MTFCA Forum

I had a flat on the rear of our '21 Touring yesterday just as I got home with it. The rear tubes have rubber stems in them and the one that failed was because the stem broke off at the base. I removed the tube and put in a metal(brass) stem, like I have done earlier on both fronts. I used a bridge washer and it seems to be "too much". The tire won't fully seat on the rim there at the stem. Seems like I had the same problem with the first front so I didn't use bridge washers on the fronts. I guess I'll take the rear back down and discard that bridge washer too. Anybody else run without bridge washers?

No such problem here. I always use them.

The bridge washer on he left is one of the inferior modern ones. I always use the ridged ones. Without that ridge pressing into the rubber I believe leaks are more likely.

The earliest bridge washers were flat but there was a washer that went between the tube and it that had the ridge embossed in it. Later they got rid of the washer and just embossed the bridge washer. The flat ones sould work fine on tubes that have the stem hot vulcanized onto a tube as it's just acting as a lock to keep the stem from turning not as a seal.

To add to Mark's post above, see this thread where I posted a diagram showing the washer that was used with a flat or non-embossed bridge washer:

http://www.mtfca.com/discus/messages/33 ... 1377072854

I did pretty much the same as Mr Carter in his how-to. My tube looked like the one in pic 6b when I took it out. Only thing is, the only stems I had were probably truck stems and were about 5" long. I had a little trouble getting the tube back in, with the long stem and might have "disturbed?" the seal. I have ordered a new tube from Lang's and will look into replacing the stem in the old one with a shorter one, and keep it for a spare. My tires are Lincoln Hiway tires and are thick and difficult to work with. I always have sore fingers for several days after a tire repair.

As you're mounting the tire keep the valve stem and bridge washer pushed in far enough so that the tire ridge will seat then pull on the stem and air up the tire.

Ed aka #4

Not to change the subject, but what exactly is the purpose of the bridge washer anyway?

It's what squeezes the rubber tube against the valve's flange, thus sealing it (which is why the repops are so utterly lacking in utility for their original use). It also supports the valve off of the tire casing and provides resistance to being yanked free from the outside. Any one of those things is important to the usefullness and efficiency of the metal stem valve. These benefits are diminished some when used by modern vulcanized metal stems, but the mere fact that they are vulcanized in is in itself a bit of a tragedy quite frankly. I think it is remarkable that 100 year old valves can still be put into service just as reliably as when new, and on top of that, modern cores while slightly different in their form, still retain the original function and make most valves "like new". I am a new and enthusiastic convert to them, myself.

I'm wondering if somehow when I was wrestling the too-long stem into the tire, the bridge washer might have turned sideways, thus holding off the tire beads from the rim? Maybe I will find out when I break it back down.

Tommy, it would seem you are fitting one side of the tyre, and then stuffing the valve stem through the rim hole before mounting the second side. If you mount both sides of the tyre at once, this is not a problem. Simply assemble the tube [and flap if you must] into the tyre first, drop the valve stem through the hole, clamp the assembly to hold the two beads and valve stem in place, and lever away on both sides at once.

Hope this helps.
Allan from down under.

I think I posted a photo of the second to the left Schrader bridge washer recently, along with the separate washer that went under it. Just after that, Schrader began to crimp the washer to the bridge washer. The sequence is pretty clear looking at the rest of the bridge washers posted.

...the bridge washer might have turned sideways...

Very unlikely. The stem would have to turn with it. For that to happen it would have to be too loose to hold air.

I agree with Allan's method. Both sides together.

I just found another photo of the early style bridge washer. I second style bridge washer is on the left.

I'd like to add, if you are not familiar with bridge washers, you will need to use the early small hole design. I believe the modern incorrect ones use the big hole.