Bought replacement bolts as the old ones were in bad shape but forgot to get washers. Do the Dyna oil pan bolts need washers?

 

Year of your Dyna?

 

Washers help spread the clamping load and prevent damage between the fastener and part being fastened. So I'd vote yes, get the washers.

 

Did the old ones have washers? Perhaps purchase OEM replacement bolts from a dealer.

 

Look up your bike here and you can see what it needs. Harley OEM parts

I looked up a random model Dyna and no washers are shown. Just a bolt with lockpatch.

Edit: The black bolt in your picture looks to have a smaller head. That may be a problem with no washer.

 

4741a ... Oil Pan Bolt w/washer ... Yes

I guessed at your year 2011 Dyna

 

Yes + your original had one

The partsfinder doesn't show a separate washer because I believe it's a captive washer. (an assembly)

You really don't need a year for this dyna part

.

 

Yes, and look up AN washers, they are the small tight fit design like the factory ones that won't come off.

 

But will...

 

Typically, if a screw has a captive washer, the specs in the hardware list will include "SEMS" (see 4688 & 4705). The specs for the oil pan screw (4741A) doesn't include SEMS.