Glad Hand Seals - Big End Or Little End In First?

I just replaced my tractor glad hand seals for the first time. I looked it up on U Tube, and a shop mechanic was demonstrating how to replace them with the big end in first, which is the way I did mine. Taking off the old ones, however, I noticed that all the seals (tractor and trailer) appeared to be in with the little end first.

How are the experienced drivers putting them in?

The big end in would hold better leaving the small end out, which is thicker - giving better contact , it would seem.

On the other hand, putting the small end in first would leave a larger contact area, yet a bit thinner... ... hmmmm

Hey buddy, if I'm understanding you correctly, big end in first. The seal or rubber grommet should be flush around the edges of the glad hand. if the big end is in first (which usually takes a flat head screwdriver to install and remove), small out for contact, I'd imagine it would create a better seal. All the rubber grommets in our glad hands are installed this way. In fact, I came across an experienced driver that mentioned this as a pet peeve, i.e. when drivers install the rubber grommets in backwards.

Hey buddy, if I'm understanding you correctly, big end in first. The seal or rubber grommet should be flush around the edges of the glad hand. if the big end is in first (which usually takes a flat head screwdriver to install and remove), small out for contact, I'd imagine it would create a better seal. All the rubber grommets in our glad hands are installed this way. In fact, I came across an experienced driver that mentioned this as a pet peeve, i.e. when drivers install the rubber grommets in backwards.

hmmm... OK .. here starts the confusion - lol !

The mechanic was installing the large end of the seal "inside" the glad hand. Meaning , the smaller, but thicker end is outside making the contact with the other glad hand. This leaves about a 1/4" space to the outside to the glad hand, not flush to the outside.

Like I said, the removed seals were opposite - these were closer to flush to the edge of the glad hand.

This is the bit = Installing Glad Hand Seals

I think that Video is wrong, I've been I commercial truck mechanic and driver for a while, always seen and installed glad hand Seals with the larger, Tappered side to the outside of the housing, that way when you couple your hoses, they slide together over each others tappered end to go together more easily instead of fighting each others square end, maybe I've been doing it wrong ? Don't trust the internent, look at new trucks. also a Pro Driver carries spare glad hand rubbers along with fuses/breakers, bulbs, tyraps ect, Dan

I have to agree with Dan, but you make me wonder if I've been doing this wrong for years. Any mechanic or driver I have ever witnessed installed them with the small end to the inside.

a Pro Driver carries spare glad hand rubbers along with fuses/breakers, bulbs, tyraps ect, Dan

Also agree with Dan on that statement also. You just can never tell when some little seemingly insignificant part like a glad hand seal can really mess up your whole day. Always be prepared, and you will be much more successful than the guys that sit on the side of the road waiting for an already overworked road side mechanic to show up in his service truck with a .79 cent part that you should have had in your possession.

I think that Video is wrong, I've been I commercial truck mechanic and driver for a while, always seen and installed glad hand Seals with the larger, Tappered side to the outside of the housing, that way when you couple your hoses, they slide together over each others tappered end to go together more easily instead of fighting each others square end, maybe I've been doing it wrong ? Don't trust the internent, look at new trucks. also a Pro Driver carries spare glad hand rubbers along with fuses/breakers, bulbs, tyraps ect, Dan

Thanks, Dan...

I'm going to leave the seals with the small, thicker side out for a while and see how it works. I have had several trailer hookups where the seal was loose between glad hands. Perhaps this will eliminate some of that.

I am keeping all the spare parts you mentioned plus more.... I agree with being prepared. I have already been able to fix three break downs in the field by carrying a well stocked tool box and spare parts.

... it's funny how there is no hard rule on the glad hand seal bit... I'll try both ways..

Interesting. I'm really confused now. I just watched the video, and it looks like he's installing the grommets with the smaller end into the housing, leaving the larger end on the outside. I thought you described the video just the opposite. Anyhow, I've seen it done both ways, but have always been told, by numerous folks (and watching numerous mechanics), to install with the smaller side facing out - opposite of this video.

Manufacturer recommends big side inside. Just a thought... Maybe this should be a pretrip check of manufacturer recommendation...

Interesting. I'm really confused now. I just watched the video, and it looks like he's installing the grommets with the smaller end into the housing, leaving the larger end on the outside. I thought you described the video just the opposite. Anyhow, I've seen it done both ways, but have always been told, by numerous folks (and watching numerous mechanics), to install with the smaller side facing out - opposite of this video.

no no.... he is installing the larger diameter portion into the housing with the smaller, thicker portion outside to make the contact.

....are you drinking again.. lol