension Attaching Parts

It was also used during the C3 era at some of the same locations.

Does anyone know the specs for this washer? Zinc? Or black phosphate? Grade? Is there anything that distinguishes it from a hardware store lock washer?

Thanks,

Gary

[Gary C.]

Re: Lock Washer; GM # 103328

Gary, info from 1982 P&A 24 on washer # 103328 Gary....

Lock Washer 103328_PA24 1982.jpg

[John D.]

Re: Lock Washer; GM # 103328

Gary
from the drawing - 7/16" Washer heavy helical spring lock. Carbon Steel SAE 1060 or Equivalent 38-46 HRC
Finish plain- agrees with gray's chart above

[Patrick N.]

Re: Lock Washer; GM # 103328

Gary,

This lock washer is still available from AMK products http://www.amkproducts.com/Catalog_PDF/177-189.pdf, $3 for 20 pk, AMK part number B-1305 pg 187. The AMK and original lock washer share the same knurled texture on the outside flat of the washer- that is missing on the over the counter washers.

[Gary B.]

Re: Lock Washer; GM # 103328

John,

Thanks for the spec. I think something is fishy with the table that Gary Chestnut posted. That lists the 103328 lock washer as having a 3/4" hole and a 1.19" OD, but that is too large.

Gary

[Gary B.]

Re: Lock Washer; GM # 103328

Gary,

This lock washer is still available from AMK products http://www.amkproducts.com/Catalog_PDF/177-189.pdf, $3 for 20 pk, AMK part number B-1305 pg 187. The AMK and original lock washer share the same knurled texture on the outside flat of the washer- that is missing on the over the counter washers.

Thanks Pat. The AMK Products washer sounds correct. In the AMK photo I don't see the knurled surface on 103328. But I think I know what you mean, but I think the serrations on the original GM washers are on the thin outer edge, not the nut-facing surfaces.

Gary

[Gary B.]

Re: Lock Washer; GM # 103328

Gary,

This lock washer is still available from AMK products http://www.amkproducts.com/Catalog_PDF/177-189.pdf, $3 for 20 pk, AMK part number B-1305 pg 187. The AMK and original lock washer share the same knurled texture on the outside flat of the washer- that is missing on the over the counter washers.

Patrick,

PS. Yesterday someone told me the GM 103328 lock washers have a thickness of around 0.184", and that hardware store washers are 0.14". The 0.14" thickness is what is quoted for the AMK Products lock washer, so maybe the AMK washer is not exactly like the original 103228.

Gary

[Gary B.]

Re: Lock Washer; GM # 103328

Gary
from the drawing - 7/16" Washer heavy helical spring lock. Carbon Steel SAE 1060 or Equivalent 38-46 HRC
Finish plain- agrees with gray's chart above

John,

Does the drawing list the thickness of 103328? I thought that the AMK Products lock washer was a match until I noticed the 0.14" thickness, which is less than the 0.184" thickness of an original GM 103328 based on what I was told yesterday by someone who had an original handy to measure.

Gary

[Patrick N.]

Re: Lock Washer; GM # 103328

Patrick,

PS. Yesterday someone told me the GM 103328 lock washers have a thickness of around 0.184", and that hardware store washers are 0.14". The 0.14" thickness is what is quoted for the AMK Products lock washer, so maybe the AMK washer is not exactly like the original 103228.

Gary

I have found AMK to be accurate with the fasteners I have ordered in the past but anything is possible, I don't have one to measure but this would be good to chase down to find out what thickness is needed / spec'd. Might be good to call AMK to see what they say.

Best,
Pat

[John D.]

Re: Lock Washer; GM # 103328

Gary, I agree with you as there appears to be a typo in Gary Chestnus chart form the Standard Parts Catalog.
Notice it lists 3/8 3/8 3/4 7/16 etc. The 103328 washer is NOT a 3/4 hole.
Definitely an error on that chart.
Typical 7/16 split lock washers are .109 thick. Heavy duty are .133 thick. High collar split locks are .140 thick. Looking in MSC Industrial Supply .140 thick is the thickest they list. And to repeat the thick ones are called High collar. Finish on originals I have seen was bare/rusty. For your kits I think Zinc would be nice but that's your business.
Today's washers are not like yesterdays at all. On the FI units if I want to buy 1/4" split lock washers they always are too thick in comparison to the ones Rochester Products used.
Check McMaster Carr and see what they have. John

[Gary C.]

Re: Lock Washer; GM # 103328

John, wrong or not GM had the same info from 1982 on in their P&A 24 Fastener books for lock washer 103328. Gary....

[Gary C.]

Re: Lock Washer; GM # 103328

Gary, looks like the Parts Counter replacement is a 120383. P&A 24 #120383 is 7/16" Zinc with O/D 25/32, Medium (thickness). Gary....

[Gary B.]

Re: Lock Washer; GM # 103328

Gary, I agree with you as there appears to be a typo in Gary Chestnus chart form the Standard Parts Catalog.
Notice it lists 3/8 3/8 3/4 7/16 etc. The 103328 washer is NOT a 3/4 hole.
Definitely an error on that chart.
Typical 7/16 split lock washers are .109 thick. Heavy duty are .133 thick. High collar split locks are .140 thick. Looking in MSC Industrial Supply .140 thick is the thickest they list. And to repeat the thick ones are called High collar. Finish on originals I have seen was bare/rusty. For your kits I think Zinc would be nice but that's your business.
Today's washers are not like yesterdays at all. On the FI units if I want to buy 1/4" split lock washers they always are too thick in comparison to the ones Rochester Products used.
Check McMaster Carr and see what they have. John

John,

Thanks for the thickness dimensions on the various types. I'll check what I think are originals tonight to see what I get for the thickness.

Gary

[John H.]

Re: Lock Washer; GM # 103328

The inside diameter on the P&A chart has to be a mis-print; I have a slew of 7/16" split lock washers, and they all measure .444" ID.

[Rich P.]

Re: Lock Washer; GM # 103328

The original St Louis installed lock washers I have are all thicker and have squared edges, some are knurled most are smooth. They were unique and I always stashed them away when I could. Many new lock washers have more rounded edges. It may be as simple as finding a heavier speck lock washer for the current suppliers.