I have the Harley pump with air gauge and it works very well no problems in two years . Progressive sell a very good pump with gauge . The local pushbike shop would sell pumps
The one Harley sells is the best. It was the second accessory I bought for my Glide after the Run-Turn-Brake module!
Ditto on both those items - the H-D air shock pump and the signal light kit!
Never use a regular bicycle pump or an air compressor. These will BLOW your shocks cuz the amount/volume of air is VERY tiny. Use the H-D pump - it works great and is very well made and compact.
When I purchased my SG I didn't know anything about the HD pump. After riding a few hundred miles I decided to check the air pressure. So, I removed the right side bag and attempted to use my pressure gauge. I had to unhook the valve from the mount to get the guage to seat. I found 0 PSI. That's when I learned about the HD pump. Now my shop is 50 miles away, so I went to the local bicycle shop and bought a pump. I knew that too much pressure would blow the system. So, being very careful, I applied a slight amount of pressure, pushing down about an inch. I measured the pressure again and found I had put in 7 PSI. Istopped at that. It needs a little more pressure to be exactly where I want it, but it hasn't lost any pressure since then, about 4 months ago.
I have the HD pump no problems. If you are going to let air out you should pump a little in first to push any oil that may be in the line back into the shock. Then let some out. I also got the brake light module, I think it was $53.00 if I remember right.